Writers : Delavar, Z.; Sadeghian, M.
Refference : 28th Symposium on Geosciences and the 14th Symposium on Geological Society of Iran
Publishing Year : 1389

Abstract :

In the southwest of Birjand cropped out a numerous adakitic domes with dominantly thrachyandesitic composition and with younger than Eocene age. Their host rocks are Eocene volcano sedimentary rocks and Cretaceous-Paleocene ophiolitic complex. Geochemical investigations indicate that fractional crystallization had been the most important process during evolution of magma forming rocks of the studied domes. Mafic microgranular, micaschistic, gneissic and amphibolitic enclaves are evidences of magma mixing and magma contamination. Based on, geochemical characteristics, rocks forming of these domes are belonging to the high silica adakites. With respect the subduction of Neotetian oceanic slabs beneath to the accretionary prisms (include of to historical geology of east Iran area, we can say, ophiolitic slices and Eocene volcano sedimentary rocks in the margins of Helmand and Lut blocks), associated with dehydration, metamorphism and melting of subducted oceanic slabs, accompanied sediments and metasomatism of overlaid mantle wedge, have been produced melts which finally resulted to form of the studied adakitic domes.

Subject List : Adakit