Eocene/Oligocene paleoceanography from ODP Hole 113-689B and Hole 113-690B ...
Middle Eocene to Late Oligocene sediments from near the crest (Site 689B, water depth 2080 m) and flank (water depth 2914 m) of the Maud Rise (62°S) have been investigated by coarse fraction analysis and have revealed the following:(1) The middle Eocene (50-40 Ma) was a period of pure carbonate sedi...
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| Format: | Article in Journal/Newspaper |
| Language: | English |
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PANGAEA
1991
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| Online Access: | https://dx.doi.org/10.1594/pangaea.759819 https://doi.pangaea.de/10.1594/PANGAEA.759819 |
| Summary: | Middle Eocene to Late Oligocene sediments from near the crest (Site 689B, water depth 2080 m) and flank (water depth 2914 m) of the Maud Rise (62°S) have been investigated by coarse fraction analysis and have revealed the following:(1) The middle Eocene (50-40 Ma) was a period of pure carbonate sedimentation, with good preservation of carbonate microfossils. No opal > 40 µm is present.(2) In the late Eocene (40-36.5 Ma) opal fossils (mainly radiolaria, and some diatoms > 40 µm) appeared for the first time. Three maxima in opal sedimentation (Eocene/Oligocene boundary, middle early Oligocene and early/late Oligocene boundary) are separated by increases in carbonate sedimentation. The dissolution of carbonate fossils is strong in the opal-rich layers. Opal sedimentation is attributed to cooling and probably more vigorous atmospheric circulation and increased upwelling.(3) Carbonate dissolution increased with water depth in the Oligocene, whereas in the middle Eocene excellent carbonate preservation in ... : Supplement to: Diester-Haass, Lieselotte (1991): Eocene/Oligocene paleoceanography in the Antarctic Ocean, Atlantic sector (Maud Rise, ODP Leg 113, Site 689B and 690B). Marine Geology, 100(1-4), 249-276 ... |
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