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Post Info TOPIC: Chesapeake Bay Impact
Blobrana


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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” - Greg Gohn, 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 travelling 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 centre 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.

Source

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Blobrana


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More than a dozen countries are taking part in a drilling project at the site of a 35-million-year-old impact crater on Virginia's Eastern Shore.
A drilling rig arrived last month and set up on a farm near Cape Charles that was settled by colonists in the early 1600s.
From samples of rock and sediment that are collected, scientists hope to learn about the prehistoric climate, the effects of an asteroid or comet collision, how life survives after natural disasters and why groundwater in the Hampton Roads area is salty, among other things.

"None of us will probably ever drill a 7,000-foot hole again" - Greg Gohn, U.S. Geological Survey, one of four principal investigators for the project.

The crater is about 56 miles wide and at least a mile deep. Core samples already have been taken from other drilling locations, but the latest site near Cape Charles is by far the deepest.
"We'll be crossing bridges that nobody's crossed" -David Powars, Geological Survey scientist.
In 1994, Mr. Powars and other scientists announced the crater's existence. They had been trying to figure out why some aquifers were salty and why older fossils could be found lying on top of younger ones.
The project is being funded by the Geological Survey and the International Continental Scientific Drilling Program – a consortium of science agencies in 13 countries, including China, Canada, Germany and South Africa.
The Chesapeake Bay impact crater was created by an object from outer space. Because it is buried under layers and layers of sediment, it is one of the best-preserved craters in the world.

British scientist Charles Cockell will lead the search for microbes that could have survived the impact. If any are uncovered, he will try to grow some in a lab, and Penn State microbiologist Jennifer Macalady will examine their DNA.
Science teams plan to look into how the crater formed and its physical properties. The potential immediate effects of the big impact also will be explored – including tsunamis, wildfires across the East Coast and melted sand that formed glass beads carried thousands of miles on the wind.
Modellers will project what could happen in the event of another space rock collision. In the newer sediment layers at the crater site, geologists hope to find information on historic climate changes that affected sea levels and ice sheets.

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Blobrana


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Yesterday afternoon, an international team of scientists used a 24 metre-tall drill rig to pull out yet another 3 metre core of clay and silt that sits atop the 85 kilometre-wide crater buried below the Chesapeake Bay.

Drilling will continue for the next three months at the Buryn family farm in the Eyreville area northwest of Cheriton. The farm is just off-centre from where the 3 kilometre-wide space rock exploded more than 35 million years ago, creating an inverted sombrero-shaped crater that quickly filled with tons of water and debris.

The £750,000 Eyreville project aims to dig 2,195 metres -- more than twice the depth of previous crater drills at more than a dozen sites around Tidewater Virginia and the Eastern Shore.
Since last Wednesday, the team has drilled to a depth of 437 metres.

"We're moving along really well. We're hoping to break through at any second" into the layer of rubble just above the filled-in crater" - Greg Gohn, U.S. Geological Survey scientist leading the project.

Four-dozen scientists are working with technicians at the site in 12-hour shifts around the clock to take cores in 1.5 or 3 metre segments. They expect to reach the crater floor and unearth traces of the space rock. They also may find water trapped in the crater's depths by the impact's aftermath and perhaps descendants of the original microbes that floated in the waters off Virginia millions of years ago, said microbiologist Charles Cockell of Open University in the United Kingdom.
The Chesapeake Bay impact crater is the largest in the United States and the sixth-largest in the world. As deep as the Grand Canyon, it sits below about 305 metres of rubble and sediment beneath the lower part of the Chesapeake Bay, its surrounding peninsulas and the inner continental shelf of the Atlantic Ocean.

"The cores are really telling us the story of this crater" - David Powars, USGS, one of the crater's co-discoverers.

Geologists hope the drill will tell them more about the effect the prehistoric impact had on the seabed and provide better estimates of the space rock's speed, size and energy as it slammed into the sea floor.
In the rubble brought up by the drilling, scientists hope to find clues about the Earth's primeval climate and where thirsty Tidewater residents can find drinkable water.
Geological research off the coast of New Jersey and in Virginia, begun in 1983, led to the crater's discovery a decade later. Drilling and further study of seismic data narrowed the location in the Chesapeake Bay and identified Cape Charles as "ground zero."

The impact sent a shock wave about 11 kilometre underground, melted rock, spewed debris, briefly exposed the seafloor and vaporized water. The deep gouge was then covered beneath a thick blanket of debris, rock and sediment and water. As this crater settled, it set the stage for Virginia's baffling coastal groundwater system, with its pockets of salty groundwater.

Its legacy is well-known to residents who try to drill for drinkable water and encounter the saltwater "wedge," pockets of brackish groundwater nestled in an arc from the lower Eastern Shore to the Hampton Roads-Newport News area.
The USGS has spearheaded the Chesapeake Bay impact-crater research. The agency is now partnering on the Eyreville drill with the International Continental Scientific Drilling Program, which is putting £500,000 toward the project.

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Blobrana


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An international project involving 13 countries will drill more than a mile deep into an ancient impact crater on the Eastern Shore, looking for clues to prehistoric climate, modern-day water problems and the beginnings of life on Earth and Mars.
In three weeks, the first samples of rock and sediment should start coming out of a hole on a farm just north of Cape Charles. From them, scientists hope to learn about Earth’s climate history, what really happens when an asteroid or comet collides with a planet, how life survives in the presence of tsunamis, massive fires and shock and, of more local concern, why groundwater in Hampton Roads is so salty.


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"We hope to drill entirely through the crater and into its floor. None of us will probably ever drill a 7,000-foot hole again." - Greg Gohn, U.S. Geological Survey, one of four principal investigators for the project.

The USGS has drilled eight holes into the outer trough and edges of the crater, which is about 56 miles wide and at least a mile deep. Core samples – long tubes of rock and dirt – have been taken from sites in Hampton, Newport News, Mat hews County, Gloucester and several places on the Eastern Shore. But the deepest of those was only 2,699 feet, less than half of the ambitious attempt to go 7,218 feet that will begin in early September.

"We’ll be crossing bridges that nobody’s crossed" - USGS scientist David Powars, one of the first to suspect an impact crater lay under the Chesapeake Bay.

Powars and other scientists, trying to figure out why some aquifers were salty and why older fossils could be found l ying on top of younger ones, announced the existence of the crater in 1994. For decades prior, such strange evidence had been considered the results of poor sampling and poorer science, rather than the ground truth of a cosmic collision.
The Chesapeake Bay impact crater is the sixth -largest in the world. Its centre is under Cape Charles, and it is concealed under layers of sediment that have filled the gigantic hole in the 35 million years since it was blasted out by an object from outer space. Because it is buried, it is one of the best preserved craters in the world.

"This is going to be so exciting to see what comes out of this hole" - David Powars.

The $1.3 million project is funded by the USGS and the International Continental Scientific Drilling Program. The program is 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.
The program focuses on globally significant sites, such as the Chicxulub crater (possible cause of dinosaur extinction) on the Yucatan Peninsula, the San Andreas earthquake fault, plate tectonics in Crete and volcanoes in Hawaii.
In addition, 118 scientists have made 44 proposals to use core samples; that research will be funded separately from the drilling budget.
The drilling rig is expected to arrive on Sept. 9 and set up in the midst of soybean fields at Eyreville, a farm that was settled by Englishmen in the early 1600s. But the original occupants may have been there much longer.
British scientist Charles Cockell will lead the search for microbes that could have survived the impact and still be colonizing the rocks deep in the earth. Such extremophiles, as they are called for their ability to live in extreme environments, could have quietly taken up residence in the spaces that formed in the rock when it was blasted out of the hole, then fell or washed back into the crater.

If microbes are found, Cockell will attempt to grow some in a lab, and Penn State microbiologist Jennifer Macalady will examine their DNA. Large amounts of iron in water samples taken from the crater may indicate microbes that can use electrons from iron for energy.

"The meek shall inherit the Earth, that’s what I always say. That’s the thing about microbes. They don’t just survive, they find new opportunities. Catastrophes create new opportunities for life" - Charles Cockell.

Crater scientists, including Powars, presented information in July at the Lunar and Planetary Institute’s conference about Martian impact craters. The shape of the Chesapeake Bay crater – a central peak surrounded by a deep ring, which is then surrounded by a wide, more shallow brim – could be a useful comparison to craters on the Red Planet. The Bay crater was formed by an object that landed in a shallow sea. The wet sediments of the sea floor broke off in chunks and slumped toward the deep inner ring, making the crater much larger than it might have been had the object hit land.
Similar-looking impact craters on Mars could mean they also formed in water or in comparable sediments, the researchers wrote. And there’s more:

"These impact craters were possibly the source of life, and that’s not just whistling 'Dixie. A crater with hydrothermal activity on other planets could be the place where life begins" - David Powars.

Other science teams will look at how the crater formed and what physical properties it has. In the melted rock deep inside, traces of the object that made the crater may exist as chemical signatures of elements rare in Earth’s crust. The immediate effects of such a large impact also will be examined – tsunamis that could have hit Europe and bounced back, wildfires that set the entire East Coast ablaze, melted sand that formed glass beads to float thousands of miles in the wind.
Modelers will take information from the core hole and project what might happen if another space rock were to hit Earth today. In the younger sediment layers at the top of the crater, geologists hope to find information on historic climate changes that affected sea level and ice sheets.
Of local interest, hydrologists will look at how the crater disrupted freshwater aquifers that supply drinking water in Hampton Roads. Samples from other holes have produced water saltier than the sea, and scientists hope to gain understanding on how the crater impedes the flow of water.
Once drilling begins, it will continue 24 hours a day for three months. During that time, farmer Roger Buyrn will likely be inconvenienced by traffic on his narrow farm lane, drilling lights and noise, and publicity from international media. He has no regrets.

"My father had a saying: 'It’s a very good day when you learn something. He also would say, 'Try to learn something every day.’ How would you say no when there’s an opportunity to learn so much?" - Roger Buyrn.

Source

-- Edited by Blobrana at 21:12, 2005-08-22

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Blobrana


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Researchers plan to drill more than a mile under the bay to search for watery pockets of a prehistoric ocean, bacteria that thrive in boiling heat and clues about the meteorite that left a 83 kilometre hole in Earth's surface.

About 35 million years ago, a meteorite smashed into what is now Virginia's Chesapeake Bay with so much force that debris flew for thousands of kilometres.
This autumn, scientists will try to figure out what else it did.
Researchers plan to drill more than a kilometre under the bay to search for watery pockets of a prehistoric ocean, bacteria that thrive in boiling heat and clues about the meteorite that left a Rhode Island-sized dent in Earth's surface.

"Whatever we find is going to be interesting" - Charles Cockell, a professor of geomicrobiology at England's Open University.

Cockell, who met with U.S. scientists in June to discuss the drilling project, is coordinating the search for microscopic life amid the rocks and sediment that rushed into the crater in the moments after the impact.
Scientists believe that the mile-wide meteorite that splashed into the sea millions of years ago created a tsunami, shattered rocks and incinerated everything in its path as it plunged a mile below the surface.

"Material as big as houses flooded into the impact area" - Gregory S. Gohn, a U.S. Geological Survey geologist who is one of the scientists overseeing the project.

Since the bay impact crater was discovered in 1993, scientists have drilled at least 12 holes. But previous drilling projects were mainly designed to assess the crater's effect on groundwater supplies.
By going deeper and studying the microfossils, rocks and sediment they dig up, scientists hope to better determine how fast the meteorite was travelling, its size, and its effect on surrounding rocks and whether it was an asteroid or comet.
More than 40 researchers from the United States, Austria, South Africa and Japan will also study the sediments and rocks to learn more about East Coast geology and Earth's climatic past.

"It can tell us things about what sea levels and ice formations were like thousands of years ago and essentially how the climate has changed" - Kenneth Miller, chairman of geological sciences at Rutgers University. He will examine rocks and sediment to look for patterns in Earth's climate history.

The 1 million euro drilling effort is being funded by the U.S. Geological Survey and the International Continental Scientific Drilling Program, a consortium of scientists that funds drilling projects at fault lines, volcanoes and craters around the world. Scientists will probably spend an additional 2.5 million euros conducting their own studies of the rocks and sediment.
Beginning in September, crews will use a drill to dig 2,195 metres, deeper than they've gone before. They'll work about five miles north of the Cape Charles, Va., site where drillers reached a depth of 884 metres last year.

"We're hoping to get the best look yet at the impact the crater had on the environment back then and, really, the impact it still has today" - J. Wright Horton Jr., a USGS geologist.

The impact carved out geological rifts instrumental in creating the Chesapeake Bay. It also left a basin of sediment and seawater, which disrupts the flow of fresh water to aquifers, forcing nearby communities to build desalinization plants to treat their well water.
Researchers will dig through the crater into a region known as the “moat,” which surrounds the crater's central core. By drilling there, scientists hope to hit pockets of ancient seawater left over from the impact and a mother lode of rocks and sediment.

"That's where the action is. That's where the most evidence is of alterations caused by the impact" - C. Wylie Poag, one of the USGS scientists credited with discovering the crater.

The bay crater is the largest in the United States and the sixth largest of 170 known impact craters in the world. A number of factors make it an ideal place for exploration.
Because the meteorite struck in an ocean and remains covered by water, the site is better preserved than most impact craters. Also, the location makes it accessible.
Researchers hope to tap into the remnants of untouched pockets of salty water from the original ocean, areas sealed off by clay sediments that washed into the crater after the impact. Previous drilling projects turned up some of the salty water, but it has never been recovered in sufficient quantities to study it.

"This water is definitely different than anything above it or below it" - Mary Voytek, a USGS expert on microscopic life.

The rocks could also yield clues. The meteor strike is believed to have heated up, smashed and sterilized subterranean rocks, creating habitats for thermophiles and halophiles, types of bacteria that might have evolved in the crater's superheated rocks and salty water. They could still be living down there, experts say.
Cockell says meteorites shatter rocks in unique ways, creating tiny fissures that make ideal habitats for rarely seen microscopic organisms. He's optimistic that researchers will find them in the crater.

"We should keep in mind how impact events have created environments for life; they haven't just destroyed life" - Charles Cockell.

Such life has been found in the unlikeliest of places, including impact craters, deep-sea thermal vents and arctic ice shelves.

"Basically, the research shows that we've found bacteria in just about every environment where we've looked" - Mary Voytek.

Adapted from source .

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