{"title":"印度西部褐煤矿始新世早期至中期古环境变化记录","authors":"S. Khanolkar, J. Sharma","doi":"10.5194/JM-38-1-2019","DOIUrl":null,"url":null,"abstract":"Abstract. Various Eocene hyperthermal events have been recorded from lignite sections\nof western India in the past decade. To infer the paleoenvironment, during a\nwarm paleotropical climate of India, we have assessed multiple microfossil\ngroups like pollen/spores, dinoflagellates and foraminifera from Early Eocene\nlignite mine sections from the Cambay (Surkha) and Barmer (Giral) basins and\nMiddle Eocene sections from the Kutch Basin (Matanomadh and Panandhro mines) of\nwestern India. The Surkha and Giral sections exhibit a dominance of\nrainforest elements (Arengapollenites achinatus, Longapertites retipilatus), thermophilic mangrove palm Nypa and (sub)tropical\ndinoflagellate cyst Apectodinium, Cordosphaeridium and\nKenleyia. This palynomorph assemblage is indicative of a marginal\nmarine setting within a hot and humid climate. During the Middle Eocene, the\ndiversity of dinocyst assemblage increased and a decrease in percentage of\nmangrove elements was observed in the Matanomadh and Panandhro mine sections of\nthe Kutch Basin as compared to the Early Eocene sections of western India.\nBloom of triserial planktic (Jenkinsina columbiana) and rectilinear\nbenthic (Brizalina sp., Trifarina advena rajasthanensis) foraminifera indicates eutrophic conditions of deposition during the Late\nLutetian–Early Bartonian in the lignite sections of the Kutch Basin which later changed\nto oligotrophic, open marine conditions towards the Bartonian (planktic E12\nzone). This change to oligotrophic conditions coincides with a drastic\nincrease in diversity of planktic foraminifera in the top portion of lignite\nmines of the Kutch Basin which may be correlated with the Kirthar–Wilson Bluff\ntransgression event in the Bartonian observed across basins in India, Pakistan and\nAustralia potentially linked to sea level rise around the Middle\nEocene Climatic Optimum.\n","PeriodicalId":54786,"journal":{"name":"Journal of Micropalaeontology","volume":"1 1","pages":""},"PeriodicalIF":4.1000,"publicationDate":"2019-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"22","resultStr":"{\"title\":\"Record of Early to Middle Eocene paleoenvironmental changes from lignite mines, western India\",\"authors\":\"S. Khanolkar, J. Sharma\",\"doi\":\"10.5194/JM-38-1-2019\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Abstract. Various Eocene hyperthermal events have been recorded from lignite sections\\nof western India in the past decade. To infer the paleoenvironment, during a\\nwarm paleotropical climate of India, we have assessed multiple microfossil\\ngroups like pollen/spores, dinoflagellates and foraminifera from Early Eocene\\nlignite mine sections from the Cambay (Surkha) and Barmer (Giral) basins and\\nMiddle Eocene sections from the Kutch Basin (Matanomadh and Panandhro mines) of\\nwestern India. The Surkha and Giral sections exhibit a dominance of\\nrainforest elements (Arengapollenites achinatus, Longapertites retipilatus), thermophilic mangrove palm Nypa and (sub)tropical\\ndinoflagellate cyst Apectodinium, Cordosphaeridium and\\nKenleyia. This palynomorph assemblage is indicative of a marginal\\nmarine setting within a hot and humid climate. During the Middle Eocene, the\\ndiversity of dinocyst assemblage increased and a decrease in percentage of\\nmangrove elements was observed in the Matanomadh and Panandhro mine sections of\\nthe Kutch Basin as compared to the Early Eocene sections of western India.\\nBloom of triserial planktic (Jenkinsina columbiana) and rectilinear\\nbenthic (Brizalina sp., Trifarina advena rajasthanensis) foraminifera indicates eutrophic conditions of deposition during the Late\\nLutetian–Early Bartonian in the lignite sections of the Kutch Basin which later changed\\nto oligotrophic, open marine conditions towards the Bartonian (planktic E12\\nzone). This change to oligotrophic conditions coincides with a drastic\\nincrease in diversity of planktic foraminifera in the top portion of lignite\\nmines of the Kutch Basin which may be correlated with the Kirthar–Wilson Bluff\\ntransgression event in the Bartonian observed across basins in India, Pakistan and\\nAustralia potentially linked to sea level rise around the Middle\\nEocene Climatic Optimum.\\n\",\"PeriodicalId\":54786,\"journal\":{\"name\":\"Journal of Micropalaeontology\",\"volume\":\"1 1\",\"pages\":\"\"},\"PeriodicalIF\":4.1000,\"publicationDate\":\"2019-01-18\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"22\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Micropalaeontology\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://doi.org/10.5194/JM-38-1-2019\",\"RegionNum\":3,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"PALEONTOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Micropalaeontology","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.5194/JM-38-1-2019","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"PALEONTOLOGY","Score":null,"Total":0}
Record of Early to Middle Eocene paleoenvironmental changes from lignite mines, western India
Abstract. Various Eocene hyperthermal events have been recorded from lignite sections
of western India in the past decade. To infer the paleoenvironment, during a
warm paleotropical climate of India, we have assessed multiple microfossil
groups like pollen/spores, dinoflagellates and foraminifera from Early Eocene
lignite mine sections from the Cambay (Surkha) and Barmer (Giral) basins and
Middle Eocene sections from the Kutch Basin (Matanomadh and Panandhro mines) of
western India. The Surkha and Giral sections exhibit a dominance of
rainforest elements (Arengapollenites achinatus, Longapertites retipilatus), thermophilic mangrove palm Nypa and (sub)tropical
dinoflagellate cyst Apectodinium, Cordosphaeridium and
Kenleyia. This palynomorph assemblage is indicative of a marginal
marine setting within a hot and humid climate. During the Middle Eocene, the
diversity of dinocyst assemblage increased and a decrease in percentage of
mangrove elements was observed in the Matanomadh and Panandhro mine sections of
the Kutch Basin as compared to the Early Eocene sections of western India.
Bloom of triserial planktic (Jenkinsina columbiana) and rectilinear
benthic (Brizalina sp., Trifarina advena rajasthanensis) foraminifera indicates eutrophic conditions of deposition during the Late
Lutetian–Early Bartonian in the lignite sections of the Kutch Basin which later changed
to oligotrophic, open marine conditions towards the Bartonian (planktic E12
zone). This change to oligotrophic conditions coincides with a drastic
increase in diversity of planktic foraminifera in the top portion of lignite
mines of the Kutch Basin which may be correlated with the Kirthar–Wilson Bluff
transgression event in the Bartonian observed across basins in India, Pakistan and
Australia potentially linked to sea level rise around the Middle
Eocene Climatic Optimum.
期刊介绍:
The Journal of Micropalaeontology (JM) is an established international journal covering all aspects of microfossils and their application to both applied studies and basic research. In particular we welcome submissions relating to microfossils and their application to palaeoceanography, palaeoclimatology, palaeobiology, evolution, taxonomy, environmental change and molecular phylogeny.