An Integrated Sedimentological and Multi-proxy Geochemical Investigation of the Neoproterozoic Climatic Paradox

新元古代气候悖论的综合沉积学和多代理地球化学研究

• 批准号: 14474487
• 负责人: Professor Dr. Thilo Bechstädt
• 金额: --
• 依托单位: Forschungsschwerpunkt Krustendynamik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2011-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/14474487?language=en
• 关键词: Integrated; Sedimentological; Multi; proxy; Geochemical

The unique geological paradox of glaciomarine diamictites intercalated within apparently warm-water carbonates at tropical latitudes on all major cratons during the Neoproterozoic remains an unsolved puzzle. A global preglacial negative carbon excursion begins 10 to 20 of metres below the tillites, and the carbon isotope profile is negative for several tens of metres in the postglacial cap carbonate succession before returning to Neoproterozoic background levels. Several models have been proposed to explain these apparent rapid swings between climatic extremes, termed the Neoproterozoic climatic paradox (NCP), and the associated isotopic changes in seawater chemistry. The "soft" and "hard" Snowball Earth models have generated most scientific interest and propose at least two global glaciations occurred. Several other models exist, not all of which invoke dramatic climatic changes. We propose an integrated sedimentological and multi-proxy geochemical study in outcrop and core to investigate the NCP. The study will use a multidisciplinary approach involving collaboration of a larger group of specialists. Research will focus on the critical intervals in three areas, Namibia, Southern Australia and the Urals and include the succession below (preglacial) and above (postglacial) the diamictites, the diamictite units themselves, and the interglacial rocks between the older Sturtian and younger Marinoan diamictites.

在新元古代期间，在热带纬度所有主要大陆上，冰海杂岩夹在明显的温水碳酸盐岩中的独特地质悖论仍然是一个未解之谜。一个全球性的冰前负碳漂移开始10至20米以下的冰碛岩，和碳同位素剖面是负的几十米的冰后帽碳酸盐岩演替之前，返回到新元古代的背景水平。已经提出了几种模型来解释这些明显的快速波动之间的气候极端，称为新元古代气候悖论（NCP），以及相关的同位素变化的海水化学。“软”和“硬”雪球地球模型引起了最大的科学兴趣，并提出至少发生了两次全球冰川。还有其他几种模型，但并非所有模型都能引起剧烈的气候变化。我们建议在露头和岩心中进行综合沉积学和多指标地球化学研究来调查NCP。这项研究将采用多学科方法，涉及更多专家的合作。研究将集中在三个地区的关键间隔，纳米比亚，澳大利亚南部和乌拉尔山，包括继承以下（冰前）和以上（冰后）的杂岩，杂岩单位本身，和间冰期岩石之间的老斯特阶和年轻的马里诺杂岩。