Origin and tectonic environtment of Tertiary volcanic rocks of Damash area in Guilan province(North of Iran)
Subject Areas :
Mohammad Hosein
Mokhtari
1
(Yazd University)
Keywords: Damash volcanic rocks Intra-continental rift , MORB-like mantle Crustal contamination.,
Abstract :
Tertiary volcanic rocks of Damash area have outcraps about 70km for from east of Roudbar in Guilan province. From geochemical Point of view negative anomaly of P, Ba,Zr ,Ti ,Ta ,Nb and positive anomaly of K,Th,Pb,Rb indicate crustal contamination. The ratios of (Tb/Yb)N,Nb/Yb,Zr/Yb,Zr/Y,Zr/Nb,Y/Nb show that the MORB-like depleted mantle source with Spinel Facies. Study of the rang of incompatible elements pattern and compare with the crustal data range and incompatible elements ratios show that the volcanic rocks have been concerned to intra-continental rift magmatism wich are contaminated with continental crust. As a result of the crustal contamination, the original geochemical properties of the volcanic rocks were changed untruthly subduction zones geochemical features.