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Faculty Focus features the work of individual
faculty members in each of the departments in the College of Natural
Sciences. In addition to a description of the projects and a brief
listing of the person's related publications, the article includes
his or her e-mail address so that you can ask questions or make comments.
Studying the Paleontological
Record:
Mass Extinctions and Microfossils
 John
Groves is pondering an enigma, one that he characterizes as Lazarus
vs. Elvis. The assistant professor of geology is studying whether
or not a particular group of microfossils survived a major mass extinction,
when almost all life on earth was wiped out, at the end of the Permian
system.
Rocks above the boundary that marks the event are almost devoid of
fossils, containing only primitive organisms that can survive in hostile
environments, but rocks immediately below this abrupt boundary contain
a normal assemblage of fossils. This worldwide phenomenon manifests
itself in a belt extending from Greenland through the Alps, into the
Himalayas, and down into south China.
The group of microfossils Groves specializes in, called foraminifera,
occurs in the geologic record above (about 5 million years after)
the event, and they very much resemble the microfossils immediately
below (before) the event. And there is the heart of the puzzle: Are
they the same fossils making a Lazarus-type reappearance, or are they
unrelated but mimicking, in the style of Elvis impersonators, the
older forms?
This is the question that Groves will be studying during the next
three years with the aid of a grant from the American Chemical Society.
Part of the grant will provide funding for undergraduate research.
Groves will travel to Italy in the summer of 2003 to sample across
the boundary and above the transition zone.
In the summer of 2001 he studied that interval in Turkey, where he
hopes to return this summer, with the help of a research award he
received from the Geological Society of America. During his first
trip to Turkey, he was literally able to stand with one foot in each
world, pre- and post-mass extinction (see photo above).
Italy and Turkey are the two places where he will collect samples.
While doing fieldwork in those countries, he will locate natural rock
exposures of this particular age, measure the thickness of the rock,
and collect very closely spaced rock samples. Back at UNI, he will
saw the rock samples, make microscope slides, and view the fossils
in transmitted light.
The group of organisms that produced the microfossils are protists,
neither animal nor plant. They consist of a single cell with a calcium
carbonate shell, so they have a rich fossil record. Groves has been
studying them for about 25 years; his main interest is documenting
their evolutionary history.
These microfossils are extremely useful for determining the ages of
rocks because they have rapid rates of evolution. Very primitive organisms,
they are known for repeating the same types of appearances through
geologic time and have experimented with only a small number of basic
shapes. They are also useful for determining past environments because
they are very sensitive to slight changes in the environment.
In recent years mass extinctions have drawn considerable interest.
Scientists want to find out their cause, the aftermath of such events,
and what lessons we can derive for today's environment. Although this
particular mass extinction has been studied extensively (with recent
evidence pointing to asteroid impact as the cause), the microfossils
that Groves is interested in have not been investigated in depth.
So he ponders the question of Lazarus vs. Elvis. If the microfossils
above the disaster boundary are impersonators, what is it about their
shape or appearance that was so useful to the organisms that they
evolved it repeatedly? There must be some adaptive significance to
that shape.
If, on the other hand, the organisms reappeared like Lazarus, then
presumably they did survive the mass extinction. What was it about
their ecology or life habits, then, that allowed them to survive when
so many other life forms became extinct?
Whatever the answer, some interesting secondary questions are raised.
For example, if they did survive, why is there no fossil record? Perhaps
small pockets of survivors existed in ecological refuges. This is
one of many questions Groves will be studying during the next three
years.
Following is a selected list of Groves's publications related to the
work discussed above, as well as his e-mail address.
Groves, J. R. (2000). Suborder Lagenina and other smaller foraminifers
from uppermost Pennsylvanian-Lower Permian rocks of Kansas and Oklahoma.
Micropaleontology 46(4): 285-326.
Groves, J.R. (1997). Repetitive patterns of evolution in Late Paleozoic
foraminifers. In Ross, C.A., Ross, J.R.P., & Brenckle, P.L. (Eds.),
Late Paleozoic foraminifera--Their biostratigraphy, evolution and
paleoecology, and the mid-Carboniferous boundary (pp. 51-54). Cushman
Foundation for Foraminiferal Research, Special Publication No. 36.
Groves, J.R., & Boardman, D.R., II. (1999). Calcareous smaller foraminifers
from the Lower Permian Council Grove Group near Hooser, Kansas. Journal
of Foraminiferal Research 29(3): 243-262.
Groves, J.R., Nassichuk, W.W., Rui, Lin, & Pinard, S. (1994). Middle
Carboniferous fusulinacean biostratigraphy, northern Ellesmere Island
(Sverdrup Basin, Canadian Arctic Archipeligo). Geological Survey
of Canada Bulletin 469, p. 55.
Groves, J. R., Nemyrovska, T.I., & Alekseev, A.S. (1999). Correlation
of the type Bashkirian State (Middle Carboniferous, South Urals) to
the Morrowan and Atokan Series of the midcontinental and western United
States. Journal of Paleontology 73(3): 529-539.
Groves, J.R., & Wahlman, G. P. (1997). Biostratigraphy and evolution
of Upper Carboniferous and Lower Permian smaller foraminifers from the
Barents Sea (offshore Arctic Norway). Journal of Paleontology 71(5):
758-779.
john.groves@uni.edu
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