Geochemical and Tectonomagmatic Characteristic Investigations of Intermediate Volcanic Rocks-North of Saveh
Subject Areas :
Sepideh
Aghaverdizadezagheh
1
(1- دانش آموخته ی کارشناسی ارشد زمین شناسی، دانشگاه آزاد اسلامی واحد اسلامشهر، اسلامشهر، ایران)
Shiva
Ansari
2
(استادیار دانشگاه آزاد اسلامی واحد اسلامشهر، اسلامشهر، ایران)
Naser
Ebadati
3
(استادیار دانشگاه آزاد اسلامی واحد اسلامشهر، اسلامشهر، ایران)
Keywords: Saveh, Andesite, Basalt Andesite, Urmia-Dokhtar,
Abstract :
The study area is a part of Urmia-Dokhtar volcanomagmatic belt, the main outcrops of this magmatic belt form the Eocene volcanic units with the northwest-southeast trend. The unit is composed of basaltic, basaltic andesite, dacite, ignimbrite and tuff which is repeated throughout the Urmia-Dokhtar area in the geological map and the intrusive masses are more granite, granodiorite to tonalite. The volcanic rocks of the region belong to the age of Eocene including andesitic, trachy andesitic, basaltic andesite, alkaline basalt, dacite and basalt composition which have porphyritic textures with glass groundmass, hyalo microlithic porphyritic, porphyry, porphyritic textures with microlithic groundmass, trachytic, trachytic, microlithic porphyry and Poikilitic textures. The studied samples are often calc-alkaline, high-K calc-alkaline and shoshonitic but some samples have tholeiitic nature. Some of the main elemental oxides such as CaO, TiO2 and MgO with decreasing trend and some of them such as K2O with increasing trend from basic rocks to intermediate-acidic rocks are compatible with the magmatic differentiation process. Some of the dispersions shown in these graphs can be attributed to processes such as alteration, emission and contamination of the magma of the volcanic rocks with crustal materials.
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