Maastrichtian climate, productivity and faunal turnovers in planktic Foraminifera in South Atlantic DSDP sites 525A and 21

Author(s): Li, Liangquan; Keller, Gerta
Author Affiliation(s): Primary:
Princeton University, Department of Geosciences, Princeton, NJ, United States
Volume Title: Marine Micropaleontology
Source: Marine Micropaleontology, 33(1-2), p.55-86. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0377-8398 CODEN: MAMIDH
Note: In English. 67 refs.; illus., incl. 2 plates, 4 tables, strat. col.
Summary: Stratigraphic, faunal and isotopic analyses of the Maastrichtian at DSDP sites 525A and 21 in the South Atlantic reveal a planktic foraminiferal fauna characterized by two major events, an early late Maastrichtian diversification and end-Maastrichtian mass extinction. Both events are accompanied by major changes in climate and productivity. The diversification event which occurred in two steps between 70.5 and 69.1 Ma increased species richness by a total of 43% and coincided with the onset of major cooling in surface and bottom waters and increased surface productivity. The onset of the terminal decline in Maastrichtian species richness began at 67.5 Ma and the first significant decline in surface productivity occurred at 66.2 Ma, coincident maximum cooling to 13°C in surface waters and the reduction of the surface-to-deep temperature gradient to less than 5°C. Major climatic and moderate productivity changes mark the mass extinction and the last 500 kyr of the Maastrichtian. Between 200 and 400 kyr before the K-T boundary surface and deep waters warmed rapidly by 3-4°C and cooled again during the last 100 kyr of the Maastrichtian. Surface productivity decreased only moderately across the K-T boundary. Species richness began to decline during the late Maastrichtian cooling and by K-T boundary time, the mass extinction had claimed 66% of the species. Viewed within the context of Maastrichtian climate and productivity changes, the K-T mass extinction could have resulted from extreme environmental stress even without the addition of an extraterrestrial impact. Abstract Copyright (1998) Elsevier, B.V.
Year of Publication: 1998
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Atlantic Ocean; Biodiversity; C-13/C-12; Carbon; Cenozoic; Climate change; Cooling; Cretaceous; DSDP Site 21; DSDP Site 525; Deep Sea Drilling Project; Extinction; Faunal studies; Foraminifera; IPOD; Invertebrata; Isotope ratios; Isotopes; K-T boundary; Leg 3; Leg 74; Lower Paleocene; Maestrichtian; Mesozoic; Microfossils; O-18/O-16; Oxygen; Paleocene; Paleoclimatology; Paleogene; Planktonic taxa; Productivity; Protista; Sediments; Senonian; South Atlantic; Stable isotopes; Stratigraphic boundary; Tertiary; Upper Cretaceous
Coordinates: S283506 S283506 W0303551 W0303551
S290415 S290414 E0025908 E0025907
Record ID: 1998042319
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands