(From Lori Stiles, UA News Services, 520-621-1877)

University of Arizona scientists in the next week or two will begin field
work on the Chicxulub Scientific Drilling Project (CSDP) near Merida,
Yucatan, Mexico — an international project to core 1.8 kilometers into an
immense crater created by the impact of an asteroid or comet 65 million
years ago.

The Cretaceous-Tertiary (K/T) impact is thought to have led to one of the
greatest mass extinctions in Earth history, including dinosaur extinction.
The impact generated ten thousand times more energy than in the world’s
nuclear arsenal, and six million times more energy than the 1980 Mount St.
Helens volcanic eruption.

“This is a very special collaboration with our neighbors in Mexico and
highlights the success of international cooperation among scientists
throughout the world,” said David A. Kring, UA associate professor of
planetary sciences and co-investigator in the CSDP. “We appreciate the
opportunity to work with our colleagues from UNAM and ICDP member-nations.”

Universidad Nacional Autonoma de Mexico (UNAM) is the lead institution on
the project. Kring collaborates closely with Jaime Urrutia Fucugauchi of the
UNAM Instituto de Geofisica, who directs the drilling project. Other
principal investigators include Dante Moran Zenteno (UNAM), Virgil Sharpton
(University of Alaska), Richard Buffler (University of Texas), Dieter
Stoeffler (Humbolt-Universitat zu Berlin, Germany) and Jan Smit (Vrije
University, Netherlands).

“The hypothesis that a meteorite impact caused the demise of the dinosaurs
and consequently, perhaps paved the way for mammalian evolution has been one
of the most important recent findings in Earth sciences,” said UA College of
Science Dean Joaquin Ruiz, professor of geosciences. Discovering what the
object was and the details of the impact “is very important,” he added. “The
fact that the University of Arizona has one of the leading investigators in
the field testifies to the quality of science that goes on at this

Ruiz and Rene Drucker, UNAM coordinator of scientific investigation,
tomorrow (Jan. 15) in Mexico City will sign a memoradum of understanding
that will facilitate and pay for the exchange of students and faculty on
this project and future projects involving UA College of Science

The Chicxulub Scientific Drilling Project is being run under the auspices of
the International Continental Scientific Drilling Program (ICDP),
headquartered in Potsdam, Germany. In addition to Mexico, Germany, and the
United States, nations funding ICDP operations include Canada, China, Japan,
and Poland. Corporate affiliates include UNESCO, the international Ocean
Drilling Program, and Schlumberger Inc.

Kring and undergraduate geosciences major Jake Bailey will join operations
at the Yaxcopoil-1 site, 40 kilometers southwest of the province’s capital,
Merida. Ruiz will visit the site in a few weeks on a future trip to Mexico.

Workers cleared the site of vegetation, constructed a well to supply water
to the drilling rig, and installed the drilling rig in November and early
December. The governor of Yucatan, UNAM scientists and officials, and a
German delegation inaugurated the project with opening ceremonies on Dec.3.
Actual drilling began Dec. 12, and the crew reached impact breccias late
last week.

“We expect to reach the 1.8-kilometer (one and one-tenth mile) depth after
69 days of drilling,” Kring said, at a cost of $1.5 million from the ICDP.

“We planned to hit rocks in the crater between 500 meters (1,640 feet) and
one kilometer (3,280 feet), then continue through the impact crater itself
— through breccias and the impact melt layer — all the way down to
continental crust bedrock. If we succeed in getting more funds, we’ll core
down to 2.5 kilometers (1 and a half miles),” he added.

The hypothesis that an asteroid or comet impact caused K/T mass extinction
was first proposed in 1980 by Nobel laureate Luis Alvarez, his geologist
son, Walter, and others at the University of California-Berkeley.

Kring was one of seven scientists who confirmed the highly controversial
theory in the early 1990s.

During oil exploration, PEMEX geophysicists Antonio Carmargo-Zanoguera and
Glen Penfield identified the Chicxulub structure as a possible impact
crater. Alan Hildebrand of the University of Calgary (then a UA graduate
student), Kring, and UA planetary sciences professor William Boynton,
working with Penfield, Carmargo-Z., Mark Pilkington of the Canadian
Geological Survey and Stein Jacobsen from Harvard University, confirmed with
petrologic and geochemical studies that the 180-kilometer (110-mile)
diameter Chicxulub structure was indeed formed by giant asteroid or comet

Scientists will analyze cores for details on exactly how the Chicxulub
impact suddenly, catastrophically changed Earth’s environment and ecology,
killing more than 75 percent of the plant and animal species on land and in
the oceans.

At the Yaxcopoil-1 site, a professional drilling crew uses a diamond-tipped
drill to extract 64mm-diameter (2 and a half inch-diameter) core in segments
up to 6-meters (19 and a half feet) long. Core segments are placed on a
bench at the work site.

UNAM staff and students — soon to be joined by the UA team — then wash,
label, measure, and box the cores. The boxed cores are processed on site and
at a laboratory in Merida, where cores also are scanned as digital images
that Kring and other scientists can view over the Internet.

Kring, his students, and researchers from other institutions will be able to
further analyze the core samples at the Lunar and Planetary Laboratory and
other labs after the drilling is complete.

Kring’s work on the Chicxulub impact crater and K/T boundary mass extinction
event has been supported by NASA, the National Science Foundation, ICDP, and
the University of Arizona.

Related Links

UA Space Imagery Center – Impact Cratering


Downloadable schematic of the drilling site


International Continental Drilling Program

Contact Information

David A. Kring

520-621-2024, kring@lpl.arizona.edu

Joaquin Ruiz

520-621-4090, jruiz@u.arizona.edu