Writers : Vosoughi Abedini,Mansoor
Refference : Geosciences Scientific Quarterly Journal,No.23_24
Publishing Year : 1376

Abstract :
in order to determine the petrologic characteristics, recent volcanic rocks in east Iran has been sampled and studied. In previous published geological maps, these rocks are known as Quaternary basalts" although by using different pathological methods they seem to be andesite and dacite rather than baslt. In east Iran, is basalt only found in two restricted regions: one near Mud village, southeast o Birjand, the other in Ferdows area. This paper deals with the petrographic petrologic and tectonomagmatic aspects of these two localities Petrographic and geochemical studies show that, these rocks have an alkaline nature and normative nepheline is present in most o
the samples. From the geochemical point of view the samples has a genetic relation and derived from the same parental magma
In some cases the chemical composition is very similar to a basaltic parental magma, however, in other ones fractional crystallization it
the major process of magma evolution. In diagrams, these basalts, in spite of their alkaline nature , plotting in calcalkaline field tectonomagmatic. Probably because of a distinctive mode of magma evolution, of course this evolution had not enough intensity to remove the alkaline nature completely. In general consideration a rifting origin seems to be acceptable and for the better deduction, isotopic study it needed.
Subject List : Basalt