Opal accumulation rates in the equatorial Pacific and mechanisms of deglaciation
Opal accumulation rates in the equatorial Pacific and mechanisms of deglaciation
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DOI：
10.1029/2010pa002008
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发表时间：
2011-02-18
期刊：
影响因子：
--
通讯作者：
Fleisher, M. Q.
中科院分区：
文献类型：
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作者：
Hayes, C. T.;Anderson, R. F.;Fleisher, M. Q.
南极洋翻转的冰消作用对赤道太平洋沉积物的一个可能的影响是蛋白石积累率的增加。这可能是由于富含二氧化硅的深水通过亚南极模式水传输到赤道温跃层以及硅藻生产力的相关增加。在寻找这个印记，从中央（TT 013-PC 72）和东部（V19-30）赤道太平洋的沉积物岩心进行了分析Th-230标准化蛋白石积累率在过去的五个和三个冰川终端，分别。赤道蛋白石积累率持续相对较低的价值观，在大部分的记录，并打断了大幅度增加集中在一些终端，但不是全部。此外，增加蛋白石通量的两个时期，观察到不符合终止。在赤道太平洋的二氧化硅收支中可能需要考虑南大洋以外的来源，但Neogloboquadrina dutertrei的C-13三角洲可用于支持每种情况下深水营养信号的存在。尽管对于每一次晚更新世冰期，一个共同的冰消机制，或一个共同的印记仍然是难以捉摸的，蛋白石通量和N。dutertrei为过去向赤道潜流注入深水营养物提供了诊断。
A possible imprint on equatorial Pacific sediments of a deglacial reinvigoration of the Southern Ocean overturning is increased opal accumulation rate. This would arise from the transmission of silica-rich deep water to the equatorial thermocline via Subantarctic Mode Water and an associated increase in diatom productivity. In search of this imprint, sediment cores from the central (TT013-PC72) and eastern (V19-30) equatorial Pacific have been analyzed for Th-230-normalized opal accumulation rates over the past five and three glacial terminations, respectively. Equatorial opal accumulation rates sustained relatively low values over much of the records and were punctuated by large increases centered on some terminations, but not all. Furthermore, two periods of increased opal flux were observed that do not coincide with terminations. Sources other than the Southern Ocean may need to be considered in the silica budget of the equatorial Pacific, but the delta C-13 of Neogloboquadrina dutertrei can be used to support the presence of a deepwater nutrient signal in each case. Although a common deglacial mechanism, or a common imprint thereof, for each of the late Pleistocene glaciations remains elusive, the combination of opal flux and delta C-13 of N. dutertrei provides a diagnostic for past injection of deepwater nutrients into the Equatorial Undercurrent.