Heavy mineral studies on late quaternary red sediments of Bhimunipatnam, Andhra Pradesh, East coast of India

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• 作者：K. N. Murali Krishna ; K. S. N. Reddy…
• 关键词：Red Sediments ; Heavy Minerals ; Light yellow sands ; Brick red sands ; Reddish brown sands and Yellow sands ; Andhra Pradesh
• 刊名：Journal of the Geological Society of India
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：88
• 期：5
• 页码：637-647
• 全文大小：
• 刊物类别：Earth and Environmental Science
• 刊物主题：Geology; Hydrogeology;
• 出版者：Geological Society of India
• ISSN：0974-6889
• 卷排序：88

文摘

Thirty one sediment samples from different varieties viz. yellow, reddish brown, brick red and light yellow sands from red sediments of Bhimunipatnam, Andhra Pradesh were studied to understand the heavy mineral assemblage, their fractionwise distribution and concentration. The heavy mineral assemblage in red sediments is ilmenite, magnetite, sillimanite, garnet, zircon, rutile, kyanite, monazite etc. Total heavy minerals (THM) wt. % varies from 16.67 to 23.99% and their concentration is not uniform in all the sedimentary samples. The higher THM wt% in brick red sands (23.99%) followed by reddish brown sands (20.24%), light yellow sands (17.10%) and yellow sands (16.67%). The finer fractions have more concentration of THM wt% than coarse fraction. The vertical distribution of heavy minerals in each sedimentary unit indicates that these units are not formed in single phase of deposition. Less concentration of garnets in yellow and light yellow sedimentary units indicates that the garnets might be chemically altered into iron hydroxide–limonite which gives yellow colour to the sediments under slightly oxidizing environment. Low concentration of garnets in brick red and reddish brown sediments indicates that garnets might have been undergone chemical decomposition under acidic conditions leads to produce iron oxides (Hematite) causes for red colorization of these units. The heavy mineral assemblage in different sand units indicates that they are derived from Eastern Ghat Group of rocks (khondalites and charnockites).