Stable Isotopic Evidence of the pCO2 Response to the Central Atlantic Magmatic Province

pCO2 对中大西洋岩浆省响应的稳定同位素证据

• 批准号: 0958867
• 负责人: James Wright
• 金额: $ 14.55万
• 依托单位: Rutgers University New Brunswick
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2013-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0958867&HistoricalAwards=false
• 关键词: Stable; Isotopic; Evidence; pCO2; Response

Stable isotopic evidence of the pCO2 and temperature response to the Central Atlantic Magmatic ProvinceJames Wright and Dennis Kent, Rutgers UniversityEAR-0958867ABSTRACTOur planet is habitable because the carbon cycle maintains a balance between the supply and the consumption of atmospheric pCO2. Plate tectonics influence the long-term (105 yr.) cycling of carbon, controlling both the rate of volcanic CO2 outgassing and the removal of CO2 through the exhumation of weatherable rocks. Earth has undergone several periods of large-scale volcanic eruptions termed Large Igneous Provinces (LIPs). Three of the largest and most recent LIPs are the Deccan Traps at 65 Myr, Central Atlantic Magmatic Province (CAMP) at ~200 Myr, and Siberian Traps at ~250 Myr. Various researchers have postulated that volcanic outgassing associated with the emplacement of each LIP led to large-scale environmental/climatic changes, which are closely linked to mass extinctions and subsequent evolutionary recovery. However, a major tenet of these hypotheses, that large-scale outgassing is associated with LIPs, has yet to be demonstrated. Here, PIs will reconstruct atmospheric CO2 levels using stable isotope measurements from sediments deposited before, during, and after the emplacement of the CAMP. They make use of a ?paleo-barometry? method that is based on stable carbon isotope values in both the inorganic and organic phases of paleosols (e.g., Cerling et al. 1999). Variations in the carbon isotope values respond directly to the levels of CO2 in the atmosphere. In the Newark and Hartford Basins, numerous paleosol horizons are found interbedded with igneous rocks of the CAMP; such superposition combined with cycle stratigraphy allows very little age uncertainty. These paleosol isotope reconstructions will test the hypothesis that atmospheric pCO2 increases with LIP emplacements. An under appreciated consequence of LIP emplacement is that well after the initial injection of CO2, long-term weathering of the CAMP rocks may lower atmospheric CO2 below pre-event levels. PIs sampling strategy will collect data to test whether chemical weathering of CAMP volcanic rocks resulted in a long-term decrease in pCO2.

稳定同位素证据的pCO 2和温度响应的中大西洋岩浆省詹姆斯赖特和丹尼斯肯特，罗格斯大学地球-0958867摘要我们的星球是宜居的，因为碳循环保持平衡之间的供应和消耗的大气pCO 2。 板块构造影响长期（105年）碳的循环，控制火山CO2放气的速率和通过风化岩石的折返去除CO2。 地球经历了几次大规模的火山爆发，称为大火成岩省（LIPs）。 三个最大和最新的LIP是6500万年前的德干圈闭，约20000万年前的中大西洋岩浆区（CAMP）和约25000万年前的西伯利亚圈闭。各种研究人员假设，与每个LIP的就位相关的火山释气导致大规模的环境/气候变化，这与大规模的灭绝和随后的进化恢复密切相关。 然而，这些假设的一个主要原则，即大规模的脱气与LIPs有关，尚未得到证实。 在这里，PI将重建大气中的二氧化碳水平使用稳定同位素测量沉积物之前，期间和之后的CAMP安置。 他们利用一个？古气压学基于古土壤的无机和有机相中的稳定碳同位素值的方法（例如，Cerling等人，1999年）。 碳同位素值的变化直接与大气中的CO2水平有关。 在纽瓦克和哈特福德盆地，发现许多古土壤层与CAMP的火成岩互层;这种叠加与旋回地层学相结合，使得年龄的不确定性很小。 这些古土壤同位素重建将测试的假设，大气pCO 2增加与LIP定位。 LIP就位的一个未被充分认识的后果是，在初始注入CO2之后，CAMP岩石的长期风化可能会使大气CO2低于事件前的水平。 PI采样策略将收集数据，以测试CAMP火山岩的化学风化是否导致pCO 2的长期下降。