First, there must be no argon
other than that of atmospheric composition trapped in the rock or
mineral when it forms. Second, the rock or mineral must not lose
or gain either potassium or argon from the time of its formation
to the time of analysis. By many experiments over the past three
decades, geologists have learned which types of rocks and
minerals meet these requirements and which do not. The K-Ar clock
works primarily on igneous rocks, i.e., those that form from a
rock liquid (such as lava and granite) and have simple
post-formation histories. It does not work well on sedimentary
rocks because these rocks are composed of debris from older
rocks. It does not work well on most metamorphic rocks because
this type of rock usually has a complex history, often involving
one or more heatings after initial formation.
radioactive decay involves the ejection of one or more
sub-atomic particles from the nucleus. Alpha decay occurs when an
alpha particle (a helium nucleus), consisting of two protons and
two neutrons, is ejected from the nucleus of the parent isotope. Beta decay involves the ejection of a beta particle (an electron)
from the nucleus. Gamma rays (very small bundles of energy) are
the device by which an atom rids itself of excess energy.
Age of galaxies from the travel time of light
The same sort of line will be obtained by plotting any
pair of naturally occurring isotopes of the same element
normalized by any nonradiogenic isotope, including
87Rb/86Sr ratio versus 85Rb/86Sr ratio. Contrary to Slusher’s (117) statement, these plots demonstrate only elemental variations in
nature, not isotopic fractionation, and they have nothing to do
with the validity of the Rb-Sr isochron. Two extensive
K-Ar studies on historical lava flows from around the world
(31, 79) showed that excess argon is not a serious problem for dating
lava flows. The authors of these reports “dated”
numerous lava flows whose age was known from historical records. In nearly every case, the measured K-Ar age was zero, as expected
if excess argon is uncommon.
However, their original abundances in some objects can still be determined by the isochron method. By comparing the original abundances of a short-lived radionuclide in different objects, scientists can determine their relative ages. If one or more of these objects also have had their absolute ages determined by using long-lived radionuclides, the relative ages can be converted into absolute ones. Trying to establish absolute ages for relative ages that have been determined from various short-lived radionuclides has been the focus of much modern research, but it has proved to be difficult.
Whereas Lanphere and his colleagues referred to these two K-Ar
ages of 163 and 186 million years, the ages are actually from
another report and were obtained from samples collected at two
localities in Canada, not Alaska. There is nothing wrong with
these ages; they are consistent with the known geologic relations
and represent the crystallization ages of the Canadian samples. Where Woodmorappe obtained his 140-million-year
“expected” age is anyone’s guess because it
does not appear in the report he cites.
The location of the point on concordia depends only on the
age of the sample. If at some later date (say, 2.5 billion years
after formation) the sample loses lead in an episodic event, the
point will move off of concordia along a straight line toward the
origin. At any time after the episodic lead loss (say, 1.0
billion years later), the point Q in Figure 4 will lie on a chord
to concordia connecting the original age of the sample and the
age of the lead loss episode. The upper intercept of discordia
with concordia gives the original age of the rock, or 3.5 billion
years in the example shown in Figure 4. There are several
hypotheses for the interpretation of the lower intercept, but the
most common interpretation is that it indicates the age of the
event that caused the lead loss, or 1 billion years in Figure 4. Note that this method is not only self-checking, but it also
works on open systems.
So all plants, animals, and people have a small, but measurable quantity of c-14 in their body. But, while alive, plants and animals replenish the c-14 by taking in additional carbon from their environment. Therefore, https://yourhookupguide.com/meetby-review/ the ratio of c-14 to c-12 in a living animal or plant is roughly the same as it is in the atmosphere. And since helium is a gas, it can leak through the rocks and will eventually escape into the atmosphere.
Our planet was pegged at a youthful few thousand years old by Bible readers (by counting all the “begats” since Adam) as late as the end of the 19th century, with physicist Lord Kelvin providing another nascent estimate of 100 million years. Kelvin defended this calculation throughout his life, even disputing Darwin’s explanations of evolution as impossible in that time period. So in order to date most older fossils, scientists look for layers of igneous rock or volcanic ash above and below the fossil. Scientists date igneous rock using elements that are slow to decay, such as uranium and potassium. By dating these surrounding layers, they can figure out the youngest and oldest that the fossil might be; this is known as “bracketing” the age of the sedimentary layer in which the fossils occur. Geologists use radiometric dating to estimate how long ago rocks formed, and to infer the ages of fossils contained within those rocks.
The assumption of slow geologic processes and radiometric age dating has drastically inflated the age of the Earth and its strata. One likely explanation is that
sometime in the past the radioactive decay rate was greatly accelerated. The
decay rate was accelerated so much that helium was being produced faster
than it could have escaped, causing an abundant amount of helium to remain
in the granite. The RATE group has gathered evidence that at some time in
history nuclear decay was greatly accelerated. Since we did not observe the initial conditions when the hourglass time
started, we must make assumptions. If scientists fail to consider each of these three critical
assumptions, then radioisotope dating can give incorrect ages.
If enough free neutrons did exist, they would produce other
measurable nuclear transformations in common elements that would
clearly indicate the occurrence of such a process. No such
transformations have been found, and so Morris’ claims are
disproved. The K-Ar method
is probably the most widely used radiometric dating technique
available to geologists. It is based on the radioactivity
of 40K, which undergoes dual decay by electron capture to
40Ar and by beta emission to
40Ca. The ratio of 40K atoms that decay to
40Ar to those that decay to 40Ca is 0.117, which is called the branching ratio.