Late Cretaceous-Paleogene Indian monsoon climate vis-à-vis movement of the Indian plate, and the birth of the South Asian Monsoon
Late Cretaceous-Paleogene Indian monsoon climate vis-à-vis movement of the Indian plate, and the birth of the South Asian Monsoon
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DOI：
10.1016/j.gr.2021.01.010
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发表时间：
2021-02-13
影响因子：
6.1
通讯作者：
Roy, Kaustav
中科院分区：
文献类型：
--
作者：
Bhatia, Harshita;Khan, Mahasin Ali;Roy, Kaustav
印度从冈瓦纳分离后，从南半球向北航行9000公里，直到现在与欧亚大陆相连的位置，花了1.6亿年。在这段旅程中，由于长期气候变化和纬度位置的变化，印度经历了一系列气候条件。记录印度在穿越赤道的旅程中的气候，使我们能够在全球气温异常高的时候，对低纬度地区的气候进行采样，就像我们将来可能经历的那样。在此，我们定量地重建了印度在其航行期间的古气候，重点是马斯特里赫特晚期-丹尼世早期，晚古新世，早始新世和晚渐新世的时间片。我们利用化石叶片形态与气候的关系，利用气候-叶片分析多元程序重建了24个单独的古气候参数，而化石叶片特征也使我们能够识别不同的季风类型。我们发现，在整个古近纪，印度持续经历了与现代印尼-澳大利亚相似的季风气候；今天主要作为热带辐合带（ITCZ）季节性跨赤道迁移而存在的季风系统。重建的印度近赤道热区温度较低，季节性温度变化较大，表明整个古近纪ITCZ有更广泛的季节性纬度迁移。显示适应南亚季风的叶片特征是在古近纪末期才发展起来的。(c) 2021年国际冈瓦纳研究协会。Elsevier B.V.版权所有。
After India separated from Gondwana, its 9000 km northward voyage from the Southern Hemisphere to its modern position joined with Eurasia took 160 million years. During that journey, India experienced a range of climatic conditions due to secular climate variations and its changing latitudinal position. Documenting India's climate during its trans-equatorial journey allows us to sample climate across the low latitudes, at a time when global temperatures were exceptionally high, such as we might experience in the future. Here, we reconstruct, quantitatively, the palaeoclimate of India during its voyage, focussing on the latest Maastrichtian-earliest Danian, late Paleocene, early Eocene and late Oligocene timeslices. We exploit the relationship between fossil leaf form and climate and use the Climate-Leaf Analysis Multivariate Program to reconstruct 24 individual palaeoclimate parameters, while fossil leaf traits also allow us to identify different monsoon types. We find that throughout the Paleogene India persistently experienced a monsoon climate similar to that of modern Indonesia-Australia; a monsoon system that exists today primarily as a function of seasonal trans-equatorial migrations of the Intertropical Convergence Zone (ITCZ). The reconstructed near-equatorial thermal regime of India was cooler, and showed a greater seasonal temperature variation than at similar latitudes today, suggesting a wider seasonal latitudinal migration of the ITCZ throughout the Paleogene. Leaf traits showing adaptation to the South Asia Monsoon only developed after the end of the Paleogene. (c) 2021 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.