Chicxulub impact structure, IODP-ICDP Expedition 364 drill core: Geochemistry of the granite basement

Jean-Guillaume Feignon, Sietze Jan De Graaff, Ludovic Ferriere, Pim Kaskes, Thomas Dehais, Steven Goderis, Philippe Claeys, Christian Koeberl

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3 Citaten (Scopus)
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Samenvatting

The IODP-ICDP Expedition 364 drilling recovered a 829 m core from Hole M0077A, sampling ~600 meters of near continuous crystalline basement within the peak ring of the Chicxulub impact structure. The bulk of the basement consists of pervasively deformed, fractured, and shocked granite. Detailed geochemical investigations of forty-one granitoid samples, i.e., major and trace element contents, and Sr–Nd isotopic ratios, are presented here, providing a broad overview of the composition of the granitic crystalline basement. Mainly in situ granite, but also granite clasts (in impact melt rock), granite breccias, and aplite were analyzed, yielding relatively homogeneous compositions between all samples. The granite is part of the high-K, calc-alkaline metaluminous series. Additionally, they are characterized by high Sr/Y and (La/Yb)N ratios, and low Y and Yb contents, which are typical for adakites. However, other criteria (such as Al2O3 and MgO contents, Mg#, K2O/Na2O ratios, Ni concentrations, etc.) do not match the adakite definition. In addition, initial 87Sr/86Srt=326 Ma is indicative of an hydrothermal fluid metasomatic event occurring shortly after the granite formation, affecting mainly samples crosscut by shear fractures or in contact with aplite,, where the fluid circulation was enhanced, and would have preferentially affected fluid-mobile element concentrations. The initial εNd (t=326 Ma) values range from -4.0 to 3.2 for the samples which were less affected by the hydrothermal overprint and indicate that a minor Grenville basement component may be involved in the granite genesis. Our results are consistent with previous studies, further supporting that the cored granite unit intruded the Maya block during the Carboniferous, in an arc setting with crustal melting related with the closure of the Rheic ocean associated with the assembly of Pangea. Then, an hydrothermal metasomatic event, possibly related to the initial breakup of Pangea, occurred ca. 50 Myr after the granite crystallization. Importantly, the granites sampled in Hole M0077A are unique in composition when compared to granite or gneiss clasts from other drill cores recovered from the Chicxulub impact structure. This marks them as valuable lithologies that provide new insight into the Yucatán basement.
Originele taal-2English
Artikelnummer13705
Pagina's (van-tot)1243-1273
Aantal pagina's31
TijdschriftMeteoritics & Planetary Science
Volume56
Nummer van het tijdschrift7
DOI's
StatusPublished - 29 jul 2021

Bibliografische nota

Funding Information:
This paper is dedicated to the memory of Hervé Martin (1951–2021) who developed the well‐known “adakitic” model, constituting a reference in the characterization of adakites and related rocks. The Chicxulub drilling was funded by the IODP as Expedition 364, with co‐funding from ICDP. Expedition 364 was implemented by ECORD, with contributions and logistical support from the Yucatán state government and Universidad Nacional Autónoma de México. Partial funding was provided by the University of Vienna doctoral school IK‐1045 (P.I.: C.K.). We thank Peter Nagl and Marianne Schwarzinger for XRF sample preparation and analysis, Dieter Mader for INAA and data processing, and Monika Horschinegg and Wencke Wegner for sample preparation and TIMS Sr–Nd isotopic analysis. J.‐G. F. thanks Wencke Wegner for constructive discussions on Sr–Nd isotopic data interpretation, and Jiawei Zhao for general discussions. The AMGC team is supported by Research Foundation Flanders (FWO‐Vlaanderen) and BELSPO; P.K. is an FWO PhD fellow (project 11E6619N; 11E6621N). S.G. and P.C. thank the EoS project “ET‐HoME” for support and the VUB Strategic Research Program. P.C. thanks the FWO—Hercules Program for financing the μXRF instrument at the VUB. J‐G. F. thanks Jean‐François Moyen for valuable comments on adakites and granites in general. We thank Lutz Hecht and Stephen Prevec for their detailed and constructive reviews, as well as Jeffrey Plescia for editorial handling.

Funding Information:
This paper is dedicated to the memory of Herv? Martin (1951?2021) who developed the well-known ?adakitic? model, constituting a reference in the characterization of adakites and related rocks. The Chicxulub drilling was funded by the IODP as Expedition 364, with co-funding from ICDP. Expedition 364 was implemented by ECORD, with contributions and logistical support from the Yucat?n state government and Universidad Nacional Aut?noma de M?xico. Partial funding was provided by the University of Vienna doctoral school IK-1045 (P.I.: C.K.). We thank Peter Nagl and Marianne Schwarzinger for XRF sample preparation and analysis, Dieter Mader for INAA and data processing, and Monika Horschinegg and Wencke Wegner for sample preparation and TIMS Sr?Nd isotopic analysis. J.-G. F. thanks Wencke Wegner for constructive discussions on Sr?Nd isotopic data interpretation, and Jiawei Zhao for general discussions. The AMGC team is supported by Research Foundation Flanders (FWO-Vlaanderen) and BELSPO; P.K. is an FWO PhD fellow (project 11E6619N; 11E6621N). S.G. and P.C. thank the EoS project ?ET-HoME? for support and the VUB Strategic Research Program. P.C. thanks the FWO?Hercules Program for financing the ?XRF instrument at the VUB. J-G. F. thanks Jean-Fran?ois Moyen for valuable comments on adakites and granites in general. We thank Lutz Hecht and Stephen Prevec for their detailed and constructive reviews, as well as Jeffrey Plescia for editorial handling. The authors declare no conflict of interest.

Publisher Copyright:
© 2021 The Authors. Meteoritics & Planetary Science published by Wiley Periodicals LLC on behalf of The Meteoritical Society (MET)

Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.

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