جستجوی مقالات مرتبط با کلیدواژه « jan mine » در نشریات گروه « زمین شناسی »

The study area is a part of the Sanandaj- Sirjan zone that is located in the NW of Azna city and NE of the dimension stone mine of Jan between 49° 11' 41"and 49° 16' 07" E longitude and 33° 36'35" and 33° 38'12" N latitude., A pluton of mylonitic granite-gneiss is exposed in the area which contains abundant tourmalines as black and patchy or subgrain association. Geochemically, the studied granite-gneiss is A-type, peraluminous to slightly metaluminous and calc – alkaline to slightly alkaline (Moradi et al., 2017). The electron microprobe analyses of the tourmalines display shorl-dravite in composition with more tendency to shorl (Moradi et al., 2015). In this paper we try to study the petrological sites of tourmaline formation with associated minerals, controller factors of crystallization using mineral chemistry of tourmaline, comprehensive behavior of trace elements in the tourmaline, synthetic phase diagrams and finally relationships between the associated minerals.
The results of trace-element and major-element analyses were obtained from one polished thin section including 2 tourmaline grains. Major-element analyses of tourmaline were obtained at Oklahama City University of America using the JEOL 8200 electron microprobe with a spot size of 5 μm and trace-element analyses were performed on just a sample by Laser Ablation-Inductively Coupled Plasma-Mass Spectroscopy (LA-ICP-MS) a 193nm ArF excimer laser ablation system (MicroLas GeoLas 200Q) in combination with a quadrupole ICP-MS (Micromass Platform ICP) at Utrecht University of Netherland. Representative EMP and LA-ICP-MS analyses of tourmaline samples are presented in Tables1 and 2.
The results of LA-ICP-MS on tourmalines of Jan mine in the North east of mylonitic granite-gneiss body show that distribution and diffusion of trace elements during the growth of tourmaline trend is positive on the plots of binary Mn versus Fetot / (Fetot ) and it represents the formation of the tourmaline mineral from the melt is along with the progress of the differentiation (Jolliff et al., 1987; Kontak et al., 2002). Also the average composition of tourmaline – bearing mylonitic granite-gneiss pluton normalized spider diagram for the studied tourmaline shows positive anomaly and negative anomaly in Eu that indicates tourmaline minerals surrounded by quartz and feldspar grains (Copjakova et al., 2013). Secondary phases such as zircon and allanite very much effect on the REE patterns (Rollinson, 1993). Therefore, in the final stages of differentiation, allanite appeared earlier than it appeared in areas without tourmaline crystalliziation and LREE soon after tourmaline crystalized and they are deposited (Cuney and Friedrich, 1987). Using a combination of phase diagrams, the controlling factors of creation of tourmaline associated with biotite-tourmaline can be assessed, and the relationship between tourmaline and associated minerals, chemistry of tourmaline – bearing granitoid pluton, and location of petrological minerals tourmaline can be sought (Pesquera et al., 2005).
The results of LA-ICP-MS on tourmalines of mylonitic granite-gneiss body in the north east of Jan mine in Sanandaj – Sirjan Zone represents tourmaline crystallization from the melt along with the progress of the differentiation. Also, the average composition of tourmaline – bearing mylonitic granite-gneiss pluton normalized spider diagram for the studied tourmaline shows positive anomaly and negative anomaly in Eu that indicates that tourmalines are surrounded by quartz and feldspar grains. According to petrographic evidence of tourmaline and biotite, it can be seen with muscovite. Therefore, where tourmaline is dominant, biotite and associated minerals are limited or do not exist. Using a combination of phase diagrams controlling factors of tourmaline crystallization associated with biotite-tourmaline can be assessed, and the relationship between tourmaline and associated minerals, chemistry of tourmaline – bearing granitoid pluton, and location of petrological of tourmaline minerals can be sought.

The outcrop of mylonitic granite-gneiss in the northwest of Azna city and the northeast of the Jan building stone mine is a part of Sanandaj-Sirjan zone. The tourmalines from these rocks are black and patchy or fine association. Based on EPMA data the tourmalines studied are shorl-dravite in composition with more tendency towards shorl. They belong to granitic environment and precipitated during hydrothermal condition. The chemical composition of the host granite is a major factor in distribution of elements in the studied tourmaline structural framework during the process of differentiation, as well as, faulting and uplifting of granitoid body. Some of the dominant substitution mechanisms in the structure of the investigated tourmalines are as follow: □X Al (Na R2+)-1, 21 xNa-1 zAl-1+xCa1 YR (OH)-1, Fe2+ Fe3+) (Mg Al)-1.

The study area is a part of Sanandaj- Sirjan Zone that is located in the northeastern of the dimension stone of Jan mine in north of Doroud city on Lorestan Province. It is mainly composed of deformed metamorphic rocks including deformed marbles associated with mylonitic gneiss- granite and amphibolite. The main texture of the marbles is lepidogranoblastic and their mineralogical composition are calcite, quartz, phengitic muscovite, epidote, sphene, opaque minerals and minor plagioclase. Calcite grains have preferred orientation, which show strain and crystal-plastic deformation. The formation of flayser texture in the quartz lenses, undulatory extinction in the quartz grains, existence of pining microstructures, dynamic recrystallization as grains boundary migration (GBM) between calcite and quartz, bulging recrystallization (BLG) in the quartz grain boundaries along fracture planes, Subgrain Rotation (SGR) and also, deformation twinning in calcite crystals show the temperature of deformation ranges from 150 to 300 °C for the marbles.