GSINET | Geological Survey of Iran , North - East Territory

Writers : Saeidi, S.; Sadeghian, M.; Jafarian, A.
Refference : 28th Symposium on Geosciences and the 14th Symposium on Geological Society of Iran
Publishing Year : 1389

Abstract :

A numerous subvolcanic domes with late Eocene� to Early� Oligocene ages cropped out in the southwest of Birjand. Rech, Allahyar and Givshad domes are their typical examples. These domes emplaced in the Late Cretaceous-Paleocene ophiolitics rocks and or Ecocene� volcanic and volcanosedimentary rocks. Their composition mainly is thrachyandesite and andesite, and meanwhile they produced by fractional crystallization of andesitic magmas. There some evidences of magma contamination and magma assimilation. Based on, geochemical characteristics, rocks forming of these domes are belonging to the high silica adakites. With respect to historical geology of east Iran area, these rocks resulted from the magmatism related
�to the� sub duction of Neotetian oceanic slabs beneath to the accretionary prisms (include of ophiolitic slices and Eocene volcanose� dimentary rocks in the margins of Helmand and Lut blocks. Some processe such as dehydration, metamorphism and melting of subducted�� oceanic slabs, accompanied sediments and� metasomatism of overlaid mantel wedge, have been contributed in producing of magma forming these domes.

Subject List : Adakit

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