TY - JOUR
T1 - High-resolution geochemical record of Cretaceous-Tertiary boundary sections in Mexico
T2 - New constraints on the K/T and Chicxulub events
AU - Stüben, Doris
AU - Kramar, U.
AU - Harting, M.
AU - Stinnesbeck, W.
AU - Keller, Gerta
N1 - Funding Information:
This study was supported by the Deutsche Forschungsgemeinschaft (grants Sti 128/2 and 128/7 and Stu 169/10-1-3), the National Science Foundation (grant OCE-9021338), and the Petroleum Research Fund (ACS-PRF grant 2670-AC8). Falk Lindenmaier provided PGE data of Los Dos Plebes and La Lajilla. We thank Dr. José Guadalupe López-Oliva, Linares, for valuable suggestions, discussions, and help during our field work in NE Mexico. We also thank the staff of our laboratory—Gesine Preuss, Claudia Möβner, Peter Schaupp, Manfred Gerken, and Stefan Höhne. Without their efforts this investigation would not have been possible. We thank Uwe Reimold and Henning Dypvik, and two anonymous reviewers, for their helpful suggestions and comments.
Copyright:
Copyright 2011 Elsevier B.V., All rights reserved.
PY - 2005/5/15
Y1 - 2005/5/15
N2 - The investigation of eight Cretaceous-Tertiary (K/T) sections in Mexico, based on major and trace element, platinum group element (PGE), stable isotope, and multivariate statistical analysis, reveals a complex depositional history across the Chicxulub and K/T boundary events. At the biostratigraphically determined K/T boundary, a minor but significant Ir-dominated PGE anomaly (0.2-0.8 ng/g) is present in most sections. This Ir anomaly originated from an impact event and is always stratigraphically and geochemically decoupled from the underlying spherule-rich ejecta deposit related to the Chicxulub event. In all sections examined, one to three glass spherule ejecta layers and one or two chondrite-dominated PGE anomalies are separated by a bioturbated siliciclastic deposit and/or hemipelagic marl, which indicates the occurrence of at least two impact events separated by a considerable amount of time. In addition, bentonite layers and Pt and Pd-dominated PGE anomalies below and above the K/T boundary indicate volcanic activity. Above the K/T boundary, reduced bioproductivity is documented by a decrease in the biogenically bound fraction of nutrients and fluctuating ratios of immobile elements (e.g., Ti/Zr). Variations in detrital elements reflect changes in the depositional environment. Carbon and oxygen isotope and trace element distribution patterns indicate a gradually changing climate during the latest Maastrichtian, an abrupt change at the K/T boundary, and a slight recovery during the lowermost Paleocene.
AB - The investigation of eight Cretaceous-Tertiary (K/T) sections in Mexico, based on major and trace element, platinum group element (PGE), stable isotope, and multivariate statistical analysis, reveals a complex depositional history across the Chicxulub and K/T boundary events. At the biostratigraphically determined K/T boundary, a minor but significant Ir-dominated PGE anomaly (0.2-0.8 ng/g) is present in most sections. This Ir anomaly originated from an impact event and is always stratigraphically and geochemically decoupled from the underlying spherule-rich ejecta deposit related to the Chicxulub event. In all sections examined, one to three glass spherule ejecta layers and one or two chondrite-dominated PGE anomalies are separated by a bioturbated siliciclastic deposit and/or hemipelagic marl, which indicates the occurrence of at least two impact events separated by a considerable amount of time. In addition, bentonite layers and Pt and Pd-dominated PGE anomalies below and above the K/T boundary indicate volcanic activity. Above the K/T boundary, reduced bioproductivity is documented by a decrease in the biogenically bound fraction of nutrients and fluctuating ratios of immobile elements (e.g., Ti/Zr). Variations in detrital elements reflect changes in the depositional environment. Carbon and oxygen isotope and trace element distribution patterns indicate a gradually changing climate during the latest Maastrichtian, an abrupt change at the K/T boundary, and a slight recovery during the lowermost Paleocene.
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U2 - 10.1016/j.gca.2004.11.003
DO - 10.1016/j.gca.2004.11.003
M3 - Article
AN - SCOPUS:19044393897
SN - 0016-7037
VL - 69
SP - 2559
EP - 2579
JO - Geochimica et Cosmochimica Acta
JF - Geochimica et Cosmochimica Acta
IS - 10
ER -