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CHHATTISGARH BASIN

ContentsContents Introduction Chhattisgarh Basin Lithology Classification

Singhora Group

Chandrapur Group

Raipur Group Evidence of life in Chhattisgarh Basin Conclusion References

IntroductionIntroduction

These are also called “Purana” basins in Indian Stratigraphy. Purana basins are has a deposites of Limestone and Dolomite, and other economic minerals like phosphorite, chrysotile asbestos, Base metals and building stones.

Chhattisgarh basin is one of the Proterozoic Sedimentary Basin, these basins contain orthoquartzite-shale-carbonate suites varying in thickness from 100-10,000m and deposited alternately with frequent breaks in sedimentation, over a time of 1,000 Ma.

TECTONIC MAP OF INDIAN SHIELD

Chhattisgarh basin

Chhattisgarh BasinChhattisgarh Basin

Chhattisgarh basin is the largest Purana basin in Bastar craton.

Chhattisgarh basin covering an area of about 36,000sq.km is situated on northern edge of Bastar craton.

It is bounded by Kotri-Dongargarh orogen in the West, Satpura mobile belt in the North, Gondwana graben of Mahanadi in the North-East and the Eastern Ghats mobile belt in the South-East.

Chhattisgarh basin extends for about 300km in the E-W and 200km in the N-S directions.

The basin contains about 2500m thick sediments of orthoquartzite-carbonate-pelite suite, deposited in multiple sedimentary cycles, and also with minor felsic volcanics and pyroclastics.

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 occur in the east at Singhora and Barapahara.

LithologyLithology

The basement in the south of the basin consist of Gneisses, Kanker-Mainpur granitoids Sonakhan greenstone belt.

Sambalpur granite lies in the North-East, and in the South-East the margin is sheared at the contact with the marginal zone of Eastern Ghat mobile belt.

The Bilaspur-Raigarh-Sarguja supracrustals underlie the Chhattigarh sediments partly unconformably and partly in faulted contact with Satpura mobile belt.

Singhora Group

The oldest Singhora Group is exposed in the Singhora proto-basin in the southeast and the Barapahar sub-basin in the northeast.

Bhalukona Sandstone is probably a shore line sediment, overlain by the shale-chert-stromatolitic limestone-dolemite association of Chhuipali Shale that is deposited in a shallow offshore environment.

After Singhora Group the deposition followed by a conglomerate and coarse arkosic sandstone in shale dominated sequence of Chandrapur Group and it is followed by a limestone –shale dominated sequence of Raipur Group.

Chandrapur GroupChandrapur Group

Chandrapur Group consist of three sandstone intervals, separated by two mud bearing sequence.

The basal conglomerate is called either as a alluvial fan-fan delta deposit or as a beach deposit with sandstone lenses resulting from stroms.

Choparadih shale is interpreted to have a variable from prodelta and intertidal –lagoonal zone.

Kansapathar Sandstone is a strom-tide because of shoreface and shelf deposit.

Raipur GroupRaipur Group

Raipur Group conformably overlies Chandrapur Group and consists of three carbonate-shale cycles.

It starts from brown calcareous shale and green shale about 100m thick and is called as Bijepar Shale, and succeeding is carbonate-siliciclastic succession deposited and upper member of pelagic limestone grading into deep water Gunderdehi Shale.

Raipur Group is believed to be deposited in two separate basins Hirri and Baradwar , separated by the Sonakhan high.

Basic dykes intruded the sedimentary sequence at different levels in many places.

Evidence of life in Chhattisgarh basin

Stromatolites have been reported from Chhattisgarh basin, these indicate middle and upper Riphean age.

Microbiota- mostly prokaryotic cyanobactiria (filamentous) and arcitarchs were recorded from Chhattisgarh basin.

Zircon from Raipur Group have been subjected to SHRIMP analysis, which gives around 990-1020 Ma (Deb et al., 2007) for the Chhattisgarh basin.

ConclusionConclusion

Chhattisgarh basin is the third largest Purana basin after the Vindhyan and Cuddapah.

The vast Limestone and Dolomite resources of the basin feed the Bhilai Steel Plant and Cement factories of the surrounding area.

The Granitic terrain surrounding the basin has been recently found to host number of Kimberlite pipes.

In comparison with the other Purana basins, a time span between 1600 and 900 Ma may be assigned to Chhattisgarh basin.

REFERENCE

Ramakrishnan. M and Vaidyanadhan. R (2008): Geology Of India (volume 1) ,Geological Society of India Bangalore.pp-473-478

WEBSITES

www.wikipedia/chattisgarhbasin

www.geology.com/stratigraphy of chattisgarh basin

www.encyclopedia/chattisgarh basin

BOOKS

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