Geochemistry, zircon U-Pb age, and tectonic constraints on the Bazman granitoid complex, southeast Iran

Abstract

The Bazman granitoid complex (BGC), including a large zoned pluton, intrudes into the upper Paleozoic sedimentary cover of the Lut block. It crops out on the southern slope of the Bazman volcano in Baluchestan Province of Iran. The intrusive rocks range from gabbro to various metaluminous to weakly peraluminous granites, and they are classified as I-type magmatic series. They display geochemical characteristics of typical volcanic arc magmatism at continental margins. Major-and trace-element variation diagrams show that fractional crystallization was the major process and crustal contamination, a subordinate process during the evolution of the BGC. The decrease in CaO, MgO, Al 2 O 3 , Fe 2 O 3 , TiO 2 , P 2 O 5 , and Sr, as well as the increase of K 2 O and Rb with increasing silica, are possibly related to the fractionation of plagioclase, hornblende, apatite, and titanite, whereas the increasing K, Rb, Cs, Pb, and light rare earth elements (LREEs) can be explained by crustal contamination. The BGC rocks are enriched by large ion lithophile elements (e.g., Rb, K, Cs) and the LREEs with respect to the high field strength elements (e.g., Zr, Hf, Nb, Ta, Y) and heavy rare earth elements. New ID-TIMS U-Pb dating performed on zircon and titanite extracted from the granitic samples indicates that the BGC was emplaced during the late Cretaceous period at 83-72 Ma by subduction of the Neo-Tethyan oceanic crust beneath the Eurasian continent. Subsequently, the complex became part of the Lut block when it probably rotated counter-clockwise with respect to the Sanandaj-Sirjan zone and the Urumieh-Dokhtar volcano-plutonic belt.

Late Eocene Uplift of the Al Hajar Mountains, Oman, Supported by Stratigraphy and Low‐Temperature Thermochronology

“…There are several volcanic arcs located in the Eurasian Plate reflecting subduction of Neotethys under Eurasia (Figure ). Along the Zagros Suture and into western Makran the Sanandaj‐Sirjan Magmatic Arc (SSMA) consists of Middle Jurassic to Late Cretaceous plutonic and volcanic rocks (Berberian & King, ; Ghodsi, ). A second arc located 200–300 km northeast and parallel to the SSMA is the Urumieh‐Dokhtar Magmatic Arc (UDMA).…”

Strain rate and stress fields in the West and South Lut block, Iran: Insights from the inversion of focal mechanism and geodetic data

“…The ratio of the seismic to geodetic moment rate shows the lowest values for triangles 2, 1, 4, and 3 with the high ones for triangles 10 and 11. The higher released energy observed in triangles 10 and 11 can be related to the presence of the igneous brittle rocks in this area where the southeast part of the Urumieh-Dokhtar volcano-Plutonic belt (the Jebal-e Barez mountain ranges) and the southwest part of the Makran Volcanic Arc (the Bazman volcanic field) are located in this area (Firouzkouhi et al, 2017;Ghodsi et al, 2016;Rasouli et al, 2016). According to the geodetic and seismic moment rates, the seismic hazards in triangles 1, 8, 13, 9, 5, and 6 are high.…”