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标题：Determination of Sandstone classification by using Geochemical aspect: A Case Study of Garudamangalam Formation, Cretaceous of Ariyalur, Tamilnadu, India
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作者：K. Babu ; R. Prabhakaran ; P. Subramanian 等
期刊名称：International Research Journal of Earth Sciences
电子版ISSN：2321-2527
出版年度：2014
卷号：2
期号：2
页码：40-43
语种：English
出版社：International Science Community Association
摘要：The composition of sandstone may be expressed in terms of its bulk chemical composition. Such bulk chemical analyses are very useful. To understand fully the geochemical processes and the evolution of various types of sediment or differentiates, chemical analyses needed. Chemical data has value for classification, but the limitations of using chemical data for classification must be identified. The Cretaceous formation of Ariyalur area, Tamilnadu is one of the best developed sedimentary formations in southern India. The staratigraphy of this formation is divided into three groups, Uttatur, Trichinopoly, and Ariyalur. The Trichinopoly group later designated as Garudamangalam Formation. Representative 10 sandstone samples were collected from the Garudamangalam formation, and analysed for major oxide composition by using XRF. The relative concentrations of three major groups- silica, alumina, alkali oxides plus magnesia have been used to classify the Garudamangalam sandstone samples. From the study area samples SiO ranging from (12.93-42.56%), Al (3.49-8.47%), Fe(2.29-22.02%) and strongly depleted to S, NaO, KO, MnO, TiO and . The very high content of CaO ranging from 23.53-45.90%, it indicates they are rich in calcite cement, or it may mean shell fragments in the sandstone particles. Based on the following reference set, guidelines are proposed for chemical classification of sandstones. 1.quartz arenite: log(SiO/Al1.5, 2.Greywacke: log (SiO/Al)1 and log(KO/NaO)03. Arkose(includes subarkose): log(SiO/Al)1.5 and log(KO/NaO)0 and log (Fe+MgO)/ (KO+NaO)04. Lithic arenite: log(SiO/Al)1.5 and eighter log(KO/NaO)0 or log(Fe+MgO)/ (KO+NaO)0. If log (KO/NaO)0, lithicarenite can be confused with greywacke. Based on the above guidelines the study area sandstone samples reflects log (SiO/Al ratios from 0.47 to 0.92. The log (KO/NaO) Vs log (Fe+MgO)/ (NaO+KO) scatter diagram shows lithicarenites field. The study area samples reveals that they are rich in Litharenite sediments are evidences of a probable deposition of the felsic rich source rock and deposited in a marine environment.
关键词：Sandstone;Garudamangalam;classification;lithicarenite and arkose