Paleodepositional environment and source rock potential of Paleogene lignite and shale horizons in the Saurashtra Basin,Western India
Alok Kumar1
Khairul Azlan Mustapha2
Vikram Partap Singh3
Bodhisatwa Hazra4
P.Gopinathan4
Runcie P.Mathews3
1.Department of Geology,Faculty of Sciences,Universiti Malaya,50603 Kuala Lumpur,Malaysia;MP Singh Lab of Coal and Organic Petrology,Department of Geology,Banaras Hindu University,Varanasi,India2.Department of Geology,Faculty of Sciences,Universiti Malaya,50603 Kuala Lumpur,Malaysia3.Organic Petrology Group,Birbal Sahni Institute of Palaeosciences,Lucknow,India4.CSIR-Central Institute of Mining and Fuel Research,Dhanbad,India
摘要：Coal is formed from ancient plants through biochemical and physicochemical stages.Lignite gives a low amount of energy compared to higher rank coal.The Eocene Khadsaliya Formation lignite(Surkha mine)and shale(Khadsaliya mine)sediments were collected to investigate their evolution,maturity,and source rock potential.The main objectives of this study were to update and verify previous claim of possible hydrocarbon showings and to gain new insights about the petroleum potential and paleodepositional conditions using different geochemical analysis approach.The primary methodology employed in this study is the pyrolysis technique and complemented by petrographic analysis.Petrographic indices indicate that Khadsaliya shale and Surkha lignite were deposited in limnic and limno-telmatic conditions,respectively,with slow subsidence rates under mesotrophic hydrological condition.Significant concentration of corpogelinite indicates highly varying water table and low oxygen levels during peat accumulation.At the same time,the presence of funginite,framboidal pyrite,and relatively high sulfur in some studied samples shows marine water influence in the basin.The reflectance values(0.37％-0.57％)reveal that organic matter(OM)in Surkha lignites is immature,while immature to marginally mature in Khadsaliya shale.Furthermore,the pyrolysis data like Tmax(385 ℃-430 ℃)and production index(PI 0.02-0.13)also indicate immature to marginally mature OM.Oxygen index(OI)versus hydrogen index(HI),Tmax versus HI,and Total organic carbon(TOC)versus S2 plots of lignite and shale of Khadsaliya Formation indicate that the OM is mainly type Ⅲ kerogen and can act as fair to good source rock.The distribution of n-alkene/n-alkane doublets,o-Xylene,and 2,3-dimethylthiophene in the Py-GC pyrogram exhibits that most studied shale and lignite samples have type Ⅲ kerogen and the capability to produce mainly gas.
机标关键词：environmentwesternshalesourcerockbasindepositionhorizons
论文发表日期：2025-10-31
在线出版日期：2026-01-31（本平台首次上网日期，不代表文献的发表时间）
页数：20( 107-126 )
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