Petrology and geochemistry of Arood granitoid mass, north of Alamkuh‚ West of Central Alborz.

Document Type : Original Article

Authors

1 Tehran - Intersection of Jalal Al Ahmad and Chamran Highways - Under Geisha Bridge - Tarbiat Modares University - Faculty of Basic Sciences - Department of Geology

2 Postgraduate student of petrology, Department of Geology, Faculty of Science of Tarbiat modares, Tehran, Iran

Abstract

Aroud granitoid intrusive is located in the north of Alam Kooh and west of Central Alborz. Based on field, petrographic and geochemical characteristics, this massif can be divided into three units: granite, quartzmonzonite and syenite. The main minerals of these rocks are alkaline feldspar, plagioclase, quartz, mafic minerals, biotite and amphibole, the frequency of which varies in these rocks. accessory mineral include zircon, sphene and muscovite, the texture of these rocks is mainly granular heterogeneous and textures such as types myrmekitic include (mainly granophyric and graphic), Poikilitic, exsolution, metasomatic and sieve in the syeniti part, Millonite fabric is observed. These rocks are metaaluminous in nature, but some granites are inclined to peraluminous. On the other hand, they are of the magnesium type. However, some granite specimens tend to feroan. Tectonically, a magmatic arc environment is introduced by a tensile mechanism, mainly post orogenic. In the Harker diagrams of the trace and major elements against silica, the main process of magma evolution, crystallization, is introduced. In the spider diagrams, the patterns of the elements in the rocks of the said mass, which were normalized to the primary mantle and chondrite, are in perfect harmony. Most researchers believe that most of the shoshonitic masses are produced by melting the lithosphere mantle, which is enriched by melts or fluids from metasomatized slabs.

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Articles in Press, Accepted Manuscript
Available Online from 15 December 2024
  • Receive Date: 19 May 2024
  • Revise Date: 09 December 2024
  • Accept Date: 15 December 2024