EAPSI: Analyzing lithium and boron isotopes in hot springs and rivers of Taiwan

EAPSI：分析台湾温泉和河流中的锂和硼同位素

• 批准号: 1415104
• 负责人: Kirstin Washington
• 金额: $ 0.51万
• 依托单位: Washington Kirstin
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-01 至 2015-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1415104&HistoricalAwards=false
• 关键词: EAPSI; Analyzing; lithium; boron; isotopes

Atmospheric carbon dioxide is a direct external driver of Earth's climate. Over geological timescales, carbon dioxide is released through volcanism and is balanced by weathering of silicate minerals. To constrain our understanding of how weathering processes affect Earth's carbon cycle and climate, this project will employ geochemical tools to characterize the chemistry of hot springs and rivers on the island of Taiwan. Taiwan serves as an ideal natural environment for studying hydrothermal inputs to river systems and has been shown to have some of the highest rates of chemical weathering. Lithium and boron isotopes can be used as proxies for chemical weathering intensities through Earth history and today. Interpretations of weathering processes via lithium and boron isotopes are confounded by a lack of data from hot springs; records of chemical weathering should correct for these isotopic inputs through mass balance. Hot spring and river water chemistry will be analyzed in collaboration with Dr. Chen-Feng You's Isotope Geochemistry Laboratory (IGL) at the National Cheng Kung University. Dr. You's expertise in low-temperature geochemistry, and IGL's equipment affords an opportunity to employ unique methods to address the problems presented by this project. In addition to isotopic measurements using a Multi-Collector Inductively-Coupled Plasma Mass Spectrometer (MC-ICP-MS) for lithium and a Thermal Ionization Mass Spectrometer (TIMS) for boron, major elements will be measured for chemical geothermometry. Chemical geothermometry will estimate the subsurface water temperature in hot springs during interaction with rock. This will help to constrain the temperatures lithium and boron isotopes experience during the fractionation. Mixing calculations for hot springs inputs to rivers using lithium and boron isotopes will determine inputs of hot springs, which can inform the global budgets of the isotopes. This NSF EAPSI award is funded in collaboration with the National Science Council of Taiwan.

大气中的二氧化碳是地球气候的直接外部驱动力。在地质时间尺度上，二氧化碳通过火山活动释放，并通过硅酸盐矿物的风化平衡。为了限制我们对风化过程如何影响地球碳循环和气候的理解，本项目将采用地球化学工具来描述台湾岛温泉和河流的化学特征。台湾是研究河流系统热液输入的理想自然环境，并已被证明具有最高的化学风化率。锂和硼同位素可以作为地球历史和今天化学风化强度的替代物。通过锂和硼同位素的风化过程的解释是混淆了缺乏数据的温泉，化学风化的记录应纠正这些同位素输入通过质量平衡。温泉水和河水的化学成分将与国立成功大学尤振峰博士的同位素地球化学实验室（IGL）合作进行分析。尤博士在低温地球化学方面的专业知识和IGL的设备为采用独特的方法解决该项目提出的问题提供了机会。除了使用多接收器电感耦合等离子体质谱仪（MC-ICP-MS）对锂进行同位素测量和使用热电离质谱仪（TIMS）对硼进行同位素测量外，还将对主要元素进行化学地质测温测量。化学地质测温法将估计温泉与岩石相互作用期间的地下水温度。这将有助于限制锂和硼同位素在分馏过程中经历的温度。使用锂和硼同位素混合计算温泉输入河流将确定温泉的输入，这可以为同位素的全球预算提供信息。这个NSF EAPSI奖是与台湾国家科学理事会合作资助的。