TY - JOUR
T1 - Extended period of extinctions across the Cretaceous/Tertiary boundary in planktonic foraminifera of continental-shelf sections
T2 - implications for impact and volcanism theories
AU - Keller, Gerta
PY - 1989
Y1 - 1989
N2 - The extinction of planktonic foraminiferal species across the Cretaceous/Tertiary (K/T) boundary has been examined in continental-shelf sections at El Kef, Tunisia, and Brazos River, Texas. These sections are considered to contain the most complete boundary transition record known to date. In both sections, an extended period of species extinctions spans from about 300 000 yr below to about 200 000-300 000 yr above the K/T boundary. Species extinctions selectively affect large, ornate, tropical to subtropical species first and small, primitive, nonornate, subtropical to temperate species last. This pattern of species extinction is likely caused by increased ecological stresses as a result of a late Maastrichtian sea-level regression and global cooling. The extended period of species extinctions and absence of extinctions at the K/T boundary at Brazos River is not entirely compatible with either impact or volcanism theories. Perhaps, multiple unrelated causes should be considered, including a sea-level regression, global cooling, a K/T boundary impact of limited extent, and extensive volcanism. -from Author
AB - The extinction of planktonic foraminiferal species across the Cretaceous/Tertiary (K/T) boundary has been examined in continental-shelf sections at El Kef, Tunisia, and Brazos River, Texas. These sections are considered to contain the most complete boundary transition record known to date. In both sections, an extended period of species extinctions spans from about 300 000 yr below to about 200 000-300 000 yr above the K/T boundary. Species extinctions selectively affect large, ornate, tropical to subtropical species first and small, primitive, nonornate, subtropical to temperate species last. This pattern of species extinction is likely caused by increased ecological stresses as a result of a late Maastrichtian sea-level regression and global cooling. The extended period of species extinctions and absence of extinctions at the K/T boundary at Brazos River is not entirely compatible with either impact or volcanism theories. Perhaps, multiple unrelated causes should be considered, including a sea-level regression, global cooling, a K/T boundary impact of limited extent, and extensive volcanism. -from Author
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U2 - 10.1130/0016-7606(1989)101<1408:EPOEAT>2.3.CO;2
DO - 10.1130/0016-7606(1989)101<1408:EPOEAT>2.3.CO;2
M3 - Article
AN - SCOPUS:84879888499
SN - 0016-7606
VL - 101
SP - 1408
EP - 1419
JO - Geological Society of America Bulletin
JF - Geological Society of America Bulletin
IS - 11
ER -