Geochemical characteristics of Holocene sediments from Chuadanga district, Bangladesh: Implications for weathering, climate, redox conditions, provenance and tectonic setting

作     者：Ismail Hossain Krisna Kanta Roy Pradip Kumar Biswas Mahbubul Alam Md. Moniruzzaman Farah Deeba 

作者机构：Department of Geology and Mining University of Rajshahi Bangladesh Institute of Mining Mineralogy and Metallurgy (IMMM) Joypurhat Bangladesh Water Resource Planning Division Institute of Water Modelling (IWM) Dhaka Bangladesh Institute of Nuclear Science and Technology (INST) Atomic Energy Commission Dhaka Bangladesh 

出 版 物：《Chinese Journal Of Geochemistry》 (中国地球化学学报)

年 卷 期：2014年第33卷第4期

页      面：336-350页

核心收录：

学科分类：070905[理学-第四纪地质学] 070902[理学-地球化学] 0709[理学-地质学] 0819[工学-矿业工程] 07[理学] 0708[理学-地球物理学] 

主　　题：地球化学特征 氧化还原条件 化学风化 沉积物 构造背景 孟加拉国 气候趋势 全新世 

摘      要：The present research deals with the geochemical characteristics of the Holocene sediments from Alamdanga area, Chuadanga district, Bangladesh. Main goals of the study are to delineate source rock characteristics, degree of chemical weathering and sorting processes and behavior of redox conditions during deposition of the sediments. Geochemical characteristics of the sediments show comparatively a wide variation in accordance with stratigraphy in their major element contents(e.g. Si O2 69.46–82.13, Al2O3 2.28–8.88 in wt%), reflecting the distinctive provenance and in part an unstable period in terms of tectonic activity. Geochemical classification of the sediments shows mostly sub-arkose with few sub-litharenites. Some major and trace elements display comprehensible correlation with Al2O3 confirming their possible hydraulic fractionation. The chemical index of alteration(CIA*), W* index, index of compositional variability(ICV), plagioclase index of alteration(PIA*) values and the ratio of Si O2/Al2O3, suggest low degrees of chemical weathering in the source areas as well as immature to moderately mature the sediments. The sediments suggest semi-arid climatic trends within oxic deltaic depositional conditions during the Holocene, at 3–12 ka. Whole rock geochemistry and discrimination diagrams demonstrate the continental signature derivatives, which might have been derived from the felsic to intermediate igneous rocks(granitic plutonic rocks) as well as from quartzose sedimentary/metamorphic provenance. These typical sources are present in a vast region of the Himalayan belt and catchment areas of Ganges. The tectonic setting of the sediments demarcates typically passive margin with slightly continental arc system.