Probing a post-impact hydrothermal system in the Chicxulub Crater with core recovered by IODP-ICDP Expedition 364

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doi: 10.1130/abs/2017AM-302280
Author(s): Kring, David A.; Schmieder, Martin; Riller, Ulrich; Simpson, Sarah L.; Osinski, Gordon R.; Cockell, Charles S.; Coolen, Marco J. L.
Author Affiliation(s): Primary:
Lunar and Planetary Institute, Houston, TX, United States
Universität Hamburg, Germany
University of Western Ontario, Canada
University of Edinburgh, United Kingdom
Curtin University, Australia
Volume Title: Geological Society of America, 2017 annual meeting & exposition
Source: Abstracts with Programs - Geological Society of America, 49(6); Geological Society of America, 2017 annual meeting & exposition, Seattle, WA, Oct. 22-25, 2017. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0016-7592 CODEN: GAAPBC
Note: In English
Summary: The Chicxulub impact event created a high-temperature anomaly in the crust of the Earth that produced a subsurface hydrothermal system that is a potential proxy for impact-related hydrothermal systems during the early evolution of thermophilic and hyperthermophilic life on Earth. A key objective of IODP-ICDP Expedition 364 was to drill into the peak ring of the crater to determine peak temperatures and the lifetime of the hydrothermal system. Analyses of the newly recovered core indicate Ca-Na- and K-metasomatism was prevalent at temperatures >300 °C, producing metasomatic fronts that moved through impact melt rocks and K-feldspar veins in the underlying granite. Relict quartz from the target entrained in the melt has been partially to wholly dissolved, implying a hot Si-undersaturated fluid, and the resulting void space later filled with secondary calcite. Deeper within the peak ring (1256 mbsf), the granite is honeycombed with quartz dissolution cavities that may be a consequence of that metasomatism at temperatures of 300 to 400 °C. At 1313 mbsf, andradite garnet precipitated. Secondary muscovite cross-cuts shock-metamorphic kinking of feldspar and is probably of post-impact hydrothermal origin at temperature in excess of 350 °C. The preservation of shock-produced TiO2-II suggests that those temperatures are close to the maximum temperature. As the system cooled, Mg-Fe and Na-K sheet silicates precipitated. Melt fragments in the suevite are, for example, altered to saponite and montomorillonite-like smectite-group minerals with significant chemical zoning and variable nH2O. Lower temperature fillings of vugs and open cavities followed, producing surfaces covered with analcime, dachiardite, and other secondary minerals. The initially high temperatures would have sterilized local regions within the peak ring sequence. As the system cooled, it could have supported hyperthermophilic and thermophilic microorganisms for 104 to 105 years.
Year of Publication: 2017
Research Program: IODP Integrated Ocean Drilling Program
IODP2 International Ocean Discovery Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Chicxulub Crater; Emplacement; Expedition 365; Hydrothermal alteration; Integrated Ocean Drilling Program; International Continental Scientific Drilling Program; International Ocean Discovery Program; Intrusions; Metasomatism; NanTroSEIZE; North Pacific; Northwest Pacific; Pacific Ocean; Ring complexes; West Pacific
Coordinates: N331233 N331236 E1364113 E1364110
Record ID: 2018022326
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States