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藏南定日遮普惹山剖面主要是Albian 晚期到古近纪海相沉积, Willems 等( 1996 )对岩石地层和沉积微相进行了详细研究,并通过浮游有孔虫研究建立生物地层格架。在与岗巴地区地层对比基础上,该剖面被认为是整个藏南地区白垩纪—古近纪海相地层的标准剖面。2004 年我们与中国、德国同行一道对该剖面上白垩统地层进行再考察,重点对无脊椎动物化石样品进行采集和研究。与西藏大多数白垩纪剖面一样,尽管沉积环境为陆棚环境,该剖面以前却几乎没有菊石和叠瓦蛤类化石的报道,而同样环境下的世界其他地区剖面含有大量的菊石和叠瓦蛤类化石。藏南定日剖面重新调查后发现了少量的菊石和叠瓦蛤类化石。化石数量少一方面是由于灰泥质灰岩和泥灰质灰岩内化石保存状况差,另一方面采样条件也不理想。还有,当时的环境条件可能不利于大多数无脊椎动物类群的生存,这一点或许从大量存在于岗巴群上部的小个体双壳类碎片可以得到证实。尽管获得的化石分散并且保存差,本次研究仍获得了一些有价值的生物地层数据。岗巴群上部发现的化石Calycoceras?,指示其时代为Cenomanian 晚期,随后出现不能鉴定的desmoceratids类的幼体。之上,菊石Forresteria sp.的发现表明岗巴群顶部地层属于Coniacian下部,这被同一地层内发现的其他化石所支?
The Zhanpujashan section in southern Tibet is dominated by late-Albian marine deposits. Willems et al. (1996) studied the lithostratigraphic and sedimentary microfacies in detail and established biostratigraphic frameworks by studying planktonic foraminifera . Based on the comparison with the Gamba area strata, this section is considered as a standard section of the Cretaceous-Paleogene marine strata throughout southern Tibet. In 2004, we worked with Chinese and German colleagues to re-examine the Cretaceous strata in this section and focus on the collection and study of invertebrate fossil samples. As with most of the Cretaceous profiles in Tibet, the section was previously barely covered by ammonites and fossil clam fossils although the sedimentary environment was a shelf environment, while the rest of the world in the same environment contained large amounts of ammonites and shrubs Fossil-like. A small amount of ammonites and fossil clam fossils were found after a re-survey of the Dingnan section of southern Tibet. The small number of fossils is due to the poor preservation of fossils in the stucco limestone and marl limestone and the unsatisfactory sampling conditions on the other hand. Also, the prevailing environmental conditions may not be conducive to the survival of most invertebrate species, perhaps as evidenced by the large number of small individual bivalve fragments present in the upper part of the Ganga group. Despite the scattered and poorly preserved fossils, some valuable biostratigraphic data have been obtained in this study. The fossil Calycoceras? Was found in the upper part of the Gangpachi, indicating that its age was late Cenomanian, followed by unidentifiable desmoceratids larvae. The discovery of the ammonite Forresteria sp. Shows that the top of the Gamba basin belongs to the lower part of the Coniacian, which is supported by other fossils found in the same formation.