摘要：

藏南聂拉木县、岗巴县的古错-岗巴盆地呈东西向展布，位于北喜马拉雅构造分区。早白垩世沉积以碎屑物质为主，其黑色页岩主要集中于下白垩统古错四组、古错五组和东山组。黑色页岩沉积物颗粒微细，以泥质、粘土质组分为主，砂/泥比值低，局部夹有海底扇沉积的细砂岩、粉砂岩等韵律层，富含菱铁矿、钙质结核，少见菊石等生物化石。其沉积环境应为相变缓慢、水体低能且较为特殊（受火山活动影响）的海相还原环境。黑色页岩中的粘土质所反映出的稀土配分模式与玄武岩标准模式极为接近，显示出当时的沉积可能伴随有火山活动及基性物质的介入。综合地质特征显示出本区下白垩统黑色页岩厚度巨大，构造简单，具有较好的成烃条件，虽然有机质成熟度较高，但黑色页岩仍是未来本区油气资源潜力评价中值得重视的积极因素之一。

Abstract:

The Kuco-Gamba basin with east-west direction of apical axis is located at the Nyalam and Gamba Counties in Southern Tibet. This area belongs to the northern Himalayas tectonic district. The major sedimentary materials were clastics in Lower Cretaceous and black shale mainly concentrates to the Fourth-Fifth Kuco Formation and Dongshan Formation. The sedimentary materials of black shale were very fine-clastic and they were mainly composed of argillaceous and douke sedimentary. The ratio of sand/mud when the sedimentary process finished was low. There were some rhythmic layering which was composed by fine grained sandstone and siltite in submarine fan. The black shale richly contains lot of siderite and calcareous aerites produced under a reduction special marine condition. There are a few ammonite fossils and so on in it. The sedimentary face changed slowly and the seawater was in a low-energy and strong reduction environment. The rare earth assemblage pattern of douke in black shale extremely approach the basalt standard pattern and this demonstrated that the sedimentary possibly accompanied by the volcanic activity even involved with mantle materials. The thickness of Lower Cretaceous black shale in this
basin is huge and the structure is simple. Its comprehensive geological characteristic demonstrated there are good conditions for hydrocarbon producing. Some positive factors will be worth taken in the future potential appraisal of oil gas resources in northern Himalayas.