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Near‐K/T age of clastic deposits from Texas to Brazil: impact, volcanism and/or sea‐level lowstand?
Author(s) -
Keller Gerta,
Stinnesbeck Wolfgang
Publication year - 1996
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/j.1365-3121.1996.tb00757.x
Subject(s) - clastic rock , geology , volcanism , sea level , deposition (geology) , paleontology , geochemistry , oceanography , sedimentary rock , sediment , tectonics
Near‐K/T boundary clastic deposits from Texas, Mexico, Haiti, Guatemala and Brazil, often described as impact‐generated tsunami deposits, are stratigraphically below well‐defined K/T boundary horizons and appear not to be causally related to the K/T boundary event. Stratigraphic evidence indicates that their deposition began during the last 170–200 kyr of the Maastrichtian, coincident with a major eustatic sea‐level lowstand that lowered sea level by as much as 70–100 m. Clastic deposition ended a few tens of thousands of years before the K/T boundary during a rapidly rising sea level. The presence of glass in clastic deposits in Haiti, northeastern Mexico and Yucatan suggests that the sea‐level lowstand coincided with a time of major volcanism or pre‐K/T boundary bolide impact.