西藏仲巴县隆格尔地区渐新统日贡拉组孢粉组合的发现及其意义

The discovery and significance of the sporopollen assemblages from the Oliogene Rigongla Formation in the Lunggar region,Zhongba,Xizang

关键词:  隆格尔地区  日贡拉组  渐新世  古气候和古植被

Key words:  Lunggar region  Rigongla Formation  Oliogene  palaeoclimatology and palaeovegetation

摘要:

笔者在西藏仲巴县隆格尔地区进行1:5万区域地质调查过程中,在渐新统日贡拉组地层中上部采集了孢粉化石,为裸子植物花粉(Abietineaepollenites sp.、Pinuspollenites sp.、Tsugaepollenites sp.、Piceapollis sp.)、被子植物花粉(Artemesiaepollenites sp.、Betulaceoipollenites sp.、Rutaceoipollenites sp.、Betulaepollenites sp.、Graminipidites sp.)、蕨类植物孢子(Deltoidospora sp.、Lycopodiumsporites sp.、Toroisporis sp.)等组合,时代属于古近纪渐新世,可能跨及中新世。孢粉组合的发现对隆格尔地区日贡拉组地层的划分、对比及沉积时期的古气候、古地理和古植被的分析提供了依据,丰富了地层的古生物数据。在这一时期,古植被以松科和蒿属为主,反映了一次与构造运动密切相关的古环境变化事件,同时指示了古气候的轨迹及特征,揭示了构造的演化发展和沉积盆地响应过程与古气候的耦合关系。

Abstract:

The sporopollen fossils were collected by the authors from the middle-upper part of the Oliogene Rigongla Formation during the 1:50 000 geological survey in the Lunggar region,Zhongba,Xizang. The collected sporopollen assemblages consist of the gymnospermous pollens including Abietineaepollenites sp.,Pinuspollenites sp.,Tsugaepollenites sp. and Piceapollis sp.; the angiospermous pollens including Artemesiaepollenites sp., Betulaceoipollenites sp.,Rutaceoipollenites sp.,Betulaepollenites sp. and Graminipidites sp.,and the spores of Pteridophytes including Deltoidospora sp.,Lycopodiumsporites sp. and Toroisporis sp. These assemblages belong to the Oliogene or even the Miocene in age. During these periods,the dominant Pinaceae and Artemisia represent a tectonic movement-associated palaeoenvironmental event. The discovery of the sporopollen assemblages in this region has provided helpful data for the stratigraphic division and correlation of the Rigongla Formation,and the analysis of palaeoclimatology, palaeogeography and palaeovegetation during the deposition of the Rigongla Formation,and also reflected the trajectory and characteristics, and the coupling relationship between the palaeoclimatic changes and the tectonic evolution and responses of sedimentary basins.