Petrology
Abdolhamid Ansari
Abstract
The Chahargonbad batholite is located close to Sirjan and southeast of Urumieh-Dokhtar magmatic zone. The batholite's composition is acidic to intermediate that is intruded into the Eocene volcanic rocks. Although the main volume of these rocks consisted of granodiorite and monzogranite, this mass ...
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The Chahargonbad batholite is located close to Sirjan and southeast of Urumieh-Dokhtar magmatic zone. The batholite's composition is acidic to intermediate that is intruded into the Eocene volcanic rocks. Although the main volume of these rocks consisted of granodiorite and monzogranite, this mass contains numerous mafic microgranular enclaves with a combination of diorite and monzodiorite. Also, microgranular dykes have cut the mafic mass. Existence of field evidence such as mafic microgranular enclaves with spherical to oval shapes, bell and rod shaped mafic microgranular enclaves, the presence of synplutonic mafic dykes, as well as textural disequilibrium evidences indicate the absence of plagioclase with oscillatory zoning and repeated analytical levels, and Osley quartz in the presence of enclaves. As they grow, they are minerals and evidence for magmatic mixing. Enclaves show higher values than the host rock in most of the basic elements, such as Al2O3, CaO, MgO, Fe2O3, TiO2, P2O5. The elements (REE), host granite rocks and associated enclaves show relatively differentiated REE patterns with sloping LREE patterns and flat MREE and HREE patterns. Based on the tectonomagmatic environment determination diagrams, all samples from the Chahargonbad (studied area) are located in the arc island setting due to subduction and show the characteristic of active continental margin setting.
