期刊名称：International Journal of Environmental Protection and Policy
印刷版ISSN：2330-7528
电子版ISSN：2330-7536
出版年度：2019
卷号：7
期号：3
页码：86-92
DOI：10.11648/j.ijepp.20190703.11
语种：English
出版社：Science Publishing Group
摘要：Matamuhari anticline is one of the largest anticline situated at Bandarban district of Bangladesh which is 60 km long and 20 km wide in the part of Bangladesh. Like other part of Bangladesh the whole sequence of exposed rocks of Matamuhari anticline is composed with Neogene sedimentary rocks of shale, sandstone, siltstone, silty shale, tabular and spheroidal calcareous concretions. Seven outcrop black shale samples were collected during February 2013 from the different parts of the anticline namely Boro Bari Jhiri, Ochir Jhiri and Tak Chara area were mineralogically and geochemically examined in order to better understand the depositional environment in the studied area. The major and trace elements were analyzed using XRF spectrometry. Two distinct lithofacies assemblages, mud and silty-clay are found in the collected sediments. The shales are predominated by quartz, kaolinite, chlorite, mica (muscovite and biotite), feldspar (both K-feldspar and plagioclase), and in addition to a variable ratio of vermiculite. Lithologial characteristics and geochemical data demonstrated that sediments are enriched with TOC contents ranging from 0.39 to 0.67 wt.% and shows distinctive correlation to concentration of TOC and particle size distribution. These shales are characterized by a low Mg and K as well as high Al and Fe contents. Studies also show that the values of MgO/Al2O3 and K2O/Al2O3 ratio ranges from 0.15 to 0.17 and 0.18 to 0.20 respectively. The relationship of log MgO/Al2O3 and log K2O/Al2O3 values reveals that all of the studied samples fell within the marine environment. Ni/Co ratio of the studied shale samples ranges from 2.84 to 3.88 (average 3.36). These low values of Ni/Co ratio suggest that the sediments were deposited under oxic conditions. However, the above observations suggest that the sediments of Matamuhari anticline area were deposited in a shallow marine environment under oxic conditions.
关键词：Matamuhari Anticline; Black Shale; Environment; Total Organic Carbon
