Abstract The spatial and temporal pattern of sedimentation in a rift basin is a result of complex interplay between tectonically induced vertical crustal movement and climatic condition. Though the conceptual and numerical models for tectono-sedimentary evolution of half grabens are available, the stratigraphic arrangement of lithofacies produced by the environments on hangingwall block is poorly documented till date. Additionally, the stratigraphic record resulting from the interactions between the hangingwall processes and those of the basin trough is less known. The purpose of this work is to delineate the tectonic and climatic factors controlling the distribution of sedimentary environments from the stratigraphic architecture of a Late Triassic to Early Jurassic syn-rift strata of a continental half-graben of India. This work also aims to characterize the deposits formed in the transitional environments that occur in between the fluvial system of the hangingwall dip slope and the lacustrine system at the basin trough. This work involves a detailed sedimentological study including facies analysis and palaeocurrent analysis. The studied syn-rift sediments record i) a changeover from axial to transverse fluvial system in the end of Triassic, ii) transition from fluvial to lake marginal environment in the Early Jurassic and iii) evolution of an extensive palustrine system in the Middle Jurassic. The corresponding changes in lithological and geochemical characters for the first change points towards incresed tectonic movement along the main boundary fault that caused the progradation of the hangingwall fans towards the basin trough. Later changes can be attributed to the reconfiguration of the sedimentary environments due to increase in aridity that influenced the introduction of coarse clastics to the basin.

中文翻译：

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晚三叠世至中侏罗世早期印度大陆裂谷盆地沉积模式的演化：构造和气候控制

摘要 裂谷盆地沉积的时空格局是地壳垂直运动与气候条件复杂相互作用的结果。尽管半地堑构造沉积演化的概念模型和数值模型是可用的，但迄今为止，关于由上墙块体环境产生的岩相的地层排列的记录很少。此外，由上盘过程与盆地海槽相互作用产生的地层记录鲜为人知。这项工作的目的是描绘控制沉积环境分布的构造和气候因素，从印度大陆半地堑的晚三叠世地层结构到早侏罗世同裂谷地层。这项工作还旨在表征在上盘倾斜斜坡的河流系统和盆地槽的湖泊系统之间发生的过渡环境中形成的沉积物。这项工作涉及详细的沉积学研究，包括相分析和古流分析。所研究的同裂谷沉积物记录了i）三叠纪末从轴向到横向河流系统的转变，ii）早侏罗世从河流到湖泊边缘环境的转变以及iii）中侏罗世广泛的沼泽系统的演化。第一次变化的岩性和地球化学特征的相应变化表明沿着主要边界断层的构造运动增加，导致上盘扇向盆地槽进积。