CAREER : A Research and Education Plan in Global Biogeochemical Cycles: Seawater Calcium Isotopes and Carbonate Deposition History

职业：全球生物地球化学循环的研究和教育计划：海水钙同位素和碳酸盐沉积历史

• 批准号: 0449732
• 负责人: Adina Paytan
• 金额: $ 74.78万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-05-15 至 2007-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0449732&HistoricalAwards=false
• 关键词: CAREER; Research; Education; Plan; Global

PaytanAbstractFunds are provided for a study of Ca concentrations and Ca isotopes in marine barite to study global biogeochemical cycles back to the last glacial maximum, and then use this data to better understand the Ca cycle and CaCO3 depositional history in the oceans and to ultimately relate them to tectonic and climate changes. This will be a two-part investigation. First, the calcium isotopic composition (delta 44Ca values) of barite in box core-tops will be compared with the known constant delta 44Ca of modern seawater to determine the fractionation between barite and seawater, and to evaluate the constancy of this fractionation in a range of modern environments. Then, a roughly 130 million year record of barite delta 44Ca will be produced, using existing deep-sea cores at a resolution of about 0.5 m.y., with higher-resolution sampling in a few key intervals. On the education side the PI will develop student-focused problem-based classes and a school-wide education outreach program at Stanford.This field of study could provide valuable information regarding the sources and sinks of Ca, including carbonate production/burial and hydrothermal exchange reactions. Given linkages between the carbonate and carbon cycles, this work could also yield valuable perspectives on the long-term history of ocean pH and atmospheric CO2.

摘要通过对海洋重晶石中Ca浓度和Ca同位素的研究，研究可追溯到末次盛冰期的全球生物地球化学循环，并利用这些数据更好地了解海洋中Ca旋回和CaCO3沉积历史，最终将其与构造和气候变化联系起来。调查将分为两部分。首先，将盒状岩心顶部重晶石的钙同位素组成（δ 44Ca值）与现代海水中已知的δ 44Ca常数进行比较，以确定重晶石与海水之间的分馏，并评估这种分馏在一系列现代环境中的稳定性。然后，利用现有的深海岩心，以大约0.5米的分辨率，在几个关键间隔进行更高分辨率的采样，将产生大约1.3亿年的重晶石三角洲44Ca记录。在教育方面，PI将在斯坦福大学开发以学生为中心的问题为基础的课程和全校范围的教育推广计划。这一领域的研究可以为钙的来源和汇提供有价值的信息，包括碳酸盐的产生/埋藏和热液交换反应。考虑到碳酸盐和碳循环之间的联系，这项工作也可以对海洋pH值和大气二氧化碳的长期历史产生有价值的看法。