| NSF Org: |
OCE Division Of Ocean Sciences |
| Recipient: |
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| Initial Amendment Date: | August 10, 2017 |
| Latest Amendment Date: | May 11, 2021 |
| Award Number: | 1736951 |
| Award Instrument: | Continuing Grant |
| Program Manager: |
Kevin Johnson
ktjohnso@nsf.gov (703)292-7442 OCE Division Of Ocean Sciences GEO Directorate for Geosciences |
| Start Date: | August 15, 2017 |
| End Date: | July 31, 2022 (Estimated) |
| Total Intended Award Amount: | $193,343.00 |
| Total Awarded Amount to Date: | $193,343.00 |
| Funds Obligated to Date: |
FY 2018 = $102,582.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
201 OLD MAIN UNIVERSITY PARK PA US 16802-1503 (814)865-1372 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
535 Deike Building University Park PA US 16802-1503 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): |
PREEVENTS - Prediction of and, Marine Geology and Geophysics |
| Primary Program Source: |
01001819DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
The latest of Earth?s five largest mass extinction events occurred coeval with the impact of a ~14 km asteroid into the Yucatan Peninsula (Mexico), ending the Mesozoic Era. In April-May 2016, the International Ocean Discovery Program (IODP), with co-funding from the International Continental Scientific Drilling Program (ICDP), successfully cored with nearly 100% recovery from 505-1337 m below seafloor into the resulting 200 km-wide Chicxulub impact crater. These cores record an extraordinary sequence of impact and post-impact events. This project will investigate these unique cores further to understand the local and global effects of the only impact conclusively linked to a mass extinction event. This research is part of a larger international effort, including ~40 scientists from 14 countries, and also supports education and mentoring at the graduate and post-graduate level. Project researchers will continue to engage in outreach and education through media interviews, museum displays, and other activities to highlight the research to the general public.
The recent IODP-ICDP drilling expedition at Chicxulub recovered the first-ever samples of an unequivocal peak ring. A peak ring is a discontinuous ring of mountains observed within the central basin of all large impact craters on rocky planets. The discovery that Chicxulub?s peak ring consists of largely granitic crust uplifted by ~10 km calibrates impact models, allows for observation of impact processes, and for a first-order assessment of the environmental consequences of the impact (?kill mechanisms?). Newly recovered cores include the uplifted target rocks: melt-rich impact generated rock types, hydrothermal deposits, a tsunami bed coupled with a settling layer, and the resumption of carbonate sedimentation. These lithologies record processes spanning from minutes to millions of years post-impact. The proposed work will:
1. Reconstruct thermal history of the peak ring and the duration of the impact-induced hydrothermal system to determine how these processes affected the return of life to the crater.
2. Compare rock fragments in the impact rocks to pre-impact stratigraphy to quantify the volatiles released and constrain models of impact-induced climate change and extinction.
3. Find the first conclusive evidence of the asteroid within the crater to tie to global K-Pg boundary records and identify the possible influence of metal toxicity.
4. Investigate the fossil record of the boundary sequence, in concert with the sedimentology, stratigraphy, and environmental chemistry, to illuminate possible killing mechanisms and determine the pace and timing of the recovery within the crater from the weeks after the impact through the early Paleocene.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
This project has made significant advances in our understanding of the causes of the mass extinction and subsequent recovery of life after the impact of an asteroid 66 million years ago. The focus has been on cores recovered from the Chicxulub Crater that was formed during the impact. The cores show that life in the crater recovered from the environmental effects of the impact rapidly with very primitive life forms such as bacteria leading the way, followed by organisms higher up the food chain. Within a few thousand years the crater was teaming with more advanced life including crustaceans and fish. The crater cores contain compounds that show that burning of oil buried under the crater contributed soot that blocked out sunlight and led to extreme cold in the centuries after the impact. Cooling was exacerbated by sulfate aerosols; this is demonstrated by the complete absence of minerals containing sulfur in the crater cores suggesting that they were vaporized during impact. Discovery of bacterial fossils in the crater led us to recognize similar fossils in locations around the world, proving that these primitive lifeforms were able to tolerate harsh environmental conditions such as extreme cold. The bacteria paved the way for the global recovery of life after the impact.
Last Modified: 12/02/2022
Modified by: Timothy J Bralower
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