Professor's research technique
renders better information of geological record
By Anna Herkamp
Summer
Reporter
In research communities it is sometimes said that
'changes in science come only with death and retirement.' The research
of one Purdue professor may stir up some long-held beliefs about the
classic debate of the extinction of dinosaurs.
Professor William Zinsmeister, a researcher known
for his work in evolutionary studies, has developed a new technique
for exploring the geologic record.
The new technique, called stratigraphic plane analysis,
uses a three-dimensional computer display to show various data associated
with where fossils are located.
Older methods use a one-dimensional method that
only shows one aspect of the fossil's location: time.
"When you put data into only one dimension, it
can obscure many important details," said Zinsmeister.
For many years, researchers have put fossils through
statistical analysis in order to look for patterns in location and time.
These research methods are necessary, but have many inaccuracies because
they do not look for the small over-looked data that may be vital to
the understanding of fossils, he said.
"When people do statistical analyses of the data
and find a single point, they just throw it out because they can't analyze
in terms of confidence levels, or they consider it just an artifact,"
he said in a recent press release. "But these single point events can
be very important when you recognize that these are real events not
just and artifact."
For very short periods, there are visible deviations
from climactic patterns of prehistoric times, he said. These periods
help us to see that despite the long-held theory of a catastrophic asteroid
extinction, there is evidence of climatic stress on the biosphere.
Professor of Earth and Atmospheric Sciences James
Ogg also agrees that climate played a part in the extinction.
"About five million years before the end of the
Cretaceous, it is evident in the fossil record that something was happening
in the tropical seas," he said.
The interesting question this raises is if there
hadn't been stress on the biosphere to begin with, would the asteroid
have contributed to the extinction the way the theory says it did, said
Zinsmeister.
Zinsmeister says his new technique may change the
way many in the paleontological community look at the mass extinction
at the end of the Cretaceous period.
Zinsmeister's technique shows data that coincide
with deep-sea drillings from around the world. The oxygen isotopes indicate
temperature change in the oceans at different periods of geologic time.
These temperature changes show patterns of climate change and also the
more short-term deviations from the pattern.
For instance, towards the end of the Cretaceous
period, there seems to be a steady average temperature, however, there
are several "climatic events" that may have had serious consequences
for the biosphere at that time, he said. These are what may have been
the major trigger for mass extinction at the end of the Cretaceous period.
Seymour Island, the area in Antarctica where Zinsmeister
works, is home to some of the only known fossils that died after the
asteroid hit.
These fossils are some that have prompted him to
ask the question of whether they would have gone extinct were it not
for climate change that was taking place to begin with. Also whether
or not they would have died had the asteroid not hit is the other question
he hopes to invoke.
One example Zinsmeister gave is that 450 million
years ago the biggest volcanic explosion in earth's history did not
cause a mass extinction. Examples such as this may serve to testify
that an asteroid may not have been the only factor leading to destruction
of life after the Cretaceous period.
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