Constraints on Black Sea out£ow to the Sea of Marmara during the last glacial^interglacial transition
New cores from the upper continental slope off Romania in the western Black Sea provide a continuous, high-resolution record of sedimentation rates, clay mineralogy, calcium carbonate content, and stable isotopes of oxygen and carbon over the last 20 000 yr in the western Black Sea. These records al...
| Main Authors: | , , , |
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| Other Authors: | |
| Format: | Text |
| Language: | English |
| Published: |
2001
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| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.498.3591 http://www.geo.edu.ro/sgr/mod/downloads/PDF/Major-MarGeo-2002-190-19.pdf |
| Summary: | New cores from the upper continental slope off Romania in the western Black Sea provide a continuous, high-resolution record of sedimentation rates, clay mineralogy, calcium carbonate content, and stable isotopes of oxygen and carbon over the last 20 000 yr in the western Black Sea. These records all indicate major changes occurring at 15 000, 12 800, 8400, and 7100 yr before present. These results are interpreted to reflect an evolving balance between water supplied by melting glacial ice and other river runoff and water removed by evaporation and outflow. The marked retreat of the Fennoscandian and Alpine ice between 15 000 and 14 000 yr is recorded by an increase in clays indicative of northern provenance in Black Sea sediments. A short return toward glacial values in all the measured series occurs during the Younger Dryas cold period. The timing of the first marine inflow to the Black Sea is dependent on the sill depths of the Bosporus and Dardanelles channels. The depth of the latter is known to be 3808 5 m, which is consistent with first evidence of marine inundation in the Sea of Marmara around 12 000 yr. The bedrock gorge of the Bosporus reaches depths in excess of 3100 m (relative to present sea level), though it is now filled with sediments to depths as shallow as 332 m. Two scenarios are developed for the connection of the Black Sea with the Sea of Marmara. One is based on a deep Bosporus sill depth (effectively equivalent to the Dardanelles), and the other is based on a shallow Bosporus sill (less than 335 m). In the deep sill scenario the Black Sea’s surface rises |
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