Global Climatic Consequence of CO2 Released During Eocene Regional Metamorphism

始新世区域变质作用释放的二氧化碳对全球气候的影响

• 批准号: 9304939
• 负责人: Derrill Kerrick
• 金额: $ 24.17万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-08-01 至 1997-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9304939&HistoricalAwards=false
• 关键词: Global; Climatic; Consequence; CO2; Released

9304939 Kerrick Collisional orogenesis may provide a climatically important source of CO2, thus requiring a re-examination of the role of mountain building and orogenic metamorphism in long-term global change. The elevated paleoatmospheric CO2 levels proposed for the Eocene may have resulted from CO2 released during Eocene regional metamorphism that affected extensive segments of the Tethys and Circum-Pacific orogenic belts. Based on the geologic record, the regional metamorphism in the Tethyan Himalayan orogen alone may have provided enough CO2 to produce a significant Eocene climatic impact. The quantities and fluxes of CO2 released to the atmosphere by decarbonation reactions in carbonate and carbonaceous lithologies (e.g., siliceous dolomites, marls, black shales) during prograde regional metamorphism represents a much neglected problem. From estimates of the size of the Himalayan orogen affected by Eocene metamorphism, the proportion of metacarbonate and graphitic rocks involved in this metamorphism, and geochronologic analysis of the duration of prograde metamorphism, and Eocene atmosphere could have received a large flux of metamorphic CO2 ( 1019 moles/Ma). Geochronologic analyses reveal a remarkable similarity in peak metamorphic ages (i.e., 40-50 Ma) for many areas within the Tethys and Circum-Pacific orogens, thus supporting the concept of a major, world-wide Eocene regional metamorphism. There are two primary thrusts of our proposed interdisciplinary research: (1) analysis of the geologic record to quantify the amount and rate of metamorphic CO2 production during the Eocene, and (2) modeling the impact of metamorphic CO2 fluxes on the Eocene atmosphere. ***

小行星9304939 碰撞造山作用可能提供一个气候上重要的CO2来源，因此需要重新审视造山作用和造山变质作用在长期全球变化中的作用。 提出的始新世古大气CO2水平升高可能是由于始新世区域变质作用期间释放的CO2影响了特提斯和环太平洋造山带的广泛部分。 根据地质记录，仅特提斯喜马拉雅造山带的区域变质作用就可能提供足够的二氧化碳来产生重大的始新世气候影响。 通过碳酸盐和碳质岩性中的脱碳反应释放到大气中的CO2的量和通量（例如，硅质灰岩、泥灰岩、黑色页岩）是一个被忽视的问题。 从喜马拉雅造山带的大小受始新世变质作用的影响，在这种变质作用中所涉及的变质岩石和石墨岩石的比例，以及对岩石变质作用的持续时间的地质年代学分析的估计，始新世的大气可能已经收到了大通量的变质CO2（1019摩尔/Ma）。 地质年代学分析揭示了峰变质年龄的显著相似性（即，40 - 50 Ma），从而支持了一个主要的，世界性的始新世区域变质作用的概念。 我们提出的跨学科研究有两个主要目标：（1）分析地质记录，以量化始新世变质CO2产生的量和速率，以及（2）模拟变质CO2通量对始新世大气的影响。 ***