Chuck Bednar for redOrbit.com – @BednarChuck
For the first time, scientists plan to conduct an expedition to collect and analyze core samples from the 125-mile-wide Chicxulub impact site in Mexico, a crater believed to have been caused by the asteroid that wiped out the dinosaurs more than 65 million years ago.
The expedition, which is scheduled to begin in spring 2016, will drill at depths of nearly 5,000 feet below the seabed from an offshore platform, collecting the first complete samples from the rock layers from near the center of the crater. Once the core is extracted, it will be split in two, with half of it undergoing immediate analysis and the other half being stored for later use.
The Chicxulub crater has been filled in by sediments over the millions of years since impact. Using a gravity map, the crater’s topological features can be visualized. The red and yellow are gravity highs, and green and blue are gravity lows. The white dots indicate a network of sinkholes called “cenotes,”which were formed as a result of the impact. (Credit: NASA)
Examining the crater’s peak ring for the first time
Dr. Sean Gulick, a researcher at The University of Texas at Austin Institute for Geophysics (UTIG), and Joanna Morgan of Imperial College London will co-lead the expedition, overseeing a team of scientists from the US, UK and Mexico as they sample the Chicxulub crater’s “peak ring” (an enigmatic ring of topographically elevated rocks surrounding its center).
The peak ring rises above the floor and has been buried by other sediments throughout the past 65.5 million years, the researchers explained in a statement. The expedition is scheduled to last two months, and afterwards, half of the core sample will be sent to Germany for analysis by an international team while the rest will be kept at a core repository at Texas A&M University.
“Fundamentally we wish to understand the way large impacts change the surfaces and crust of planets,” Dr. Gulick told redOrbit via email. “Peak rings are a ring of mountains that surround the center of every large impact and yet we do not know how they are formed. Models suggest these mountains are emplaced as deeply source crustal rocks that rise up from the impact site and then splash outward, however no one has ever recovered a rock from a peak ring.”
“Therefore we hope to test how deep the rocks came from in the Earth’s crust at the Chicxulub impact crater and by what mechanism these rocks were weakened to be able to flow upwards and outwards during the impact,” he continued, adding that even though the expedition was a year away, he and his colleagues were “very excited” about its potential.
Studying impact mechanisms and seeking signs of life
The apocalyptic events that saw a nine-mile-wide asteroid collide with the Earth, ending the 135 million year reign of the dinosaurs, allowed mammals and ultimately humans to assume control of the planet. However, precious few geologic samples have been recovered from that impact site – something that Dr. Gulick and his colleagues are hoping to change with their research.
By sampling and studying samples from the peak ring, they hope to provide new insight into the mechanisms of large impact on Earth and other rocky planets. They are also hoping to examine traces of life that may have been present within the peak ring’s rock, which density readings note are likely broken and porous, features indicative of a preserved post-impact lifeforms.
“We are interested in the hydrothermal system that like existed within the peak ring after the impact and what kind of exotic life may have populated such an environment,” Dr. Gulick told redOrbit. “These extremophiles (extreme condition loving organisms) might be similar to where some life may have started on early Earth when impacts were much more common.”
“We are confident we will recover the layers of rocks above the impact crater that show how life recovered from the extinction event,” he added. “If you truly want to understand evolution its information to examine a place where life took a significant step back and then evolved to fill the ecosystem niches that were vacated due to the mass extinction.”
“Tune back in a year when we can report some of our early results from the expedition,” the UT researcher concluded, noting that the expedition members are also “a series of outreach and education activities,” including “models of the cores” that are “being created for use in museums and educational modules created in English and Spanish for use in science classes.”
—–
Follow redOrbit on Twitter, Facebook, Google+, Instagram and Pinterest.
Comments