New Clues to the Dinosaur-Killing Impact Unearthed
A team of scientists, including Universities Space Research Association’s David Kring of the Lunar and Planetary Institute (LPI), is studying rock cores recovered by a joint drilling expedition of the Chicxulub Impact Crater
Organized by the International Ocean Discovery Program (IODP) and International Continental Scientific Drilling Program (ICDP) for a first pass at understanding the effects of the impact on life and as a case study of how impacts affect planets.
In April and May, 2016, a team of international scientists drilled into the site of the asteroid impact, known as the Chicxulub Impact Crater, which occurred 66 million years ago. The crater is buried several hundred meters below the surface in the Yucatn region of Mxico. Until that time, dinosaurs and marine reptiles dominated the world, but the series of catastrophic events that followed the impact caused the extinction of all large animals which led to the rise of mammals and evolution of mankind. This joint expedition recovered a nearly complete set of rock cores from 506 to 1335 meters below the modern day seafloor.
Illustration: A borehole was drilled into the peak ring of the Chicxulub crater in April and May, 2016. International Ocean Discovery Program (IODP) in collaboration with the International Continental Drilling Program (ICDP) drilled ~30 kilometers northwest of Progreso and the north shore of the Yucatn Peninsula of Mexico. That borehole, labeled Chicx-03A (now named IODP site M0077A) on a gravity map (inset), is targeting the peak ring in that quadrant of the crater. Expedition 364 Chicxulub Impact Crater project is a Mission Specific Platform Expedition, meaning it was drilled from a platform specially selected for the project, rather than IODP’s JOIDES Resolution or Chikyu ships. The selected drilling site is in an area with ecologically-sensitive reefs and a shallow 17 to 18 meter water depth, demanding the specialized equipment. The background image is a detail from a map produced by Reto Stockli, NASA Earth Observatory, as part of the Blue Marble project. The gravity map was produced by Lukas Zurcher and David A. Kring (2004) and updated with the Expedition 364 borehole location (Chicx-03A). Illustration Credit: David A. Kring/USRA/LPI
“The borehole has pierced time, bringing us the products of an impact event that changed Earth forever,” says Kring. He further states “with nearly fourteen tons of rock pulled from the depths of the crater, our team is searching for details about the crater’s formation and its effect on the dinosaur’s world.”
LPI Director Louise Prockter says “we are very glad to be working on this exciting project with the IODP and its U.S. Science Support Program at Lamont-Doherty Earth Observatory of Columbia University. We also thank the University of Bremen for hosting the scientific team in its initial analysis of the core.”
The cores are at the IODP Core Repository at the MARUM Center for Marine Environmental Sciences, University of Bremen (Germany). There the cores are being split in halves and the 31 person science team, supported by a team of technicians and students, are undertaking a suite of IODP standard measurements on these cores. They take samples for further measurements happening on half of each core with the other half being preserved for future study by the science community and public.
The cores include 120 meters of limestone sediments deposited between 66 million years ago and approximately 50 million years ago, as well as some 120 meters of broken and melted rocks burying a ring of mountains the peak ring that surrounds the center of the crater. There is abundant evidence that a vigorous hydrothermal system existed in the wake of the impact with fluids flowing through the broken and melted rocks that cover the peak ring.
While the crater marks the impact infamous for causing 75 percent of life on Earth to go extinct the team has also found that microbial life found a foothold in the crater, likely taking advantage of the chemistry and porous nature of the broken and melted rocks. The team also notes that the sediments that bury the crater, which were recovered in the IODP Expedition 364 cores, include the critical time intervals of when marine life made a recovery at ground zero where ocean conditions may have been toxic for an extended period of time after the impact.
The expedition is conducted by the European Consortium for Ocean Research Drilling (ECORD) as part of the International Ocean Discovery Program (IODP). The expedition is also supported by the International Continental Scientific Drilling Programme (ICDP). The expedition would not have been possible without the support and assistance of the Yucatn Government, Mexican federal government agencies and scientists from the National Autonomous University of Mexico (UNAM) and the Centro de Investigacin Cientfica de Yucatn (CICY).
More information:
About the expedition – http://www.eso.ecord.org/expeditions/364/364.php
About the research program www.iodp.org
About the European part of the program www.ecord.org
