Petrography of ultramaphic rocks of Razan area

Category Petrology
Group GSI.IR
Location The 25 Symposium of Geosciences
Author Reza Zarei Sahamieh
Holding Date 01 July 2007
 

Abstract:

Razan ultramafic and mafic rocks complex could be considered as a part of mafic rocks sequences in zagros suture zone. This complex itself is a part of a 3000 kilometers belt. Which started from syrea after crossing south Turkey and zagros leading to oman.

Lithologically, in general, the present lithology of the area content of harzburgitic peridotites, I sotrope and mylonitic gabbros, and small outcrop of plagiogranite sequence. Ultramafic rocks mainly contain of harzburgite, dunite, lehrzolite, pegmatitoidic gabbro, olivine gabbro and mylonitic gabbros. Olivines and pyroxnenes as gabbroic sequence constituents showing trace of high temperature deformation.

Trace of low temperature deformation is a result of thrusting that could be seen as my lonitization and porphyroclastic textures on gabbros.

On the basis of major elements diagrams and petrlogical diagrams, this complex resulted from a ocean floor tholeiitic basalt. Mineralogical, petrographical, geochemical and petrological evidences showing that parent magma were high my tholiitic sub- alkaline magma. Tholeiitic nature of magma were.

Responsible for the formation of oceanic crast, and their positions on to the mid oceanic ridige were formed during a high spreading sea floor conditions. Razan rocks is contacted by limestones, marls and sandstones rocks of Cenozoic. In structurally point of view, these rocks belong to zagros zone.

tags: QAZVIN HAMEDAN