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

中大西洋岩浆省二氧化碳和温度响应的稳定同位素证据罗格斯大学的詹姆斯·赖特和丹尼斯·肯特EAR-0958867ABSTRACT地球是宜居的，因为碳循环在大气二氧化碳的供应和消耗之间保持平衡。板块构造影响长期(105年)。碳的循环，控制火山释放二氧化碳的速率，以及通过剥离风化岩石来清除二氧化碳。地球经历了几次被称为大火成岩省(LIP)的大规模火山喷发。三个最大和最新的嘴唇是65迈尔的德干圈闭，约200迈尔的中大西洋岩浆省(CAMP)，以及约250迈尔的西伯利亚圈闭。许多研究人员推测，与每一个嘴唇的就位相关的火山放气导致了大规模的环境/气候变化，这与大规模灭绝和随后的进化恢复密切相关。然而，这些假说的一个主要原则，即大规模排气与嘴唇有关，尚未得到证实。在这里，PI将使用在营地进驻之前、期间和之后沉积的沉积物的稳定同位素测量来重建大气二氧化碳水平。他们用的是古气压计？基于古土壤无机相和有机相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反映了大气中二氧化碳的水平。在纽瓦克和哈特福德盆地，发现了大量的古土壤层与营地的火成岩互层；这种叠加与旋回地层学相结合，几乎不存在年龄不确定性。这些古土壤同位素重建将检验大气中二氧化碳含量随着嘴唇位置的增加而增加的假设。LIP侵位的一个未被认识到的后果是，在最初注入二氧化碳之后，营地岩石的长期风化可能会将大气中的二氧化碳降低到低于事件前的水平。PIS抽样战略将收集数据，以测试坎普火山岩的化学风化是否导致二氧化碳的长期下降。

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.