40. BOTTOM CURRENTS AND ICE RAFTING IN THE NORTH ATLANTIC:
DSDP Leg 49 provides new data bearing on two important problems concerning the Neogene environment of the North Atlantic. First, our interpretation of three northern sites (407, 408, and 409) supports previous interpretations, based on Leg 38 data, which conclude that the deep circulation of the eas...
| Main Authors: | , , , |
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.522.127 http://www.deepseadrilling.org/49/volume/dsdp49_40.pdf |
| Summary: | DSDP Leg 49 provides new data bearing on two important problems concerning the Neogene environment of the North Atlantic. First, our interpretation of three northern sites (407, 408, and 409) supports previous interpretations, based on Leg 38 data, which conclude that the deep circulation of the eastern North Atlantic (and possibly the entire North Atlantic) did not attain its present configuration until at least the early Miocene. This is considerably younger than previous studies had suggested. For example, Berggren and Hollister (1974, 1977) inferred a deep connection between the Norwegian Sea and the North Atlantic about 50 m.y. ago. The second problem of interest to geologists and climatologists is the maximum southward extent of ice rafting in the North Atlantic during the Pliocene, and the date of initiation of ice rafting. Data from Site 410 (45°N latitude) provide a minimum southern limit for the Pliocene iceberg drift, and support the date of 3 m.y.B.P. (Berggren, 1972) for the initiation of extensive Northern Hemisphere glaciation. |
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