Tectonomagmaic evolution of intrusions from the Northeastern Qori, Southwestern Shahr-e-Babak, south Sanandaj-Sirjan zone

Document Type : Research Paper

Author

Abstract

Beginning of the Neotethys subduction beneath the south Sanandaj-Sirjan zone caused development a regional metamorphism in rocks from the southwest Shahr-e-Babak at 187 Ma (Qori complex). Continue of the subduction under the zone led to be metasomatized mantle wedge and melted the wedge at 173-170 Ma. As a result of the process, the formation of tholoiitic basic magma, injection of the magma into the base of the continental crust, fractionation of the melt, partial melting of the base of the alumina-rich continental crust and contamination of the magma with the continental crust occurred. These processes were formed the Talle-Pahlevani (mafic-ultramafi intrusion) and Chah-Bazargan (quartz diorite-anorthosite) complexes. Increasing of contamination in these melts during their injection into the middle crust caused to be formed highly contaminated parts in the Chah-Bazargan complex. Then, subduction of the mid ocean ridge of Neotethys beneath the Sanandaj - Sirjan zone caused to be formed an arc-related regional metamorphism at 149-145 Ma.

Keywords