Petrological and Geochemical Investigations of Rajpardi Lignite Deposit, Gujarat, India

et al. 2017

Int J Coal Sci Technol

Lignite samples collected from Vastan, Rajpardi and Tadkeshwar lignite mines of Cambay basin (Gujarat) were subjected to organic petrographic investigations and geochemical analyses and the data, thus generated, is used to reconstruct the paleodepositional history of these lignite sequences. The lignites of Cambay basin dominantly comprise huminite maceral group (71.6%-86.3%) followed by liptinite (10.1%-19.3%) and inertinite (3.6%-11.0%) maceral groups. The mineral matter varies from 9.0% to 20.0%. The petrography based facies model indicates that these lignites have high values of gelification index (GI) and low tissue preservation index revealing a continuous wet condition in the basin and a relatively slower rate of subsidence during the decay of organic matter. On several occasions, during the formation of seams in Tadkeshwar, Rajpardi and Vastan mines, the value of GI exceeded 10 which indicates a forest permanently flooded and the cause of pronounced degree of degradation. However, few sections in Tadkeshwar seam had relatively drier spells of environmental conditions due to fluctuation in the water table as revealed by moderately high content of inertinite macerals. This is specially indicated by the occurrence of funginite which normally thrives in the upper oxygenated peatigenic layer and indicates prevalence of oxic conditions during plant deposition. Such conditions prevailed during a transgressive phase but there were intermittent fluvial activities also giving rise to supratidal flood plain as reflected in the form of associated carbonaceous shales in the basin.

Section: Paleomiressupporting

confidence: 79%

Petrographic characteristics and paleoenvironmental history of Eocene lignites of Cambay basin, Western India

et al. 2017

Int J Coal Sci Technol

“…In Tadkeshwar upper and lower seams the ash content is 6.4% and 12% respectively ( (Table 2). Though the sulfur content is moderate but few sections have high sulfur content which is attributed to marine influence as reported by Singh et al (2010Singh et al ( , 2012. They have further reported that the formation of Vastan and Rajpardi lignites took place in limnic to limno-telmatic environment under a medium to very high water cover which resulted into anaerobic preservation of organic matter with increasing bacterial activity.…”

Section: Chemical Attributesmentioning

confidence: 73%

Eocene lignites from Cambay basin, Western India: An excellent source of hydrocarbon

Rajak

et al. 2016

Geoscience Frontiers

Self Cite

a b s t r a c tIn the present paper lignites from the Cambay basin have been studied for their hydrocarbon potential. The samples were collected from three lignite fieldseVastan, Rajpardi and Tadkeshwar, and were investigated by petrography, chemical analyses and Rock-Eval pyrolysis. The results are well comparable with the empirically derived values. The study reveals that these 'low rank C' lignites are exceedingly rich in reactive macerals (huminite þ liptinite) while inertinite occurs in low concentration. These high volatile lignites generally have low ash yield except in few sections. The Rock-Eval data indicates the dominance of kerogen type-III with a little bit of type-II. The study reveals that the lignites of Vastan (lower and upper seams) and Tadkeshwar upper seam are more gas-prone while Rajpardi and Tadkeshwar lower seams are oil-prone. Further, the fixed hydrocarbons are several times higher than the free hydrocarbons. The relation between TOC and fixed hydrocarbon indicates that these lignites are excellent source rock for hydrocarbon which could be obtained mainly through thermal cracking. The empirically derived values reveal a high conversion (94e96%) and high oil yield (64e66%) for these lignites. Ó 2015, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

“…Facies models mainly based on petrographic elements have been used to discuss the evolutionary history of the paleomires of Kachchh Basin. A number of researchers (Cohen and Spackman 1972;Styan and Bustin 1983;Cohen et al 1987;Calder et al 1991;Grady et al 1993;Hawke et al 1996;Singh and Singh 1996;Shearer and Clarkson 1998;Jasper et al 2010;Singh et al 2010a, b;Suárez-Ruiz et al 2012;Singh et al 2012aSingh et al , b, 2014 have attempted paleoecological reconstructions using petrological tools. Recently, O'Keefe et al (2013) have made a detailed discussion on 'coal rank' and 'coal type' and relation of latter to the environment of peat formation, the climate of peat formation, and the decompositional history of the mire.…”

Section: Depositional Environmentmentioning

confidence: 99%

“…It is evident from the figure that in Panandhro area maximum gelification occurred during the formation of Seam-II while in Matanomadh area high gelification was observed during the formation of Seams I, II, and V. Further, in Panandhro area, GWI was high during the formation of seams I, II, and V while in Matanomadh area the GWI was high during the formation of seams I and VI. Singh et al (2012a) proposed a ternary model for understanding the paleomires of the Eocene lignite deposit of Rajpardi. This is based on maceral composition as well as clastic minerals.…”

Section: Depositional Environmentmentioning

confidence: 99%

Understanding the paleomires of Eocene lignites of Kachchh Basin, Gujarat (Western India): petrological implications

et al. 2017

Int J Coal Sci Technol

The present paper entails the results of the investigations carried out on the lignite deposits of Kachchh Basin. The lignite samples were drawn from five lignite seams from Panandhro lignite field (Seam-I to -V) and eight lignite seams (Seam-I to -VIII) from the Matanomadh lignite field which are currently operational. The petrographic analysis of the lignites indicates a dominance of huminite group of macerals which is mainly contributed by ulminite-A, ulminite-B, attrinite, densinite, and phlobaphinite. Liptinite (chiefly sporinite, cutinite, resinite, and liptodetrinite) and inertinite (chiefly fusinite, funginite, and inertodetrinite) groups occur in subordinated amount. The mineral matter occurs in moderate concentration. Though sulfur content is high in these lignites, there is no fixed trend of variation of sulfur from bottom seam to top seam. The investigation reveals a flooded forest swamp having high rate of degradation. However, there were a few drier periods indicated by relatively more inertinite macerals. The petrography-based models indicate that the Kachchh lignites of Gujarat evolved in coastal marshy setting under transgressive phase. However, there were few intermittent fluvial activities giving rise to supratidal flood plain. This led to the formation of the associated carbonaceous shales in the basin.