新疆若羌县阿热力一带冰沟群沉积环境及层序地层分析

Analysis on Sedimnetary Environment and Sequence Stratigraphy of Binggou Group in Areli Belt of Ruoqiang County in Xinjiang Uygur Autonomous Region

摘要:

新疆若羌县阿热力一带位于东昆仑西段北坡、柴达木盆地西南缘。地层区划隶属于秦祁昆地层区、东昆仑中秦岭地层分区,该区冰沟群分布广泛。对该区开展区域地质调查、对冰沟群的沉积环境和层序地层进行分析研究具有重要地质意义。在开展区域地质调查中，采用路线调查、剖面测量、实验测试等方法对冰沟群的岩性特征、岩石组合、地球化学特征、古生物特征以及形成时代等进行了系统研究，依据岩石组合特征将其划分为狼牙山组和丘吉东沟组。把该区冰沟群与区域上都兰县冰沟群层型剖面进行了对比，通过对比研究，认为该区的冰沟群与都兰县冰沟群层型剖面具明显可对比性。依据岩性特征、岩石组合特征、古生物特征等，对冰沟群沉积环境进行了分析，认为狼牙山组沉积环境属于潮下较深水陆棚相低能环境；丘吉东沟组属于浅海陆棚相带内缘斜坡沉积环境。并对冰沟群层序地层进行了划分，将其划分为2个Ⅲ级层序，即第一层序（B1）和第二层序（B2）。

Abstract:

Areli belt in Ruoqiang county in Xinjiang Uygur Autonomous Region is in north slop of west part of eastern Kunlun mountain and southwest edge of Chaidamu basin. Stratigraphic district belongs to QinlingQilianshanKunlunshan mountain area, eastern Kunlun mountain and middle Qinling stratigraphy layers. The Binggou group is widely distributed in this area. It has important geological significance for carrying out regional geological survey and analysis on depositional environment and sequence stratigraphy of Binggou group. In carrying out regional geological survey, by using the route survey, profile measurement and test method, lithology characteritics, rock compositions, geochemical characteristics, paleontological characteristics and formation age in Binggou group were investigated sysmetically. According to rock composition characteristics, it can be divided into Langyashan formation and Qiujidonggou formation. Stratotype sections of Binggou group in this area and in Dulan county have been compared. Through comparative study, it is regarded that stratotype sections of Binggou group in these two areas have obvious comparability. According to the lithology characteristics, characteristics of rock association and paleontology, sedimentary environment of Binggou group has been analyzed. It is regarded that the sedimentary environment of Langyashan formation belongs to deep water shelf phase low energy environment under tide; while Qiujidonggou formation belongs to shallow marine shelf facies sedimentary environment of the inner slope. The Binggou group sequence stratigraphy is divided into 2 grade Ⅲ sequences, that is the first succession (B1) and second (B2) succession.