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Across
5. A radiometric dating method based
on the fact that when trace
amounts of uranium-238 decay, there is a
release of highly energy-charged
alpha particles which burn narrow
tracks, or damage trails, through
glassy materials like obsidian
(i.e., volcanic glass).
6. A radiometric dating method based
on the fact that background
radiation causes electrons to
separate from their atoms and
become trapped in the crystal
lattice of minerals. This
progressively alters the magnetic
field of the material at a
predictable rate. The magnetic
field of the atoms in a sample is
measured to determine the age.
This technique is employed
primarily to chronometrically date
calcium carbonate in limestone,
coral, teeth, and egg shells.
This method is also reffered to as
ESRdating.
7. Magnetic fields that are altered
or formed in atoms of iron by heat
in excess of
1100° F. (600° C.). Such fields
line up with the magnetic field of
the Earth at the time of the
exposure to a high temperature.
9. A term referring to techniques for
chronometric dating based on known
half-lives of particular isotopes
or the rate of other cumulative
changes in atoms resulting from
radioactivity. Examples include
electron spin resonance, fission
track, potassium-argon,
radiocarbon, and
thermoluminescence dating.
11. The point on the northern
extremity of the earth where the
axis of rotation is located.
Compared to the magnetic north
pole, this one is relatively
stable.
12. Any of two or more forms of an
element that differ in terms of
atomic mass but have the same
atomic number--for example, carbon-
12 and carbon-14.
13. A chronometric dating method based
on the fact that amino acids
progressively change to mirror
image forms following the death of an organism--i.e., from L-amino
acid to D-amino acid forms.
14. The process by which plants,
algae, and some bacteria use
energy from sun light to create
new organic molecules out of
carbon dioxide and water.
15. The amount of time for half of the
atoms of a radioactive element in
a sample to decay, or fission. |
Down
1. A dating technique using a
research instrument primarily
employed in physics to accelerate
streams of charged subnuclear
particles to high velocities in
order to sort and analyze them.
This technique is now also used to
count individual carbon isotope
atoms for carbon-14 dating. This method is also referred to as AMS
dating.
2. The study of annual growth-rings
of trees, usually for the purpose
of chronometric dating logs and,
subsequently, human remains and
artifacts found in association
with them.
3. A radiometric dating method based
on the fact that potassium-40 in
volcanic rock decays into argon-40
and calcium-40 at a known rate.
Chronometric dates are determined
by measuring the amount of argon-
40 in a sample. This method is
also referred to as K-Ar dating.
4. A chronometric dating method based
on the fact that the magnetic
north and south poles periodically
reverse.
8. A radiometric dating method based
on the fact that the amount of carbon-14 steadily decreases in
all organisms after death. This
technique is used to provide
chronometric dates for organic
materials such as bone, shell,
wood, and charcoal.
10. A radiometric dating method based
on the fact that background
radiation causes electrons to
separate from their atoms and
become trapped in the crystal
lattice of minerals. When heated
to high temperatures, the trapped
electrons are released and they
give off energy in the form of
light. The characteristic of that
light is measured to determine the
age of the sample. This technique
is mainly used to date pottery and
rock that previously had been in
an intense fire. This method is
also referred to as TL dating. |
