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Comparative paleoceanographical study using piston cores from Okhotsk Basin and Suiko Sea Mount

使用鄂霍次克盆地和Suiko海山的活塞岩心进行比较古海洋学研究

基本信息

批准号：
11640491
负责人：
KATO Yoshihisa
金额：
$ 2.24万
依托单位：
TOKAI UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2002
项目状态：
已结题

项目摘要

The object of this work is to reconstruct the change of paleo-environment after the last glacial age. For this purpose, two sediment cores were obtained using a piston corer in the Okhotsk Basin (12.8 m length) and at near the summit of Suiko Sea Mount (13.5 m length), which is one of the Emperor Sea Mounts. In the Okhotsk core, reduced suifur, biogenic opal and elemental composition of sediment were determined. In the Suiko core, biogenic carbonate and elemental composition of sediment were determined.In the Okhotsk core, the content of biogenic opal, as well as biogenic barium, was higher in the upper layer and gradually decreases with downcore, and has a maximum in the layer of 8-10 m depth, corresponding to the last glacial maximum age. Below the layer, the content of reduced sulfur gradually increases with downcore. These findings suggest that the biological production in the Okhotsk Sea is rather lower in the glacial period than in the interglacial age. On the other hand, the distributions of lithogenic elements, iron, titanium, aluminum, calcium and magnesium, were uniform in the upper interglacial period, but rapidly increased with downcore below the depth of 8-10 m. This implies that such the change of elemental composition of the sediment result from the greater supply of ice-rafted detritus in the last glacial maximum age.In the Suiko core, the concentration of biogenic carbonate varies from 4% to 94%, and the average was 69% in the whole core. The age of the layer of 2.5 m depth is estimated to 120 kyr B.P. on the basis of Narita et al. (2002). Therefore, it is suggested that the biological production in this area also has decreased during the last glacial age.

本研究的目的是重建末次冰期后的古环境变化。为此，使用活塞盖在鄂霍次克盆地（12.8 m长）和皇帝海山之一的Suiko海山山顶附近（13.5 m长）获得了两个沉积物岩心。在鄂霍次克岩心中测定了还原硫、生物蛋白石和沉积物元素组成。对绥科岩心进行了生物成因碳酸盐和沉积物元素组成测定。在鄂霍次克岩心中，生物蛋白石和生物钡的含量在上层较高，随着岩心的下降而逐渐降低，在8 ~ 10 m深度层达到最大值，与末次冰期最大年龄相对应。层下还原态硫含量随岩心下降而逐渐增加。这些结果表明，鄂霍次克海在冰期的生物产量要低于间冰期。而造岩元素铁、钛、铝、钙、镁的分布在间冰期上部较为均匀，但在8 ~ 10 m深度以下随岩心下移而迅速增加。这表明，沉积物元素组成的这种变化是由于末次冰期极大期冰筏碎屑供应增加所致。在Suiko岩心中，生物碳酸盐的含量在4% ~ 94%之间，整个岩心的平均含量为69%。根据Narita et al.(2002)，估计2.5 m深度层的年龄为120kyr B.P.。因此，该地区的生物生产在末次冰期也有所减少。