10. INITIAL DIATOM RECORD OF SITES 657 AND 658: ON THE HISTORY OF UPWELLING AND CONTINENTAL ARIDITY1
10. INITIAL DIATOM RECORD OF SITES 657 AND 658: ON THE HISTORY OF UPWELLING AND CONTINENTAL ARIDITY1
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10. 657 和 658 号地点的初始硅藻记录：关于上升流和大陆干旱的历史1
DOI：
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发表时间：
1989
期刊：
影响因子：
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通讯作者：
B. Stabell
中科院分区：
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作者：
B. Stabell
对从海洋钻探计划站点 658 取芯的高分辨率第四纪剖面中回收的样品进行的详细分析表明，海洋硅藻的丰度非常高（6.4-8.3 x I0 7 阀/克干沉积物），存在于间冰期氧同位素 7.5 和 9.3 阶段。较小的丰度峰（29-300 x I0 5 阀/g干沉积物）存在于氧同位素阶段边界1/2、5/6、9/10、11/12和13/14附近。因此，高丰度的硅藻（解释为高生产力）与终止有关。第四纪淡水硅藻的丰度最高，主要存在于间冰期沉积物中，但在冰期期间（氧同位素阶段 2 和 8）以及接近终点（阶段边界 7/8 和 15/16）也有记录。上新世淡水硅藻记录表明频率在 2.8 Ma 处下降。有人认为，淡水硅藻频率的下降表明气候变得更加潮湿（假设风成运输）或气候变得更加干旱（假设河流运输）。
Detailed analyses of samples recovered from the high-resolution Quaternary section cored at Ocean Drilling Program Site 658 reveal that very high abundances (6.4-8.3 x I0 7 valves/g dry sediment) of marine diatoms occur in interglacial oxygen isotope stages 7.5 and 9.3. Smaller abundance peaks (29-300 x I0 5 valves/g dry sediment) are present near oxygen isotope stage boundaries 1/2, 5/6, 9/10, 11/12, and 13/14. Therefore, high abundances of diatoms, interpreted as high productivity, are related to terminations. The Quaternary freshwater diatoms have their highest abundances mainly in sediments deposited during interglacial periods, but they are also recorded during glacial intervals (oxygen isotope stages 2 and 8), and near terminations (stage boundaries 7/8 and 15/16). The Pliocene freshwater diatom record indicates a frequency decrease at 2.8 Ma. It is suggested that the freshwater diatom frequency decrease indicates either a change to a more humid climate (assuming eolian transport) or a change to a more arid climate (assuming fluvial transport).