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Geoscientist from Williams College Studying Planet's Youngest Sea
http://iberkshires.com/story.php?story_id=17504
June, 14 2005
Williamstown ? Markes E. Johnson, the Charles L. MacMillan Professor of Natural Sciences at Williams College, has been awarded a Petroleum Research
Fund grant for $50,000 by the American Chemical Society.
The grant is the eighth award Johnson has received through the American Chemical Society since 1979. The Petroleum Research Fund, which promotes
research participation in geology and chemistry on both the undergraduate and graduate levels, has enabled more than 50 Williams students to accompany
Johnson on his frequent excursions to the Baja California Peninsula of Mexico since 1990.
The current grant will support research on his project, "Paleography and Correlation of Pliocene Basins in the Gulf of California." The project is
aimed at understanding the development of one of the planet's youngest seas, also known as the Sea of Cortez. Expansion of the Gulf over the last five
million years is being traced by Johnson and his students along former shorelines uplifted by as much as 650 ft. above sea level.
Johnson has been at Williams since 1977, and has taught courses in historical geology, paleobiology, and stratigraphy.
He is the author of "Discovering the Geology of Baja California ? Six Hikes on the Southern Gulf Coast" (University of Arizona Press, 2002) and
co-editor of "Pliocene Carbonates and Related Facies Flanking the Gulf of California" (Geological Society of America Special Paper, 1997), among works
most closely related to ongoing field studies in Mexico.
Previous awards include a Class of 1945 World Fellowship for his project, "Island Ecology Through Geologic Time" and grant support from the National
Geographic Society for research on former shorelines in Western Australia, Siberia, and China's Inner Mongolia.
Johnson is a fellow of the Geological Society of America and a member of the Paleontological Society, among other professional groups. He received his
B.A. from the University of Iowa in 1971 and his Ph.D. from the University of Chicago in 1977.
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Professor, students study developing sea
http://www.thetranscript.com/Stories/0,1413,103~9054~2956825...
By John E. Mitchell
WILLIAMSTOWN -- A Williams College professor has received a grant that will be utilized in his research on the Sea of Cortez.
The $50,000 from the Petroleum Research Fund allows Johnson to bring students on a research trip to the Baja California Peninsula in Mexico every year
for the last 15 years. Currently, Johnson and his students are studying the expansion of the Gulf of California (the Sea of Cortez) over the last five
million years.
"By going to places like the Sea of Cortez, you're at the birth of a young ocean and you're actually watching it progress, seeing how it develops,"
said Johnson.
Go back six million years, and the Sea of Cortez looked a lot like Death Valley, which makes it one of the planet's youngest seas. The point of a
topographically low depression where, mixed with the Earth's movements, sea water moved in, creating a body of water that is still changing and
growing.
"If you come back another 50 million years in the future, it's going to look a lot different than it does today," said Johnson.
The gulf may look like a long and narrow sea way now, but it is expanding as the oceans shrink. Being able to observe the shift as it happens gives
scientists the opportunity to understand changes in geology and biology in other areas of the world, and to predict where the earth would naturally be
heading.
"Everything is ongoing," said Johnson. "The Atlantic Ocean is getting a little bit wider every year, although the Pacific Ocean, our biggest ocean, is
getting a little bit smaller every year. People tend to look at the globe and think of it as being in its finished state, but all the continents are
moving a little bit all the time."
One of Johnson's goals is to trace the former shorelines, following how it has changed over the years. Because of the movement of the San Andreas
Fault, some former shorelines that were once right at sea level have been pushed as high as 200 feet above sea level.
"There's more than one shoreline," said Johnson. "As the shape of a gulf changes and as the global level of sea level goes up and down, the shoreline
can change quite a bit."
The dating of the shorelines is accomplished matching sites up with actual fossils that are found. Johnson likens the process to putting together a
jigsaw puzzle, albeit one with some very unusual pieces.
"There are some pretty amazing surprises that do occur," said Johnson. "You might be tracing one of these shorelines and, all of a sudden, you come to
a little lagoon, and it will be a fossil reef."
These reefs were formed from coral reefs that formed in the water and have remained in the same positions they were growing in, preserved thanks to
the geological uplift that has moved the shorelines. These have been found in places on the gulf that suggest that five million years ago, coral reefs
were able to live further north than they can now, which means that ocean water was warmer than it currently is.
"It's now high and dry and the reef is actually still there," said Johnson, "and you can walk right on it and look at it and see what the exact
contact with the shoreline was like."
Johnson takes as many as 10 students to the site every January as part of a winter study period. They spend just short of a month camping out by the
sea and studying the area using topographical maps against which they are trying to scope out a previous shoreline. The idea is to produce maps that
represent the stages of development of the Sea of Cortez by giving students a unique hands on experience far from the text books.
"You're usually in sight of the modern gulf," said Johnson, "but you're looking for these differences between limestone and the volcanic rocks that
actually form some of the basement rocks for the gulf. It's kind of like going south to Florida, except the terrain is a lot more spectacular."
Johnson likens the history of the earth to a huge book, with numerous chapters that not only work together to tell the larger story, but also hold a
fascination of their own. With the Sea of Cortez, Johnson said he is investigating one of the most recent chapters, one that only scratches the
surface of what the book has to offer.
"You're trying to look at the change in geography in the gulf itself," said Johnson, "and of course there are ramifications for how that relates to
the rest of the planet, but you are just looking at that one little corner of the world."
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