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Erhaltung geochemischer Proxies in Foraminiferen - Karbonatdiagenese im natürlichen Labor des IODP Pacific Equatorial Age Transect (PEAT)

IODP 太平洋赤道时代样带 (PEAT) 自然实验室中有孔虫 - 碳酸盐岩成岩作用中地球化学指标的保护

基本信息

批准号：
175584968
负责人：
Dr. Edmund Hathorne, Ph.D.
金额：
--
依托单位：
Forschungseinheit Paläo-Ozeanographie
依托单位国家：
德国
项目类别：
Infrastructure Priority Programmes
财政年份：
2010
资助国家：
德国
起止时间：
2009-12-31 至 2018-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/175584968?language=en
关键词：
Erhaltung geochemischer Proxies Foraminiferen Karbonatdiagenese

项目摘要

The trace element and isotopic chemistry of the calcite shells (tests) of foraminifera preserved in marine sediments has revealed, via geochemical proxies like oxygen isotope and Mg/Ca ratios, much of what we know about the global climate system in the geologic past. Such information is crucial for the understanding of the role of atmospheric CO2 in climate change and the ability of the Earth system to regulate atmospheric CO2. However, ancient foraminifera tests can be altered post deposition by a process where the original calcite is replaced by secondary crystals which take the form of the test. This process, termed “neomorphic recrystallisation”, is poorly understood but there is geochemical evidence that the secondary calcite can retain some of the original geochemical signal. IODP Expedition 320/321 recovered sediments along an age transect where sediments of similar age have been subjected to different diagenetic histories. A multi-component study of the pore waters, bulk carbonate components and foraminifera tests from selected intervals of this natural diagenetic laboratory would help quantify neomorphic recrystallisation and the preservation of geochemical proxies in foraminifera.

海洋沉积物中保存的有孔虫方解石壳（测试）的微量元素和同位素化学通过氧同位素和镁/钙比等地球化学指标揭示了我们对过去地质时期全球气候系统的了解。这些信息对于了解大气二氧化碳在气候变化中的作用以及地球系统调节大气二氧化碳的能力至关重要。然而，古代有孔虫测试可以在沉积后通过以下过程进行改变：原始方解石被采用测试形式的次级晶体取代。这一过程被称为“新形重结晶”，人们对此知之甚少，但有地球化学证据表明，次生方解石可以保留一些原始的地球化学信号。 IODP 320/321 探险队沿着年龄样带回收了沉积物，其中相似年龄的沉积物经历了不同的成岩历史。对这个自然成岩实验室选定区间的孔隙水、大量碳酸盐成分和有孔虫测试进行的多组分研究将有助于量化新形态重结晶和有孔虫地球化学代理的保存。