A New Approach to the Archean Sulfur Cycle from Marine Carbonates

从海洋碳酸盐中研究太古代硫循环的新方法

基本信息

批准号：
1349858
负责人：
Jess Adkins
金额：
$ 34.5万
依托单位：
California Institute of Technology
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2014
资助国家：
美国
起止时间：
2014-03-01 至 2017-02-28
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1349858&HistoricalAwards=false
关键词：
New Approach Archean Sulfur Cycle

项目摘要

A New approach to the Archean sulfur cycle from marine carbonatesBy Jess Adkins, Woodward FischerABSTRACTThe rise of atmospheric oxygen from an originally reduced planet surface is a central problem in Earth history. It is widely believed that the oxygenation of the Earth's oceans and atmosphere occurred in abrupt steps. The Great Oxygenation Event at the Archean-Proterozoic boundary is one of the better studied of these deep-time jumps, chiefly through the mass independent fractionation (MIF) of the stable sulfur isotopes. However, most of this evidence comes from the reduced forms of sulfur, chiefly pyrite being enriched in the MIF signal. The current understanding assumes that the complementary light MIF signal resides in oceanic sulfate at this time, a trace phase in carbonates that has been analytically inaccessible until now. PIs will use a new MC-ICP-MS method that lowers the current detection limit for sulfate in Archean carbonates by over three orders of magnitude. Micro-drilling of specific textures to unravel the simultaneous evolution of the sulfate and sulfide phases in Late Archean rocks will be used to better understand how it is that the early earth transitioned from an anoxic atmosphere to one with substantial amounts of molecular oxygen. PIs will collect new outcrop and drill core samples during a field campaign to the Campbellrand Platform in South Africa and make hundreds of new sulfur isotope measurements on these samples. Their goal is to create a history of seawater sulfate evolution during this key moment in earth history.

从海洋碳酸盐碳酸盐杰西·阿德金斯（Jess Adkins），伍德沃德·菲舍拉布尔施特（Woodward Fischerabstractrats）从最初减少的行星表面上的大气氧的兴起是地球历史上的一个核心问题，一种新的方法是大气氧的兴起。人们普遍认为，地球海洋和大气的氧合发生在突然的步骤中。 Archean-Proterokoic边界上的大氧合事件是这些深度跳跃的更好研究之一，主要是通过稳定的硫同位素的质量独立分馏（MIF）。但是，大多数证据来自硫的减少形式，主要是黄铁矿富集在MIF信号中。当前的理解假设此时互补的光MIF信号驻留在海洋硫酸盐中，这是碳酸盐中的痕迹，到目前为止在分析上无法访问。 PIS将使用一种新的MC-ICP-MS方法，该方法将硫酸盐在Archean Carbonates中的当前检测极限降低了三个数量级以上。在晚期天生岩石中硫酸盐和硫化物相的同时进化的特定纹理的微钻孔将用于更好地理解从缺氧气氛过渡到大量分子氧的早期地球。 PI将在一次现场活动中收集新的露头和钻孔样品，向南非的坎贝兰德平台，并对这些样品进行数百种新的硫同位素测量。他们的目标是在地球历史上这个关键时刻创造海水硫酸盐进化的历史。