Writers : B. Samani;Sh. Ashtari
Refference : Geosciences Scientific Quarterly Journal,No.:4,PP.:14

Abstract :
Tension Neotethys That have undergone the evolutionary stages of oceanic crust based on its particular geology and metallogeny the area can be devided into Makran Belts, Lut- Hir mand Blocks and lranshahr- Birjand Transform Fault Zone. The Makran Ophiolite and its associated Coloured Melange could be (considered) as subduction processes of the Neotethys oceanic crust.
lranshahr- Birjand Zone belongs to the transform Fault Basin and which had been created as a result of
east Lut- Harirud Faults and Lut- Hirmand rotation blocks. The magmatic activity of north Lutto continentaLCrust and Gonabad Birland is related to the Transform faults resulting from the rotation of central Iranian block. The faults caused
. tectonomagnetic reactivization and became younger from east towards the west.
Bazman- Taftan Vulcanicity is the result of subduction of oceanic crust in Indian Ocean that superimposed
the old subduction of the Neotethys. In this part, two different cycles of oceanic magmatism- Continental Margin of Andean type exist. The first cycle is related to Neotethys subduction, which alters from old low potassium magmatism, to young. calc- alkaline and alkaline type. The result of this magmatism is development of Andean magmatic arc of southern margin of Lut Block, extending from Anarak to Choghai in Pakistan.
Taftan- Bazman magmatism as yet, going through its young stages, is considered as second magmatic
cycle. Within the Sistan Faults trend, alkaline- subalkaline magmatic activity of Tertiary porphyries can be observed. In some aspects, it is considered as co- magmatic to the Khan- Neshin alkaline massif which resembles tectonomagmatic reactivization.
Although the Oligocene granite of Zahedan is considered as collisional- type, but based on residual Magnetic Map interpretation, it seems that it is a part of displaced Deh Saim Massif, that have been truncated by transform faults, and subsequently oceanic crust emplaced there. This massif has been affected by Alpine events and hence a young radiometric age is recorded on its biotites. Whereas, based on RbI Sr method, a Cretaceous age is obtained. On the other hands, if the granitic mass is the result of collisional- compressional forces, no intrusive alkaline masses could be emplaced contemporaneously in juxtaposition, in tensional tectonic regime.
Subject List : Structural evolution