Vertebrate paleontology, biostratigraphy, geochronology, and paleoenvironment of Qaidam Basin in northern Tibetan Plateau
Vertebrate paleontology, biostratigraphy, geochronology, and paleoenvironment of Qaidam Basin in northern Tibetan Plateau
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DOI：
10.1016/j.palaeo.2007.06.007
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发表时间：
2007-10
期刊：
影响因子：
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通讯作者：
Xiaoming Wang;Z. Qiu;Qiang Li;Banyue. Wang;Zhanxiang Qiu;W. Downs;Guangpu Xie;Junyi Xie;T. D
中科院分区：
文献类型：
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作者：
Xiaoming Wang;Z. Qiu;Qiang Li;Banyue. Wang;Zhanxiang Qiu;W. Downs;Guangpu Xie;Junyi Xie;T. D
柴达木盆地是青藏高原最大的陆相盆地，新生代沉积记录最完整。尽管柴达木盆地的哺乳动物化石是青藏高原已知的第一批脊椎动物化石，并在20世纪30年代的早期科学考察中被发现，但在盆地地层研究中并没有发挥重要作用。在过去的8年里，我们在柴达木盆地进行了勘探，并在那里首次收集了有据可查的脊椎动物化石。除了是新生代陆地生物地层学的最佳生物外，新的脊椎动物化石还提供了一个独特的窗口，可以了解古代生物地层，记录高原晚新生代的隆升和相关的环境变化。本文首次建立了早渐新世至上新世早期的动物群序列。已识别出4个哺乳动物群：奥隆布鲁克哺乳动物群（中新世中期）、托苏哺乳动物群（中新世晚期早期）、深沟哺乳动物群（中新世晚期早期）和怀头塔拉哺乳动物群（上新世早期）。所有四个哺乳动物群都可以直接或间接地与奥隆布鲁克-怀图塔拉地区的古地磁剖面联系起来，从而可以对这些动物群的年代学进行可靠的校准。至少有4个鱼类动物群：鲁勒河鱼类动物群（渐新世早期至晚期早期）、深沟鱼类动物群（中新世早期）、鄂博梁鱼类动物群（中新世晚期至上新世早期）和雅湖鱼类动物群（上新世早期）。这些鱼类动物群是青藏高原上它们各自时代的唯一记录，因此它们本身不能用于年龄测定。然而，这些鱼类动物群要么被整合到古地磁部分，要么直接与已知年龄的哺乳动物群联系在一起，允许对其年代进行独立评估。动物地理学上，柴达木哺乳动物区系表现出越来越多的特有性，随着时间的推移，可能与地形障碍所形成的青藏高原的增长和隆升，以及由同一构造过程所引发的气候变化。被困在内部排水盆地的鱼类发展的厚骨形态所造成的高盐环境，这是与青藏高原自上新世早期以来日益干旱。
Qaidam Basin is the largest terrestrial basin of the Tibetan Plateau and has the most continuous sedimentary record in the Cenozoic. Although constituting the first known fossil vertebrates of the Tibetan Plateau and discovered in early scientific expeditions in the 1930s, mammalian fossils from Qaidam Basin have not played a significant role in studying the basin stratigraphy. Our explorations in the Qaidam Basin during the past 8 years have resulted in the first well documented collection of fossil vertebrates from there. In addition to being the best organisms for terrestrial biostratigraphy in the Cenozoic, the new fossil vertebrates offer a unique window into the ancient biotas that chronicle the late Cenozoic uplift of the plateau and associated environmental changes. Here we establish for the first time a faunal sequence of early Oligocene to early Pliocene age. Four mammalian faunas are recognized: Olongbuluk Mammal Fauna (middle Miocene), Tuosu Mammal Fauna (early late Miocene), Shengou Mammal Fauna (early late Miocene), and Huaitoutala Mammal Fauna (early Pliocene). All four mammal faunas can be directly or indirectly tied to a paleomagnetic section in the Olongbuluk–Huaitoutala area, permitting robust calibration of the chronology of these faunas. At least four fish faunas are also found: Lulehe Fish Fauna (late early to early late Oligocene), Shengou Fish Fauna (early late Miocene), Eboliang Fish Fauna (late late Miocene to early Pliocene), and Yahu Fish Fauna (early Pliocene). The fish faunas represent the only records of their respective times in the Tibetan Plateau and thus by themselves cannot be used for age determination. However, these fish faunas are either integrated into paleomagnetic sections or directly tied to mammal faunas of known ages, permitting independent assessment of their chronology. Zoogeographically, Qaidam mammal faunas show increasing endemism through time, presumably related to topographic barriers formed by the growth and uplift of the Tibetan Plateau and to climatic changes triggered by the same tectonic process. Fishes that were trapped in internally drained basins developed pachyostotic morphologies caused by hypersaline environments, which are associated with the increasing aridity of the Tibetan Plateau since early Pliocene.