EAGER: Towards a High Resolution Record of Phanerozoic Ocean Chemistry: Links to Plate Tectonics and Climate

走向显生界海洋化学的高分辨率记录：板块构造和气候的链接纽约州立大学石溪分校的特洛伊·拉斯伯里，EAR-1028663 ABSTRACT海洋是我们星球的心脏，也是使地球不同于我们所发现的其他行星的主要特征。限制地球系统相互联系的模型的困难很大程度上来自缺乏可靠的过去海水化学档案。Pi选择将重点放在海洋无脊椎动物化石中锶和镁的关系上，以研究古海水的变化。海水化学被认为是来自海脊扩张中心和大陆通量的热液混合的结果，以及各种元素的下沉，如新矿物的形成或在现有矿物表面的吸附。一些海水的地球化学模型利用海平面和火山活动的变化来暗示洋脊的扩展速度及其相应的通量的变化。这些模型密切预测了海洋代理记录中测量到的变化。然而，其他科学家坚持认为，没有证据表明自侏罗纪以来传播率发生了变化。这些科学家没有解决海水化学限制，因此他们的解释需要寻求另一种机制来产生海平面、气候和海水化学之间的观察到的关系。与海水的地球化学记录相矛盾的另一点是锶的行为。尽管基于低镁化石壳层中锶浓度的研究表明，锶在海水中的行为与镁相反，但最近的一篇科学论文认为，锶在海水中的行为与镁相同。他们认为，这种差异可能是对生物碳酸盐中锶的Kd了解较少。然而，这只会影响计算出的变化的幅度，而不会导致相反的关系。PIS的研究目标是从海洋化石中产生高分辨率的镁和锶的记录，以解决海水化学如何与新生代已知的构造事件和气候变化联系起来的问题--这样做可能是为了解决最重要的问题，即是什么导致了板块构造速率的变化，以及这种变化与全球气候变化的联系。

Towards a High Resolution Record of Phanerozoic Ocean Chemistry: Links to Plate Tectonics and ClimateTroy Rasbury, SUNY StonybrookEAR-1028663ABSTRACTThe oceans are the heart of our planet and are the primary feature that makes Earth different from other planets we have found. Much of the difficulty in constraining models for interlinking of the Earth systems comes from the paucity of reliable archives of past seawater chemistry. PI has chosen to focus on the relationship between Sr and Mg in marine invertebrate fossils to study changes in paleo-seawater. Seawater chemistry is thought to result from the mixing of hydrothermal fluids from ridge spreading centers and continental fluxes as sources, and the sinks of various elements such as in new mineral formation or sorption on existing mineral surfaces. Some geochemical models for seawater have used changes in sea level and volcanism to imply changes in the spreading rates of ocean ridges and their corresponding flux. These models closely predict the changes measured in the marine proxy record. However, other scientists maintain there is no evidence that spreading rates have changed since the Jurassic. These scientists do not address seawater chemistry constraints, and therefore their interpretation requires that another mechanism be sought to produce the observed relationships between sealevel, climate, and seawater chemistry. Another point of conflict with the geochemical record of seawater is the behavior of Sr. While studies based on Sr concentrations in low Mg fossils shells show that Sr behaves inversely to Mg in seawater, a recent Science paper argues that Sr behaves the same Mg in seawater. They suggest that the difference may be a poor understanding of the Kd for Sr in biogenic carbonates. However this would only impact the magnitude of calculated changes, not cause an inverse relationship. PIs research goal is to produce a high resolution record of Mg and Sr from marine fossils to address the issue of how seawater chemistry ties to known tectonic events and climate change in the Cenozoic- and by doing so to perhaps address the overarching question of what causes changes in rates of plate tectonics and how this links to global climate change.