School Of Environment And Earth Sciences

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Subject: search.filters.subject.Clay minerals

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    Clay minerals as paleo-climate proxy in Quaternary Dun sediments, NW Himalaya, India
    (Springer Science and Business Media Deutschland GmbH, 2023-10-17T00:00:00) Amrutha, K.; Ahmad, Samad; Kumar, Pankaj; Pattanaik, Jitendra Kumar
    Purpose: Clay mineral assemblages are widely used for deciphering paleoclimatic information, where diagenetic and detrital clays provide different signatures. The type and amount of clay present in the alluvial fan sediments account for the prevailing climate, topography, transport dynamics, diagenesis, and lithology of the catchment area. Clay mineral analysis of sediments collected from the younger lobe of Kiratpur Fan, Pinjaur dun, NW Himalaya, will help to understand the late-Quaternary climatic perturbations during marine isotope stage (MIS)-3 and to evaluate the suitability of clay minerals as paleoclimatic proxy. Materials and methods: Samples were collected from three sites along the Kiratpur Nadi near Paploha village, Haryana, where exposed sections had a total height of ~ 28�m. In this study, 31 samples from these sediment sections were collected and after initial processing, clay minerals were separated and oriented slides were prepared. These samples were analysed using X-ray diffractometer (XRD) with/without glycolation and heating treatments. One aliquot of dried clay from selected samples were used for FTIR to complement the XRD analysis. For FTIR analysis, about 1�mg of clay samples was mixed with ~ 10�mg of KBr and press pellets were prepared. Results and discussion: The clay fraction of these sediments constitute illite (~ 52 � 0.8%), kaolinite (~ 13 � 1.6%), and chlorite-montmorillonite interstratified clay (~ 35 � 1.5%). Shale and mudstone distributed in the catchment area might be the source of these clay minerals. Illite chemistry index of ~ 0.37 � 0.14, kaolinite/illite ratio (0.21�0.29), illite crystallinity (IC) (0.23 � 0.04), and kaolinite percentage suggest the dominance of physical weathering in the catchment area. These sediments are generated during a cold and dry period, and deposited during an aggradational phase associated with warm and wet phase within MIS-3 (40�30 Ka). Further, it was found that illite is the dominant clay throughout the Himalayas, Ganga plain, and Bay of Bengal (BoB) sediments, irrespective of their distance from the source. Hence, associating illite to younger and less-transported sediment does not work in this setting. Conclusion: Though the proxies based on clay percentage is very useful, only limited data is available. There is a significant difference in the value of IC in the Himalayan front and BoB sediments may be due to the modifications during the transportation of sediments. Overall, when sediments are transported for a longer distance, correlating clay mineral percentage with the maturity of sediment is not apparent. � 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
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    Paleoclimatic and Environmental Interpretation using Clay Mineralogy and Surface Textural Analysis of Quartz Grains from Miocene deposits of Tapar, Kutch, Gujarat
    (Central University of Punjab, 2018) Mahmud, Hassan; Sharma, Milankumar
    The Tapar area situated in Kutch district of Gujarat is exposed of the miocene deposit. Extensive work has been done on Kutch basin on paleontological aspects but very less on sedimentological aspect. Clay assemblages is a great tool to understand the paleoclimate and environment of deposition. The study of the clay assemblages in the area show a higher amount of kaolinite and very less amount of dickite assemblages with negligible amount of Vermiculite and clinochlore indicating a tropical climate. Quartz being highly resistive mineral can withstand normal chemical weathering and physical weathering. Surface textural study of quartz grains indicates towards fluvial condition
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    Paleoclimate And Paleoenvironment Analysis Of Panchet Formation Of Damodar Basin, India Using Xrd Analysis
    (Central University of Punjab, 2018) Boral, Nandan; Sharma, K Milankumar
    The bulk rock geochemistry of 14 samples collected from the Asansol district, West Bengal, India, from the Northern bank of the river Damodar were analysed using XRD. The studied area belongs to the Panchet Formation of Lower Triassic age of Lower Gondwana group of rocks. The major analysis has been done using the clay mineralogy. These data enables to reconstruct the ancient environmental and climatic condition during the deposition. Samples were dried in an oven up to 65°c temperature for a week and grinded to finest level in Retch RS200.Raw XRD data receive were analysed in X'Pert high software. SEM samples were prepared by disintegrating sandstone with Hydrogen peroxide. Equal sized quartz grains were analyzed under Carl Zeiss Merlin Compact 6073 Field Emission Scanning Electron Microscope and their surface textures observed. Three major clays (Smectite, Illite and Kaolinite) have been identified for the correlation with different sections. The percentage of these three clays calculated manually. Presence of high Smectite with Kaolinite indicates warm humid environment of formation, with rainfall ranging from 50-150 cm, higher amount of Smectite over Kaolinite indicates variation in seasonality during the deposition.