Basin Introduction :
Chhattisgarh basin is the largest Purana basin I Bastar craton. The craton is dotted with several smaller basins like Khariar, Ampani, Indravati and sabari (Sukma), besides many outliers like Keskal, Singanpur and Chedrapal. Although Kale (1991) believed that each Purana basin is unique with well-defined boundaries and not an erosional remnant or atectonic depression, the prevailing opinion is that the isolated basins and outliers in Bastar craton are part of once-continuous basin fill that got fragmented by basement doming and denudation (Ahmad, 19558; Ramakrishnan, 1987; Chaudhuri et al. 2002).
Chhattisgarh basin covering as area of about 36000 sq. km is situated on the northern edge of Bastar craton. It is bounded by the Kotri-Dongargarh orogen in the west, Satpura mobile belt in the north, Gondwana graben of Mahanadi in the northeast and the Eastern Ghats mobile belt in the southeast. In the south, the basin overlies the basement gneiss enclosing the Sonakhan greenstone belt. Chhattisgarh basin is the third largest Purana basin after the Vindhayan and Cuddapah, and extends for about 300 km in the E-W and 200 km in the N-S directions, with an irregular rectangular configuration. Vast limestone and dolomite resources of the basin feed the Bhilai Steel Plant and the cement factories in the vicinity. The granitic terrain surrounding the basin has been recently found to host a number of kimberlite pipes.
Pioneering geological work in the basin was carried out by V. Ball, W. King and F.D. Smith, followed by N.V.B.S. Dutt in 1964 and W.A. Schnitzer in 1971. Muti (1987, 1996), Das et al. (1992, 2001), Chaudhari et al. (2002) and Deb (2004) provide recent geological summaries of the basin. The basin contains about 2500 m thick sediments of orthoquartzite-carbonate-pelite suite, deposited in multiple sedimentary cycles, intercalated with minor felsic volcanics and pyroclastics and punctuated by uncomformities. Each cycle starts with arreaceous facies and ends up with shale-limestone facies. The basin is divided into two sub-basins, the Hirri in the west and Baradwar in the east separated by the Sonakhan high over the Sonakhan greenstone belt. Two small proto-basins containing the oldest sequences in the east at Singhora and Barapahar.
|Raipur Group (1900 m)||Maniari Shale (70)||Purple shale, dolomite, gypsum|
|Hirri Dolomite (70)||Grey dolomite|
|Tarenga Shale (180)||Dolomitic shale, shale-chert beds, purple shale, limestone|
|Chandi Limestone (670)||Stromatlitic dolomite, limestone, glauconitic sandstone, shale|
|Gunderdehi Shale (430)||Shale with limestone interbeds, arenite-shale, ignimbrite|
|Charmuria Limestone (490)||Phosphatic limestone with shale interbeds, cherty limestone and phosphatic dolomite, chert-shale interbeds|
|Bijepur Shale (100)||Green and brown calcareous shale with sandy interbeds|
|Chandrapur Group (400 m)||Kansapathar Sandstone (200)||Galuconitic sandstone|
|Chaporadih Shale (200)||Shale with arenite interbeds|
|Lohardih Conglomerate (20)||Purple arkose, gritty arenite and basal conglomerate|
|Singhora Group (400 m)||Chhuipali Shale (300)||Shale with chert, limestone, dolomite, siltstone|
|Bhalukona Sandstone (20)||Sandstone, siltstone, minor shale|
|Saraipali Shale (60)||Variegated shale with siltstone, limestone, porcellanite, felsic tuff|
|Rehatikhol Conglomerate (20)||Felspathic arenite, arkose and basal conglomerate|
|Crystalline basement of Bastor craton|