Collaborative Research: Unlocking the Cenozoic/Cretaceous seawater sulfate record via inclusion of 17O in marine barite

PI将测量海洋沉积物一种以前从未分析过的化学性质--硫酸钡颗粒中两个微量氧同位素的变化。这些数据将提供过去1.25亿年来海洋化学变化的记录，这些变化是由地球碳、氧和硫循环的变化驱动的。了解这些元素(碳、氧和硫)的全球循环历史将有助于我们了解地质过程、自然气候变化和陆地和海洋中的生物过程之间的联系。活动还包括公共宣传(通过科学描述的卡通模块)，该项目将支持对一名研究生的培训。该项目将使用最近开发的一种方法，建立过去1.25亿年来海洋重晶石中硫酸盐中17O的记录，从而能够对重晶石中的17O进行高精度分析。海洋沉积物化学在地质时间尺度上是气候演化和地表变化的中心目录之一。海洋硫酸盐(在重晶石中捕获)的硫和氧同位素组成是过去1.25亿年来海洋化学的两个关键记录。它们之所以重要，是因为硫酸盐是微生物生命的能源，大约是大气氧的10倍，并可整合到广泛的生物地球化学过程和循环中，包括碳和铁的过程和循环。最近，又出现了一个新的假设，即大火成岩省的形成对硫同位素记录的影响。这里提出的新数据-重晶石中的17O-将被用来检验这一假设，更广泛地，以更好地理解白垩纪和新近纪的C、S和O旋回。这一裁决反映了美国国家科学基金会的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

The PIs will measure a never-before-analyzed chemical property of ocean sediments – variations in two trace isotopes of oxygen in barium sulfate particles. These data will provide a record of changes in ocean chemistry over the last 125 million years, changes that are driven by variations in the Earth’s carbon, oxygen and sulfur cycles. Understanding the history of the global cycles of these elements (carbon, oxygen, and sulfur) will help us understand the links between geological processes, natural climate change, and biological processes on land and in the ocean. Activities also include public outreach (via cartoon modules described the science), and the project will support training of a graduate student.This project will build a record of the 17O in sulfate from marine barite over the last 125 million years, using a recently-developed method that enables high-precision analysis of 17O in barite. The chemistry of marine sediments stands as one of the central catalogs of climatic evolution and earth surface change on geological timescales. The sulfur and oxygen isotopic composition of marine sulfate (as captured in barite) are two key records ocean chemistry over the last 125 million years. They are important because sulfate serves as an energy source for microbial life that is roughly 10 times larger than atmospheric oxygen, and that integrates across a wide range of biogeochemical processes and cycles, including those of carbon and iron. Recently, a new hypothesis was generated involving the influence of large igneous province formation on the sulfur isotope record. The new data proposed here – 17O in barite – will be used to test this hypothesis, and more broadly, to better understand the C, S, and O cycles through the Cretaceous and Cenozoic.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.