Geochemistry of Neogene Mudrocks from Sitakund Anticline, Bengal Basin: Implications for Provenance, Weathering, Tectonic Setting and Depositional Environment

• 作者: Aminur Rahman Md. Ashraful Islam Md. Badrul Imam Md. Yousuf Gazi S. M. Mainul Kabir
• 来源期刊: 地球科学和环境保护期刊(英文)
• 学科: 地球科学
• 关键词: GEOCHEMISTRY NEOGENE MUDROCKS Tectonic setting PROVENANCE WEATHERING Depositional Environment Sitakund ANTICLINE and Bengal Basin
• 年，卷（期）: 2017,（6）
• 页码范围: 147-171
• 页数: 25页
• 分类号: P5

摘要

Geochemical analysis of Neogene mudrocks from Sitakund anticline, Chittagong Tripura Fold Belt (CTFB), Bengal Basin, Bangladesh, was deployed to delineate the provenance, tectonics and depositional environments. Representative samples went through mineralogical and geochemical analysis concerning major, trace and rare earth element analysis. Rigaku ZSX Primus and NITON XL3t 800 XRF instruments were utilized for the determination of major and trace elements. The experiment results reveal that the Neogene mudrocks are rich in silica having concentration of 58.10% to 62.60% with an average of 59.90%. Therefore, the geochemical response from the experiments apparently proved the existence of the active continental margin setting for the Neogene mudrocks. Different concentrations and ratios of major oxides satisfy that the mudrocks were derived from felsic source rocks. In addition, chemical index of alteration (CIA) values for the Neogene mudrocks vary from 67.81 to 77.57 with an average 74.41 indicating significant weathering at the source areas. Moreover, U/Th, Cu/Zn, Ni/Co and V/Cr ratios designate that the mudrocks were deposited in oxidizing depositional environment.