International Ocean Discovery Program; Expedition 364 scientific prospectus; Chicxulub; drilling the K-Pg impact crater; in collaboration with the International Continental Scientific Drilling Program

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doi: 10.14379/iodp.sp.364.2016
Author(s): Gulick, Sean; Morgan, Joanna; Mellett, Claire L.; Urrutia Fucugauchi, Jaime
Author Affiliation(s): Primary:
University of Texas-Austin, Institute for Geophysics, Austin, TX, United States
Imperial College London, United Kingdom
British Geological Survey, United Kingdom
National University of Mexico, Mexico
Source: Scientific Prospectus (International Ocean Discovery Program), Vol.364, 21p. Publisher: International Ocean Discovery Program, College Station, TX, United States. ISSN: 2332-1385
Note: In English. 63 refs.
Summary: The Chicxulub impact crater in Mexico is unique. It is the only known terrestrial impact structure that has been directly linked to a mass extinction event and the only terrestrial impact with a global ejecta layer. Of the three largest impact structures on Earth, Chicxulub is the best preserved. Chicxulub is also the only known terrestrial impact structure with an intact, unequivocal topographic "peak ring." Chicxulub's role in the Cretaceous/Paleogene (K-Pg) mass extinction and its exceptional state of preservation make it an important natural laboratory for the study of both large impact crater formation on Earth and other planets and the effects of large impacts on Earth's environment and ecology. Our understanding of the impact process is far from complete, and despite more than 30 y of intense debate, we are still striving to answer the question as to why this impact was so catastrophic. International Ocean Discovery Program (IODP) Expedition 364 proposes to core through the peak ring of the Chicxulub impact crater to investigate (1) the nature and formational mechanism of peak rings, (2) how rocks are weakened during large impacts, (3) the nature and extent of postimpact hydrothermal circulation, (4) the deep biosphere and habitability of the peak ring, and (5) the recovery of life in a sterile zone. Of additional interest is the transition through a rare midlatitude record of the Paleocene/Eocene Thermal Maximum (PETM); the composition and character of impact breccias, melt rocks, and peak-ring rocks; the sedimentology and stratigraphy of the Cenozoic sequence; and any observations from the core that would help us constrain the volume of dust and climatically active gases released into the stratosphere by this impact. Petrophysical property measurements on the core and wireline logs will be used to calibrate geophysical models, including seismic reflection data. Proposed drilling directly contributes to the IODP science plan initiatives (1) Deep Biosphere and the Subseafloor Ocean and (2) Environmental Change, Processes and Effects, in particular the environmental and biological perturbations caused by the Chicxulub impact. Expedition 364 will be implemented as a mission-specific platform expedition to obtain subseabed samples and downhole logging measurements from the peak ring of the Chicxulub impact crater. The expedition aims to core a single borehole as deep as 1500 meters below seafloor (mbsf) to recover rock cores from above and into the Chicxulub impact crater preserved under the Yucatan continental shelf.
Year of Publication: 2016
Research Program: IODP2 International Ocean Discovery Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Atlantic Ocean; Breccia; Cenozoic; Chicxulub Crater; Cretaceous; Downhole methods; Drilling; Expedition 364; Gulf of Mexico; Hydrothermal alteration; Impact breccia; Impact craters; Impact features; Impactites; International Ocean Discovery Program; K-T boundary; Lower Paleocene; Marine drilling; Mesozoic; Metamorphic rocks; Metasomatism; North Atlantic; Paleocene; Paleocene-Eocene Thermal Maximum; Paleogene; Peak rings; Planning; Sedimentary rocks; Stratigraphic boundary; Tertiary; Upper Cretaceous; Well-logging; Yucatan Shelf
Coordinates: N212700 N212700 W0895700 W0895700
Record ID: 2016028289
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