Using Mg-Paleotheromometry to Deconvolute the Marine Oxygen Isotope Record

本计画将探讨有孔虫方解石中Mg/Ca值作为水温示踪剂的效用。 如果Mg/Ca与水温具有一致的相关性，并且不受生理分馏或沉积后成岩作用等复杂因素的影响，则可以将其与18 O/16 O结合使用，以估计作为冰量函数的海面温度和平均海洋组成，从而确定地质历史中的两个重要变量。 将对不同的样品组进行Mg/Ca和18 O/16 O的配对分析，以测试（1）物种特异性分馏，（2）生长速率和（3）溶解的影响。 研究将包括至少两个来自热带太平洋的冰/间冰期时间尺度的岩心分析，以测试该方法的适用性。 由相同分析产生的13 C/12 C数据将用于评估过去海洋碱度和二氧化碳分压的记录，使用先前在实验室建立的校准。

This project will explore the utility of Mg/Ca in foraminiferal calcite as a tracer of water temperature. If Mg/Ca has a consistent correlation with water temperature and is not subject to complications such as physiologic fractionation or post-depositional diagenesis, it can be used in conjunction with 18 O/16 O to estimate sea surface temperature and mean ocean composition as a function of ice volume, allowing the determination of two important variables in the geologic past. Paired analyses of Mg/Ca and 18 O/16 O will be done on various sample sets to test for effects of (1) species-specific fractionation, (2) growth-rate, and (3) dissolution. Studies will incorporate analyses in at least two cores from the tropical Pacific over glacial/interglacial time scales to test applicaiton of the method. 13 C/12 C data generated by the same analyses will be used to evaluate the record of past ocean alkalinity and partial pressure of CO 2, using calibrations previously established in the laboratory.