Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

Omprakash S. Sarate ¹, Navita Budhraja ¹

Affiliations
1 Birbal Sahni Institute of Palaeosciences, 53, University Road, Lucknow -226 007, IN

Abstract

The present paper deals with the critical observation of a thallus section recorded in one of the samples prepared for the coal petrographic study (Pellet No 3) This sample represents a coal band lying above the 'Queen seam" from Koyagudem area of the Godavan valley coalfield, Andhra Pradesh The shape of this specimen in transverse section and its cellular organization very closely resemble the anatomical features of extant thalli of the bryophytic (liverwort)family Reboulzaceae, a big group of Marchantiales (Hepaticopsida) A thallus with cellular details assignable to Hepaticae 1s recorded from the Lower Gandwana Sequence of Godavari valley coalfield.

Keywords

Marchantiales, Permian, Hepaticae, Koyagudem, Godavari valley, Andhra Pradesh.

Full Text

     

Omprakash S. Sarate ¹

Affiliations
1 Birbal Sahni Institute of Palaeobotany 53, University Road, Lucknow - 226 007, IN

Abstract

Recent sub-surface investigations have proved the existence of coal deposits in Makardhokada area of Nagpur District, Maharashtra Structurally, Makardhokada area represents the western extension of Umrer coalfield. As far as the economic potentialities of these coal deposits are concerned, out of the six seams intersected, only four viz Seam I, II, IV and V have attained workable thickness of more than a metre. The maceral constitution and rank estimations have been considered as the parameters to interpret the depositional environment and economic importance of these coal deposits. The maceral study suggests that the coal of seam I contains a mixture of all the three coal types i.e. vitric (Vitrinite rich), fusic (Inertinite rich) and mixed (Vitrinite + Inertinite rich). However, the seams II and IV are constituted by fusic and mixed coal types. Seam V contains both the vitric and mixed coal types. The maturation (reflectance) studies have indicated low vitnnite reflectivity (R₀ max %) of 0 42-0.53%, which suggests that the coals have attained sub-bituminous C to high volatile bituminous C stage of the rank. The coal constitution suggests frequent floods at the depositional site and alternate dry oxidizing and cold climatic seasonal changes caused the formation of vitric and fusic coal types.

Keywords

Lower Gondwana, Coal Seams, Depositional Environment, Umrer Coalfield, Makardhokada, Maharashtra.

Full Text

     

H. K. Sabot ¹, Omprakash S. Sarate

Affiliations
1 AMD Hyderabad - 500 016, IN

Abstract

No Abstract.

Full Text

   

Kamal Jeet Singh ¹, Omprakash S. Sarate ¹, A. P. Bhattacharya ¹, Shreerup Goswami ¹

Affiliations
1 Birbal Sahni lnstitute of Palaeobotany, 53, University Road, Lucknow - 226 007, IN

Abstract

A rich collection of Lower Gondwana mega-Plant fossils have been recorded from the outcrops exposed along the Kharkhara Nala section in Nand coalfield, Nagpur District, Maharashtra, mapped as Lameta Formation. The Lower Gondwana rocks are deposited mainly in Nagpur, Chandrapur and Yeotmal Districts of Maharashtra. Palaeobotanical investigations (megafloral and xylotomical) so far known from Wardha Valley are mostly confined to Barakar and Kamthi Formations. Megafloral assemblage very similar to assemblage of Karharbari Formation has been recovered for the first time from the Lower Gondwana beds exposed in the Nand coalfield. The plant assemblage consists of two species of Gangamopteris, one species each of the genera Buriadia, Noeggerathiopsis and Allatocarpus along with the genus Glossopteris represented by seven species. The conifer genus Buriadia dominates the flora (17 72%) followed by Glossopteris communis (16 46%). The sediments were also investigated for the purpose of palynology but no pollen and spore types could be recovered. An Early Permian age has been assigned on the basis of overall assemblage.

Keywords

Lower Gondwana, Mega Flora, Nand Coalfield, Nagpur District, Maharashtra.

Full Text

     

Omprakash S. Sarate ¹

Affiliations
1 Birbal Sahni Institute of Palaeobotany, 53, University Road, Lucknow - 226 007, IN

Abstract

The coal sequences concealed below the Deccan Trap in Mahadoli (northwestern part) and in the vicinity of Kosar and Dongargaon areas (Kayar Block) delimiting the western boundary of the Wardha Valley Coalfield, Maharashtra, have been analyzed. A comparative study about their maceral constitution, rank evaluation and depositional envit onment has also been discussed. The coals in these areas are classified under fusic and mixed types barring the top seam of Dongargaon area containing vitric type of coal. In general, these coals have attained high volatile bitulnilious C stage of rank.

Keywords

Biopetrology, Depositional Milieu, Rank, Gondwana, Wardha Valley Coals, Maharashtra.

Full Text

     

Omprakash S. Sarate ¹

Affiliations
1 Birbal Sahni Institute of Palaeobotany, 53, University Road, Lucknow - 226 007, IN

Abstract

Critical analysis of the constitution and rank of the sub-surface coal deposits from Krishnavaram area in the Chintalapudi sub-basin of Godavari valley coalfield is presented. Three coallshale zones viz. A, B and C (in the ascending order) are encountered from Barakar Formation and lower Kamthi Member of the Lower Gondwana sequence. Zone C mostly contains shaly beds interbedded with thin coal bands (mostly shaly coal), and as such has no economic significance. Zone B is dominated by the vitric and mixed type of coal which has attained high volatile bituminous B and C ranks. The lowermost Zone A is characterised by mixed and fusic coal types with high volatilc bituminous C rank. Both the zones A and B contain good quality coal and bear high economic potential. Cold and humid climate with alternating dry and oxidising spells have been interpreted from the constitution of coal. Moreover, the accumulation of thick pile of sediments rich in organic matter is attributed to the sinking of the basin floor due to the activation of faults. Later tectonic events either caused extinction or drastically reduced the number of the floral elements and formed thick shaly horizons interrupting the continuity of the coal facies.

Keywords

Biopetrology, Macerals, Coal, Chintalapudi Sub-Basin, Godavari Valley Coalfield, Andhra Pradesh.

Full Text

     

Omprakash S. Sarate ¹

Affiliations
1 Birbal Sahni Institute of Palaeobotany, 53, University Road, Lucknow - 226 007, IN

Abstract

The study of coal succession from bore hole No. Q-448 of Yellendu area of the Godavari valley coalfield, Andhra Pradesh reveals that the coals of Queen seam are high volatile bituminous C in rank and have vitrinite reflectance (R_o max %) varying between of 0.52 and 0.62%. The petrographic constitution however, suggests that the depositional site appears to be a slowly sinking and tectonically controlled basin, having received continuous supply of vegetal matter rich resource at regular intervals. The formation of inertinite rich coal suggests, oxidising enviornment of deposition. The dominence of vitrinite and liptinite constituents in these coals postulates the existence of alternating cold and humid spells. The present study indicates that these coals originated under an alternate oxic and anoxic moor condition.

Keywords

Yellendu, Godavari Valley, Queen Seam, Maceral, Reflectance, Andhra Pradesh.

Full Text

     

Omprakash S. Sarate ¹

Affiliations
1 Birbal Sahni Institute of Palaeobotany, 53, University Road, Lucknow - 226 007, IN

Abstract

A detailed study of maceral composition and vitrinite reflectance of the coal deposits from Marki-Jhari-Jamni area, situated in the northwestern extremity of Wardha valley coalfield, Yeotmal district, Maharashtra has been carried out with special reference to their depositional set up. These coals have two distinct types of maceral organization, one having significantly high distribution of the vitrinite group of macerals (35-41%) and the other containing the dominance of inertinite (26-49%). Liptinite maceral group is recorded between 14 and 24%, barring a few coal bands having liptinite maceral group as high as 33-37%. The vitrinite reflectivity ranges from 0.38-0.43%. Thus, they have attained sub-bituminous C rank. Mineral matter in these coals varies between 15 and 22%. The present study suggests that the basin primarily experienced cold climate having intermittent brackish water influx with alternating dry oxidizing spells.

Keywords

Maceral, Reflectance, Environment of Deposition, Rank, Yeotmal, Wardha Valley Coalfield, Maharashtra.

Full Text

     

Omprakash S. Sarate ¹

Affiliations
1 Birbal Sahni Institute of Palaeobotany, 53, University Road, Lucknow - 226 007, IN

Abstract

The quantitative maceral study of the Queen seam from Mailaram coalfield of Godavari valley has displayed alternate coal bands rich in vitrinite/liptinite or inertinite. The random vitrinite reflectance (R_o max. %) of these coals, from top part ranges from 0.50 to 0.64%. However, the bottom part of the seam has indicated lower reflectance, between 0.49 and 0.52%. Thus, the Queen seam, in general, has attained high volatile bituminous C rank. The study indicates that the depositional site has been a slowly sinking basin that witnessed alternate dry (oxidizing) and wet (reducing) spells. This subsequently caused fluctuation in water table of the basin and the formation of oxic and anaoxic moor condition, where accumulated vegetal resource transformed into mixed and fusic coal types in due course of time. Being high in liptinite and vitrinite contents and low mineral matter, the Queen seam of Mailaram coalfield has high economic potential.

Keywords

Petrography, Coal, Godavari Valley, Andhra Pradesh.

Full Text