Carbon and oxygen isotope data for carbonates and benthic foraminifers from ODP Hole 113-689B ...
At Ocean Drilling Program Site 689 (Maud Rise, Southern Ocean), d18O records of fine-fraction bulk carbonate and benthic foraminifers indicate that accelerated climate cooling took place following at least two closely spaced early late Eocene extraterrestrial impact events. A simultaneous surface-wa...
| Main Authors: | , , , , |
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| Format: | Article in Journal/Newspaper |
| Language: | English |
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PANGAEA
2000
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| Subjects: | |
| Online Access: | https://dx.doi.org/10.1594/pangaea.713007 https://doi.pangaea.de/10.1594/PANGAEA.713007 |
| Summary: | At Ocean Drilling Program Site 689 (Maud Rise, Southern Ocean), d18O records of fine-fraction bulk carbonate and benthic foraminifers indicate that accelerated climate cooling took place following at least two closely spaced early late Eocene extraterrestrial impact events. A simultaneous surface-water productivity increase, as interpreted from d13C data, is explained by enhanced water-column mixing due to increased latitudinal temperature gradients. These isotope data appear to be in concert with organic-walled dinoflagellate-cyst records across the same microkrystite-bearing impact-ejecta layer in the mid-latitude Massignano section (central Italy). In particular, the strong abundance increase of Thalassiphora pelagica is interpreted to indicate cooling or increased productivity at Massignano. Because impact-induced cooling processes are active on time scales of a few years at most, the estimated 100 k.y. duration of the cooling event appears to be too long to be explained by impact scenarios alone. This ... : Supplement to: Vonhof, Hubert B; Smit, Jan; Brinkhuis, Henk; Montanari, Alessandro; Nederbragt, Alexandra J (2000): Global cooling accelerated by early late Eocene impacts? Geology, 28(8), 687-690 ... |
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