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- 1. Theory Lecture forB. Sc. IV Semester, 2019-20 Batch STRATIGRAPHY OF THE GONDWANA SUPERGROUP by PROF. VIBHUTI RAI DEPARTMENT OF GEOLOGY, UNIVERSITY OF LUCKNOW DISCLAIMER: Many figures, chats, tables and other content may have been borrowed from Internet, books and other e-resources for teaching purposes only. No reproduction is allowed as the copyright remains with the original producers of these contents. The author of this lecture presentation would not be responsible for any such copyrite violation..
- 2. ORGANIZATION OF CONTENTS •INTRODUCTION • DISTRIBUTION • LITHOLOGY • CLASSIFICATION • ECONOMICC SIGNIFICANCE
- 3. INTRODUCTION • THE TERMGONDE OF WANA WAS COINED BY H.B. MEDLICOTT IN 1872. • IT WAS DERIVED FROM THE KINGDOM OF GOND, AN ANCIENT TRIBE OF CENTRAL INDIA. THIS TRIBE STILL EXISTS IN THE STATE OF MADHYA PRADESH. • THE TERM SUPERGROUP IS USED HERE FOR ITS STRATIGRAPHICAL HIEARCHY AS IT CONTAINS SEVERAL GROUPS AND FORMATIONS. • GONDWANA TERM IS ALSO USED IN A TECTONOSTRATIGRAPHIC MANNER – THE SUPERCONTINENT OF THE GONDWANALAND. • THIS SUPERCONTINENT EXISTED BETWEEN PERMIAN TO CRETACEOUS PERIOD AS THE SOUTRHERN HALF OF PANGAEA.
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- 7. THE GONDWANA BASINS •GONDWANA BASINS OF INDIA ACCOUNT FOR NEARLY 99% OF COAL RESOURCE OF THE COUNTRY. THE BASINS OCCUR ALONG MAJOR RIVER VALLEYS EITHER AS DISCRETE BODIES OR ARE UNIFIED BY POST-PERMIAN STRATA AND ARE NAMED AFTER THE RIVERS DAMODAR, SON, MAHANADI, GODAVARI ETC. OR THE LINEAR HILL RANGES LIKE SATPURA AND RAJMAHAL. • THE SEDIMENTS CONSTITUTES UPTO FIVE KM. THICK STRATA, DEPOSITED OVER 200 MILLION YEARS (FROM UPPER CARBONIFEROUS TO LOWER CRETACEOUS) WHICH ARE PRESERVED IN THESE BASINS AND ARE CLUBBED INTO GONDWANA SUPERGROUP.
- 8. • GONDWANA SUPERGROUPIS SUB¬DIVIDED INTO PERMO- CARBONIFEROUS LOWER GONDWANA GROUP, CHARACTERIZED BY GANGOMOPTERIS- GLOSSOPTERIS FLORA AND MESOZOIC UPPER GONDWANA GROUP CONTAINING DICROIDIUM–LEPIDOPTERIS- PTYLOPHYLUM FLORA. • THE COAL SEAMS ARE FOUND ONLY IN THE LOWER GROUP WITHIN KARHARBARI AND BARAKAR FORMATIONS OF LOWER PERMIAN AND RANIGANJ FORMATION AND ITS EQUIVALENTS OF UPPER PERMIAN AGE. • BARAKAR FORMATION IS THE MAJOR STOREHOUSE OF COAL IN ALL THE BASINS HAVING MORE THAN 90% OF TOTAL RESOURCE OF THE COUNTRY. KARHARBARI AND RANIGANJ FORMATIONS PRESENT ONLY IN A FEW BASINS.
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- 12. THE SEDIEMNTARY BASINS OFINDIA THE GONDWANA BASINS IN THREE LINEAR DEPRESSIONS
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- 36. FLORA OF THEGONDWANA
- 37. FAUNA OF THEGONDWANA
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- 43. NOTES Gondwana Basins ofIndia account for nearly 99% of coal resource of the country. The basins occur along major river valleys either as discrete bodies or are unified by post-Permian strata and are named after the Rivers Damodar, Son, Mahanadi, Godavari etc or the linear hill ranges like Satpura and Rajmahal. Upto five km thick strata, deposited over 200 million years, from Upper Carboniferous to Lower Cretaceous, are preserved in these basins and are clubbed into Gondwana Supergroup. Upper Cretaceous Lameta-Bagh beds and Deccan Trap have not been included within Gondwana Supergroup since by that time India was completely separated from the rest of Gondwanaland and moved far towards north. Gondwana Supergroup is sub¬divided into Permo-carboniferous Lower Gondwana Group, characterized by Gangomopteris-Glossopteris flora and Mesozoic Upper Gondwana Group containing Dicroidium– Lepidopteris-Ptylophylum flora. The coal seams are found only in the lower group within Karharbari and Barakar Formations of Lower Permian and Raniganj Formation and its equivalents of Upper Permian age. Barakar Formation is the major storehouse of coal in all the basins having more than 90% of total resource of the country. Karharbari and Raniganj Formations present only in a few basins.
- 44. GEOLOGICAL SETUP The GondwanaBasins of Peninsular India occur along four major linear belts namely (1) Trans-Indian basin belt that include ENE-WSW trending Satpura and Son Valley Basins and EW to WNW-ESE trending Damodar-Koel Valley Basins (2) NNW -SSE trending Wardha-Pranhita-Godavari Valley Basin belt, (3) NW-SE trending Mahanadi Valley Basin belt that swerves to WNW-ESE direction in southernmost Talcher coalfield and (4) NNW-SSE trending Purnea-Rajmahal- Galsi basin belt. The Gondwana Basins of Bangladesh are often considered to be part of this fourth belt with easternmost exposure of Gondwana sediments at Singrimari in Meghalaya. • In addition, in the eastern part of Extra-Peninsular India some isolated outcrops of Lower Gondwana Group occur as thrusted sheets overriding the Neogene- Quaternary sediments extending from Arunachal Pradesh in the east to central Nepal in the west. Presence of Gondwana sediments have also been established in boreholes drilled in the offshore Bay of Bengal along the extension of Godavari and Mahanadi Rivers.
- 45. Apart from thesetraditional coal-bearing Gondwana Basins, sediments identical to the non-coal bearing basal part of Lower Gondwana Group of rocks are present in Jaisalmer Basin of Rajasthan, Salt Range in Punjab (Pakistan), along the Palaeo-Tethyan margin (stretching from Kashmir to Garhwal Himalaya) and along East Coast (in Palar and as a number of detached outliers). Besides, the Mesozoic basins of Kachchh and Eastern Pericratonic basins have temporally overlapping relation with Gondwana Basins. Although these basins are not generally included in the traditional Gondwana Basins, their geological history throws important light in the evolutionary history of Gondwana geology of India. Special emphasis needs to be given to Salt Range in Punjab (Pakistan),
- 46. MARINE INTERCALATIONS Marine bedsin association with Lower Gondwana rocks are known to occur at Umaria. In Umaria Marine Beds, 3 meters shelly limestone containing fossils of shells of Productus, Spiriferina, Reticularia and others. The Umaria Marine Beds overlies the Talchir Boulder Beds but passes upwards without any visible break into the overlying Barakar rocks. The fossil assemblage is suggestive of Lower Permian age and warmer climate. In Rajasthan marine beds equivalent to Umaria Marine Beds are known as Bap Beds after Bap village near Jaisalmer. The marine beds also occur in several patches near Manendragarh in CG. The marine rocks occur in the basal part of the Talchir succession. The fauna includes Protoretepora, Spirifer, Aviculopecten, Eurydesma, Hyperammina and Glomospiria. The total absence of Productus and abundance of Eurydesmids make these beds distinctly different from those at Umaria. •