国際廃棄物資源ジャーナル

概要

Interpretation the Origin and Tectonic Setting of Coastal Sediments in the Northeastern of Oman Sea

Ahrari Rudi M and Afarin M

This study investigates geochemistary of major and trace elements of sandstones and mudstones in the Chabahar area located of northeastern Oman Sea. In this study, 52 samples were taken from 5 sections included of Tiss, Ramin, Lipar, Gorankash and Garindar estuary. Then have been done grain size and chemical analysis using XRF and ICP AES methods in geological survey of Iran. Comparison of major elements values with the average amounts of upper continental crust indicate due to sedimentation processes or the lack of source rocks contain sodium plagioclase, the amount of Na2O and Fe2O3 in continental crust is highly depleted. Plotted geochemical data of major elements from Late Miocene-Pleistocene, age 10 mudstone and sandstone samples in east coasts of Chabahar in Makran zone, on siliciclastic rocks classification diagrams, showed that the sandstones are genus wackstone, Mudstones and shale. Values range the chemical index of alteration (CIA) and plagioclase index of alteration (PIA) respectively is from 40 to 60 and 40 to 64. However, most samples have values less than 50, suggesting a low to moderate degree of alteration (weathering) and arid to semi-arid climate during deposition in the source area. Major elements geochemistry is not useful for interpreting the tectonic setting. Discrimination plots based on assotiated trace elements, such as Ti, Zr, La, Sc and Th, show that most data located in the active continental margin field and tectonic setting have developed in active continental margin (ACM). Finally, geochemical data and using from sediments silisiclastic discriminate diagrams on the major elements in these rocks shows that the quartzose sedimentary provenance.