Abstract: Antimony mineralization occured in Hamedan district (Faghireh) which is related to Alvand Granitoids. The mineralization occured as a series of veins. Thickness of veins are variable and reach up to 0.7m. The veins are emplaced along high angle faults. These faults acted as a pathway for migration of ore fluids. Veins are composed of stibnite, pyrite, realgar and orpiment with quartz as a gangue. The textures of veins are open space filling, however brecciations also occured. Monzogranites, which formed the main part of Alvand pluton, is the host of quartz - stibnite veins. Monzogranites are composed of quartz, sodium plagioclase (oligoclase), orthoclase, biotite and sometimes muscovite.The veins are composed of 30.5% antimony, 0.83 ppm gold and 498 ppm arsenic. Based on geochemical studies, Sb, Au, AS, Ag, Hg, Sn, Ni, Co and Cr contents of host rocks are much higher than the world's average monzograniets and have probably anomalies. Spiderdiagrams show an identical pattern for host rocks and veins, which strongly suggests that these veins are cogenetic with the intrusive rocks (monzogranite).In summary, with all geological evidences in the region, it can be concluded that the mineralization is probably occured in the epithermal type.

Shah-Kuh granitic massif (South of Birjand) is mainly composed of monzogranite- granodiorite and syenogranite units which enclose large microgranitic bodies. Small outcrups of greisenized granites, occurred in the eastern part. The massif is cut by dacitic, andesitic, and aplitic dykes and mineralized quartz- tourmaline veins.The Presence of magnetite, magmatic allanite, amphibole and the lack of muscovite, aluminosilicates and pegmatitic veins attests to the I-type affiliation of these rocks. The monzogranite- granodiorite unit is distinct from syenogranites by the lack of amphibole, lower Xmg of biotites and lower An% of plagioclase in the later.Based on thin section studies, four types of microstructures including magmatic, submagmatic, high temperature subsolidus and low temperature subsolidus (mylonitic) are recognized.Hydrothermal alteration effects on the pluton can be summarized as:1-Formation of K-feldspar megacrysts; 2- Alteration of biotite to muscovite (or K-feldspar) + rutile + sulfides; 3- Formation of pale green biotite from magmatic biotite; 4 - Chloritization of biotite ; and 5- Complete destruction of biotite and feldspar during greisenization.K- Ar dating was performed 13 biotite separates from main rock types. This gives an age of 165± 3.1 Ma (middle Jurassic) for the Shah- Kuh granite. With an average age of 168.3 ± 3.17 Ma, the microgranites represent the oldest unit among the dated samples. Monzogranite - grandiorite and syenogranite unites, which have been dated 165.2 ± 3.1 (Ma) and 161.6 + 2.5 (Ma), respectively, are somewhat younger unites. It can be concluded that all of the granitic rock types in the suite, formed in a very short period of time.

Skarn occuring in the Sangan area was formed within two different rock roups, graitoids and skarns. Based on the new amphibole classification and nomenclature, the general formula of amphibols is (AB2C5T8O22OH)2. Amphibole of granitoids is a ferroedenite in which Si = 6.87 - 7.75, CaB> 1.5, (Na+K)A> 0.5 and Ti < 0.5. Skam amphiboles are mostly developed within amphibole skarns and gamet-pyroxene skarns during retrograde stage of skarn evolution. High-temperature amphiboles are rich in Al while low-temperature amphiboles are poor in AI. Skarn amphiboles are classified in two groups: (a) hastingsite in which Si = 5.99- 6.08,CaB> 1.5, (Na+K)A > 0.5, Ca < 0.5 and Al < Fe+3. (b), ferroactinolite in which Si = 7.61 - 7.90, CaB>1.5, (Na+K)A< 0.5 and CaA< 0.5. Amphibole in (a) is Al-rich while amphibole in (b) is Al-poor.

The studied area is located in south-eastern Iran with a measurement about 510 Km2. The Igneous nicks of this area belong to teriary. The oldest part is eocene volcanic and pyroclastic rocks, as andesite-basalt, andesite, lathite andesite, dactie, acidic to intermediate tuffs and ignimbrite. A batholitic body intruded in the volcanic rocks in miocene. This batholite is composed of diorite and granithoidic (tonalite, granodiorite porphyry" granodiorite porphyry granitc porphyry and granophyre) rocks. According to field observation, geochemical and tectonomagmatic studies, there are two different magmatic episode as volcanism and plutonium. In this area differentiation of calk - alkline pyroxene and plagioclase is the main reason of evolution for the calcalkine volcanic rocks. There was a dioritic magma in the miocene which a small part of it intruded in the volcanic rocks directly. The differentiation of pyroxene, plagioclasc and titonomagnetite minerals changed the composition of the magma. Then different granitoidic rocks were formed in respect to composition and the depth of magma. The granitioidic rocks are I type and belong to (VAG) group. According to their spider diagrams they are very similar to Lima granite in Peru, which is a continental margine granite.

Khezr-Abad pluton is cropped out in North-West of Taft. This granitoid seems to be younger than the surrounding metamorphosed rocks, particularly the lower cretaceous limestones and probably is implaced during Oligo-Miocene. The most volumetric abundances of the igneous rocks are: granodiorite, granite, quartzmonzo-diorite, quartz-diorite, and in a lesser amount tonalite, quartz-syenite and syenite. All granitoid rocks show Ba, K, Rb enrichment, and Nb, Sr, Ti depletion. From the economical potential point of view, mineraliiation of marble, Fe-Cu-Pb-Zn skarn and non-metalic minerals such as kaolinite are considerable. Geothermobarometry of rock forming minerals of this pluton indicates temperature of 810- 985 .C and pressures of 2.43 - 6.2 kilobars (kbar).

Kohian pluton is located 32 km north-east of Zanjan in Tarom area. This pluton has emplaced in volcanoclastic rocks of Karaj Formation (Eocene) indicating a younger age.Data analysis of Kohian pluton in various tectonomagmatic diagrams show a similarity to continental arc granites or post collisional granites. Even in some cases it has some of the characteristics of intraplate, and rift related or epirogenic intrusive rocks.The presence of two groups of acidic and basic rocks(bimodality) and the lack of geochemical relationship between them(Daly gap) in most of the diagrams, as well as the absence of normal increasing or decreasing trends of elemental oxides with respect to silica during the fractional crystallization suggest a separate origin for the formation of each groups of rocks. In other words, after the Pyrenean orogeny, in a extensional phase, a sodic alkali basaltic magma originated from the mantle asended the crust through the active faults and caused partial melting and anatexy of the crust.This process led to the formation of a potassic and acidic magma, an indication of the role of post collisional tectonic setting. Bimodality and Daly gap observed in rock groups are considered the characteristics of continental rift environments.

Granitoid bodies of  south of Damghan with northeast-  southwest trend have intruded into the  Eocene volcanic,volcanoclastic and Cretaceous carbonate deposits. Recent studies have revealed that the Al content of hornblende in calc-alkaline granitoids varies linearly with pressure of crystallization, thereby providing a mean of determining depth of pluton emplacement. Based on results of electron microprobe analyses, amphibole minerals present in these bodies, according to Leake are ploted in the field of calcic amphiboles and show Actinolite, Actinolite-Hornblende and Magnesio hornblende composition. Calculated pressures of emplacement , using the Al-content of Hornblende, for these bodies ranging from about 0.51 to 0.98 Kbar (about depth of 1.8 to 3.5 Km).The altimate equilibration temperatures of minerals were calculated using different thermometers ranging from 613 to 772 oC.

The Hasan Salaran granitoid complex consists of two distinct granitoid types with various genesis. This complex is situated in NW of the Sanandaj-Sirjan metamorphic belt. Major stratigraphic units of the study area and its adjacent areas are Permian limestones, andesitic-basaltic lavas of Jurassic age and shale, sandstone, limestone and andesitic volcanic rocks of Cretaceous period. Two granitoid plutons are distinguished: The first type is G1 granitoid which is mainly composed of alkali-feldspar granite, syenogranite and alkali-feldspar quartz syenite. This complex displays geochemical characteristics of the ferroan alkalic to ferroan alkali-calcic, peralkaline, A-type and A2 subtype. The intrusion under study shows mineralogical and geochemical characteristics of post-orogenic or post-collision (within plate) granites. Also the mineralogical and geochemical properties indicate an enriched mantle origin with contribution from the crust in generation of source magma of this intrusion. The second type is G2 granitoid is composed of monzogranite, granodiorite and tonalite. The above mentioned complex has calc-alkaline, magnesian calcic, metaluminous with I-type geochemical characteristics. The presence of abundant mafic microgranular enclaves points to mingling of mafic and felsic magmas and is responsible for generation of G2 granitoid magma, which may be formed in a volcanic arc environment.