[meteorite-list] Deepest Core Samples Yet Pulled From Chesapeake Bay Crater

From: Gerald Flaherty <grf2_at_meteoritecentral.com>
Date: Mon Dec 5 20:44:07 2005
Message-ID: <003a01c5fa06$86e3a1e0$6402a8c0_at_Dell>

Magnificent!
Thanks Ron.
Jerry Flaherty
----- Original Message -----
From: "Ron Baalke" <baalke_at_zagami.jpl.nasa.gov>
To: "Meteorite Mailing List" <meteorite-list_at_meteoritecentral.com>
Sent: Monday, December 05, 2005 11:51 AM
Subject: [meteorite-list] Deepest Core Samples Yet Pulled From Chesapeake
Bay Crater


>
> http://home.hamptonroads.com/stories/story.cfm?story=96415&ran=187009
>
> Deepest core samples yet pulled from Bay crater
> By DIANE TENNANT
> The Virginian-Pilot
> December 5, 2005
>
> An attempt to drill more than a mile into an ancient impact crater under
> the Chesapeake Bay ended Sunday morning, a little short of the goal.
>
> Rock samples from 5,795 feet below ground were pulled from the ground at
> about 7:45 a.m. Scientists from the U.S. Geological Survey endured
> gusting winds and rain to collect the last of the boxes of core samples
> - tubes of rock and sediment - that will be studied in labs around the
> world.
>
> "I think it's a clear success," said Greg Gohn of the USGS, one of four
> principal investigators .
>
> The drilling project, in the soybean fields of a privately owned farm
> north of Cape Charles, was the deepest look ever taken into the
> Chesapeake Bay impact crater, which was created 35 million years ago,
> when an asteroid or comet traveling between 15 and 40 miles per second
> slammed into a shallow sea that covered much of the East Coast. The
> resulting crater is at least a mile deep and about 56 miles across. The
> center lies under Cape Charles, and the edges lie under parts of Norfolk
> and Virginia Beach, the Peninsula and the Middle Peninsula.
>
> Studies on the crater have focused largely on groundwater. The crater
> disrupts the normal layers of freshwater aquifers in the region, either
> trapping saltwater or allowing it to penetrate farther inland than would
> be expected.
>
> Eight holes had already been drilled into outer parts of the crater to
> collect core samples. The deepest of those was 2,699 feet, less than
> half of the latest effort, which had aimed for 7,218 feet.
>
> Seven science teams and 118 scientists from around the world are
> involved in the project. The teams plan to examine such things as
> immediate environmental effects of the impact, long-term effects and
> geophysics such as temperature and density of rocks. Biologists also are
> searching for microbes that can survive extreme conditions.
>
> It is believed that when the crater formed, tsunamis topped the
> Appalachian Mountains and bounced off Europe, wildfires raged along the
> East Coast and sand was melted into glass beads that were carried
> thousands of miles away by the wind.
>
> Drilling began in mid-September and ran 24 hours a day for nearly three
> months. When it ended, it was 1,423 feet short of the goal. Several
> hundred feet of granite slowed the drillers.
>
> Still, scientists were pleased with the results. The crater is buried
> beneath more than 1,000 feet of sediment at that location. Samples were
> taken of those sediments as well as rock that was melted by the heat of
> the impact, found at more than 4,000 feet under ground.
>
> The last core brought to the surface contained pegmatite, a rock that is
> similar to granite but full of large crystals of quartz, garnet and
> other minerals.
>
> The deep drilling project was funded in part by the International
> Continental Scientific Drilling Program, a consortium of science
> agencies in 13 countries, including China, Canada, Germany and South
> Africa. In the United States, the National Science Foundation is the
> funding partner.
>
> Analysis of the samples is expected to take months . The first results
> will probably be published in scientific journals 12 to 18 months from
> now.
>
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Received on Mon 05 Dec 2005 08:43:58 PM PST