Strontium isotope ratios of middle Eocene to Oligocene sediments from Maud Rise, Antarctica ...
A 87Sr/86Sr isotope curve of the middle Eocene to Oligocene was produced from analysis of foraminifera in Ocean Drilling Program Hole 689B, Maud Rise, near the coast of Antarctica. Sediments from the hole are well preserved with no evidence of diagenetic alteration. The sequence is nearly complete f...
| Main Authors: | , |
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| Format: | Article in Journal/Newspaper |
| Language: | English |
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PANGAEA
1995
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| Online Access: | https://dx.doi.org/10.1594/pangaea.708179 https://doi.pangaea.de/10.1594/PANGAEA.708179 |
| Summary: | A 87Sr/86Sr isotope curve of the middle Eocene to Oligocene was produced from analysis of foraminifera in Ocean Drilling Program Hole 689B, Maud Rise, near the coast of Antarctica. Sediments from the hole are well preserved with no evidence of diagenetic alteration. The sequence is nearly complete from 46.3 to 24.8 Ma, with an average sampling interval of 166 kyr. Excellent magnetostratigraphy in Hole 689B allows calibration to the geomagnetic polarity time scale of Cande and Kent (1992). Marine strontium isotopic ratios were nearly stable from 46.3 to 35.5 Ma, averaging near 0.70773, after which they began to increase. A slow increase began after 40.4 Ma, rising at a rate of only about 8*10**-6/m.y. from base values of 0.707707. From 35.5 Ma to 24.8 Ma the average slope increased to 40*10**-6/m.y. The slope remained constant at least until 24.8 Ma, when the record becomes discontinuous owing to unconformities. We evaluate several possible controls on the marine strontium isotope curve that could have led to ... : Supplement to: Mead, Gregory; Hodell, David A (1995): Controls on the 87Sr/86Sr composition of seawater from the middle Eocene to Oligocene: Hole 689B, Maud Rise, Antarctica. Paleoceanography, 10(2), 327-346 ... |
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