TY - JOUR
T1 - Maastrichtian climate, productivity and faunal turnovers in planktic foraminifera in South Atlantic DSDP sites 525A and 21
AU - Li, Liangquan
AU - Keller, Gerta
N1 - Funding Information:
This study benefited from discussions with Wolfgang Stinnesbeck, Thierry Adatte and Hedi Ober-hansli. We thank Daniel Bryan for analysis of stable isotopes and two anonymous reviewers for their comments. Samples from DSDP Site 525A and Site 21 were provided by the Ocean Drilling Program. This study was supported by NFS grant OCE 9021338.A02.
PY - 1998/2
Y1 - 1998/2
N2 - 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.
AB - 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.
KW - Climate
KW - Maastrichtian
KW - Planktic foraminiferal biostratigraphy
KW - Productivity
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U2 - 10.1016/S0377-8398(97)00027-3
DO - 10.1016/S0377-8398(97)00027-3
M3 - Article
AN - SCOPUS:0032005401
SN - 0377-8398
VL - 33
SP - 55
EP - 86
JO - Marine Micropaleontology
JF - Marine Micropaleontology
IS - 1-2
ER -