Early Eocene warming events and the timing of terrestrial faunal exchange between India and Asia
Early Eocene warming events and the timing of terrestrial faunal exchange between India and Asia
复制标题
DOI：
10.1130/g31585.1
复制
发表时间：
2011-01-01
期刊：
影响因子：
5.8
通讯作者：
Prasad, V.
中科院分区：
文献类型：
--
作者：
Clementz, Mark;Bajpai, S.;Prasad, V.
亚洲和印度之间大陆-大陆碰撞开始的时间存在争议，但这一重大构造事件通常被认为发生在始新世早期，即约 100 年前。 50马。来自印度西部瓦斯坦褐煤矿早始新世边缘海洋层序（坎贝页岩）的锶同位素、稳定碳同位素、微化石生物地层学和哺乳动物化石的新的独立数据表明，亚洲和印度次大陆之间的陆地动物群交换以及因此发生的大陆碰撞发生在 53.7 Ma 之前。这个年龄恰逢第二个始新世最热期（ETM2），这是继古新世-始新世最热期（PETM）之后的短暂变暖事件。 55.5马。我们的数据还首次记录了低纬度地区陆地有机物质中 ETM2 的清晰记录，表现为褐煤和分散有机碳 δ C-13 值中 3%-4% 的碳同位素偏移 (CIE)。该地点的 CIE 震级与在北冰洋海洋岩芯中观测到的震级非常接近，这支持了一种解释，即这一高温事件虽然震级较低，但其特征与 PETM 类似，是一种影响陆地和海洋生态系统的全球现象。
The timing of initiation of continent-continent collision between Asia and India is controversial, but this major tectonic event is generally thought to have occurred in the Early Eocene, ca. 50 Ma. New and independent data from strontium isotopes, stable carbon isotopes, microfossil biostratigraphy, and mammal fossils from an Early Eocene marginal marine sequence (Cambay Shale) at the Vastan Lignite Mine of western India indicate that terrestrial faunal exchanges, and therefore continental collision, between Asia and the Indian subcontinent took place before 53.7 Ma. This age coincides with the second Eocene Thermal Maximum (ETM2), a short-lived warming episode that followed the Paleocene-Eocene Thermal Maximum (PETM) ca. 55.5 Ma. Our data also document, for the first time, a clear record of the ETM2 in terrestrial organic material from a low-latitude site, which is represented by a 3%-4% carbon isotope excursion (CIE) in lignite and dispersed organic carbon delta C-13 values. The magnitude of the CIE at this location closely matches that observed in marine cores from the Arctic Ocean, which supports an interpretation that this hyperthermal event, though of lower magnitude, was similar in character to that of the PETM, being a global phenomenon that affected both terrestrial and marine ecosystems.