Abstract: The Cuoqin Basin is a large tectonic composite basin in Mesozoic Tethys tectonic domain. Its main part is located on Gangdisi-Nianqing -Tangula slab,including three tectonic-sedimentary units:northern downwarped zone, median slope zone,and southern magmatite zone. In Mesozoic era,the basin had different developing stages of primary rifting(T₃-J₁),peripheral foreland basin(J₂-J₃)and retroarc foreland basin(K₁-K₂).Thousands meters Mesozoic strata was developed in the northern downwarped zone. Upper Triassic and lower-middle Jurassic strata have metamorphosed near the Bangong lake-Nu river faults. These strata have good source-reservoir-seal assemblage far away the faults,maybe formed some hydrocarbon reservoir about thrust fold and overlap. Lower Cretaceous belong to retrograding sedimentary sequence of tide-flat-carbonate platform facies,and have good hydrocarbon source rock and reservoir rock but no good cap rock. Some little hydrocarbon reservoirs about thrust maybe formed near the Gaize-Nima faults and Jiangma-Geang lake faults.Cenozoic uplift of the Tibetan Plateau is main reason that huge oil-gas field like in the Persia Gulf Basin didn't form in the Cuoqin Basin.

Key words: Tibet, Cuoqin Basin, tectonic-sedimentary, hydrocarbon potential

摘要： 西藏措勤盆地是中生代特提斯构造域的一个大型构造复合盆地,主体位于冈底斯-念青唐古拉板块之上,包括北部坳陷带、中部斜坡带、南部岩浆岩带三个构造沉积单元。中生代盆地演化上经历了初始裂谷(T₃-J₁)、周缘前陆盆地(J₂-J₃)、孤后前陆盆地(K₁-K₂)等阶段。其中,北部坳陷带发育了近万米厚的中生代地层。上三叠统、中上侏罗统巨厚海相沉积地层在接近班公湖-怒江断裂带发生变质作用,但在远离该断裂带的盆地前隆地带仍具有良好的生储盖组合,有条件形成一些超覆油气藏或者与后期冲断褶皱有关的构造岩性油气藏。下白垩统属退积的潮坪-碳酸盐岩台地沉积序列,生、储油层发育,但盖层发育相对较差,有可能在靠近改则-尼玛断裂带附近形成一些与逆冲断层有关的小型油气藏。第三纪以来青藏高原迅速隆升所造成的本地区海水快速退出、海相地层大范围暴露剥蚀是措勤盆地难以形成如波斯湾一样巨型油气田的主要原因。

关键词: 西藏, 措勤盆地, 构造沉积, 油气远景