U-Pb zircon geochronology, Sr-Nd isotope geochemistry, and petrogenesis of oxidant granitoids at Keybarkuh, southwest of Khaf
Journal: Journal of Economic Geology (Vol.4, No. 2)Publication Date: 2015-07-01
Authors : Ehsan Salati; Mohammad Hassan Karimpour; Azadeh Malekzadeh Shafaroudi; Mohammad Reza Hydarian Shahri; Lang Farmer; Chuck Stern;
Page : 285-301
Keywords : Keybarkuh; subduction; oxidant series intrusions; radiogenic isotope; zircon geochronology;
Abstract
Keybarkuh area is located 70 km southwest of Khaf, Khorasan Razavi province. The study area is situated in northeastern Lut block. The rock units in the area are Paleozoic metamorphic rocks and Cretaceous to Tertiary subvolcanic intrusions intruded as dike, stock and batholith; their composition varies from granite to diorite. Based on magnetic susceptibility, the intrusive rocks are divided into oxidant and reduced series. In this study, the oxidant intrusions are discussed. These intrusions are mostly high-K to shoshonitic and also meta-aluminous type. Their magma formed in subduction magmatic arc and they belong to I-type granitoid series. Enrichment of Large Ion Lithophile Elements (LILE) such as Rb, Cs, K, Ba, and Th relative to High Field Stength Elements (HFSE) such as Nb, Zr, and Ti supported the idea. Enrichment of Light Rare Earth Elements (LREE) and depletion of Heavy Rare Earth Elements (HREE) are also typical of subduction magmatism. Negative anomalies of Eu/Eu* can be attributed to the presence of residual plagioclase in a mantle source and contamination of magma by reduced continental crust. The amount of Nb > 11 ppm, lower ratio of Zr/Nb < 2, the initial 87Sr/86Sr isotope ratio (> 0.706), initial 143Nd/144Nd (> 0.512) and εNd (< -3.5) indicate that magma contaminated by reduced continental crust. Hornblende biotite granodiorite porphyry dated using U-Pb zircon geochronology at 43.44 Ma (Middle Eocene). Based on calculated TDM, magma derived from ancient slab with 820 Ma age in the Keybarkuh area, was affected by the highest continental crust contamination during its ascent.
Other Latest Articles
- Petrology of metabasites in the south of Arousan, northeastern Isfahan province
- The application of stream sediment and heavy mineral exploratory methods on evaluation of mineralization potential in Soltan Meydan basalts, north of Shahroud
- Mineralization and geochemical studies in the Kalchouyeh occurrence, southwest of Naein
- Systematic sulfur stable isotope and fluid inclusion studies on veinlet groups in the Sarcheshmeh porphyry copper deposit: based on new data
- Comparison of data and spectral driven methods for kaolinite-bearing area mapping in Masahim volcano, using Hyperion images
Last modified: 2015-07-01 14:39:59