Browsing by Author "Mohammad Arif"

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Hydroclimatic conditions and sediment provenance in the northeastern Arabian Sea since the late Miocene: Insights from geochemical and environmental magnetic records at IODP Site U1457 of the Laxmi Basin
(Cambridge University Press, 2023) Mahboob Alam; Tripti Muguli; G.P. Gurumurthy; Mohammad Arif; Yoshiki Sohrin; Arun Deo Singh; T. Radhakrishna; Dhananjai Kumar Pandey; Komal Verma
Palaeo-monsoon and palaeoclimate conditions over Southeast Asia are a matter of debate despite notable studies on the continental and oceanic sedimentary record. The present study investigates the environmental magnetic and geochemical records preserved in the deep marine sediments of the northeastern (NE) Arabian Sea to elucidate the erosion history of the western Himalayas and its link with the prevailing hydroclimatic conditions since the late Miocene. For this, the sediment core retrieved during International Ocean Discovery Program (IODP) Expedition 355 at Site U1457 in the NE Arabian Sea has been explored. The results reveal that the hydroclimatic conditions were predominantly arid during the late Miocene, except for humid intervals from 6.1 Ma to 5.6 Ma. Humid climate conditions in the Indus River Basin returned during the mid-Pliocene and continued to the Pleistocene with an intense chemical weathering regime from 1.9 Ma to 1.2 Ma. The dominant sediment source to the NE Arabian Sea at Site U1457 during the late Miocene and the Pliocene was the Indus River, while during the Pleistocene, mixed sediments brought by the Indus River and the Peninsular Indian rivers were observed. The sediment contribution from a chemically less altered mafic source (the Deccan basalts) increased between 1.2 Ma and 0.2 Ma, possibly linked to a weak Indian Summer Monsoon. The summer monsoon wind strength and associated shift in the Inter-Tropical Convergence Zone (ITCZ) influenced the dominant sediment provenance at Site U1457 of the Laxmi Basin. © The Author(s), 2023. Published by Cambridge University Press.
Late Maastrichtian vegetation and palaeoclimate: Palynological inferences from the Deccan Volcanic Province of India
(Academic Press, 2022) Shreya Mishra; Sarvendra Pratap Singh; Mohammad Arif; Arvind Kumar Singh; Gaurav Srivastava; B.R. Ramesh; Vandana Prasad
Our understanding of the low latitude terrestrial climate of the late Maastrichtian is far from satisfactory. We have attempted to reconstruct the late Maastrichtian vegetation and climate of the Deccan Volcanic Province (DVP), central India. Palaeomagnetic results suggest that the Deccan lava flows were emplaced during the late Maastrichtian C29r magnetochron. Sedimentological studies reveal a swampy to shallow brackish lacustrine depositional setup in a warm and humid climate with low to moderate energy conditions. The floristic composition indicates an overall dominance of Arecaceae followed by Malvaceae and Ephedraceae. The vegetation prevailed under five palaeoecological associations viz., mangrove, coastal fringes, Tropical Rain Forests (TRFs), forest outliers and upland flora. The assemblage envelops taxa belonging to TRFs (54%), coastal (13%), tropical moist deciduous (13%), herbaceous (8%), mangrove (8%), and sub-tropical (4%) vegetation. The TRFs include taxa presently prevailing within the Western Ghats of India and in the TRFs of Africa. The Coexistence Approach (CA) analysis suggests a mean annual temperature of 24.5 ± 2.3 °C, cold month mean temperature of 18.5 ± 3.3 °C, warm month mean temperature of 27.5 ± 0.3 °C, mean annual precipitation of 1890.5 ± 208.5, precipitation during the wettest month 335 ± 15 mm, precipitation during the driest month 26 ± 7 and precipitation during the warmest month 111 ± 1. The inferred climatic conditions were apt for sustaining the high diversity within the close canopy multi-storeyed TRFs. The palaeoclimatic data also indicates a strong seasonality, and most likely, a monsoon type of climate during the late Maastrichtian of India. © 2021 Elsevier Ltd
Magnetostratigraphy and Sedimentology of Deccan Intertrappean Succession from Sagar, Central India: Insights into Palaeo-environment and End-Cretaceous Palaeogeography
(Geological Society of India, 2024) Sarvendra Pratap Singh; Arvind Kumar Singh; Mohammad Arif; Vandana Prasad; Mamilla Venkateshwarlu; Amiya Shankar Naik
The study of Deccan volcano-sedimentary successions is significant for understanding the palaeomagnetic correlation, eruption history and palaeoenvironmental conditions of the Central India during the Cretaceous-Paleogene (K-Pg) transition. In this study, we applied an integrated magnetostratigraphic and sedimentological approach to the Deccan Intertrappean Succession exposed at the Mothi Hill (Malwa Subprovince), Sagar, to provide palaeomagnetic age constraints for the lava flows, depositional environment and end-Cretaceous palaeogeography. Palaeo-magnetic data suggest that the lower and upper Trap lava flows associated with the Mothi Intertrappean deposits are not coeval, and they correspond to C29r and C29n magnetochrons, respectively, which points to the age duration of 66.3–65.1 Ma (late Maastrichtian-early Danian). The palaeomagnetic data also marks the presence of upper magnetic polarity transition (C29r/C29n) in the eastern part of the Malwa Subprovince, which indicates the occurrence of C30n-C29r-C29n magnetostratigraphic sequence for the Subprovince. The Malwa, eastern Mandla and Western Ghats Subprovinces can be palaeomagnetically correlated and are partly synchronous with each other. The Mothi Intertrappean deposition occurred in a low energy shallow water lacustrine setup with swampy to brackish depositional condition similar to shallow coastal lake type environment. The occurrence of such coastal type depositional environment at Sagar in the central part of India, points to the influence of temporary marine incursion and existence of marine pathway up to Central India, possibly through the western corridor of Narmada-Tapti rift zone during the late Maastrichtian-early Danian period. Moderate to intense chertification within the argillaceous limestone suggests post-depositional diagenetic modification and secondary silica generation due to interaction with silica enriched meteoric water diagenesis. © 2024 Geological Society of India, Bengaluru, India.
Provenance, weathering, and paleoclimatic records of the Pliocene-Pleistocene sequences of the Himalayan foreland basin, NW Himalaya
(Springer Science and Business Media Deutschland GmbH, 2021) Sajid Ali; Binita Phartiyal; Ajay Taloor; Mohammad Arif; Birendra Pratap Singh
We present major oxides, trace element compositions, rare earth elements (REEs), clay mineral assemblages, and magnetic mineral parameters data for the siliciclastic fraction from the Upper Siwalik Subgroup (Parmandal, Nagrota, and Boulder Conglomerate formations) in the Tawi sub-basin of the Himalayan foreland basin, NW Himalaya in order to identify source rock compositions, continental weathering, and paleoclimate over the past 5.6 million years. The trace elemental ratios of Th/Co, Th/Sc, La/Sc, and Cr/Th suggest Upper Siwalik Subgroup sediments initially originated from a stable felsic source, which is possibly in the High Himalayan crystalline and Lesser Himalayan source regions. The REE patterns of the studied sediments with prominent negative Eu anomalies also suggest a felsic source for the Upper Siwalik Subgroup sediments deposited in the basin. The chemical index of alteration (CIA), plagioclase index of alteration (PIA), Rb/Sr ratio, and clay mineral assemblages as well as mineral magnetic parameters demonstrate the variable intensity of weathering and environmental conditions during the deposition of Parmandal, Nagrota, and Boulder Conglomerate formations between 5.6 and 0.6 Ma. The weathering proxy records of Parmandal (5.6 to 3.9 Ma) and Boulder Conglomerate (1.7 to 0.2 Ma) formations indicate relatively strong chemical weathering associated with the warm and wet climates in the source region. On the other hand, a decrease in chemical weathering intensity and change in environmental conditions during the formation of Nagrota formation (3.9–1.7 Ma) suggest a dry and cold climate in the source region. © 2021, Saudi Society for Geosciences.