Sequence Stratigraphic Model of Middle Permian Barakar Formation from a Marginal Gondwana Basin, India  

作　　者：Joyjit Dey Souvik Sen 

机构地区：[1]Coal India Limited, Central Mine Planning and Design Institute (CMPD1), Regional Institute-3, Jharkhand 829 103, India [2]Geologix Limited, Dynasty Building, Level-4, Wing-A, Andheri Kurla Road, Andheri (E), Mumbai 400 059, India

出　　处：《Journal of Earth Science》2018年第4期745-754,共10页地球科学学刊（英文版）

摘　　要：Gondwana deposits are extensively found across the continents. Here we study the Mid- dle Permian Barakar Formation from the marginal Gondwana Basin, eastern India, being deposited in a normal fault setting. Availability of extensive cores as well as geophysical log suites （gammaresistivity-density from drilled wells） from the study area helped us achieving high resolution interpretation. Core study identifies fluvial sedimentary architectures, which were correlated with the geophysical logs and modeled field-wide to understand vertical and horizontal facies disposition. The facies analysis has been used to establish a sequence stratigraphic model of the cyclic Barakar deposition. Four major fining upward depositional sequences were identified, each sequence comprises of low accommodation system tract （LAST） at base and high accommodation system tract （HAST） at top. LAST is characterized by vertically stacked, multistory amalgamated channel sandstone dominated facies, while floodplain dominated facies characterizes HAST, reflecting a gradual shift from braided to meandering depositional system from bottom to top of each cycle. Study reveals depocenter to be in the western part, supported by eastward thinning of sediment packets, all being deposited in a halfgraben setting.Gondwana deposits are extensively found across the continents. Here we study the Mid- dle Permian Barakar Formation from the marginal Gondwana Basin, eastern India, being deposited in a normal fault setting. Availability of extensive cores as well as geophysical log suites （gammaresistivity-density from drilled wells） from the study area helped us achieving high resolution interpretation. Core study identifies fluvial sedimentary architectures, which were correlated with the geophysical logs and modeled field-wide to understand vertical and horizontal facies disposition. The facies analysis has been used to establish a sequence stratigraphic model of the cyclic Barakar deposition. Four major fining upward depositional sequences were identified, each sequence comprises of low accommodation system tract （LAST） at base and high accommodation system tract （HAST） at top. LAST is characterized by vertically stacked, multistory amalgamated channel sandstone dominated facies, while floodplain dominated facies characterizes HAST, reflecting a gradual shift from braided to meandering depositional system from bottom to top of each cycle. Study reveals depocenter to be in the western part, supported by eastward thinning of sediment packets, all being deposited in a halfgraben setting.

关 键 词：fluvial sequence stratigraphy Gondwana sediment Middle Permian Barakar Formation. 

分 类 号：P534.46[天文地球—古生物学与地层学] P539.2[天文地球—地质学]