Geology and geochemistry of Yakhab Granodiorite, Yazd Province, East Central Iran
Mollai, Habib; Hashemi, Seyed Mohammed; Kardani, Yosef
published: Sep 1, 2014
ArtNo. ESP155027303004, Price: 29.00 €
The Yakhab Granodiorite is part of the Ozbak-Kuh and is located to the southeast of Yakhab village, in the Zeber-Kuh mountains of Yazd Province, Central Iran. To the southwest of Yakhab village more than five masses of igneous bodies occur, of which the Yakhab Granodiorite is the largest. This body is part of a zonal structure of the Zeber-Kuh region. The Yakhab Granodiorite is a stock exposed over an area of 35 km2 and is in contact with mica schist. All granodiorite bodies are bounded by the Daroneh Fault to the north and the Great Kavir Fault to the south. Yakhab Granodiorite is coarse to medium-grained, red to pink in color, parts contain xenomorphic K-feldspar phenocrysts, and it is rich in dioritic xenoliths. Based on its major and trace element geochemistry, especially the behaviour of the immobile trace elements Y (32-81 ppm), Zr (33-1082) and Nb (3-104), fractional crystallization is suggested as the process that produced the intrusive rocks. The parental magma was rich in SiO2, which ranges from 67.7 to 80.5 wt% (average 74.0 wt%), and had high to medium concentrations of alkaline elements of which Na2O reaches values of 2.8 to 6.5 wt% (average 3.8 wt%) and K2O varies from 0.2 to 4.2 wt% (average 2.3 wt%). The Al2O3 content, however, covers a wide range from 9.5 to 13.9 wt%, with an average value of 12.3 wt. %. In general, Yakhab granodiorite is rich in LILE, depleted in HFSE and also shows negative anomalies for La, Ce, Ta, Nb, Sr, P, Ti and positive anomalies for Th and Pb. Major and trace element classification shows this intrusion to be a calk-alkaline, metaluminous to peraluminous, subduction-related I-type arc granodiorite originating from continental crust.