M Daryapeyma Hormozi; H Biabangard; S Bagheri; M.R Bakhshi Mohebi
Abstract
Dasht Kuh volcanic complex is located to ~75 km to the north of Iranshahr. It consists of two parts: A (main body) and B (the isolated part in the northern Dasht Kuh). Based on the geological maps of the area, the volcanic bodies intruded the flysch type rocks of the East Iran in Cretaceous; the rocks ...
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Dasht Kuh volcanic complex is located to ~75 km to the north of Iranshahr. It consists of two parts: A (main body) and B (the isolated part in the northern Dasht Kuh). Based on the geological maps of the area, the volcanic bodies intruded the flysch type rocks of the East Iran in Cretaceous; the rocks are separated from Eocene conglomerate across a fault zone. The Dasht Kuh volcanic complex essentially consists of basalt, andesite, basaltic andesite and trachybasalt. The main rock-forming minerals are plagioclase, pyroxene, hornblende, and sanidine with dominant porphyritic texture. Minor pyroclastic materials occur in the lower parts of the complex.Samples rocks from of Dasht Kuh in the rare earth elements diagram relative to abundance of these elements in the Chondrite, shows a significant negative slope observed that the samples are enriched in light rare earth elements (LREE) and depletion of heavy earth elements (HREE). Different chemical composition, Tectono-magmatic and origin digrams shows that rocks in these bodies have alkaline nature of mantle origin and were formed in continental volcanic arc. It seems Dasht Kuh volcanic comlex are part of island arc that wide arc from northern Pakistan to Iran that have been separated from their origin by younger tectonic events.
A Biabangard; H Biabangard; S Bagheri
Abstract
The Deh-Salm metamorphic complex (DMC), late Jurassic in age, is exposed at the west of Nehbandan and at the the eastern margin of the Lut block. This is one of the exceptional outcrops of the Lut block’s basement in East Iran. The metamorphosed ultramafic rocks in this complex are identified ...
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The Deh-Salm metamorphic complex (DMC), late Jurassic in age, is exposed at the west of Nehbandan and at the the eastern margin of the Lut block. This is one of the exceptional outcrops of the Lut block’s basement in East Iran. The metamorphosed ultramafic rocks in this complex are identified and introduced for the first time, and are studied in association with the metabasites. Extensive field excursions as well as satellite image investigations represented the metabasites and metaperidotites of the DMC in three elongated and separate belts, parallel to the extension of the complex; we named the belts as the east, central, and the west belts. A tectonic, broken to dismembered units of greenschist, amphibolite, metaperidotite, serpentinite, and talc-schist can be recognized in the east and central belts, while, amphibole-calcschist is the most important rock constituent of the west belt in the Galugah complex. The main minerals in the rocks of these belts are hornblende, epidote, plagioclase (andesine), and sporadic pyroxene in the metabasite, and olivine, ortho-amphibole, augite, talc, and spinel in metaperidotite, respectively. On the basis of the geochemical studies, the protoliths of the mentioned rocks are classified in the basalt and peridotite groups. However, due to metamorphic and intense metasomatic processes, it is impossible to suggest a distinct origin and tectonic setting for the above metamorphic assemblages. The presence of mafic and ultramafic metamorphic rocks adjacent to the other rock units of the DMC indicates that the mafic-ultramafic rocks were initially emplaced in the eastern margin of the Lut block in a time before the late Jurassic, then they were metamorphosed in their recent arrangement.
