[meteorite-list] Chesapeake Bay Crater Drilling Declared Major Success

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Jan 12 16:20:36 2006
Message-ID: <200601122025.k0CKPRQ16200_at_zagami.jpl.nasa.gov>

http://www.eurekalert.org/pub_releases/2006-01/usgs-cdd011206.php

Public release date: 12-Jan-2006

Contact: Gregory Gohn
ggohn_at_usgs.gov
703-648-4382
United States Geological Survey

Crater drilling declared major success
    
More than a mile-long core retrieved

Following three months of around-the-clock work, the Chesapeake Bay
Impact Crater Deep Drilling Project successfully completed its
operations, extracting more than a mile-long segment of rocks and
sediments from the Earth. On Dec. 4, the drill bit reached a final depth
of 5,795 ft (1.1 miles, 1.77 kilometers) within the structure of the
crater.

The impact crater was formed about 35 million years ago when a rock from
space struck the Earth at hypersonic speed. Scientists have only
recently begun to explore the consequences from that distant event and
learn how it has greatly affected the population living in southeastern
Virginia today.

"The drilling project was a major success," said Greg Gohn, a U. S.
Geological Survey (USGS) scientist in Reston, Va. "We recovered a nearly
complete set of core samples from the top of the crater fill to the
crater floor." USGS and the International Continental Scientific
Drilling Program (ICDP) are the project's sponsors.

Gohn is a co-principal investigator of the drilling project, along with
Christian Koeberl of the University of Vienna in Austria, Kenneth Miller
of Rutgers University in New Brunswick, NJ, and Uwe Reimold, at Humboldt
University in Berlin, Germany.

"This is one of the most complete cores ever obtained in an impact
structure," said Koeberl, "and will allow us to understand a
shallow-marine impact event at an unprecedented level."

The team successfully recovered the complete succession of post-impact
sediments above the crater, the entire sequence of rocks broken up
during the impact, and rocks from the crater floor. These samples will
allow the project's international science teams to research the
post-impact environment, impact-related processes, and the impact
process itself. In addition, the team completed geophysical down-hole
logging to collect additional data, such as the temperature gradient
within the corehole.

Important in this multidisciplinary venture is the analysis of the
groundwater reservoir in the Chesapeake Bay impact crater. Findings have
direct implications for the millions of people living in the area along
Virginia's eastern shore and to future development. Several teams from
the U.S. and Europe are investigating the microbial life present in the
impact crater, part of intriguing recent studies of life in exotic
environments.

"The post-impact sediments record the recovery of the continental-shelf
target area from devastating impact mega-tsunamis to the passive
continental shelf and coastal plain that continues today," said Ken
Miller, who chairs the Department of Geological Sciences at Rutgers
University. "Comparison of the section in Virginia with more complete
sections sampled in New Jersey and Delaware will yield new insight into
global sea-level changes and the distribution of water-bearing units in
the coastal plain."

The drillsite is located on private land in Northampton County on
Virginia's Eastern Shore. The site was chosen because of its location
above the central part of the buried crater. Drillsite activities began
with extensive site preparations in July 2005. The drill rig arrived in
early September, and scientists recovered the first core sample on
September 15th.

Cores are being stored at the USGS in Reston, VA and will be
photographed and documented during the next 3 months. In March 2006
members from all international teams will gather at the USGS to obtain
samples of the core for their various studies.

###

ICDP and USGS provided the initial funding for the drilling project. The
project received supplementary funding in late November from ICDP and
USGS, and from the Solar System Division of the NASA Science Mission
Directorate, which allowed drilling to continue into December. The
National Science Foundation, Earth Science Division, is supporting the
post-impact studies.

DOSECC (Drilling, Observation, and Sampling of the Earth's Continental
Crust) managed the drillsite operations, and Major Drilling America,
Inc. performed the core drilling. DOSECC is a nonprofit corporation
whose mission is to provide leadership and technical support in
subsurface sampling and monitoring technology for scientific and
societal importance.

Relevant Web URLs:

    * ICDP/Chesapeake: http://chesapeake.icdp-online.org
    * USGS/Chesapeake Crater: http://geology.er.usgs.gov/eespteam/crater/
    * DOSECC: http://www.dosecc.org/

The International Continental Scientific Drilling Program is a
multinational program which funds and supports geosciences in the field
of Continental Scientific Drilling. The ICDP has currently a total of 13
member countries and two corporate affiliates. The GFZ Potsdam in
Germany serves as Executive Agency for the ICDP.

The USGS serves the nation by providing reliable scientific information
to: describe and understand the Earth; minimize loss of life and
property from natural disasters; manage water, biological, energy, and
mineral resources; and enhance and protect our quality of life.

 
Received on Thu 12 Jan 2006 03:25:26 PM PST


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