Zircon and apatite U-Pb and (U-Th)/He geo- and thermochronometry of the crystalline basement in the Chicxulub's peak ring structure (IODP Exp. 364)

Author(s): Stockli, Daniel F.; Rasmussen, Cornelia; Ross, Catherine; Stockli, Lisa D.; Gulick, Sean P. S.; Chatterjee, Rudra; Christeson, Gail L.; Wittmann, Axel; Schmieder, Martin; Kring, David A.; Xiao Long; Morgan, Joanna
International Ocean Discovery Program-International Continental Scientific Drilling Program, Expedition 364 Science Party
Author Affiliation(s): Primary:
University of Texas at Austin, Department of Geological Sciences, Austin, TX, United States
Arizona State University, United States
Lunar and Planetary Institute, United States
NASA, Solar System Exploration Research Virtual Institute, United States
Macau University of Science and Technology, China
Imperial College London, United Kingdom
Volume Title: Geological Society of America, 2018 annual meeting & exposition
Source: Abstracts with Programs - Geological Society of America, 50(6); Geological Society of America, 2018 annual meeting & exposition, Indianapolis, IN, Nov. 4-7, 2018. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0016-7592 CODEN: GAAPBC
Note: In English
Summary: IODP-ICDP Expedition 364 drilled the peak ring of the K-Pg Chicxulub impact structure and recovered 580 m of shocked granitic basement. We used zircon U-Pb depth-profile LA-ICP-MS analysis to constrain the pre-impact tectono-magmatic evolution of the impact site at the northern edge of the Yucatan/Maya block, while apatite U-Pb depth-profile LA-ICP-MS and zircon and apatite (U-Th)/He thermochronometry were employed to elucidate the thermal evolution of the granitic basement in the NW portion of the Chicxulub peak ring. These plutonic rocks yielded ∼320-350 Ma zircon U-Pb crystallization ages with evidence for earliest Paleozoic inherited zircon cores and Permian zircon rims associated with younger E Mexican arc magmatism. These data document Carboniferous arc magmatism, associated with southward Rheic ocean subduction beneath Yucatan, intruding into peri-Gondwanan Maya block basement (∼540 Ma). Detailed LA-ICP-MS depth profiling also revealed that only high-U metamict zircon domains were affected by partial or complete Pb loss attributable to the K-Pg Chicxulub impact. In contrast, apatite U-Pb depth-profiling ages only yielded late Carboniferous ages in response to rapid exhumation associated with post-magmatic cooling or Ouachita orogenic uplift. The apatite U-Pb ages are not reset by the impact and clearly show that the bulk of the felsic rocks in the peak ring were not heated >400C. Zircon (U-Th)/He data for the drilled basement section mostly gave earliest Paleocene ages, clustering around 58-66 Ma, demonstrating impact resetting of the ZHe ages and possible minor age rejuvenation due to post-impact hydrothermal heating. He diffusion experiments on zircon with variable degrees of impact shock microstructures showed ZHe kinetics similar to un-shocked zircons, with the exception of zircon with granular textures. Apatite (U-Th)/He ages range from 15 to 30 Ma and are mostly younger than the impact and likely (partially) reset in response to younger tectonic and deposition events in S Mexico. Together these zircon and apatite U-Pb and (U-Th)/He data from the felsic basement of the Chicxulub in the peak ring allow the reconstruction of its pre-impact tectono-magmatic and thermal evolution, the estimation of the maximum heating during impact (<400C), and post-impact thermal history reconstruction.
Year of Publication: 2018
Research Program: IODP2 International Ocean Discovery Program
Key Words: (U-Th)/He; 03 Geochronology; 05 Petrology, Igneous and Metamorphic; Absolute age; Apatite; Atlantic Ocean; Basement; Carboniferous; Cenozoic; Chicxulub Crater; Cretaceous; Expedition 364; Granites; Gulf of Mexico; Igneous rocks; Impacts; International Ocean Discovery Program; K-Pg boundary; Lower Paleocene; Magmatism; Mesozoic; Metamorphism; Nesosilicates; North Atlantic; Orthosilicates; Paleocene; Paleogene; Paleozoic; Phosphates; Plutonic rocks; Shock metamorphism; Silicates; Stratigraphic boundary; Tertiary; U/Pb; Upper Cretaceous; Zircon; Zircon group
Coordinates: N212701 N212701 W0895658 W0895658
Record ID: 2019010718
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States