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Coccolithophorid (calcareous nannofossil) fossilization process response to paleoceanographic environmental reconstruction

颗石藻（钙质超微化石）化石过程对古海洋环境重建的响应

基本信息

批准号：
16540434
负责人：
TANAKA Yuichiro
金额：
$ 2.3万
依托单位：
National Institute of Advanced Industrial Science and Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

项目摘要

It is important how to draw out the oceanic condition of the fossil assemblage to reconstruct the paleooceanographical environment. The coccolithophorid assemblages change according to the seasonal change is clarified by using the sediment trap samples. The assemblages transition by the deposition process is clarified. In addition, it aimed to analyze the coccolith thanatocoenoses in the surface sediment is analyzed in the trap location, and to clarify the relation among the assemblages seasonal change, the vertical transport process, and the dissolution process.It became clear the following from the sediment trap experimentation result of mooring at depth 1371m and 4787m in northwest Pacific Ocean. It has been understood that the dominant three species, Emiliania huxleyi, Gephyrocapsa oceanica and Florisphaera profunda, from the analysis of the trap during year in this sea area are leveled assemblages. Therefore, it turned out that expecting the environment of the annual mean of surfa … More ce water would be reflected was appropriate in the environmental analysis with these taxa in the surface sediment in this sea area. On the other hand, because Coccolithus pelagicus was recognized increasing from April to May in the trap, it turned out that this species in the surface sediment indicated the period when the biological production from April-June was high.Increase of Oolithotus fragilis had been confirmed the increasing nutrients periods from the trap experiment. Detailed environmental transition analysis was done about the relation between the seasonal variation of the deposition process of the coccolithophorid and the surface sediment assemblages in the equator Pacific Ocean during past 250,000 years. The increase in the production frequency of this species was recorded in the oxygen stages 1, 3, 5, and 5/6 boundary. This species of increase periods were suggested to be a result of reflecting the influence in winter more strongly in this sediment core, because this species of increase season by the trap experiment has been limited in winter.The characteristic of the proxy taxa became clear different in each region and the paleooceanographical environmental variation's detailed analysis was enabled based on the result of the depositional processes and the considering of the characteristic coccolithophorid assemblages with the seasonal change. Less

如何提取化石组合所处的海洋环境，对重建古海洋环境具有重要意义。利用沉积物捕获器样品阐明了球石藻组合随季节变化的规律。阐明了沉积过程对组合的影响。此外，还对沉积物中的颗石化石群落进行了分析，阐明了其组成的季节变化、垂直输运过程和溶解过程之间的关系，并对西北太平洋1371 m和4787 m水深的沉积物捕获实验结果进行了分析。通过对该海域全年捕集器的分析，认为该海域优势种Emiliania huxleyi、Gephyrocapsa oceanica和Florisphaera profunda为水平组合。因此，对年平均海面环境的预期， ...更多信息该海域表层沉积物中的这些分类群在环境分析中反映出海水的特征是适当的。另一方面，在诱捕器中发现4 - 5月浮游球壳虫（Coccolithus pelagicus）数量增加，说明4 - 6月是浮游球壳虫生物生产力的高峰期，而脆弱齿象（Oolithotus fragilis）数量的增加则证实了诱捕器中浮游球壳虫数量的增加是营养盐增加的时期。对近25万年来赤道太平洋球石藻沉积过程的季节变化与表层沉积物组合的关系进行了详细的环境变迁分析。在氧阶段1，3，5，和5/6边界记录在该物种的生产频率的增加。这种增加周期的变化可能是由于该沉积物柱在冬季的影响更为强烈，由于诱捕实验所确定的该种的增长季节仅限于冬季，因此，在沉积过程的基础上，考虑到各海区的环境因素，各海区的代用分类群特征明显不同，从而对古海洋环境的变化进行了详细的分析。具有季节变化特征的颗石藻组合。少