Life and death in the Chicxulub impact crater: a record of the Paleocene–Eocene Thermal Maximum
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COPERNICUS GESELLSCHAFT MBH
Date
2020Referencia bibliográfica
Smith, V., Warny, S., Grice, K., Schaefer, B., Whalen, M. T., Vellekoop, J., ... & Schwark, L. (2020). Life and death in the Chicxulub impact crater: a record of the Paleocene–Eocene Thermal Maximum. Climate of the Past, 16(5), 1889-1899. doi: 10.5194/cp-16-1889-2020.
Sponsorship
CENEX (Center for Excellence in Palynology) Endowed Chair Fund; Louisiana State University; Paleontological Society; Australian Research Council DP180100982; Curtin University; IODP-France; FWO 12Z6618N; NERC Natural Environment Research Council NE/P005217/1; National Science Foundation (NSF) 14-50528 1737199 1736951 1737351Abstract
Thermal stress on the biosphere during the extreme warmth of the Paleocene–Eocene Thermal Maximum
(PETM) was most severe at low latitudes, with sea surface temperatures at some localities exceeding the 35 ◦C at
which marine organisms experience heat stress. Relatively
few equivalent terrestrial sections have been identified, and
the response of land plants to this extreme heat is still poorly
understood. Here, we present a new record of the PETM from
the peak ring of the Chicxulub impact crater that has been
identified based on nannofossil biostratigraphy, an acme of
the dinoflagellate genus Apectodinium, and a negative carbon isotope excursion. Geochemical and microfossil proxies show that the PETM is marked by elevated TEXH
86-based
sea surface temperatures (SSTs) averaging ∼ 37.8
◦C, an in crease in terrestrial input and surface productivity, salinity
stratification, and bottom water anoxia, with biomarkers for
green and purple sulfur bacteria indicative of photic zone euxinia in the early part of the event. Pollen and plants spores in
this core provide the first PETM floral assemblage described
from Mexico, Central America, and the northern Caribbean.
The source area was a diverse coastal shrubby tropical forest
with a remarkably high abundance of fungal spores, indicating humid conditions. Thus, while seafloor anoxia devastated
the benthic marine biota and dinoflagellate assemblages were
heat-stressed, the terrestrial plant ecosystem thrived.