TY - JOUR
T1 - Multiple impacts across the Cretaceous-Tertiary boundary
AU - Keller, Gerta
AU - Stinnesbeck, W.
AU - Adatte, T.
AU - Stüben, D.
N1 - Funding Information:
We thank Andrew Glikson for a tremendously helpful review and for liberally sharing his knowledge with us. We also thank Robert Hargraves for his many stimulating discussions and his untiring pursuit of impacts. This study has benefited from various student projects in Mexico over the past 6 years and we gratefully acknowledge the contributions by W. Affolter, C. Ifrim, M. Lindinger, L. Schilli and P. Schulte. We also thank Brian Holland, Belize Minerals, and Jorge de la Cruz and Carlos de Leon, Perenco, Guatemala, for many lively discussions and field guidance in Belize and Guatemala. We are grateful to J.G. Lopez-Oliva for logistical support and making facilities available at the Geology Department of the University of Nuevo Leon, Linares, G. L. Julio Cesar (Instituto Mexicano del Petroleo) for logistical information of the Bochil-1 and Trinitaria sections and Markus Harting (Institut for Minearlogy and Geochemistry, University of Karlsruhe) for PGE analysis of the Actela section. Research was supported by the German Science Foundation grants STI 128/7-1 and -2 and STU 169/10-2, the Swiss National Fund no. 8220-028367 (TA) and NSF Grant EAR-0207407 (GK).
PY - 2003/9
Y1 - 2003/9
N2 - The stratigraphy and age of altered impact glass (microtektites, microkrystites) ejecta layers from the Chicxulub crater are documented in Late Maastrichtian and Early Danian sediments in Mexico, Guatemala, Belize and Haiti. In northeastern Mexico, two to four ejecta layers are present in zone CF1, which spans the last 300 ky of the Maastrichtian. The oldest ejecta layer is dated at 65.27±0.03 Ma based on sediment accumulation rates and extrapolated magnetostratigraphy. All younger ejecta layers from the Maastrichtian and Early Danian Parvularugoglobigerina eugubina zone Pla(l) may represent repeated episodes of reworking of the oldest layer at times of sea level changes and tectonic activity. The K/T boundary impact event (65.0 Ma) is not well represented in this area due to widespread erosion. An Early Danian Pla(l) Ir anomaly is present in five localities (Bochil, Actela, Coxquihui, Trinitaria and Haiti) and is tentatively identified as a third impact event at about 64.9 Ma. A multiimpact scenario is most consistent with the impact ejecta evidence. The first impact is associated with major Deccan volcanism and likely contributed to the rapid global warming of 3-4 °C in intermediate waters between 65.4 and 65.2 Ma, decrease in primary productivity and onset of terminal decline in planktic foraminiferal populations. The K/T boundary impact marks a major drop in primary productivity and the extinction of all tropical and subtropical species. The Early Danian impact may have contributed to the delayed recovery in productivity and evolutionary diversity.
AB - The stratigraphy and age of altered impact glass (microtektites, microkrystites) ejecta layers from the Chicxulub crater are documented in Late Maastrichtian and Early Danian sediments in Mexico, Guatemala, Belize and Haiti. In northeastern Mexico, two to four ejecta layers are present in zone CF1, which spans the last 300 ky of the Maastrichtian. The oldest ejecta layer is dated at 65.27±0.03 Ma based on sediment accumulation rates and extrapolated magnetostratigraphy. All younger ejecta layers from the Maastrichtian and Early Danian Parvularugoglobigerina eugubina zone Pla(l) may represent repeated episodes of reworking of the oldest layer at times of sea level changes and tectonic activity. The K/T boundary impact event (65.0 Ma) is not well represented in this area due to widespread erosion. An Early Danian Pla(l) Ir anomaly is present in five localities (Bochil, Actela, Coxquihui, Trinitaria and Haiti) and is tentatively identified as a third impact event at about 64.9 Ma. A multiimpact scenario is most consistent with the impact ejecta evidence. The first impact is associated with major Deccan volcanism and likely contributed to the rapid global warming of 3-4 °C in intermediate waters between 65.4 and 65.2 Ma, decrease in primary productivity and onset of terminal decline in planktic foraminiferal populations. The K/T boundary impact marks a major drop in primary productivity and the extinction of all tropical and subtropical species. The Early Danian impact may have contributed to the delayed recovery in productivity and evolutionary diversity.
KW - Ir
KW - Maastrichtian-Danian
KW - Microkrystites
KW - Microtektites
KW - Multiple impacts
KW - PGE anomalies
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U2 - 10.1016/S0012-8252(02)00162-9
DO - 10.1016/S0012-8252(02)00162-9
M3 - Article
AN - SCOPUS:0041786772
SN - 0012-8252
VL - 62
SP - 327
EP - 363
JO - Earth-Science Reviews
JF - Earth-Science Reviews
IS - 3-4
ER -