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东部地区区块评价与优选及相关研究表明，箕状断陷盆地可分为早、中、晚期断陷、坳陷和萎缩隆升五个演化阶段。不同阶段，其变形和沉积充填特征不一。断陷早期，构造坡折带不发育，以干旱的冲积—滨浅湖沉积体系为主；断陷中期，发育单断式构造坡折带，以比较湿润的冲积—滨浅湖—半深湖沉积体系为主；断陷晚期是断陷湖盆扩张的鼎盛时期，发育多断式构造坡折带，以湿润的滨浅湖—深湖相沉积体体系为主；坳陷期，构造稳定，地势平坦，相类型比较齐全；萎缩阶段，湖盆遭受强烈的剥蚀，沉积基本缺失。文章最后指出，中、晚期断陷和坳陷〖JP3〗阶段是盆地烃源岩和储集层发育的黄金时期，经历了这三个演化阶段的成熟和过成熟箕状断陷的油气勘探前景较好。

Tectonic Evolution and Sedimentation-filling Characteristics of the Halfgraben-like Rift-subsidence Basins in East China

The development and distribution of sequence strata in the halfgraben like rift subsidence basins in East China are closely related to the tectonism and climatic conditions. It is very important to analyze the control action of tectonic condition on stratigraphic sequence in different tectonic evolution stages and the relevant sedimentation filling characteristics according to the characters of halfgraben like rift subsidences, thus guiding hydrocarbon exploration. Through the evaluation, optimization and related study of the tracts in East China, the halfgraben like rift subsidence basin may be divided into five evolution stages, i.e. early rift subsidence, middle rift subsidence, late rift subsidence, depression and shriveled uplift stages. The tectonic deformation and sedimentation filling characteristics were various in different stages, i.e. in early rift subsidence stage, the structural slope break belts were not developed, an arid alluvial-beach-shallow lacustrine sedimentation system being in majority; in middle rift subsidence stage, the single faulted structural slope break belts were developed, a relatively humid alluvial-beach-shallow-semideep lacustrine sedimentation system being in majority; the late rift subsidence stage was the heyday of extending the rift subsidence lake basins and the multiple faulted structural slope break belts were developed, a humid beach-shallow-deep lacustrine sedimentation system being in majority; in depression stage, the tectonic activity was weakened, the terrain was smooth and the kinds of sedimentary facies were relatively complete; and in shriveled uplift stage, the lake basins were strongly eroded, the depositions being lost basically. Finally, in the paper it is pointed out that the middle and late rift subsidence stages and depression stage were the golden times of forming hydrocarbon source rocks and reservoir beds in the basins and the prospect of oil and gas exploration is relatively excellent in the mature and post mature halfgraben like rift subsidences which suffered the three tectonic evolution stages.