Megafossils of Betulaceae from the Oligocene of Qaidam Basin and their paleoenvironmental and phytogeographic implications
Megafossils of Betulaceae from the Oligocene of Qaidam Basin and their paleoenvironmental and phytogeographic implications
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DOI：
10.1016/j.pld.2023.03.007
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发表时间：
2023-03
期刊：
影响因子：
4.8
通讯作者：
Tao Yang;Jia-Hao Cai;Yanzhi Dai;Hongyu Chen;Lei Han;Li Zhang;Weiyu Liang;Xu-Jun Li;Wenjia Li;Jing-Yu Wu;S. Xie;De-Fei Yan
中科院分区：
文献类型：
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作者：
Tao Yang;Jia-Hao Cai;Yanzhi Dai;Hongyu Chen;Lei Han;Li Zhang;Weiyu Liang;Xu-Jun Li;Wenjia Li;Jing-Yu Wu;S. Xie;De-Fei Yan
然而，柴达木盆地被子植物化石较少，对其古植被的认识较少。本文报道了柴达木盆地西北部（花土沟地区）渐新统上干柴沟组中发现的桦树科叶和果实化石。比较形态学分析表明，果实属于桦木亚属（betulassubgenusbetula），叶子属于carpinus grandis。这些发现与同一地区已报道的其他植物化石一起，揭示了柴达木盆地与欧洲在渐新世的植物区系联系密切。这种植物区系交换的北部通道可能在古近纪晚期穿越了柴达木盆地。图尔盖海峡的持续变窄和较强的西风带输送了水分，提供了有利的气候条件，可能促进了这种植物区系联系。柴达木盆地植物化石表明，该地区在渐新世存在温暖湿润的落叶阔叶林，这与该地区的现代植被不同，表明柴达木盆地可能是渐新世这些植物生长和传播的适宜地区。
Understanding the paleoenvironment and phytogeographical history of the Tibetan Plateau, China relies on discovering new plant fossils. The Qaidam Basin has long been regarded as an ideal ‘field laboratory’ to investigate the paleoclimate and paleobiological evolution of the northern Tibetan Plateau. However, fossil angiosperms from the Qaidam Basin are rare, and our knowledge of its paleovegetation is poor. Here, we report fossil leaves and fruits of Betulaceae found from the Oligocene Shangganchaigou Formation of northwestern Qaidam Basin (Huatugou area). Comparative morphological analysis led us to assign the fruits to theBetulasubgenusBetulaand the leaves toCarpinus grandis. These findings, together with other reported fossil plants from the same locality, reveal a close floristic linkage between the Qaidam Basin and Europe during the Oligocene. The northern pathway of this floristic exchange may have crossed through the Qaidam Basin during the late Paleogene. This floristic linkage may have been facilitated by the continuous narrowing of the Turgai Strait and stronger westerlies, which transported moisture and provided favorable climatic conditions. Indeed, fossil plants collected from the Qaidam Basin suggest that during the Oligocene this region had warm and humid deciduous broad-leaf forest, which differs from the region’s modern vegetation and indicates that the Qaidam Basin may have been a suitable region for these plants to flourish and spread during the Oligocene.