Quantifying the 18O/16O of Glacial Meltwater Pulses Using a Novel LA-ICPMS/IRMS Multiproxy Approach

使用新型 LA-ICPMS/IRMS 多代理方法量化冰川融水脉冲的 18O/16O

• 批准号: 1061676
• 负责人: Howard Spero
• 金额: $ 35.96万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1061676&HistoricalAwards=false
• 关键词: Quantifying; 18O; 16O; Glacial; Meltwater

The growth and decay of large ice sheets over the North American continent during the last glacial period had far reaching effects on climate and ocean circulation. Meltwater input into the oceans during deglaciation caused sea level to rise and has been invoked as a cause for rapid climate change. However, the relative volumetric contributions of individual meltwater pulses has been difficult to constrain, and often relies on assumptions about the stable isotope composition of the North American (Laurentide) ice sheet meltwater geochemistry. The fact that the ice sheets themselves had heterogeneous compositions, varying in both time and space, makes reconstruction a challenge.This research, carried out by scientists at the University of California at Davis, develops a novel technique to determine the instantaneous oxygen isotope composition of meltwater from the North American ice sheet. Measurements of both trace element (Mg/Ca and Ba/Ca) and oxygen isotope (δ18O) composition will be made on individual shells of planktonic foraminifera preserved in sediments of the Gulf of Mexico. Specific goals of the project are to: 1) refine the sample preparation and measurement protocols, 2) improve the calibration of the Ba/Ca salinity proxy, 3) test the technique by computing modern Mississippi River water using the new method, and 4) compute the oxygen isotope composition or river/meltwater during selected intervals of the deglaciation (Termination I) and Marine Isotope Stage 3. In terms of broader impacts, funding supports a female doctoral candidate and offers the opportunity for undergraduates to be exposed to state of the art analytical methods. The methods developed in the course of this work method could potentially be widely applied in paleoceanographic studies.

在最后一个冰川时期，北美大陆上大型冰盖的生长和衰变对气候和海洋循环产生了巨大影响。脱气过程中对海洋的融化输入导致海平面上升，并被援引是气候变化的原因。但是，各个融合脉冲的相对容量贡献很难限制，并且通常依赖于对北美（Laurentide）冰片融化地球化学稳定同位素组成的假设。冰盖本身具有异质作品，在时间和空间上都不同，这使重建成为挑战。这项研究是由加利福尼亚大学戴维斯分校的科学家进行的，它开发了一种新型技术，以确定北美冰盖中融合材料的瞬时氧同位素组成。 将在保存在墨西哥湾沉积物中的浮游有孔虫的单个壳上，对痕量元件（mg/ca和ba/ca）和氧同位素（＆＃948; 18o）组成均测量。该项目的具体目标是：1）完善样品制备和测量协议，2）改善BA/CA盐度代理的校准，3）通过使用新方法计算现代密西西比河水来测试该技术，以及4）计算氧同位素组成或河流/融合阶段的阶段和河流的阶段（等级iS）和MARINGE IS IS IS IS IS IS IS IS IS IS IS IS IS IS IS CRAIME IS IS IS IS CAINS IS IS CAINS IS IS IS IS IS IS IS IS属于IS IS IS IS IS属于Mar i）。支持女性博士候选人，并为本科生提供了接触最先进的分析方法的机会。在这项工作方法过程中开发的方法可能会广泛应用于古文化研究。