Basic
Worldview:
103
Science, the Bible,
and Creation
Origins
- Section Four:
General Radiometric Problems
Origins - Section One: Introduction
and the Basics
Origins - Section Two: Premature
Dismissals
Origins - Section Two: Application
of the Basics
Origins - Section Three: Creation
Origins - Section Three: Evolution,
Origin of Life
Origins - Section Three: Evolution,
Environment for Life 1
Origins - Section Three: Evolution,
Environment for Life 2
Origins - Section Three: Evolution,
Another Planet
Origins - Section Three: Evolution,
Origin of Species
Origins - Section Three: Evolution,
Speciation Factors
Origins - Section Three: Evolution,
Speciation Rates
Origins - Section Four: Time and
Age, Redshift
Origins - Section Four: Philosophical
Preference
Origins - Section Four: Cosmological
Model 1
Origins - Section Four: Cosmological
Model 2
Origins - Section Four: Dating Methods,
Perceptions, Basics
Origins - Section Four: Global Flood
Evidence
Origins - Section Four: Relative
Dating
Origins - Section Four: Dating and
Circular Reasoning
Origins - Section Four: The Geologic
Column
Origins - Section Four: Radiometric
Dating Basics
Origins - Section Four: General
Radiometric Problems
Origins - Section Four: Carbon-14
Problems
Origins - Section Four: Remaining
Methods and Decay Rates
Origins - Section Four: Radiometric
Conclusions, Other Methods
Origins - Section Five: Overall
Conclusions, Closing Editorial
Origins - Section Five: List
of Evidences Table
Origins Debate Figures and
Illustrations
Focus
on Critical Evidence:
The General Problem of Critical Unknowns
During
the previous segment, which was an introduction to the basic
concepts of radiometric dating, we briefly outlined 4 pieces
of information that must be known in order for radiometric
dating calculations to be performed. However, due to the primary
importance of this issue, we promised to return and discuss
those criteria and the problems they pose to radiometric dating
in more detail during this segment.
For
review, those 4 factors, which must be known in order to calculate
radiometric ages, are as follows. First, we must know that
the decay rate is constant, not fluctuating, and we must know
what that constant decay rate is. Second, we must know the
ratio of parent and daughter elements that were already present
in a rock when it originally formed. And we must be able to
identify, distinguish between, and “correct” for
those daughter-type atoms, which were originally present,
and those which result from decay. If we don’t know
how much the rock began with, we cannot determine how much
decay has occurred, or consequently, how old the rock is.
Third, we must know what the current amounts of both parent
and daughter atoms are in the item to be dated. And fourth,
we must know how many parent or daughter isotopes migrated
into or out of the rock, because such migration also alters
our perception of the original parent-to-daughter ratios and
the current parent-to-daughter ratios. These 4 factors are
described in the following 2 quotes.
“Dating
Methods, III ABSOLUTE DATING METHODS. E Radiometric Dating,
E1 Basic Theory –Radiometric dating techniques are based
on radio-decay series with constant rates of isotope decay.
Once a quantity of a radioactive element becomes part of a
growing mineral crystal, that quantity will begin
to decay at a steady rate, with a definite percentage of daughter
products in each time interval. These "clocks in rocks" are the geologists'
timekeepers.” – "Dating Methods," Microsoft®
Encarta® Encyclopedia 99. © 1993-1998 Microsoft Corporation.
All rights reserved.
“Dating,
Absolute dating, Principles of isotopic dating
– Likewise, the conditions that must be met
to make the calculated age precise and meaningful are in themselves simple: 1. The rock or mineral must have remained closed to the
addition or escape of parent and daughter atoms since the
time that the rock or mineral (system) formed.
2. It must be possible to correct for other
atoms identical to daughter atoms already present when the
rock or mineral formed.
3. The decay constant must be known. 4.
The measurement of the daughter-to-parent ratio
must be accurate because uncertainty in this ratio contributes directly
to uncertainty in the age. Different schemes have
been developed to deal with the critical assumptions stated
above. In uranium–lead dating,
minerals virtually free of initial lead can be isolated
and corrections made for the trivial amounts present. In whole rock isochron
methods that make use of the rubidium–strontium or samarium–neodymium
decay schemes (see below),
a series of rocks or minerals are chosen that can
be assumed to have the same age and identical abundances of
their initial isotopic ratios. The
results are then tested for the internal consistency that
can validate the assumptions…Such checks include dating
a series of ancient units with closely spaced but known relative
ages and replicate analysis
of different parts of the same rock body with samples collected
at widely spaced localities.” –
Encyclopaedia Britannica 2004 Deluxe Edition
The
quotes below plainly state that migrations can both significantly
raise and significantly lower radiometric ages. Notice that
the first quote, which is affirms that migrations can generate
ages that are “too old” begins by also affirming
that this phenomenon is relevant “in all dating systems.”
“Dating,
Absolute dating, Principles of isotopic dating
– As in all dating systems, the ages calculated
can be affected by the presence of inherited daughter products.
In a few cases, argon ages older than that of the
Earth which violate local relative age patterns have even been determined for
the mineral biotite. Such situations occur mainly
where old rocks have been locally heated, which released argon-40
into pore spaces at the same time that new minerals grew.”
– Encyclopaedia Britannica 2004 Deluxe Edition
In
addition, although the next quote is focused on the potential
lowering of radiometric ages by reheating and migration, notice
that this quote affirms the commonness and ease of reheating
and migration with the phrase “All it takes for such
an element to be purged from the mineral is sufficient heat.”
Such phrasing clearly indicates that this is frequent and
simple to achieve.
“Dating,
Absolute dating, Evaluation and presentation schemes in dating,
Multiple ages for a single rock; the thermal effect –
Fossils record the initial, or primary, age of a
rock unit. Isotopic systems, on the other hand, can yield either the
primary age or the time of a later event,
because crystalline materials are very specific in the types
of atoms they incorporate, in terms of both the atomic size
and charge. An element formed by radioactive decay is quite
different from its parent atom and thus is out of place with
respect to the host mineral. All it takes for such
an element to be purged from the mineral is sufficient heat
to allow solid diffusion to occur. Each mineral has a temperature
at which rapid diffusion sets in, so that, as a region is
slowly heated, first one mineral and then another loses its
daughter isotopes. When this happens, the isotopic “clock”
is reset to zero, where
it remains until the mineral cools below the blocking temperature…Another
problem arises if a region undergoes a second reheating event.
Certain minerals may record the first event, whereas others
may record the second, and any suggestion of progressive cooling between
the two is invalid.”
– Encyclopaedia Britannica 2004 Deluxe Edition
Consequently,
reheating and migration events cause parent and daughter isotopes
to both leave and enter into rock formations, at which point
the quantity of these isotopes in a rock no longer reflects
decay, the duration of decay, or age. The inability to identify
the amounts of migration into or out of a sample will create
the following obstacles to dating. Parents might be missing
through migration instead of decay, giving the mistaken impression
that more decay has occurred, that more half-lives have passed,
and that the item is older. Or, parents might be added by
migration, giving the mistaken impression that less decay
has occurred, that less time has passed, and that the item
is younger. Or, daughters might be missing through migration,
giving the impression that less decay has occurred, that less
time has passed, and that the item is younger. Or, daughters
might be added through migration, giving the impression that
more decay has occurred, that more half-lives have passed,
and that the item is older.
In
summary, reheating and migration can both raise and lower
ages, effectively making the age unknowable.
As
stated above, there are 4 pieces of information, which are
all regarded by Britannica as “critical” and as
“conditions that must be met to make the calculated
age.” Those pieces of information are the starting parent-to-daughter
ratio, the current parent-to-daughter ratio, the decay rate,
and the amount of migration. If any of these pieces of information
is not known, then determining how much decay has occurred
and how much time has passed is utterly impossible. Consequently,
the occurrence of reheating and migration pose a significant
obstacle to radiometric dating.
Insight
into how severe these problems are for radiometric dating
can be understood in 3 ways. First, we can understand how
severe the problem is in terms of the fact that evolutionary
scientists simply cannot develop any method for observationally
detecting the true numeric values for these unknown factors.
Instead of observation or evidence, evolutionary scientists
have to simply assume idealized numbers and then adjust them
as needed when calculating absolute ages. Second, we can understand
how severely pervasive the problem is in light of the fact
that migration due to heat is inherent to igneous and metamorphic
rocks, the very items that are being radiometrically dated.
And third, we can understand the severe scope of the problem
by identifying how many methods suffer from the obstacle of
migration. We will now examine each of these points individually,
beginning with point number one.
The
fact remains that 2 pieces of information necessary for calculating
absolute age are simply not available through evidence or
observation. The original parent-to-daughter ratio when the
rock was formed and the amount of migration by parent or daughter
atoms (either into or out of the rock) must be assumed and
adjusted as needed when calculating ages. This fact is illustrated
by what is known as the isochron method.
The
name isochron method is perhaps misleading since the isochron
method is not actually a dating method, as its name might
imply. Instead, it is a presentation method, a way to format
the data in order to show evolutionary geologists what numeric
values to assume for the unknown factors required to calculate
radiometric ages. The first quote below which we have seen
before lists “the conditions” or factors that
“must be met” or known in order to calculate absolulte
age. The quote then goes on to state that “different
schemes have been developed to deal with” the fact that
some of these factors (all of them except the present parent
and daughter quantities) must be “assumed.” The
isochron method is then listed as one such “scheme”
used to compensate for the fact that these crucial pieces
of data are merely assumed.
“Dating,
Absolute dating, Principles of isotopic dating
– Likewise, the conditions that must be met to make
the calculated age precise and meaningful are in themselves
simple: 1.
The rock or mineral must have remained closed to the addition
or escape of parent and daughter atoms since the time that
the rock or mineral (system) formed. 2. It must be possible to correct for other atoms identical
to daughter atoms already present when the rock or mineral
formed. 3. The decay constant must be known. 4. The measurement of the daughter-to-parent ratio must
be accurate because uncertainty in this ratio contributes
directly to uncertainty in the age. Different schemes
have been developed to deal with the critical assumptions
stated above. In uranium–lead
dating, minerals virtually free of initial lead can be isolated
and corrections made for the trivial amounts present. In
whole rock isochron methods that
make use of the rubidium–strontium or samarium–neodymium
decay schemes (see below), a series of rocks or minerals are
chosen that can be assumed to have the same age and identical abundances of their
initial isotopic ratios. The results are then tested for the
internal consistency that can validate the assumptions.”
– Encyclopaedia Britannica 2004 Deluxe Edition
The
next quote plainly states that the isochron method is used
to “display and evaluate data.” It is not a method
for measuring isotopes or for collecting data in any way.
“Dating,
Absolute dating, Major methods of isotopic dating, Samarium–neodymium
method – In theory,
the samarium–neodymium method is identical to the rubidium–strontium
approach (see above). Both use the isochron method
to display and evaluate data.”
– Encyclopaedia Britannica 2004 Deluxe Edition
Furthermore,
the quote (appearing under the subheading “The isochron
method”) likewise desribes how the isochron method is
a way “to present the data” in a particular form.
In particular, the quote also states that this presentation
format, known as the isochron method, is used to compensate
for the fact that the initial daughter abundance and the migration
amounts need to be known but are not.
“Dating,
Absolute dating, Evaluation and presentation schemes in dating,
The isochron method – Many radioactive dating methods are based on minute
additions of daughter products to a rock or mineral in which
a considerable amount of daughter-type isotopes already exists.
These isotopes did not come from radioactive decay in
the system but rather formed during the original
creation of the elements.
In this case, it is a big advantage to present the
data in a form in which
the abundance of both the parent and daughter isotopes are
given with respect to the abundance of the initial background
daughter…A second advantage of the method
relates to the fact that under high-temperature
conditions the daughter isotopes may escape from the host
minerals.” –
Encyclopaedia Britannica 2004 Deluxe Edition
Consequently,
as we can see, the isochron method is way to present and format
the data in order to show evolutionary geologists what numeric
values to assume for the unknown factors and how to adjust
those values as needed when calculating absolute ages. An
example of an isochron diagram will further demonstrate this
fact. The following isochron is provided by Britannica Encyclopedia.
When
viewing the isochron above, the important question to ask
is “What actual data do the scientists have as a result
of actual observable evidence?” What data are they starting
off with when they formulate the isochron? The answer is that
only the “closed” yellow circles on the diagram
represent actual, observed data. Specifically, these circles
represent “the values measured today,” or in other
words, these circles represent the mass spectrometer readings
showing the amount of parent and daughter isotopes presently
in the 3 different samples.
“Dating,
Absolute dating, Evaluation and presentation schemes in dating,
The isochron method, Figure 1: Isochron Diagram – With time, the line called an isochron rotates,
and data plot at the positions shown by closed circles.
These would be the values measured today,
and the slope of the line would indicate the time elapsed.”
– Encyclopaedia Britannica 2004 Deluxe Edition
Essentially,
different samples are taken from the same rock formation,
each sample is tested for its current quantity of parent and
daughter atoms, and then the quantities for each sample are
compared to the others. As indicated by the chart above, although
the samples are taken from the same rock formation, the present
isotope quantities are not the same for each sample. This
creates a problem because it indicates that migration has
occurred, and in addition it is also possible that some daughter
atoms were already present at the time when the rock was formed.
Normally, since the amount of these phenomenon are not known
and cannot be determined by observation or testing the material,
this would end the ability to radiometric date these rocks.
However, the isochron method is designed to help identify
what values can be assumed for migration and initial isotope
quantities in order to come up with a calculation that at
least works, even if it is based upon assumptions.
In
the isochron above, the open circles (R1, R2, R3) represent
assumed migration amounts and initial isotope quantities.
As indicated by the second quote below, these values are “chosen.”
They are not actually observed.
“Dating,
Absolute dating, Evaluation and presentation schemes in dating,
The isochron method – In practice, the isochron approach has many inherent
advantages. When a single body of liquid rock crystallizes,
parent and daughter elements may separate
so that, once solid, the isotopic data would define
a series of points, such as those
shown as open circles designated
R1, R2, R3 in Figure 1.” –
Encyclopaedia Britannica 2004 Deluxe Edition
“Dating,
Absolute dating, Evaluation and presentation schemes in dating,
The isochron method, Figure 1: Isochron Diagram – In this case, the value of the initial
parent-to-stable ratio in R2
has been chosen to be twice
that in R1, and R3 is set at twice that of R2.” –
Encyclopaedia Britannica 2004 Deluxe Edition
As
indicated by the quotes below, by assuming the right values,
a straight line (or isochron) can be created. And this idealized,
assumed line then indicates “a common value for the
initial daughter isotope.” Or in other words, this line
helps evolutionary scientists assume a quantity of daughter
atoms already present when the rock was formed and it helps
them to assume how many parent or daughter isotopes result
from migration. But most importantly, this isochron line helps
evolutionary scientists to assume a value that will actually
work for their calculations.
“Dating,
Absolute dating, Evaluation and presentation schemes in dating,
The isochron method, Figure 1: Isochron Diagram – With time, the line called an isochron
rotates, and data plot at the positions shown by closed circles.
These would be the values measured today, and the slope of
the line would indicate the time elapsed.”
– Encyclopaedia Britannica 2004 Deluxe Edition
“Dating,
Absolute dating, Principles of isotopic dating – When a single body of liquid rock crystallizes,
parent and daughter elements may separate so that, once solid, the isotopic data would define
a series of points, such as those shown as open circles designated
R1, R2, R3 in Figure 1. They plot along a horizontal line
reflecting a common value for the initial daughter
isotope ratio (D/S)0.
With time each would then develop additional daughter
abundances in proportion to the amount of parent present.” – Encyclopaedia Britannica 2004 Deluxe Edition
Consequently,
the isochron line indicates how much time would have passed
based upon those idealized, assumed values. Once the points
are plotted, the next quotes states that the “estimates”
(assumed values) are “examined to assess how well they
fit the required straight line.” If the assumed values
do not work to create a straight line, but many points plot
below the line, the “assumptions” are shown to
have been incorrect.
“Absolute
dating, Major methods of isotopic dating, Rubidium–strontium
method, Dating simple igneous rocks –Once plotted as R1p (i.e., rock 1 present values), R2p, and R3p, the data are examined to
assess how well they fit the required straight line. Using
estimates of measurement precision, the crucial question of
whether or not scatter outside of measurement error exists
is addressed. Such scatter would constitute a geologic component,
indicating that one or more of the underlying assumptions
has been violated and that the age indicated is probably not
valid.” – Encyclopaedia Britannica 2004 Deluxe
Edition
As
the next quote states, in dating methods where the isochron
format is “extensively employed,” such as rubidium-strontium,
“many” rocks did not give “precisely defined
linear isochrons.” In other words, points were plotting
above and below the line, an event which would not provide
any help in identify assumed migration or initial daughter
ratios that work. Consequently, calculating an age based upon
assumed values would be untenable.
“Dating,
Absolute dating, Principles of isotopic dating
– Rubidium–strontium (Rb–Sr) dating was
the first technique in which the whole rock isochron
method was extensively
employed. Certain rocks
that cooled quickly at the surface were found to give
precisely defined linear isochrons, but
many others did not.”
– Encyclopaedia Britannica 2004 Deluxe Edition
However,
as the next quote indicates, if a point should happen to plot
below the line, additional migration or additional initial
daughter atoms can be assumed, adjusting the location of the
point, and correcting the line until it matches the idealized
values necessary for the assumptions to make any working sense.
“Dating,
Absolute dating, Principles of isotopic dating, The isochron
method –Should
a point plot below the line, it could indicate that a particular
sample was open to migration
of the dating elements or that the sample was contaminated
and lay below the isochron when the rock solidified.”
– Encyclopaedia Britannica 2004 Deluxe Edition
An
earlier quote from Britannica also described this process
of “correcting” the assumed values until they
fit what is required for age calculations. Britannica specifically
lists the inability to know but only assume migration amounts
and initial daughter quantities, “assuming” initial
isotope ratios, and the use of the isochron method as one
of the “schemes” developed in order to “correct”
for these factors and “test the assumptions for internal
consistency.” In other words, even if the values have
to be assumed, at least the isochron format makes sure the
assumptions at least work among themselves.
“Dating,
Absolute dating, Principles of isotopic dating
– Likewise, the conditions that must be met
to make the calculated age precise and meaningful are in themselves simple: 1. The rock or mineral must have remained closed to the
addition or escape of parent and daughter atoms since the
time that the rock or mineral (system) formed. 2.
It must be possible to correct for other atoms identical
to daughter atoms already present when the rock or mineral
formed. 3.
The decay constant must be known. 4.
The measurement of the daughter-to-parent ratio must be accurate
because uncertainty in this ratio contributes directly to
uncertainty in the age. Different schemes have been
developed to deal with the critical assumptions stated above…In
whole rock isochron methods that
make use of the rubidium–strontium or samarium–neodymium
decay schemes (see below), a series of rocks or minerals are
chosen that can be assumed to have the same age and identical abundances of their
initial isotopic ratios. The results are then tested
for the internal consistency that can validate the assumptions.” – Encyclopaedia Britannica 2004 Deluxe Edition
However,
even descriptions of the isochron method admit that the ages
it generates are not valid if the different rock samples it
uses were not in a closed system (migration does not extend
to adjacent rock formations), do not have the same initial
ratio as one another, or are not in fact the same age.
“Dating,
Absolute dating, Principles of isotopic dating
– With time each would then develop additional daughter
abundances in proportion to the amount of parent present.
If a number of samples are analyzed and the results are shown
to define a straight line within
error, then a precise age is defined because this
is only possible if each is a closed system and each has the
same initial ratio and age.” – Encyclopaedia Britannica 2004 Deluxe
Edition
However,
whether the rock system was a closed system, whether all of
the samples had the same initial isotope quantities, or were
in fact the same age, are all additional assumptions of unknown
and unobserved factors. So, not only is the isochron format
designed to adjust the assumptions made for one set of unknown
factors, but in order to adjust for one set of assumptions,
another set of assumptions must be made for other unknown
factors. Assumption is clearly the basis of age calculations.
The
following quote also affirms that while adjusting one set
of assumptions, the isochron method actually relies upon another
set of assumptions. But, the quote below includes one additional
series of requirements in order for the isochron format to
give “valid” readings. Specifically, the quote
below states that in order for isochrons to be valid, the
rocks they are applied to must be “well-preserved, unweathered
rocks that crystallized rapidly and have not been subjected
to major reheating events.” The quote also stipulates
explicitly that “Volcanic rocks are most susceptible”
to these kinds of events, which render isochrons invalid.
“Absolute
dating, Major methods of isotopic dating, Rubidium–strontium
method, Dating simple igneous rocks – For an isochron
to be valid, each sample tested must (1) have had the same
initial ratio, (2) have been a closed system over geologic
time, and (3) have the same age. Well-preserved, unweathered
rocks that crystallized rapidly and have not been subjected
to major reheating events are most likely to give valid isochrons.
Weathering is a
disturbing influence, as is leaching or exchange by hot crustal
fluids, since many secondary minerals contain rubidium. Volcanic
rocks are most susceptible to such changes because
their minerals are fine-grained and unstable glass may be
present.” – Encyclopaedia Britannica 2004 Deluxe
Edition
Igneous
rocks are formed from volcanic processes such as the cooling
and solidification of molten rock.
“Igneous
rock – any
of various crystalline or glassy rocks formed by the cooling
and solidification of molten earth
material. Igneous rocks comprise one of the three principal
classes of rocks, the others being metamorphic and sedimentary.”
– Encyclopaedia Britannica 2004 Deluxe Edition
Likewise,
the 2 quotes below indicate the rubidium-strontium method
is used on igneous rocks and that the rocks used in the rubidium-strontium
method are susceptible to migration due to fluid movement
and chemical weathering.
“Dating,
Absolute dating, Major methods of isotopic dating, Rubidium-strontium
method, Dating simple igneous rocks – The rubidium–strontium pair
is ideally suited for the isochron dating of igneous rocks.” – Encyclopaedia Britannica 2004 Deluxe
Edition
“Dating,
Absolute dating, Principles of isotopic dating
– Rubidium–strontium (Rb–Sr) dating was
the first technique in which the whole rock isochron method
was extensively employed.
Certain rocks that cooled quickly at the surface
were found to give precisely defined linear isochrons, but
many others did not. Some studies have shown that rubidium is
very mobile both in fluids that migrate through the rock as
it cools and in fluids that are present as the rock undergoes
chemical weathering.” – Encyclopaedia Britannica 2004 Deluxe
Edition
Consequently,
from these quotes, 2 all-important factors emerge. First,
in order for the isochron format to even theoretically work
to adjust one set of assumptions, the rock samples the isochron
method is applied to cannot be subject to weathering or migration
through reheating events, factors which primarily affect igneous
rocks. Second, as we established during our introduction to
the basics of radiometric dating, igneous rocks and metamorphic
rocks, which are also formed through major heating events,
are the exact same types of rocks that most radiometric dating
methods are applied to. In fact, only the uranium-thorium
method (which tests deep-sea sediments) and the carbon-14
method can be applied to rocks other than igneous and metamorphic
rocks.
This
concludes our examination of the isochron method. The most
important point to keep in mind from this portion of our study
is this. Although the isochron method may not be used for
all radiometric dating methods, the isochron method was created
to solve a problem that faces all methods used to date igneous
and metamorphic rocks. As such, the isochron method illustrates
that radiometric dating requires making calculations that
are based upon assumed values. The actual values, which are
critical to dating, cannot be observed or experimentally detected.
As
we stated early on, we can understand the severity of the
problems facing radiometric dating in 3 ways. The first was
to understand the severity of the problem by demonstrating
that evolutionary scientists must rely on assumed values for
basic, critical factors in order to make age calculations.
The calculations are not based upon observation or actual
evidence. This is demonstrated by the isochron method, which
we have just examined above. The second way was to understand
how pervasive these problems are by demonstrating that migration
and reheating events are inherent to igneous and metamorphic
rocks. The fact that isochrons are not valid for rocks, which
were subjected to weathering and particularly to migration
and reheating events, leads us directly into this second issue.
Having
established the obstacles posed to radiometric dating by the
fact that migration amounts and initial isotope quantities
are not known or experimentally detectable, we can go on to
ask the question of how common these problems are. These problems
are common in 3 ways.
First,
the quote below highlights the previously mentioned difficulty
of distinguishing between daughter atoms that actually result
from radioactive decay as opposed to daughter atoms that were
already present, perhaps even in “considerable amounts”
when the rock was formed. Since the amount of daughter elements
produced by decay is the direct indicator of how long decay
has been occurring, like migration, this is an absolutely
critical factor that must be known with certainty, otherwise
the age could be severely exaggerated. Most importantly, the
quote states that “many radioactive dating methods”
utilize rocks into which such “considerable amounts
of daughter-type isotopes already exist.” So, the problem
of having daughter isotopes that do not result from decay
is clearly common to “many radioactive dating methods.”
Second,
the quote below also plainly states that migrations are also
common and result from very common processes, including high-temperature
reheating of the rock, fluid movement through the rock, and
chemical weathering. Consequently, it would appear that both
migration and initial daughter abundances are not only significant
problems but they are also commonly occurring problems.
“Dating,
Absolute dating, Evaluation and presentation schemes in dating,
The isochron method – Many radioactive dating methods
are based on minute additions of daughter products to a rock
or mineral in which a considerable amount of daughter-type
isotopes already exists. These isotopes did not come from
radioactive decay in the system but rather formed during the
original creation of the elements.
In this case, it is a big advantage to present the data in
a form in which the abundance of both the parent and daughter
isotopes are given with respect to the abundance of the initial
background daughter. The incremental additions of
the daughter type can
then be viewed in proportion to the abundance of
parent atoms…A second advantage of the method relates to the fact
that under high-temperature conditions the daughter
isotopes may escape from the host minerals.
In this case, a valid age can still be obtained,
provided that they remain within the rock…Some
studies have shown that rubidium is very mobile
both in fluids that migrate through the rock as it cools and
in fluids that are present as the rock undergoes chemical
weathering. Similar studies
have shown that the samarium–neodymium (Sm–Nd) parent–daughter pair
is more resistant to secondary migration
but that, in this instance, sufficient initial
spread in the abundance of the parent isotope is difficult
to achieve.” – Encyclopaedia Britannica 2004 Deluxe
Edition
“Dating,
Absolute dating, Major methods of isotopic dating, Rubidium–strontium
method, Dating simple igneous rocks – Well-preserved,
unweathered rocks that crystallized rapidly and have not been subjected
to major reheating events
are most likely to give valid isochrons. Weathering
is a disturbing influence, as is leaching or exchange by hot
crustal fluids, since many secondary minerals contain rubidium.
Volcanic rocks are most susceptible to such changes because their minerals are fine-grained and unstable glass may be present.” – Encyclopaedia Britannica
2004 Deluxe Edition
Third,
these problems, particularly the fact that migration events,
reheating events, and weathering all prevent radiometric dating
calculations altogether, are common in the sense that they
affect all the dating methods used on igneous and metamorphic
rock, which happens to be the predominant type of rocks that
can be dated, as indicated in the quote below.
“Geology,
III THE GEOLOGIC TIME SCALE, D Radiometric Dating
– Another fundamental goal of geochronology is to determine
numerical ages of rocks and to assign numbers to the geologic
time scale. The primary tool for this task is radiometric
dating, in which the decay of radioactive elements is used
to date rocks and minerals. Radiometric dating works
best on igneous rocks (rocks that crystallized from molten material). It
can also be used to date minerals in metamorphic rocks (rocks
that formed when parent rock was submitted to intense heat
and pressure and metamorphosed into another type of rock).
It is of limited use, however, in sedimentary rocks formed by the compaction of layers of sediment.”
– "Geology," Microsoft® Encarta® Encyclopedia
99. © 1993-1998 Microsoft Corporation. All rights reserved.
Notice
from the quote above that the very definition of metamorphic
rock is “rock that forms when parent rock is submitted
to intense heat and pressure.” Consequently, we can
see that while metamorphic rock is one of the main 2 types
of rock that radiometric dating can be used on, metamorphic
rock is also inherently defined by the experience of reheating
events. And reheating events in turn cause migration, raise
or lower the age in a manner that cannot be empirically detected,
and thus prevent radiometric dating.
This is not only true for metamorphic rocks. Igneous
rocks are likewise associated with intense hot environments
and volcanic activity, including extremely hot molten rock.
Notice from the first quote below that “volcanic rocks”
are synonymous with igneous rocks formed at the earth’s
surface as opposed to igneous rocks formed deeper within the
earth.
“Earth,
The major geologic features of the Earth's exterior, The surface
of the Earth as a mosaic of plates, Activity along plate boundaries,
Formation of igneous rocks – Igneous rocks are formed by the crystallization of magma. Extrusive igneous rocks (volcanic rocks) are produced bythe
crystallization of magmas at the surface. Intrusive
igneous rocks include those crystallized at shallow depth
(hypabyssal igneous rocks), typically as dikes and sills,
and those crystallized at medium to great depths (plutonic
igneous rocks).” – Encyclopaedia Britannica 2004
Deluxe Edition
“Igneous
rocks – any of various crystalline or glassy rocks formed by the cooling and solidification of molten
earth material…Igneous
rocks are formed from the solidification of magma, which is
a hot (600° to 1,300° C, or 1,100° to 2,400°
F) molten or partially molten rock material.” – Encyclopaedia Britannica 2004 Deluxe
Edition
Given
their inherent relationship to heat, it is not surprising
that igneous rocks are regarded as even more susceptible to
reheating and migration than metamorphic rocks. This is indicated
by the quote below, which we have seen previously.
“Absolute
dating, Major methods of isotopic dating, Rubidium–strontium
method, Dating simple igneous rocks – Well-preserved,
unweathered rocks that crystallized rapidly and have not been subjected
to major reheating events
are most likely to give valid isochrons. Weathering is a
disturbing influence, as is leaching or exchange by hot crustal
fluids, since many secondary minerals contain rubidium.
Volcanic rocks are most susceptible to such changes because their minerals are fine-grained and unstable glass may be present.” – Encyclopaedia Britannica
2004 Deluxe Edition
Consequently,
the severity of the problem posed by migration and reheating
can be seen by the fact that these 2 processes are inherent
to igneous and metamorphic rock by definition and these are
the exact 2 forms of rock that radiometric dating is primarily
used on.
Now
that we understand that the critical calculation values are
not observations or empirical data but assumptions and that
migrations and reheating are inherent to the very types of
rocks that radiometric dating is used on, we can further understand
the severity of the problem in terms of how many radiometric
dating methods these issues are acknowledged to affect. In
particular, as stated in the next series of quotes, potassium-argon
dating methods are affected directly by reheating and migration
events. Consequently, as indicated by the third quote below,
the isochron format, which itself doesn’t work, is used
with the potassium-argon method.
“Dating
Methods, III ABSOLUTE DATING METHODS. E Radiometric Dating,
E3 Potassium-Argon Method
– The decay of radioactive potassium isotopes
to argon is widely used for dating rocks.
(The decay of potassium-40 to calcium-40 that also takes place
is not useful.) Geologists are able to date entire rock samples
in this way, because potassium-40 is abundant in
micas, feldspars, and hornblendes.” – "Dating Methods," Microsoft®
Encarta® Encyclopedia 99. © 1993-1998 Microsoft Corporation.
All rights reserved.
“Archeology,
VIII DETERMINING THE AGE OF FINDS, B Absolute Dating, B4 Potassium-Argon
Dating – Potassium-argon
dating provides approximate
dates for sites in early prehistory. Geologists
use this method to date volcanic rocks that
may be as much as 4 billion to 5 billion years old.”
– "Archaeology," Microsoft® Encarta®
Encyclopedia 99. © 1993-1998 Microsoft Corporation. All
rights reserved.
“Dating,
Absolute dating, Principles of isotopic dating
– As in all dating systems, the ages calculated
can be affected by the presence of inherited daughter products.
In a few cases, argon ages older than that of the
Earth which violate local
relative age patterns have even been determined for the mineral
biotite. Such situations occur mainly where old
rocks have been locally heated, which released argon-40 into
pore spaces at the same time that new minerals grew. Under
favourable circumstances the isochron method may be helpful,
but tests by other techniques
may be required. For example, the rubidium–strontium
method would give a valid isotopic age of the biotite sample
with inherited argon.” – Encyclopaedia Britannica 2004 Deluxe
Edition
Rubidium-strontium
dating, which is “frequently used to check potassium-argon”
dating, is also affected substantially by reheating and migration
events.
“Dating
Methods, III ABSOLUTE DATING METHODS. E Radiometric Dating,
E4 Rubidium-Strontium Method –Used to date ancient igneous
and metamorphic terrestrial rocks as
well as lunar samples,
this method is based on disintegration by beta decay of rubidium-87
to strontium-87. The method is frequently used to
check potassium-argon dates, because the strontium daughter
element is not diffused by mild heating, as is argon.” – "Dating Methods," Microsoft®
Encarta® Encyclopedia 99. © 1993-1998 Microsoft Corporation.
All rights reserved.
“Dating,
Absolute dating, Major methods of isotopic dating, Rubidium–strontium
method, Dating metamorphic rocks – Should a simple igneous
body be subjected to
an episode of heating
or of deformation or of a combination of both, a well-documented
special data pattern develops. With heat, daughter
isotopes diffuse out of their host minerals
but are incorporated into other minerals in the rock. Eventually
the 87Sr/86Sr ratio in the minerals becomes identical. When
the rock again cools, the minerals close and again accumulate
daughter products to record the time since the second event…Although
rubidium–strontium dating is not as precise as theuranium–lead method, it was the first
to be exploited and has provided much of the prevailing
knowledge of Earth history…The mobility of rubidium
in deep-level crustal fluids and melts that can infiltrate
other rocks during metamorphism as well as in fluids involved
in weathering can complicate the results.” – Encyclopaedia Britannica 2004 Deluxe Edition
Uranium-lead
is also subject to reheating and migration events. For reference,
the mineral titanite, also called sphene, is found in igneous
rocks.
“Dating,
Absolute dating, Major methods of isotopic dating, Importance
of zircon in uranium-lead dating – Given the two related uranium–lead parent–daughter
systems, it is possible
to determine both the time of the initial, or primary,
rock-forming event and the time of a major reheating, or secondary,
event. This is illustrated in Figure 3. Here, the uranium–lead
isotopes in the mineral titanite
(CaTiSiO5) from a series of rocks that have a common geologic
history plot on a straight line. The minerals first
formed 1,651 million years ago but were later heated and lost
varying amounts of lead 986 million years ago.” –
Encyclopaedia Britannica 2004 Deluxe Edition
“Sphene
– Sphene, calcium
titanosilicate, formerly called titanite, chemical formula CaOTiO2SiO2…Sphene
occurs as a microscopic accessory mineral in different types
of igneous rocks-especially granite-and in larger crystals
in pegmatites.” – "Sphene," Microsoft®
Encarta® Encyclopedia 99. © 1993-1998 Microsoft Corporation.
All rights reserved.
And
lastly, fission-track dating, which is used to date items
in the gap between potassium-argon and carbon-14, is also
a method used on igneous and metamorphic rocks, such as micas
and tektites. As such, these rocks are also likely to be subject
to reheating and migration events.
“Dating
Methods, III ABSOLUTE DATING METHODS. E Radiometric Dating,
E7 Fission-Track Dating – The method works best for micas, tektites, and meteorites. It has been used to help date the period
from about 40,000 to 1 million years ago, an interval not
covered by carbon-14 or potassium-argon methods.”
– "Dating Methods," Microsoft® Encarta®
Encyclopedia 99. © 1993-1998 Microsoft Corporation. All
rights reserved.
“Mica,
Origin and occurrence –Micas may originate as the result
of diverse processes under several different conditions. Their
occurrences, listed below, include crystallization from consolidating
magmas, deposition by fluids derived from or directly associated
with magmatic activities, deposition by fluids circulating
during both contact and regional metamorphism, and formation as the result of alteration processes—perhaps
even those caused by weathering—that involve minerals such as feldspars…The
common rock-forming micas are distributed widely. The more important
occurrences follow: Biotite
occurs in many igneous rocks
(e.g., granites and granodiorites), is common in many pegmatite
masses, and constitutes one of the chief components
of many metamorphic rocks (e.g., gneisses, schists, and hornfelses). It alters
rather easily during chemical weathering and thus is
rare in sediments and sedimentary rocks.”
– Encyclopaedia Britannica 2004 Deluxe Edition
“Tektite
– any of a class of small, natural glassy
objects that are found only in certain areas of the Earth's
surface. The term is derived fromthe Greek word tektos, meaning
“melted,” or “molten.” Tektites have been the subject of intense scientific scrutiny throughout
much of the 20th century owing to their unknown and possibly
extraterrestrial origins, but they are now recognized
as having formed from the melting and rapid cooling of terrestrial
rocks that have been vaporized by the high-energy impacts
of large meteorites, comets, or asteroids upon the surface
of the Earth. The extremely high temperatures and enormous
pressures generated by such impacts melted the rocks at the
site, producing clouds of molten silicate droplets that quickly
cooled to a glassy form before falling back to Earth.” – Encyclopaedia
Britannica 2004 Deluxe Edition
As
we can see, not only are igneous and metamorphic rocks the
primary subject of radiometric dating, but almost all of the
methods used to date these rocks specifically stipulate that
they are plagued by the calculation obstacles posed by reheating
and migration. In fact, the next quote specifically summarizes
that “all dating systems” are susceptible to false
ages because of the addition of daughter atoms into the rock
through migration, citing reheating as the common causes of
such migrations.
“Dating,
Absolute dating, Principles of isotopic dating
– As in all dating systems, the ages calculated
can be affected by the presence of inherited daughter products.
In a few cases, argon ages older than that of the Earth which
violate local relative age patterns have even been determined
for the mineral biotite. Such situations occur mainly
where old rocks have been locally heated, which
released argon-40 into pore spaces at the same time that new
minerals grew.” – Encyclopaedia Britannica 2004
Deluxe Edition
In
conclusion to our examination of the fact that radiometric
dating in general does not work we have established the following
facts. First, there are 4 pieces of information, which are
all regarded by Britannica as “critical” and as
“conditions that must be met to make the calculated
age.” Those pieces of information are the starting parent-to-daughter
ratio, the current parent-to-daughter ratio, the decay rate,
and the amount of migration. The starting ratio and the migration
amounts are not observable, empirically determinable, or ultimately
knowable. They have to be assumed.
Second,
as we have seen, the processes used to help make sure such
assumptions at least work are entirely subjective, employing
idealized data that is adjusted as needed to make age calculations.
Furthermore, those processes themselves require even more
assumptions, which do not fit with reality, such as the assumptions
that the rocks have remained closed to migrations, had the
same initial isotope ratio, have the same age, and have not
been subjected to weathering or reheating events.
Third,
as we have seen, the first and last of these events (migration
and reheating) happen frequently to the main 2 types of rocks
that radiometric dating is applied to. Consequently, as if
using assumed data weren’t problematic enough, the assumption
process itself is shown to be invalid by known
geological data.
And
fourth, these problems are so widespread that all radiometric
dating methods (except for carbon-14 and uranium-thorium,
which dates deep-sea sediments) are affected by them, specifically
including: potassium-argon, rubidium-strontium, uranium-lead,
and fission-track dating.
Having
established these facts from secular and evolutionist sources,
we close this section with comments from creationist Dr. Keith
Wanser in which he likewise affirms that migration is an obstacle
to radiometric dating. As Dr. Wanser states, “the ages
can change several orders of magnitude just depending on how
much the migration coefficients are.”
“You
have a parent and it gives birth to a daughter when it decays
radioactively. You measure how many of the daughter product
you have at time t. You
assume how many there are initially. And then you’d
measure the amount of the parent species at time t.
And from that you infer the time that the system has been
going on for. That’s assuming there’s no open
system behavior. Well now, those equations get
modified to something…much more complicated when you
include the effects of things migrating in, parents migrating
in, parents migrating out, daughters migrating in, and daughters
migrating out from adjacent layers…Migration out of
one layer into the above layer, migration out into a layer
below of the parent nucleus. Then you can have parents from
the other adjacent layers migrate in from layers above and
below. So, that affects the number of atoms in the parent
species in a given layer. And then the same thing in the daughter…We
have migration out to adjacent layers of the daughter species
and we have migration in from both adjacent layers. So, there
are a lot of extra terms there. And one has to try and figure out what are these rates of migration,
what are these atomic
diffusion coefficients…How will it affect
your parent radioactive ages?...It
can still act like a closed system for when you date the thing.
But what happens is the ages can change several
orders of magnitude just depending on how much the migration
coefficients are, how
strong they are. So, that’s kind of an interesting effect
because one might expect to have a depth-dependent
kind of migration coefficient…This is preliminary…and it’s somewhat
significant.” – “Radioactive Decay Update:
Breaking Down the Old Age Paradigm,” Dr. Keith Wanser,
AnswersInGenesis.org, Copyright 2003 Answers in Genesis, 7
minutes
Focus
on Critical Evidence: Potassium-Argon Dating
So
far in our focus on radiometric dating, we have covered 2
topics. First, we covered the basic concepts, processes, and
criteria for radiometric dating. And second, we covered the
general obstacles that inhibit radiometric dating with regard
to igneous and metamorphic rocks, which happen to be the 2
rock types that radiometric dating is primarily used for.
And, as indicated in both of these previous segments, the
potassium-argon method is one of the radiometric methods used
to date igneous and metamorphic rocks. However, potassium-argon
also suffers from some other significant problems. And since
potassium-argon is the most widely-used and prominent dating
method (except for perhaps carbon-14), in this segment we
will take some time to focus on potassium-argon by itself.
We
will begin with a brief review, starting with the fact that
potassium-argon dating (along with carbon-14) is the most
widely used radiometric dating method.
“Prehistoric
People, Placing prehistoric people in time –
By measuring the amount of each isotope in a fossil, scientists
can determine how long the decay has been going on and therefore
how old the fossil is. The most commonly used dating
methods of this type are radiocarbon
dating and potassium-argon dating.”
– Worldbook, Contributor: Alan E. Mann, Ph.D., Professor
of Anthropology, Princeton University.
“Dating
Methods, III ABSOLUTE DATING METHODS. E Radiometric Dating,
E3 Potassium-Argon Method
– The decay of radioactive potassium isotopes
to argon is widely used for dating rocks.
(The decay of potassium-40 to calcium-40 that also takes place
is not useful.) Geologists are able to date entire
rock samples in this way, because potassium-40 is abundant in micas, feldspars, and hornblendes.”
– "Dating Methods," Microsoft® Encarta®
Encyclopedia 99. © 1993-1998 Microsoft Corporation. All
rights reserved.
“Geologic
Time, III DATING METHODS – The two radioactive decay sequences
most useful to geologists are the
decay of carbon-14 into nitrogen-14 and the decay
of potassium-40 into argon-40. Carbon-14,
or radiocarbon, dating works for organic materials less than
about 50,000 years old…Geologists can use
potassium-argon dating to determine ages of rocks from about
100,000 years old to as old as the earth itself.”
– "Geologic Time," Microsoft® Encarta®
Encyclopedia 99. © 1993-1998 Microsoft Corporation. All
rights reserved.
Furthermore,
as indicated by the last quote above and the next quote below,
potassium-argon is used to supply dates to the bulk of the
geologic column, from 100,000 years ago all the way back to
the 4 or 5 billion years ago, when evolution dates the formation
of the earth. Considering that the evolutionary age for the
earth is approximately 4.5 billion years and all but the most
recent 100,000 years is dated by potassium-argon dating, this
means that potassium-argon dating is the primary method for
providing dates to to 99.99778 percent of evolutionary earth
history. The most recent 100,000 years represent only about
0.00222 percent of evolutionary earth history.
Moreover,
potassium is one of “the 10 most abundant elements that
together make up 99 percent of Earth’s crust.”
“Dating,
Absolute dating, Major methods of isotopic dating, Potassium–argon
methods – The radioactive
decay scheme involving the breakdown of potassium of mass
40 (40K) to argon gas of mass 40 (40Ar) formed the basis of
the first widely used isotopic dating method.
Since radiogenic argon-40 was first detected in 1938 by the
American geophysicist Lyman T. Aldrich and A.O.Nier, the
method has evolved into one of the most versatile and widely
employed methods available. Potassium is one of the 10 most abundant
elements that together make up 99 percent of the Earth's crust and is therefore a major constituent of many rock-forming
minerals.” – Encyclopaedia Britannica 2004 Deluxe
Edition
The
large amount of potassium in the crust means that there is
a better likelihood of rocks and minerals containing potassium
than the other elements used in radiometric dating.
Consequently,
potassium-argon dating is prominent for 3 reasons. First,
it is prominent because (along with carbon-14 dating) it is
the most widely used method. Second, it is prominent because
it serves as the backbone for the bulk of the earth’s
age. And third, it is prominent because it is likely to be
applicable to more rocks and minerals than any other radiometric
dating method. Conversely, however, given its prominence,
if potassium-argon dating does not work, then the majority
of radiometric dating is lost. And, in fact, in the previous
section we have already seen that age calculations using potassium-argon
dating cannot work because migrations are frequent in the
rocks to which the potassium-argon method is applied and migrations,
in turn, prevent the isotope ratios and decay amounts from
being identified, which is a necessary step before age calculations
can be performed. So, we already know that potassium-argon
dating doesn’t work. However, in order to further substantiate
this fact, we will now provide additional obstacles, which
demonstrate that potassium-argon dating, the most prominent
dating method and the method responsible for the bulk of radiometric
dates, simply does not work.
To
demonstrate this fact, we will now take a closer look at the
procedure for measuring the present potassium-argon qauntities.
First, the daughter isotope, argon, is a gas at room temperature,
which makes this dating method different from other radiometric
dating methods. The fact that argon is a gas complicates the
measuring procedure, making it more difficult. Specifically,
measuring the present potassium-argon quantities in a sample
requires unique procedures and different technology than other
methods.
“Dating,
Absolute dating, Major methods of isotopic dating, Potassium–argon
methods –Argon dating involves a different technology
from all the other methods so far described because argon
exists as a gas at room temperature.” – Encyclopaedia Britannica 2004 Deluxe
Edition
Conventional
potassium-argon quantity measuring is described in the quote
below.
“Dating,
Absolute dating, Major methods of isotopic dating, Potassium–argon
methods – In conventional potassium–argon dating,
a potassium-bearing sample is split into two fractions: one
is analyzed for its potassium content, while the other is fused in a vacuum to
release the argon gas. After purification has been completed,
a spike enriched in argon-38 is mixed in
and the atomic abundance of the daughter
product argon-40 is measured
relative to the argon-38 added. The amount of the
argon-36 present is then determined relative to argon-38 to
provide an estimate of the background atmospheric correction.
In this case, relatively large samples, which may
include significant amounts of alteration, are
analyzed. Since potassium is usually added by alteration,
the daughter–parent ratio and the age might be too low.
A method designed to avoid such complexities was introduced
by the geochronologists Craig M. Merrihue and Grenville Turner
in 1966.” – Encyclopaedia Britannica 2004 Deluxe
Edition
As
we can see from the quote, measuring the present quantities
of potassium and argon in a sample involves the following
process. First, the sample is split in two. One part is then
tested for potassium and the other part for potassium’s
daughter isotope argon-40. A second argon isotope (argon-38)
is mixed in. And then the quantity of argon-40 is measured
against the quantity of argon-38 that was added in. Next,
the quantity of another argon isotope, argon-36, is measured
and compared to the amount of argon-38. This comparison serves
as a basis for determining how much argon is already present
in the atmosphere and is not a result of potassium decay in
the sample. Using this “estimate,” the amount
of argon-40 is “corrected.” The next sentence
informs us that “relatively large” samples “may”
include “significant amounts of alteration.” During
“alteration” potassium (the parent isotope) is
added. Consequently, the age indicated by the procedure is
deemed to be “too low” as result of “extra”
parent atoms that “may” have been added. Due to
all of these issues, this procedure is considered to have
multiple “complexities” and those complexities
are considered so problematic that an entirely different measuring
method was designed as an alternative. The important point
here is that the conventional means of measuring the present
potassium-argon quantities is not reliable.
The
alternate procedure for measuring present potassium-argon
quantities is described in the following quote.
“Dating,
Absolute dating, Major methods of isotopic dating, Potassium–argon
methods – A method designed to avoid such complexities was introduced by the geochronologists
Craig M. Merrihue and Grenville Turner in 1966. In
this technique, known as the argon-40–argon-39 method,
both parent and daughter can be determined in the mass spectrometer
as some of the potassium atoms in the sample are first converted
to argon-39 in a nuclear reactor. In this way, the problem of measuring the
potassium in inhomogeneous samples is eliminated and smaller amounts of material can be analyzed. An additional advantage
then becomes possible. The sample can be heated in stages
at different temperatures and the age calculated at each step.
If alteration is evident, the invalid low-temperature age
can be eliminated and a valid high-temperature age determined.
In some cases, partly reset systems also may be detected.”
– Encyclopaedia Britannica 2004 Deluxe Edition
As
indicated in the quote, this alternate procedure uses a nuclear
ractor to actually trigger the decay or conversion of the
parent isotope potassium into the daughter isotope argon-39.
During this conversion in the nuclear reactor, a mass spectrometer
can measure the parent (potassium) to daughter (argon-40)
ratio. As noted early on, knowing the radioactive decay rate
is required for age calculations.
“Dating,
Absolute dating, Principles of isotopic dating
– Likewise, the conditions that must be met
to make the calculated age precise and meaningful are
in themselves simple: 1. The rock or mineral must have remained closed to the
addition or escape of parent and daughter atoms since the
time that the rock or mineral (system) formed. 2.
It must be possible to correct for other atoms identical to daughter atoms
already present when the rock or mineral formed. 3. The decay constant must be known. 4.
The measurement of the daughter-to-parent ratio must be accurate
because uncertainty in this ratio contributes directly to
uncertainty in the age. Different schemes have been developed
to deal with the critical assumptions stated above.”
– Encyclopaedia Britannica 2004 Deluxe Edition
“Earth
sciences, The 20th century: modern trends and developments,
Geologic sciences, Radiometric dating – By determining the amount of the parent and daughter
isotopes present in a sample and by knowing their
rate of radioactive decay (each radioisotope has its own decay
constant), the isotopic age of the sample can be calculated.”
– Encyclopaedia Britannica 2004 Deluxe Edition
Furthermore,
as also indicated in the quotes above, the radioactive decay
rate must be constant over time because if the decay is not
constant, then more or less decay will occur at different
periods of a rock’s history and we won’t know
how long it takes for a certain amount of parent atoms to
decay into daughter atoms. Essentially, we won’t know
the half-life and so we won’t know the age of the rock
because we won’t know how long decay has been occurring.
Encyclopedia
Britannica states that we can be confident that decay rates
are known, reliable, and constant because decay processes
take place “within the atomic nucleus.” In short,
decay rates are constant because they are governed by processes
that occur in a location that is isolated from the influence
of “external forces.” Consequently, according
to Britannica, it is the fact that decay processes are isolated
from change that guarantees decay rates remain constant.
“Dating,
Absolute dating, Principles of isotopic dating, Potassium–argon
methods – The
results show that there is no known process that can alter
the rate of radioactive decay. By
way of explanation it can be noted that since the
cause of the process lies deep within the atomic nucleus,
external forces such as extreme heat and pressure have no
effect. The same is true regarding gravitational, magnetic,
and electric fields, as well as the chemical state in which
the atom resides. In
short, the process of radioactive decay is immutable
under all known conditions. Although it is impossible to predict when a particular
atom will change, given a sufficient number of atoms, the
rate of their decay is found to be constant. The
situation is analogous to the death rate among human populations
insured by an insurance company. Even though it is impossible
to predict when a given policyholder will die, the company
can count on paying off a certain number of beneficiaries
every month. The recognition that the rate of decay
of any radioactive parent atom is proportional to the number
of atoms (N) of the parent remaining at any time gives
rise to the following expression.” – Encyclopaedia
Britannica 2004 Deluxe Edition
However,
a nuclear reactor is clearly able to affect the processes
occurring in the atomic nucleus. In fact, as we have seen
described above, in this alternate procedure for measuring
present potassium-argon quantities, the nuclear reacter is
precisely being used to affect the atomic nucleus and trigger
potassium atoms to convert or decay into argon-39. Consequently,
the measuring procedure actually has the potential to affect
the decay rate and induce potassium to change into argon atoms.
With the guaranteed constancy of the decay rate now removed
and atomic conversion actually being induced by the nuclear
reactor, the factors required for making age calculations
become unattainable and age calculation becomes impossible.
It
is important to note that the next quote from Britannica Encyclopedia
immediately follows the 2 previous quotes describing the 2
forms of measuring present potassium-argon quantities. In
short, the following comments from Britannica are part of
their ongoing analysis of the potassium-argon dating method.
It is after describing both the conventional and the alternate
measuring procedures that Britannica notes that “inherited
daughter products” (daughter atoms not resulting from
decay) remain a problem that is not solved by either measuring
procedure.
“Dating,
Absolute dating, Principles of isotopic dating, Potassium–argon
methods – As
in all dating systems, the ages calculated can be affected
by the presence of inherited daughter products. In a few cases, argon ages older than that of the Earth which violate local relative age patterns have even
been determined for the mineral biotite. Such situations
occur mainly where old rocks have been locally heated, which
released argon-40 into pore spaces at the same time that new
minerals grew. Under favourable circumstances the isochron method may be helpful, but
tests by other techniques may be required. For example, the
rubidium–strontium method would give a valid isotopic
age of the biotite sample with inherited argon.”
– Encyclopaedia Britannica 2004 Deluxe Edition
As
mentioned previously, Britannica states that the “inherited
daughter” problem infects “all dating systems,”
not just the potassium-argon method. Furthermore, the result
of the inherited daughter problem is that the calculated ages
are “too old,” in one example “older than”
the earth itself. In the case of potassium-argon dating, the
inherited daughter atoms are argon atoms. And, as indicated
by the last quote above and the next quote below, despite
new technology and the development of new approaches to potassium-argon
dating, potassium-argon dating is generally so unreliable
and uncertain that other dating methods are needed to check
the potassium-argon dating method.
“Dating
Methods, III ABSOLUTE DATING METHODS. E Radiometric Dating,
E4 Rubidium-Strontium Method –Used to date ancient igneous
and metamorphic terrestrial rocks as
well as lunar samples,
this method is based on disintegration by beta decay of rubidium-87
to strontium-87. The method is frequently used to
check potassium-argon dates, because the strontium daughter
element is not diffused by mild heating, as is argon.” – "Dating Methods," Microsoft®
Encarta® Encyclopedia 99. © 1993-1998 Microsoft Corporation.
All rights reserved.
In
particular, as indicated by the last 2 quotes, it is the rubidium-strontium
method that is used to double-check and correct that potassium-argon
ages. However, as we have already established earlier, rubidium-strontium
is also extremely susceptible to inherited daughter products
due to reheating and migration events. The long quote below
states in detail how rubidium-strontium ratios are complexly
affected by migration.
“Dating,
Absolute dating, Major methods of isotopic dating, Rubidium–strontium
method, Dating metamorphic rocks – Should a simple igneous
body be subjected to
an episode of heating
or of deformation or of a combination of both, a well-documented
special data pattern develops. With heat, daughter
isotopes diffuse out of their host minerals
but are incorporated into other minerals in the rock…Here,
an essentially rubidium-free, strontium-rich phase like apatite
retains its initial 87Sr/86Sr ratio over time, whereas the
value in such rubidium-rich, strontium-poor minerals as biotite
increases rapidly with time.
The rock itself gives the integrated, more gradual increase.
At the time of heating, identical 87Sr/86Sr ratios are again
achieved as described above, only to be followed
by a second episode of isotopic divergence. Approaches to this ideal case are commonly observed, but peculiar results
are found in situations where the heating is minimal. If one assumes for a moment that only the mineral with the
lowest blocking temperature loses its daughter isotope, it
is easy to imagine that other low-temperature minerals formed
at this time may acquire extremely high 87Sr/86Sr ratios.
Epidote, a low-temperature
alteration mineral with a very high concentration of radiogenic
strontium, has been found in rocks wherein biotite
has lost strontium by diffusion.
The rock itself has a much lower ratio,
so that it did not take part in this exchange. Although
rubidium–strontium dating is not as precise as theuranium–lead method, it was the first to be exploited and
has provided much of the prevailing knowledge of
Earth history. The procedures of sample preparation, chemical separation,
and mass spectrometry are relatively easy to carry out, and
datable minerals occur in most rocks. Precise ages can be
obtained on high-level rocks (i.e., those closer to the surface)
and meteorites, and imprecise but nevertheless valuable
ages can be determined for rocks that have been strongly heated.
The mobility of rubidium in deep-level crustal fluids and
melts that can infiltrate other rocks during metamorphism
as well as in fluids involved in weathering can complicate
the results.” –
Encyclopaedia Britannica 2004 Deluxe Edition
Despite
the numerous complications and assumptions caused by reheating
and migration outlined throughout the quote and despite the
fact that the quote itself concludes by stating that rubidium
is very mobile and therefore open to migration due to heat,
“complicating the results,” rubidium-strontium
is still referred to in the quote as “providing much
of the prevailing knowledge of Earth history.” This
is very similar to potassium-argon dating. As we have seen
throughout this segment, neither the conventional nor the
alternative isotope measuring procedures work for potassium-argon
dating and the double-checking method, rubidium-strontium,
suffers from the same problems and need for assumptions as
the potassium-argon method does. Furthermore, it should be
emphasized that these are just problems measuring the present
quantities of potassium-argon isotopes. Even if these problems
were to be solved or ignored, the other factors that must
be known in order to perform radiometric dating (such as the
original quantity of parent and daughter isotopes when the
rock was formed, the amount of migration into or out of the
rock, and the decay rate) still remain unidentified, rendering
age calculation simply impossible. Yet like the rubidium-strontium
quote above, despite these insurmountable problems, potassium-argon
dating is considered to “provide a great deal of information
about the Earth’s recent and ancient past.”
“Dating,
Absolute dating, Major methods of isotopic dating –
The potassium–argon method has provided a great deal
of information about the Earth's recent and ancient past.” – Encyclopaedia Britannica 2004 Deluxe
Edition
However,
in conclusion to this segment, it is quite clear that neither
potassium-argon nor rubidium-strontium meet the requirements
for calculating absolute age. The initial starting quantities
of the parent and daughter isotopes cannot be determined.
Migration is rampant in these methods, but the amount of migration
cannot be determined. There is difficulty determining the
exact present parent and daughter isotope ratio in potassium-argon
dating. And the alternate measuring procedure for potassium-argon
dating even directly induces radioactive decay. Since these
factors must be known in order to calculate absolute ages,
calculating ages from potassium-argon dating (or rubidium-strontium
dating) is neither possible, nor reliable, nor a matter of
anything other than performing calculations using assumed,
idealized values. The ages are not objective or empirical
observations or evidence.
Focus
on Critical Evidence: Reheating, Migration, and the Flood
The
prohibitive obstacles posed to radiometric dating by reheating
events and the migration of isotopes are made even more substantial
due to the evidence for a worldwide flood. In a previous segment,
we established 3 grounds why a global (or at least near-global)
flood must be accepted. First, there is significant evidence
in the historical record in the form of independent legends
of a global flood in cultures literally all around the world.
Second, there is significant geological evidence in the form
of the earth’s physical features, including the fossil
record itself and specifically the geographic distribution
of fossils. And third, there is simply no principle within
evolution, uniformitarianism, or even atheism that remotely
prevents accepting a global flood. In short, a global-flood
is not incompatible with evolution or uniformitarianism particularly
because belief in a global flood does not require believing
in God and because of evolution’s acceptance that the
world was covered or nearly covered by ice. Consequently,
evolution and uniformitarianism are left with no reason to
reject a global (or near-global flood) and instead only with
ample historical and geologic evidence for accepting such
a flood.
In
light of the dramatic grounds for accepting a global flood,
it is also important to establish the impact that a flood
of this kind would have on reheating and migration events.
In other words, the most detailed account of the flood is
found in the Judeo-Christian historic record and that detailed
account indicates massive volcanic activity as a part of the
cataclysm.
The
Biblical account of the global Flood speaks of the “fountains
of the deep being opened,” which then spew forth the
flood waters into the sky. This water shot up into the atmosphere
as if from massive fountains and eventually, as it cooled, it came back down in the form of rain.
Genesis
7:5 And Noah did according
unto all that the LORD commanded him. 6 And Noah
was six hundred years old when the flood of waters was
upon the earth. 7 And Noah went in, and his
sons, and his wife, and his sons’ wives with him, into
the ark, because of the waters of the flood.
8 Of clean beasts, and of beasts that are not
clean, and of fowls, and of every thing that creepeth upon
the earth, 9 There went in two and two unto Noah into the
ark, the male and the female, as God had commanded Noah.
10 And it came to pass after seven days, that the
waters of the flood were upon the earth.
11 In the six hundredth year of Noah’s life,
in the second month, the seventeenth day of the month, the
same day were all the fountains (04599) of the great deep
broken up (01234), and the windows of heaven were opened.
12 And the rain was upon the earth forty days and
forty nights.
The
Hebrew word for “fountain” in the phrase “fountain
of the deep” is “ma‘yan” (Strong’s
No. 04599), which simply means, “spring.” Out
of its 23 occurrences in the Old Testament, it is translated
as “fountain” 16 times, as “well”
5 times, and as “springs” 2 times. Notice also
the word “broken up” is the Hebrew word “baqa”
(Strong’s No. 01234) which means, “to split, cleave,
break open, divide.” This could very easily convey the
idea of the crust breaking up or splitting into separate plates,
so that the fountains spewed forth along these newly formed
fault cracks were the water was exposed to the molten material
beneath. This will be significant as we move ahead to discuss
geysers and mid-ocean ridges.
This
fountain-like spewing forth of water is probably similar to
the activity of a geyser. Geysers are springs. Geysers shoot
forth jets of water. Geyser activity is a manifestation of
volcanic activity. Geyser activity is associated with volcanic
activity and water that comes close to magma or molten rock.
The following figure from Microsoft Encarta and the quotes
which follow describe the interaction between volcanic activity
and the water jets of geysers.
“[Photo
Caption] Formation of Geysers –Geysers are caused
when underground chambers of water are heated to the boiling
point by volcanic rock. When heat causes the water to boil,
pressure forces a superheated column of steam and water to
the surface. The initial
amount of water released at the surface lessens the column's
weight, which also lowers its boiling point. When
the boiling point drops, the entire column of water vaporizes
at once, shooting out of the ground in a spectacular eruption.
© Microsoft Corporation. All Rights Reserved.”
– "Formation of Geysers," Microsoft® Encarta®
Encyclopedia 99. © 1993-1998 Microsoft Corporation. All
rights reserved.
“Volcano,
Types of volcanic activity, Other manifestations of volcanic
activity, Hydrothermal features – Hot springs and geysers also are
manifestations of volcanic activity. They result from the
interaction of groundwater with magma or with solidified but
still hot igneous rocks at shallow depths. Yellowstone
National Park is one of the most famous areas of hot springs
and geysers in the world…Geysers are actually
hot springs that intermittently spout a column of hot water
and steam into the air.
This action is caused by the water in deep conduits beneath
a geyser approaching or reaching the boiling point.”
– Encyclopaedia Britannica 2004 Deluxe Edition
“Geyser
– is a spring that throws up hot water with
explosive force from time to time. Often, the water shoots
up in great columns, cloudy with steam…How
geysers form – Geysers form in areas where water drains
through the earth deep below the surface.
A deep channel reaches from the surface far into the earth.
Cold water seeps down this channel until it reaches
rocks that are hot. Then it fills the channel. The water at the bottom is heated
by the rocks…This
process, in turn, lifts the column still more, until suddenly
all the water near the bottom of the channel expands into
steam and forces out the rest in a steam explosion…Geysers
have often been compared with volcanoes, for they act similarly.
But volcanoes shoot forth melted rock, while geysers erupt
water containing dissolved mineral matter.”
– Worldbook, Contributor: Nicholas C. Crawford, Ph.D.,
Professor and Director, Center for Cave and Karst Studies,
Western Kentucky University.
“Geyser
– any of a class of hot springs that discharges
jets of steam and water
intermittently. The term is derived from the Icelandic
word geysir, meaning “to rush forth.” Geysers
are generally associated with recent volcanic activity and
are produced by the heating of underground waters that have
come into contact with, or very close to, magma (molten rock)…Geysers often make a most spectacular display as
they discharge a roaring column of steam and boiling water
high above the surface…Geysers are nearly everywhere
associated with various other, less violent manifestations
of the interaction of magmatic heat and groundwater—e.g.,
bubbling hot pools and fumaroles (steam vents).
In many areas it has
proved possible to tap and control the steam discharged from
geysers and to use it in turbines for generating electricity
(e.g., the geysers near San Francisco). The main drawback
of such operations is that frequently the site on which a
power station must be located to exploit this steam is
vulnerable to damage either by volcanic activity or by earthquakes.”
– Encyclopaedia Britannica 2004 Deluxe Edition
As
can be seen by the quotes above, volcanoes, molten rock, and
even earthquakes are also associated with geyser activity.
Given the association of geysers and earthquakes is not a
surprise to find that hot springs, such as geysers, are also
found at faults in the earth’s surface.
“Hot
springs – Hot springs are springs that discharge water heated by natural
processes within the earth. Most
hot springs are steadily flowing streams or calm pools of
water. But many are fumaroles,
geysers, or bubbling pools of mud called mudpots or mud
volcanoes (see FUMAROLE;
GEYSER). Hot springs are also called thermal springs…Hot
springs originate when surface water, which results from rain
and snow, seeps into the ground. Many springs occur
in volcanic regions where hot molten rock called magma lies
near the surface of the earth. Surface water trickles down
through layers of rock until it is heated by the magma. Then
the water rises to the surface through channels in the rock…Hot
springs also occur in regions that have faults (breaks) or
folds (bends) in the layers of rock beneath the earth's surface.
The temperature of the earth increases toward the interior.
Faults and folds enable surface water to penetrate to depths
where it is heated.” – Worldbook, Contributor: Roy M. Breckenridge, Ph.D.,
Associate Director, Research Geologist, Idaho Geological Survey,
University of Idaho.
Furthermore,
the force of a hot spring or geyser depends on the depth,
the heat supply, and rate at which the water can flow into
the fault, column, or vent.
“Geyser
–Geyser, hot spring that erupts intermittently in a
column of steam and hot water…A
geyser erupts when the base of a column of water
resting in the earth is vaporized by hot volcanic rock. The
force with which the water column is expelled depends on its
depth. The weight of
the water column increases with its depth. The weight, in
turn, increases the pressure exerted on the base of the column,
thereby increasing the boiling point of the water there. When
the water finally boils, it expands, driving some water out
into the air…Eruption
intervals depend on such variables as
the supply of heat, the amount and rate of inflow
of subsurface water, and the nature of the geyser tube and its underground
connections.” – "Geyser," Microsoft®
Encarta® Encyclopedia 99. © 1993-1998 Microsoft Corporation.
All rights reserved.
In
addition, although the activity is currently quite mild by
comparison to eruptions that would have been involved in the
flood, similar elements of hot springs, fault lines, volcanic
activity and magma are present on the ocean floors.
“Deep-Sea
Exploration, IV SCIENTIFIC RESULTS – The first large exploration using occupied
submersibles was the French-American Mid-Ocean Undersea Study
(FAMOUS) project. In 1974 the Alvin (operated by the Woods
Hole Oceanographic Institution), the French bathyscaphe Archimède,
and the French diving saucer Cyane, assisted by support ships
and the Glomar Challenger, explored the great rift
valley of the Mid-Atlantic Ridge, southwest
of the Azores. The rift valley is considered by
geologists as the separation between the Eurasian plate and
the North American plate of the earth's crust, and it constitutes
one of the many sites in the ocean bottom where molten rock
oozes forth to form new crust…In a series of dives in 1979 and 1980 into the Galápagos Rift,
off the coast of Ecuador, French, Mexican, and U.S. scientists
found chimneylike vents,
nearly 9 m (nearly 30 ft) high and about 3.7 m (about 12 ft)
across, discharging a mixture of hot water
(up to 300° C/570° F) and dissolved metals in dark,
smokelike plumes (see Hydrothermal Vent). These
hot springs play an important
role in the formation of deposits that are enriched in copper,
nickel, cadmium, chromium, and uranium.” – "Deep-Sea
Exploration," Microsoft® Encarta® Encyclopedia
99. © 1993-1998 Microsoft Corporation. All rights reserved.
“Hydrothermal
Vent – Hydrothermal Vent, spring of hot water on
the deep ocean floor.
Such springs were proposed to exist in 1965, as part of the
developing theory of plate tectonics. Since then more
than 80 such vents have been found in the Pacific Ocean at
sites of rapid seafloor spreading.
These vents emit sulfur-rich water at temperatures that can
reach 350° C (660° F). A few vents have
also been found in the Atlantic Ocean, at sites of slower
spreading; the water
from these vents tends to be cooler but still rich in sulfur.
Hydrothermal vents have also been found at sites
of seafloor spreading in the Red Sea. In 1995, scientists started looking for hydrothermal
vents in the Indian Ocean and quickly discovered one that
had previously been active.
Scientists have also found hydrothermal vents at
hot-spots where magma rises in the middle of crustal plates
to form volcanic islands, such as Hawaii. The vents form when
cold seawater sinks deep into cracks in the ocean floor until
warmed by rock heated by magma
(see Igneous Rock).” – "Hydrothermal Vent,"
Microsoft® Encarta® Encyclopedia 99. © 1993-1998
Microsoft Corporation. All rights reserved.
“Microbiology,
The study of microorganisms, Applied microbiology, Microbiology
of water supplies, wastewater, and other aquatic environments
– Large populations of archaea live in volcanic
ridges 2,600 metres (8,500 feet) below the ocean surface in
areas immediately surrounding hydrothermal vents (deep-sea hot springs). The vents spew superheated water (350 °C [662 °F]) that contains hydrogen sulfide
(H2 S); the water surrounding the vents has a temperature
range of 10–20 °C (50–68 °F).” –
Encyclopaedia Britannica 2004 Deluxe Edition
“Ocean,
Ocean basins, Oceanic ridges, Spreading centre zones and associated
phenomena – Spreading
centres are divided into
several geologic zones. The neovolcanic zone is at the very
axis. It is 1 to 2 kilometres wide and is the site
of recent and active volcanism and of the hydrothermal vents.
It is marked by chains of small volcanoes or volcanic ridges.
Adjacent to the neovolcanic zone is one marked by fissures
in the seafloor. This may be 1 to 2 kilometres wide. Beyond this point
occurs a zone of active faulting. Here, fissures develop into
normal faults with vertical offsets…Warm springs
emanating from the seafloor in the neovolcanic zone were first
found on the Galápagos spreading centre. These
waters were measured to have temperatures about 20° C
above the ambient temperature. In 1979 hydrothermal
vents with temperatures near 350° C were discovered on
the East Pacific Rise off Mexico.
Since then, similar vents have been found on the
spreading centres off the Pacific Northwest coast of the United
States, on the south end of the northern Mid-Atlantic Ridge,
and at many locations on the East Pacific Rise. Hydrothermal
vents are localized discharges of heated seawater. They result
from cold seawater percolating down into the hot oceanic crust
through the zone of fissures and returning to the seafloor
in a pipelike flow at the axis of the neovolcanic zone.” –
Encyclopaedia Britannica 2004 Deluxe Edition
These
deep ocean hydrothermal vents are present at the exact places
where the earth’s crust is breaks into multiple plates.
“Volcano,
VI VOLCANO DISTRIBUTION – The magma-forming regions of the
earth and the volcanoes built above them are not randomly
scattered but instead are confined to several zones and special
places. While these volcanically active areas have long been known,
the scientific reason for their distribution was not
understood until the emergence of the theory of plate tectonics
in the late 1960s. According to this theory, the
earth's surface is broken into a dozen or so large solid slabs
(called plates). These plates consist of both crustal and
rigid upper mantle material.
They are 50 to 150 km (30 to 95 mi) thick and ride upon hotter,
more free-flowing mantle. The plates are moving relative to
one another at average rates of several centimeters a year.
The vast majority of the world's active volcanoes,
above and below the sea, are found along or near the boundaries
between these shifting plates. Volcanoes
can also be found in the middle of tectonic plates, although
midplate volcanoes are relatively rare. The Hawaiian
Islands are the exposed part of a midplate volcanic chain…A
Volcanoes at Plate Boundaries – Even though most of the earth's volcanism
occurs along divergent boundaries, the eruptions often occur
unobserved because divergent boundaries are covered by the
oceans, except those in Iceland and East Africa.” – "Volcano,"
Microsoft® Encarta® Encyclopedia 99. © 1993-1998
Microsoft Corporation. All rights reserved.
“Ocean
and Oceanography, II OCEAN BASIN STRUCTURE – In the central parts of the oceans
are the midocean ridges, which are extensive mountain chains
with inner troughs that are heavily intersected by cracks,
called fracture zones. The ridges are sections of a continuous
system that winds for 60,000 km (40,000 mi) through all the
oceans.” – "Ocean and Oceanography,"
Microsoft® Encarta® Encyclopedia 99. © 1993-1998
Microsoft Corporation. All rights reserved.
“Volcanism
– A second major site of active volcanism
is along the axis of the mid-ocean ridge system, where the
plates move apart on both sides of the ridge, and magma wells
up from the mantle, creating
new ocean floor along the trailing edges of both plates. Virtually
all of this volcanic activity occurs under water.” –
Encyclopaedia Britannica 2004 Deluxe Edition
If
the earth’s crust was first “broken up”
into plates at the time of the Flood, this would explain why
so much water would shoot forth like “fountains”
as the ocean came in contact with the molten material underneath.
In
summary, the Judeo-Christian record of the flood indicates
massive, submarine volcanic activity similar to the manifestations
of geysers, but on a much larger scale. And the Judeo-Christian
record of the flood also indicates that the breaking up of
the earth’s crust into plates also is described as occurring
at this time. On this last point, the Judeo-Christian model
even scientifically predicts the discovery that the earth’s
crust is divided up into separate plates.
As
we have noted in previous sections, radiometric dating does
not work on sedimentary rock layers but instead is used for
igneous and metamorphic rocks.
“Geology,
III THE GEOLOGIC TIME SCALE, D Radiometric Dating
– Another fundamental goal of geochronology
is to determine numerical ages of rocks and to assign numbers
to the geologic time scale. The primary tool for this task
is radiometric dating, in which the decay of radioactive elements
is used to date rocks and minerals. Radiometric dating works
best on igneous rocks (rocks that crystallized from molten material). It
can also be used to date minerals in metamorphic rocks (rocks
that formed when parent rock was submitted to intense heat
and pressure and metamorphosed into another type of rock).
It is of limited use, however, in sedimentary rocks formed by the compaction of layers of sediment.”
– "Geology," Microsoft® Encarta® Encyclopedia
99. © 1993-1998 Microsoft Corporation. All rights reserved.
Consequently,
if a flood involved or occurred as a result of intense volcanic
activity initiated by a literally earth-shaking event, such
intense volcanic activity would by definition include massive
reheating events in igneous and metamorphic rocks. As stated
in the quote below, volcanic activity is directly associated
with continental plate activity, particularly on the ocean
floor.
“Volcano,
Volcanism and tectonic activity – Active volcanoes are not scattered
over the Earth randomly; instead, most occur in belts, especially
in the island arcs and mountain ranges bordering the Pacific
Ocean (Figure 5). The concept of seafloor spreading
and, more broadly, the theory of plate tectonics offer a logical
explanation for the location of most volcanoes…Volcanoes related to plate boundaries – Topographic maps reveal the locations
of large earthquakes and indicate the boundaries of the 12
major tectonic plates…Volcanoes
occur along both subduction and rift zones but are generally
absent along strike-slip plate margins.
Of the 1,144 volcanoes listed in Table 2, 80 percent occur
along subduction zones and 15 percent along rift zones. These
percentages are somewhat misleading, however, because most
of the Earth's rift zones are about two to three kilometres
below sea level. At those inaccessible depths active submarine
volcanoes have yet to be observed, though a few hydrothermal
areas have been found along submarine rift zones
with deep-diving submarines.” – Encyclopaedia
Britannica 2004 Deluxe Edition
Moreover,
the quote below is very specific that radiometric dating methods
are used to date rocks and minerals that are formed and “subjected
to high temperatures” where continental plates “collide”
and these “geologic events” directly impact the
ages indicate by such rocks or minerals.
“Dating,
General considerations, Distinctions between relative-age
and absolute-age measurements – Unlike ages derived from fossils, which occur only
in sedimentary rocks, absolute ages are obtained
from minerals that grow as liquid rock bodies cool at or below
the surface. When rocks are subjected to high temperatures
and pressures in mountain roots formed where continents collide,
certain datable minerals grow and even regrow to record the
timing of such geologic events.”
– Encyclopaedia Britannica 2004 Deluxe Edition
Furthermore,
the heating events caused by volcanic and continental plate
activity would in turn trigger the migration of key isotopes
around, into, and out of the various parts of those rocks.
As stated in the 2 quotes below, this migration would result
in dated ages that could be either higher or lower than the
real age of the rocks. In fact, according to the first quote
below, higher ages have been exemplified in rocks that have
dated older than the earth itself.
“Dating,
Absolute dating, Evaluation and presentation schemes in dating,
Multiple ages for a single rock; the thermal effect –
Fossils record the initial, or primary, age of a
rock unit. Isotopic systems, on the other hand, can yield either the
primary age or the time of a later event,
because crystalline materials are very specific in the types
of atoms they incorporate, in terms of both the atomic size
and charge. An element formed by radioactive decay is quite
different from its parent atom and thus is out of place with
respect to the host mineral. All it takes for such
an element to be purged from the mineral is sufficient heat
to allow solid diffusion to occur. Each mineral has a temperature
at which rapid diffusion sets in, so that, as a region is
slowly heated, first one mineral and then another loses its
daughter isotopes. When this happens, the isotopic “clock”
is reset to zero, where
it remains until the mineral cools below the blocking temperature…Another
problem arises if a region undergoes a second reheating event.
Certain minerals may record the first event, whereas others
may record the second, and any suggestion of progressive cooling between
the two is invalid.”
– Encyclopaedia Britannica 2004 Deluxe Edition
“Dating,
Absolute dating, Principles of isotopic dating
– As in all dating systems, the ages calculated
can be affected by the presence of inherited daughter products.
In a few cases, argon ages older than that of the
Earth which violate local
relative age patterns have even been determined for the mineral
biotite. Such situations occur mainly where old
rocks have been locally heated, which released argon-40 into
pore spaces at the same time that new minerals grew.”
– Encyclopaedia Britannica 2004 Deluxe Edition
Consequently,
the very rocks that radiometric dating is used to date are
rocks that would have been formed by or at least subjected
to the massive reheating and migration events occurring as
a result of the intense volcanic and continental plate activity
described as a part of the global flood. Thus, as indicated
explicitly by the first quote below, the ages of such rocks
could have been significantly raised by the volcanic and plate
activity of the flood. Therefore, as also stated in both of
the quotes below, no rock which has been subjected to these
conditions would meet the criterion necessary for calculating
radiometric ages. In short, radiometric dating would be simply
impossible for all igneous and metamorphic rocks.
“Absolute
dating, Major methods of isotopic dating, Rubidium–strontium
method, Dating simple igneous rocks –Once plotted as R1p (i.e., rock 1 present values), R2p, and R3p, the data are examined to
assess how well they fit the required straight line. Using
estimates of measurement precision, the crucial question of
whether or not scatter outside of measurement error exists
is addressed. Such scatter would constitute a geologic component,
indicating that one or more of the underlying assumptions
has been violated and that the age indicated is probably not
valid. For an isochron to be valid, each sample
tested must (1) have had the same initial ratio, (2) have
been a closed system over geologic time, and (3) have the
same age. Well-preserved, unweathered rocks that crystallized
rapidly and have not been subjected to major reheating events
are most likely to give valid isochrons. Weathering is a
disturbing influence, as is leaching or exchange by hot crustal
fluids, since many secondary minerals contain rubidium. Volcanic
rocks are most susceptible to such changes because their minerals are fine-grained and unstable glass may be present.”
– Encyclopaedia Britannica 2004 Deluxe Edition
“Dating,
Absolute dating, Principles of isotopic dating
– Likewise, the conditions that must be met
to make the calculated age precise and meaningful are in themselves simple: 1. The rock or mineral must have remained closed to the
addition or escape of parent and daughter atoms since the
time that the rock or mineral (system) formed.
2. It must be possible to correct for other
atoms identical to daughter atoms already present when the
rock or mineral formed.
3. The decay constant must be known. 4.
The measurement of the daughter-to-parent ratio
must be accurate because uncertainty in this ratio contributes directly
to uncertainty in the age. Different schemes have
been developed to deal with the critical assumptions stated
above. In uranium–lead dating,
minerals virtually free of initial lead can be isolated
and corrections made for the trivial amounts present. In whole rock isochron
methods that make use of the rubidium–strontium or samarium–neodymium
decay schemes (see below),
a series of rocks or minerals are chosen that can
be assumed to have the same age and identical abundances of
their initial isotopic ratios. The
results are then tested for the internal consistency that
can validate the assumptions…Such checks include dating
a series of ancient units with closely spaced but known relative
ages and replicate analysis
of different parts of the same rock body with samples collected
at widely spaced localities.” –
Encyclopaedia Britannica 2004 Deluxe Edition
In
conclusion to our examination of radiometric dating methods
that are applied to igneous and metamorphic rocks, we can
see that the stated conditions necessary for dating are not
met, the key factors are not known but must be assumed, the
very rocks that are used are disqualified by the additional
criteria stipulated for making assumptions, nevertheless idealized
numeric values assumed and adjusted as needed, and the most
widely-used prominent methods such as potassium-argon and
rubidium-strontium don’t work on an individual basis
either. In particular, we have seen repeatedly that reheating
and migration events disqualify igneous and metamorphic rocks
from being dated, placing key factors beyond reach, such as
the original isotope quantities and degree to which actual
radioactive day itself has contributed to present isotope
quantities. And lastly, the events surrounding the historic,
global flood (which evolutionists, atheists, and uniformitarians
have no basis for rejecting) would also create massive worldwide
heating and migration events further disabling any radiometric
dating of igneous and metamorphic rocks.
Consequently,
the age of the earth rendered from radiometric dating methods
used on igneous and metamorphic rock are shown to be inherently
unreliable and the product of mere assumption. They are not
observable or empirical scientific facts. And as a result,
the 6,000 to 10,000 year age of the earth is not disproved
or even marred in any way by the radiometric dating methods
used on igneous and metamorphic rocks. This leaves only a
2 broad issues of geologic dating to discuss. First, we need
to discuss the remaining radiometric dating methods, which
are used on items other than igneous and metamorphic rocks.
And second, we will also discuss further problems generally
affecting all radiometric dating methods that utilize long
half-life isotopes, which will also provide additional reasons
negating the methods used on igneous and metamorphic rocks.