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Mafic Magmatism, Rank Variation in Coal From the Sohagpur Subbasin

2018; Elsevier BV; Linguagem: Inglês

10.1016/b978-0-12-815218-8.00010-8

2542-9000

Abhijit Mukhopadhyay,

Hydrocarbon exploration and reservoir analysis

The Sohagpur Subbasin occupies the west central part of the Son Valley Basin belt and lies on the upper part of the gentle homoclinal upper limb. The strata dips 3–5 degrees northerly with strike varying from ENE-WSW to E-W. There are some broad folds mostly synclinal in geometry. Sediments are disturbed by normal faults mostly E-W trending (varying from 70 to 105 degrees) and also occasionally by 150 to 330 degrees trending normal faults. Faults dip in either a northerly or southerly direction and throw range from 10 to 650 m. The Bamhani-Chilpa, the Dhanpuri-Kotma, the Shahdol, and the Pali-Raniganj faults are major basement faults of the subbasin. Of these faults, the Dhanpuri-Kotma fault runs southerly, while the other faults dip northerly. West of Pakaria, Bamhani-Chilpa splays into three branches, namely, the Dulhara, Kanchanpur, and the Pakaria faults. A study of the relationship between faulting and sedimentation shows that there are at least four fault movements. Tectonically controlled subsidence aided by faulting (Fi) took over in the later phase of Talchir deposition. A second movement (Fii) during the late Barakar tie gave rise to the development of the Bamhani-Chilpa faults, the associated fault system, and other northerly dipping faults. A third fault (Fiii) movement gave rise to southerly and easterly dipping faults in the post-Parsora/Chandia (Early Cretaceous) time, when Fi faults were also reactivated. The fourth (Fiv) fault movement occurred in the post-Deccan-Trap period that also affected the basic bodies within the Gondwana sediments. During this movement, major E-W faults were also reactivated.