Ancient Atmospheric Carbon Dioxide, Paleoclimates, and the Stable Isotope Geochemistry of Low Temperature Iron (III) Oxides

古代大气二氧化碳、古气候和低温氧化铁 (III) 的稳定同位素地球化学

• 批准号: 0106257
• 负责人: Crayton Yapp
• 金额: $ 30.72万
• 依托单位: Southern Methodist University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-06-15 至 2005-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0106257&HistoricalAwards=false
• 关键词: Ancient; Atmospheric; Carbon; Dioxide; Paleoclimates

EAR-0606257Crayton J. YappAbstractAncient Atmospheric CO2, Paleoclimates, and the Stable Isotope Geochemistry of Low Temperature Iron (III) OxidesThe geologic record has revealed that climate change on Earth occurs on a wide range oftemporal and spatial scales. As a result, the search for answers to questions about causality in climate change has become more complex. Development of a deep understanding of the mechanisms by which natural systems were (and are) linked through the Earth's fluid spheres(the atmosphere and hydrosphere) requires new sources of information on both modern and ancient environments. Among the requirements are data on the composition of ancient atmospheres, surficial temperatures and the behavior of the hydrologic cycle.Studies of the oxygen and hydrogen isotope systematics of the common, low-temperatureiron oxyhydroxide, goethite ( -FeOOH), have established its value as a source of information on wet, oxidizing, continental environments such as lateritic soils. Moreover, it was discovered that a small amount of CO2 is istrapped in the crystal structure of goethite as an Fe(CO3 )OH component in solid solution. This Fe(CO3 )OH serves as a proxy for the partial pressure and carbon isotope composition of CO2 present at the time of goethite crystallization. Therefore, goethite from ancient soils can be used to determine the isotopic composition of waters, paleotemperatures, the presence of ancient biological activity, soil CO2 pressures, and, under the right circumstances, the partial pressure of CO2 in the Earth's atmosphere.A continuation of efforts to contribute information on long-term changes in continental climate and atmospheric chemistry during the Phanerozoic is proposed here. Two paleosols (Late Paleocene and Middle Eocene laterites) that bracket the Early Tertiary thermal maximum have been identified as promising candidates for study. Carbon,hydrogen and oxygen isotope, chemical, XRD and petrographic data would be obtained from multiple samples of these highly leached soils. These data should provide information on atmospheric CO2 pressures, climatic temperatures, isotopic compositions of waters and biological activity.

EAR-0606257CRAYTON J. YAPPABSTRACTINACT大气二氧化碳，古气候和稳定的低温铁（III）氧化物地质记录的同位素地球化学已显示，地球上的气候变化发生在广泛的范围内和空间尺度上。结果，寻找有关气候变化因果关系问题的答案变得更加复杂。对自然系统通过地球的流体球（大气和水圈）联系起来的机制有深刻的理解，需要有关现代和古代环境的新信息来源。其中包括有关古代大气组成的数据，表面温度以及水文周期的行为。有关湿，氧化，大陆环境（如乳酸土壤）的信息来源。此外，已经发现，少量的二氧化碳被置于谷岩的晶体结构中，作为固体溶液中的Fe（CO3）OH分量。这种Fe（CO3）OH是在谷杆菌结晶时存在的二氧化碳的部分压力和碳同位素组成的代理。因此，可以使用来自古代土壤的绿铁矿来确定水，古植物，古代生物学活动，土壤二氧化碳压力以及在正确情况下的同位素组成这里提出了有关在Phanerozoic期间大陆气候和大气化学的长期变化的努力。两种古代溶（晚古新世和中始新世后期），括号早期三级热最大值已被确定为有前途的研究候选人。将从这些高度浸出的土壤的多个样品中获得碳，氢和氧同位素，化学，XRD和岩石学数据。这些数据应提供有关大气二氧化碳压力，气候温度，水域的同位素组成和生物活性的信息。