Oxic-dysoxic Tidal Flat Carbonates from Sadara, Pachham Island, Kachchh

Kale, M. G.; Pundalik, Ashwin S.; Karmalkar, N. R.; Duraiswami, Raymond A.

doi:10.1007/978-3-030-71370-6_8

Cited by 2 publications

(1 citation statement)

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“…Significant proportion of insoluble residue (avr. 7.30%) is in accordance with their algal nature and shallow marine depositional environment (Bilal et al, 2022; Flügel, 1982; Kale et al, 2021). The thin sections of the limestones from the Lumpy Clay Member reveal their mud-supported nature, with a subordinate proportion of detrital grains, intraclasts and bioclasts.…”

Section: Discussionsupporting

confidence: 68%

Petrographic analysis of Oligocene carbonates of Kachchh basin

Patil,

Pundalik,

Pansare

2023

Journal of the Palaeontological Society of India

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The Kachchh basin is located on the northwestern margin of India. The basin consists of a relatively continuous sequence of sediments from the Mesozoic, followed by the Deccan Traps and finally a complete sequence of the Cenozoic sediments. The Cenozoic sediments of Kachchh basin are mainly shallow marine deposits characterised by five formations viz. Matanomadh, Naredi, Harudi, Fulra Limestone and Maniyara Fort Formation. The Maniyara Fort Formation belongs to the Oligocene age. The field and petrographic characteristics of the Oligocene limestones from the Golay river section were studied in order to understand the depositional environment. The petrographic investigation of the carbonate rocks of three members of the Maniyara Fort Formation, namely Lumpy Clay Member, Coral Limestone Member and Bermoti Member provides important information for understanding the depositional facies and diagenetic signatures. The Lumpy Clay Member has shale-siltstones with interbedded limestones, characteristically composed of a significant proportion of detrital grains of quartz and some lithic fragments. The lithic fragments are sub-angular to rounded, which indicates substantial transport. They are also worn down and broken, bear small cracks which are filled by micritic matrix or mud. The presence of stylolitic seams within the limestone (though not significant) along with mud filling is also noticed. The dissolution is not prominent, pointing towards shallow burial of the sediments. Paucity of marine fossils as well as the rarity of foraminifera in the Lumpy Clay Member indicate a restricted to semi-restricted shallow marine environment. The limestones of the Coral Limestone Member are petrographically classified as packstone, wackestone and mudstone. Thus, the environment of deposition seems to have varied from restricted lagoonal to shallow marine environment. The Bermoti Member is characterised by a lens of claystone, which consists of both greyish to yellow coloured claystones interbedded with limestones. The Bermoti limestones are petrographically classified as packstone, wackestone and mudstone assemblage. The limestones were observed to be highly micritised, which indicates open, shallow marine settings. The Maniyara Fort Formation, thus characterised by wackestone-packstone-mudstone facies of carbonates, is interpreted to be part of a carbonate ramp system. The limestones from Maniyara Fort Formation exhibit signatures of marine as well as meteoric diagenesis.

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Section: Discussionsupporting

confidence: 68%