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High resolution analysis of paleoenvironment and material transport during the hot-house Earth system

温室地球系统古环境和物质传输的高分辨率分析

基本信息

批准号：
15253007
负责人：
OKADA Hisatake
金额：
$ 26.87万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15253007/
关键词：
Cretaceous Ocean Anoxic Event Black Shale Paleoceanography 黒色頁画

项目摘要

This research group (Leader : Hisatake Okada) had started in 1999 a field survey and sampling project in Southern France using the Grant-in Aid for Scientific Research (No. 11691113). The project was designed as a precursory study for one of IODP (Integrated Ocean Drilling Program)'s main target, the "Paleoenvironment under Extreme Climates". The team had studied extensively the OAE1b interval of Mid-Cretaceous Warm Event, and had obtained a massive columnar section containing Paquier interval, and also had conducted several test drilling at the upper level of OAE1b interval.In this new research project (Grant-in Aid for Scientific Research No. 15253007) designed as the second project to study the paleoceanography of Mid-Cretaceous OAE sequence in Southern France, we have planed to obtain high quality cores from OAE1a and OAE 1b intervals. We have hired a professional company FORACO for this task and have succeeded to recover a 60m core from Goguel (OAE1a) level at 10km north of Barrem … More Village and also 15m cores from Killian (OAE1b) level at St.Andre. These were the first cores ever recovered from these intervals. In order to conduct high-quality analysis for these cores, we have developed new techniques : a technique to fix the whole core by a special type of resin without any disturbance of the fractured portions and a technique of precise micro drilling to obtain samples at one mm intervals.In addition to elaborate non-destructive analysis for the whole cores, various micropaleontological, geochemical and sedimentological analysis has been conducted. As a result of these analysis it is now clear that two types of oceanic conditions existed during the formation of black shales in the OAE1a event : a condition with total water column becoming anoxic resulting a devastation to marine bioshere, and the other in which anoxic water did not reached to photic zone causing a limited effect to marine biota. It is also evident that during the Killian level of OAE1b event four cycles of anoxic fluctuations occurred. The cause of this fluctuations can be deduced to fluctuation of primary production level resulted by changing amount of terrestrial nutrient supply. Less

该研究小组(组长：冈田久久)于1999年利用科学研究补助计划(11691113号)在法国南部启动了一个实地调查和抽样项目。该项目是为综合大洋钻探计划S的主要目标之一“极端气候下的古环境”而设计的前兆研究。该团队对中白垩世暖事件的OAE1b段进行了广泛的研究，获得了包含Paquier段的大块柱状剖面，并在OAE1b段的上部进行了多次试钻。在这个新的研究项目(补助科学研究项目15253007号)中，我们计划从OAE1a和OAE1b段中获得高质量的岩心。我们已经聘请了一家专业公司FORACO来完成这项任务，并成功地从巴雷姆…以北10公里处的Goguel(OAE1a)水平回收了60米的岩芯更多来自圣安德烈的基利安(OAE1B)级的1500万个村庄和核心。这是从这些间隔中发现的第一批岩芯。为了对这些岩心进行高质量的分析，我们开发了新的技术：用一种特殊类型的树脂固定整个岩心而不干扰破碎部分的技术，以及精确的微钻孔技术，以一毫米的间隔获取样品。除了对整个岩心进行详细的无损分析外，我们还进行了各种微古生物、地球化学和沉积学分析。这些分析的结果表明，在OAE1a事件中黑色页岩的形成过程中存在两种海洋条件：一种是总水柱变得缺氧，对海洋生物造成破坏；另一种是缺氧水没有到达光带，对海洋生物群的影响有限。同样明显的是，在基利安水平的OAE1b事件期间，发生了四个周期的缺氧波动。这种波动的原因可以归结为由于陆地养分供应量的变化而引起的初级生产水平的波动。较少