Re: a guide to dating - 14C

GRMorton@aol.com
Sat, 23 Sep 1995 12:51:02 -0400

Stephen Jones wrote:
>>I can accept (after much debate on the Australian Fidonet Creation v
Evolution echo) that science can date age of the Earth at 4.6 billion
years, using the Uranium-Lead method. However, I am not so sure
that it can date using such short ages as 5 MY using the U-Pb
method. Does anyone know what method was used to date Glenn's
exhibits?<<

Good question Stephen. Until the late 1980's archaeology had a lot of
difficulty dating the time periods between 50,000 and 1 million years. This
gap was called the "muddle in the middle". Several dating techniques have
now been developed to give absolute ages to the objects.

First, thermoluminescence of burnt flint can be used in a ragne of 2,000
years to 500,000 years. When a flint is burned, the crystal lattice is
annealed and becomes relatively orderly. After the fire, natural
radioactivity damages the crystal. This technique measures the amount of
crystal damage that has accumulated since the time it was burned.(I speak a
little loosely here)

The second method is Electron Spin Resonance. This measures the amount of
crystalline damage in teeth and carbonates which has occurred since the teeth
or limestone was formed. This method has been used to date the appearance of
the earliest modern humans at 100,000 years in Qafzeh cave, Israel. It can be
used on human, or non-human teeth. And since the teeth are the last undecayed
part of any carcase, there are plenty of teeth to use.

The thorium-lead method can be used to date things from 5000 to 350,000
years. But it requires flowstone or travertine. It is useful in caves but not
a lot elsewhere.

I do want it clearly understood that no modern human skeleton has been dated
to 5.5 million years ago. The earliest Australopithecus is from that time
frame. And none of the art objects I have been mentioning come from the 5.5
million year time frame. My point with the anthropological data is that
current Christian apologetics (PC, and YEC) fail to account for the time
frame of man's appearance on earth. One can go with Stephen's 2 Adam
approach, but I don't see that in Scripture anywhere. I only see one Adam.

Of the dating of the flood, (i.e., the empty Mediterranean) Bill Hamilton
wrote:
>> Geologists like to have several lines of evidence when they date things,
so I presume some additional evidence must have been available, but either I
don't remember it form the book, or Glenn didn't discuss it. In any case,
the flooding of the Mediterranean is considered pretty well established by
the geology and oceanography communities -- it was not Glenn's invention.<<

To date the time of the Mediterranean desciccation there are several lines of
evidence. There is paleomagnetism which can be used to date the deep sea
sediments in the Mediterranean. There are volcanic flows and dykes which can
be dated by potassium argon. Worldwide, as well as over large regional areas,
microscopic animals appear in the same stratigraphic order wherever we drill.
These are microcropic index fossils are tied into volcanic flows. The
appearance and disappearance of a particular suite of microfossils is also
used. They all point to a time of around 5.5 million years for the dry
Mediterranean.

Interestingly, Lyell when he set up the stages of the Tertiary, used faunal
changes to define the stage boundaries. One of the largest faunal changes in
the Mediterranean region was at the Miocene/Pliocene boundary. Since Lyell
was using sediments in Itally for his definitions, the filling of the
Mediterranean and the subsequent faunal change played a major role in how we
divide the Tertiary. Lyell knew nothing of the Mediterranean desert. He
just saw a major change in animal life at that stratigraphic level.

Bill is correct that the dry Mediterranean was not my idea. I wish it had
been and you may shower me with any kudos you want. But W. B. F. Ryan and
Kenneth Hsu are the real discoverers of this and they probably would prefer
that they get the kudos.

The one thing which would prove my view is the finding of some artifact from
the Miocene/Pliocene boundary in the Mediterranean. Unfortunately, I do not
have such evidence.

glenn