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The Cretaceous/Palaeogene (K/P) boundary at Aïn Settara, Tunisia: restructuring of benthic foraminiferal assemblages
Author(s) -
Peryt Danuta,
Alegret Laia,
Molina Eustoquio
Publication year - 2002
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 - 10.1046/j.1365-3121.2002.00394.x
Subject(s) - benthic zone , foraminifera , geology , bathyal zone , paleogene , paleontology , extinction event , cretaceous , dominance (genetics) , oceanography , extinction (optical mineralogy) , mesozoic , biozone , biostratigraphy , structural basin , biological dispersal , biology , population , biochemistry , demography , sociology , gene
Benthic foraminiferal assemblages, in contrast to planktic foraminifera, generally did not suffer mass extinctions at the Cretaceous/Palaeogene (K/P) boundary; extinctions were fewer in deeper water. However, the outer shelf, upper bathyal section at Aïn Settara, Tunisia, records a dramatic change in the structure of benthic foraminiferal assemblages across the K/P boundary. At the level of extinction of planktic assemblages and enrichment in Ir and other geochemical anomalies, highly diversified, low‐dominance Upper Maastrichtian assemblages with infaunal and epifaunal morphogroups were suddenly replaced by taxonomically impoverished assemblages, strongly dominated by epifaunal morphogroups. This extinction or temporary emigration of most infaunal morphogroups is interpreted to be the result of a sudden breakdown in food supply. This, in turn, is the consequence of a sudden collapse in primary productivity, probably resulting from the impact of the K/P asteroid.