Central Iranian microplate is an assemblage of several Precambrian fragments of Gondwanaland. It is bordered by Alborz and Kopeh-Dagh ranges to the north, Zagros and Makran ranges to the west and south, and the East Iran Ranges to the east (Figure 1(a)). Central Iranian microplate consists, from east to west, of three major crustal domains: the Lut Block, Tabas Block and the Yazd Block. These Blocks are separated by a series of intersecting regional-scale faults (Figure 1(a) and Figure 1(b)). The Tabas and Yazd Blocks are separated by a more than 1000-km-long, and up to 80-km-wide, arcuate and structurally complex belt composed of variably deformed supracrustal rocks, i.e. the KKTZ [9] . Recent work by [9] showed that the KKTZ represents an active continental-margin environment and does not show primary alkaline affinities attributable to intra-plate magmatism. It hosts the most of Bafq Fe mining district such as Chador Malu, Se Chahun, Choghart, Esfordi and Shaator. (Figure 1(b)). The Shaytor Fe deposite is located at in east of Kerman-Kashmar tectonic zone and Bafq metallogenic district (Figure 1(b)).

The Precambrian basement rocks of Iran seem to be a continuation of the Arabian shield and form from granite-gneisses and migmatite which have been reported from the Bafq to Robate-Poshte-Badam region in Central Iran [13] . Their composition varies from granite-gneiss to biotite gneiss with disthene and garnet. These include the Chapedony and Boneh-shurow Complexes. The mentioned basement complexes are overlain by metamorphic rocks, up to amphibolite facies, which include biotite schists, amphibolites, quartzitic schists and marbles, often containing garnet and andalusite. In the stratigraphic division of Iran, the “Infracambrian” is applied to the time interval between the Late Precambrian and the Cambrian [14] . In Central Iran, the KKTZ has Infracambrian age and consists of a complex set of volcano-sedimentary rocks which is very extensive from Poshte-Ba- dam to Zarand and hosts the most important iron oxide-apatite, Pb-Zn and U ore deposits in Iran (Figure 1(b)).

The volcanogenic rocks vary from acid to basic in composition, and include rhyolite, agglomeratic tuff, splitic lava and diabase, and most are subjected to widespread alkaline metasomatism. The sedimentary rocks consist of dolomites, dolomitic limestones and evaporites as Rizu and Desu series [15] and [16] . The main part of Shaytor Fe deposite in east of KKTZ has formed from Rizu formation. It consists of volcano-plutonic complexs including basalt, andesite, trachyte, rhyodacite, rhyolite as well as granite and diorite (Figure 1(c)) which having

been subject to widespread alkaline metasomatism (K-feldsparization and albitization; e.g., [17] ). Plutonic bodies of mostly granitic composition (locally associated with diorite and gabbro-diorite dikes or sills) intruded into the volcano-sedimentary rocks as well as the Upper Precambrian metamorphic rocks, which are quite common in Central Iran [18] . [19] suggests that these rocks are calc-alkaline intrusions affected by widespread sodic alteration (albitization), and proposes an evaporitic source for Na. The most important of plutonic rocks is Zarigan, the Chador-Malu granites. [9] and [20] defined an age of 525 ± 7 Ma, 529 ± 16 Ma (U-Pb on zircon) and 527 - 539 Ma (U-Pb apatite age) for the Zarigan, the Chador-Malu granites and major iron oxide-apatite deposits in the Bafq district, respectively. These ages confirm that mineralization have been related to magmatic rocks of the Bafq district. There are three areas with a dense distribution of magnetite or hematite deposits in the Bafq NNW-elongated basin (Figure 1): the Jalal Abad deposit in the South; Choghart, Esfordi and Se-Chahun, and Shaytor deposits in the center; and the Chador-Malu deposits in the north. This mineralizations are closely associated with the subvolcanic plutons. The Shaytor mining region is in the Early Cambrian Kashmar-Kerman volcano-plutonic arc in Central Iran which hosts important “Kiruna-type” magnetite-apatite deposits [19] . The ore shows different textures from fine grained to coarse grained. The mineral assemblages in the ore are mainly quartz-magnetite, apatite-magnetite, quartz-apatite-magnetite. Massive, banded and brecciated ores are identified based on their structure. The massive ores consist predominantly of magnetite, hematite and martite, with minor apatite and quartz (Figure 2(a)). These ores contains, miarolitic and amygdaloidal structures (Figure 2(b)) filled by quartz and calcite crystals, which are also common in the Kiruna-type deposit in Chile and Sweden and porphyry-type iron deposits in China ( [4] and [1] ). The banded ore is characterized by magnetite bands alternating with apatite (Figure 2(c)) or host rock bands of 2 to 3 mm to a few centimeters thick. The apatite bands (up to several centimeters wide) are mostly pure with minor magnetite or hematite, whereas the magnetite bands contain variable concentrations of apatite. brecciated ores consist of some breccia clasts have corrosion rims cemented by magnetite (Figure 2(d)). Some breccias contain veinlets of magnetite.

The representative results of EMPA and LA-ICP-MS analyses for magnetite are presented in Table 1 and 3 The anhedral and euhedral magnetite in the Shaytor is Fe-rich with average FeO_T abundances from 98.4 wt.% to 101.2 wt.%, low SiO₂ contents up to 0.9 wt.%. They do not show systematic chemical variations from core to rim. Magnetite in the Shaytor contains low MgO (up to 0.29 wt.%), low MnO (up to 0.02). In addition, the magnetite contains moderate to low Al₂O₃ (up to 0.35 wt.%). Low abundances of Al₂O₃, TiO₂ (up to 0.70 wt.%) and MgO in magnetite obtained by EMP indicate insignificant variation due to exsolution of ilmenite and spinel. The composition of the magnetites is consistent with those from Kiruna-type magnetites, which have low TiO₂ compositions (usually < 2 wt.%) [1] . Chondrite-normalized rare earth element (REE) patterns for the magnetite from the Shaytor are characterized by enriched in LREEs relative to HREEs, the LREE/HREE ratios are variable (Table 2; Figure 4).

Magnetites show moderately steep chondrite-normalized patterns with (La/Sm)N ratio 1.61 - 3 and have similar negative Eu anomalies (Eu/Eu* = 0.18 - 0.27). These characteristics are probably related to the existence of apatite because apatite controls the REE budget of the rock. Iron ores were classified by [21] based on the Ni, V, Ti, Fe content. They proposed V vs. Ni, V/Ti vs. Ni/Ti and V/Fe vs. Ti/Fe diagrams for distinguishing the apatite iron ores, titaniferous iron ores and Banded iron formations. Based on these diagrams, the Shaytor magnetite-apatite mineralization classified as apatite iron ores (Figure 5).

The major and trace element compositions of the rocks are given in Table 3 and are clearly affected by hydrothermal alteration. They show composition variations reflecting their lithologies from mafic to falsic composition (Figure 6(a)). The silica concentration ranges from 45.16 wt.% to 71.03 wt.% (Table 3) and 45.91 wt.% to 70.20 wt.% for extrusive and intrusive rocks, respectively. The alkali contents of extrusive rocks vary between 0.1 wt.% and 2.1 wt.% Na₂O and 1.56 wt.% to 8.14 wt.% K₂O, while the intrusive rocks have more Na₂O (from 0.09 wt.% to 5.14 wt.%) and less K₂O values (0.1 wt.% to 4.5 wt.%) than those of extrusive rocks. Because most of these samples have been affected by extensive alteration, alternatively, the samples have been plotted in the discrimination diagram of [22] which is widely used to discriminate between altered volcanic rocks (Figure 6(a)). In this diagram the more volcanic rocks plot in the rhyodacite-dacite, sub-alkali basalts and trachyte compositional field while the more intrusive rocks plot in the rhyodacite-dacite to sub-alkali basalts field. To distinguish between alkaline and subalkaline suites, the samples have been plotted in a diagram of Ta/Yb versus Th/Yb (Figure 6(b)). In this diagram, the intrusive as well as extrusive rocks mostly plot in the calcalkaline to shoshonitic field. These rocks are mostly peraluminous with alumina saturation index (ASI (=molar Al₂O₃/(CaO + Na₂O + K₂O) values more than 1.10 (up to 4.47) except basaltic and gabbroic samples which are plotted in metaluminous field (Figure 6(c)). Also, they mostly plot in the I type granites in a diagram P₂O₅ versus silica (SiO₂) (Figure 6(d)). The felsitic igneous rocks from Shaytor also show affinities to volcanic arc granites in the Rb against Y + Nb diagrams [23] (Figure 6(f)). Chondrite-normalized rare earth element (REE) and primitive mantle normalize patterns for the granitoids and volcanic rock from the Shaytor show two type of trend including 1) mafic rocks with enrichment in light REEs (LREEs) and LILE compared to heavy REEs (HREEs) and HFSE with negative Eu (Figure 7(a)) 2) and falsic rocks with slight enrichments in LREE without Eu anomaly. Also, in a primitive mantle-normalized [24] trace element diagram, magmatic rocks shows depletion in K, P and Ti and enrichment in LILE (Figure 7(b) and Figure 7(d)).

Major, trace and rare earth element chemistry of the Shaytor rocks demonstrate the significance of crystal frac tionation from parental magma(s). Most of the Shaytor igneous rocks have low MgO, Ni, and Cr contents, except basalt and diorite samples, suggesting that they no correspond to primary magma compositions. General fractional crystallization or partial melting trends are indicated by decreasing TiO₂, MgO, Fe₂O₃, V, Sc and Sr concentrations and increasing K₂O concentration with increasing SiO₂ contents in Shaytor igneous rocks (Table 3). These trends can be interpreted to indicate fractionation of amphibole, plagioclase, Fe-Ti-oxides, apatite and zircon. Fractionation of Fe-Ti oxides was important which is consistent with the decrease in V with increasing SiO₂. Also, fractionation of apatite, which may concentrate LREE (e.g. [25] ), is compatible with LREE valuse in chondrite normalized patterns (Figure 7). As a mentioned before, according to REE values in the chondrite normalized pattern, the igneous rocks from Shaytor show two trends that show there is two type of magmatism in this region including: (1) primary basalts magmatism with enrichment in LREEs and LILE compared to HREEs and HFSE with negative Eu (Figure 7(a)), (2) felsic volcanism and plutonism with evidences for assimilation-fractional crystalization (Figures 7(b)-(d)).

Magmatic iron ores were classified by [1] into two groups based on geochemical characteristics which are include: 1) volcanic-exhalative stratiform iron ores and 2) iron-apatite ores and apatite veins. They believed that

iron-apatite ores demonstrate depletion in Cr (less than 10 ppm), enrichment in V (1000 - 2000 ppm) and depletion in Ti (100 - 1000 ppm occasionally up to 5000 ppm). Average content of Cr, V and Ti in the Shaytor magnetite-apatite samples are 30.3 ppm, 1142.7 ppm and 0.14 ppm, respectively. In this base, Shaytor magnetite- apatite mineralization can be classified as iron-apatite ores. Among the iron ores of the world, there is a specific group of occurrences composed of the magnetite-hematite-apatite assemblage (IOA deposits) which are considered as Kiruna-type magnetite-apatite deposits. Rare earth elements (REE) are characteristically elevated in Kiruna-type deposits [26] . Enrichment in REEs is one of the specialties of the Shaytor magnetite-apatite mineralization. REEs content of these samples are high and vary between 56.77- 1087 ppm. All of the samples from magnetite ore show a similar pattern with a LREE/HREE fractionation and negative Eu anomaly (Figure 4). These similar REE patterns indicate that these units have a common origin. Moderate LREE/HREE fractionation is a common characteristic of magmatic magnetite-apatite ores connected with calcalkaline rocks. The chondrite-normalized REE patterns (Figure 6(a)) show that the samples from the igneous rocks vary substantially in terms of composition. These samples, except primary basalt, exhibit a weak enrichment of Light REEs compared to Heavy REEs and a relatively flat pattern (Figure 6(a) and Figure 6(c)). The magnetite samples from Shaytor revealed chondrite normalized REE patterns similar to those of the primary basaltic rocks with depleted Eu (Figure 4 and Figure 7(a)). So, it can be find that the Shaytor Fe deposit were generated from basaltic magmas.

Kiruna-type deposits contain variable quantities of magnetite-fluorapatite-actinolite ores in volcano-plutonic terrains that range in age from Proterozoic to Cenozoic. The best known, and one of the largest deposits is in the Kiruna region of northern Sweden ( [27] [28] ), in Missouri, U.S.A., in the Great Bear magmatic zone of Canada [29] , in Ningwu basin in the eastern China [30] , in the Avnik region of southeastern Turkey [31] , and in the Circum-Pacific belt of Chile and Peru ( [28] ). Iron oxide-apatite deposits of the Shaytor region show some similarities to the Kiruna-type deposits including (1) according to mineral assemblages, fabric and structure of the iron ores, occurrence of the orebodies and wall rock alteration zones. For example, the iron ores are mainly composed of magnetite or hematite, diopside or actinolite and apatite. These deposits are interpreted as having formed in a rift or extensional environment and mineralization is associated with alkaline magmatism. (2) Geochronological data [9] and [20] show that the time interval between the magmatism and associated mineralization is very short. Alteration, especially albitization, is very pronounced in footwall rocks under the orebodies.

As mentioned before, the Shaytor apatite-rich iron deposit is similar to Kiruna-type iron deposits. The origin and enrichment mechanisms of apatite and magnetite in Kiruna-type iron deposits have long been debated, and models proposed include exhalative-sedimentary origin [32] and [26] , magmatic origin due to liquid immiscibility [33] , and hydrothermal origin [29] and [34] . Recent studies have excluded the exhalative-sedimentary origin hypothesis. The Kiruna-type iron deposits have been interpreted as the product of crystallization of iron oxide magmas derived through immiscible liquid segregation (rich in Ti, P, and Zr) [1] [4] [31] [35] - [38] . It has been hypothesized that silicate liquid immiscibility, caused by 1) crystal fractionation, 2) magma mixing, 3) an abrupt change in oxygen fugacity, and/or 4) an introduction of phosphorus, may lead to the release of an oxide melt from silicate magma [5] . This model has been proposed for some of the magnetite-apatite deposits in the Chilean iron belt [1] and Kiruna [27] . The occurrence of large amounts of the apatite as a gangue mineral is conspicuous in Kiruna-type deposits, such as Shaytor. Also, apatite has spatial association with the iron mineralization in Shaytor. This confirms for Shaytor the model involving immiscible magmatic liquids caused by the introduction of phosphorus. The Shaytor iron deposit was formed from Fe-rich melts (or fluids) that were derived from the mafic magma and channeled along major faults and fractures. The source of the Fe can ultimately be ascribed to the mafic magmas derived from the mantle wedge.