Investigating the Origin of Quaternary Detrital Sediments of the Southern Coastal of the Caspian Sea




In this research, in order to investigate the origin of Quaternary sediments, 38 samples of surface sediments were collected from the coastlines and river mouth of the southern shores of the Caspian Sea. Laser particle sizer analysis, total organic matter measurement and determining the number of main oxides was done with the alkaline melting method and ICP-OES. Calculations of geochemical indexes showed, the chemical alteration index (CIA) was in the range of 67.75 to 90.11 (average 74.82), which showed moderate to high alteration (70-90). Also, the chemical weathering index (CIW) was in the range of 83.96 to 91.04 (average 87.83), which presented the average weathering range. On the other hand, in terms of the Index of compositional Variability (ICV), it was obtained from 1.39 to 8.05 (average 2.91),‌‌ displays that the sediments of this area are from the first sedimentary cycle. Results of this research determined that Golestan, Mazandaran and Guilan samples are originated from sedimentary, mafic and felsic igneous sources, semi-arid to tropical and humid weather conditions respectively. Tectonic discrimination diagrams specified most of the samples were created in the continental arc islands.


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