---

In 1 his experiment for SI udyi ng and co mparing of clay
m i nera Il. in t he sol is uf river terraces, fou r profi les se lec teu and
),:unpICtl a, reprc.'>enlcd profiles for mineralogical analysis. Three
profile..; were on th ree terraces of Zayanuehrood river in Pole -
ShllhrCSlan Ihal caen of them has different ages, and the forth is
loca ted un the o ld rive r alluvial pla in and is o lde r th an three
terraces. So il samples were prepared according to the proposed
method I'ly Killric and Hope. X - ray technique was used 10
determine Ihe minerals present in the rine and coarse clay
fr the pre),cm:e of Ollart:r, Kll nlin i tc, IlI i1t~, r hl ori rc ;end :1 l ill ie.
POlygorskitc in all soils. In the soil of hi gher terrace there is
Smel.:ti lc and in the old plain's so ils the Smectit e and
Pnlygorskitc arc dominant. This co nfirms the idea that Smeclite
procc.~s.

---

Anjirch Pb-Zn deposits are located 55 km wesl
of Esrahan. These deposits belong 10 a part of a large
sedimenta ry basin containing lead ttnd zinc metal epieiences,
in Sanand aj - Si rjan zone. This basin contains Lower
CretO:tceous (Albian - Abtian) sedimentary sequences. The
Anjireh deposits are typical of Mississippi-valley type
stratttbound lead-zinc deposits. The principal metal minerals
in these deposits are Cd-rich sphalerite and Ag-poor galena.
These ores arc rich in Cd, Hg and poor in Au and Ag.

---

The Ilam Formation (Santonian-Campanian) is a unit of Bangestan Group, which is overlain on the Sarvak Formation in Tang E-Rashid area, Peyon Anticline (18.5 Km North of Izeh). Due to similar lithology, recognition of the exact boundary between Ilam and Sarvak Formations in the study area was difficult. Thus it is not possible to determine boundary between these two formations based on petrographic evidence and field observations. Recognition of original carbonate mineralogy based on petrographic studies is difficult in ancient carbonate rocks, because aragonite (A) and high - Mg calcite (HMC) transformed to low Mg calcite (LMC) during diagenesis. In this study major and minor elements and carbon and oxygen isotopes values used to determine the original carbonate mineralogy of Ilam Formation in the Peyon Anticline. Bivariet plots of minor and major elements and oxygen and carbon isotopes values indicate that original carbonate mineralogy was aragonite in Ilam Formation. Elemental and isotopic compositions of Ilam carbonates also illustrate that they were affected by non-marine diagenesis in a closed system. Major and minor element variations (such as Sr, Sr/Ca, and Sr/Na) and oxygen and carbon isotopes were used to distinguish the boundary between Ilam and Sarvak Formations in the Peyon Anticline.

---

There are metabasite exposures inside ophiolitic belt of northwest Sabzevar that metamorphosed under high pressure granulite facies. On the basis of mineralogical paragenesis, reactional textures between different mineralogical assemblages, textural and mineralogical relations between inclusion and porphyroblast and stability fields of different mineralogical assemblages, five stages of evolution of metamorphism is distinguished. These stages consist of prograde metamorphic stage (M1), peak metamorphic stage (M2), garnet kelyphitisation as the formation of Pl+Am symplectite and corona (M3), partial or quite replacement of garnet by Am+Chl+Ep assemblage (M4) and the occurrence of Prh-Zl veins. The thermobarometric data of these stages represent a clock-wise P-T path. This path is consistent with the collision of the Iranian micro-continent with the Alborz block and later erosion and uplifting.   

---

Mehrabad bentonite deposit appears to be derived from the volcano- sedimentary materials of Oligo-Miocene age by transformation in a lagoon environment. Based on analysis, bentonite samples contain minerals such as montmorillonite, albite, clinoptilolite, quartz, cristobalite, calcite, gypsum, halite, muscovite and nantronite. Conversion of shard glasses to bentonite and zeolite has occurred under diagenetic conditions with acidic to intermediate composition. The bentonite deposit is halmyrolytic clays in type. According to geochemical studies, bentonite’s magmatic series is subalkaline (calc- alkaline) and their tectonic setting is volcanic arc and syn- collision.

---

The Sirzar Sb prospecting area is located in northeast of Torbat -e- Jam in Khorasan Razavi Province. Mineralization is found both as vein and replacement within carbonate rock (Permian). Two primary stages of mineralization are: 1) galena ± pyrite ± chalcopyrite ± sphalerite ± sulfosalte ± Cu-Sb sulfides, quartz and barite. 2) Stibnite ± pyrite ± sphalerite ± fuloppite, quartz, barite, dolomite and calcite. Minerals which are formed due to weathering and oxidation include valentinite, bindheimite, covellite, malachite, azurite, anglesite, cerrusite, geothite, hematite and Sb-oxides. Main alteration is: silicification, baritization and dolomitization. SEM analyses of galena revealed high content of Ag, As and Sb and low Bi. This indicates that galena was formed at low temperature. Sulfosalte within galena also contain higher Sb which prove this case. Stibnite also contains some Ag. Fluid inclusion microthermometry on quartz, calcite and barite revealed that the first stage of mineralization were formed between 371-317°C and the second stage associated with quartz, barite, and dolomite were formed between 275-188 °C and associated with calcite is between 197-132°C. Sirzar Sb mineralized area is similar to Xikuangshan mine in China with respect to host rock, mineral paragnesis and type of mineralization. Based on mineral chemistry and fluid inclusion microthermometry, Sirzar is a low temperature epithermal deposit.

---

Triassic (mostly volcanic-carbonate) and Jurassic (mainly shale and sandstone) rocks in west of Malayer were affected by a number of shear zone, folding, deformation and metamorphic events. Regional metamorphism in the area led to the formation of Triassic and Jurassic rocks such as phyllite, slate and crystalline carbonate which folded during deformational events. In the contact metamorphism event, granitoid plutons with predominantly granodiorite to quartz-diorite composition intruded the metamorphic rocks, forming mineralized skarn zones in Anjireh, Iraneh and SarabSaman areas. The present research shows that plutons producing the mineralized skarn zones in the area are on average granodioritic in composition. Pyroxene and garnet minerals in the skarn zone comprise of diopside, augite and grandite (mainly andradite), respectively. In these skarns, various sub-zones are recognized and defined on the basis of their mineral paragenesis. High temperature facies (pyroxene-fels) formed in the temperature range of 650-800 ºC and wollastonite up to 800 ºC. However, hornblende-fels and albite-epidote-fels facies formed in the temperature ranges 500-650 and 350-500 ºC, respectively.

---

Panah Kuh skarn is located about 50 km northwest of Taft City in Yazd province. The intrusion of Panah- Kuh stock with granodiorite-quartz diorite composition into the limestone Jamal Formation has led to the skarnification in this area. Field and mineralogical observations show that Panah-Kuh skarn included two endoskarn and exoskarn zones. Exoskarn is calcic type and magnesian skarn which formed in contact with the marbles whereas endoskarn formed with restrict development into intrusion. Dominated minerals are garnet (andradite) and pyroxene (diopside-hedenbergite) in the calcic skarn and forsterite, diopside, serpentine and talc in the magnesian skarn. At least two paragenetic stages of skarn formation have been recognized. The early skarn formation (stage I) was dominated by anhydrous minerals such as pyroxene and garnet in the calcic skarn and forsterite and diopside, in the magnesian skarn. According to mineral assemblages which formed at this stage, it can be concluded that the temperature range was less than 500 ⁰C. The hydrous skarn assemblage such as serpentine and talc (stage II) replaced early-formed skarn assemblages. The mineralogy and geochemical characters of Panah-Kuh skarn is consistent with deposition under oxidized conditions, formation at shallow crustal levels and similar to those of Fe bearing skarn system.                    

---

Major rock units of Robat Sefid ophiolitic complex are Late Cretaceous in age. The abundance of rock units in this area in ascending order are: dunit, harzburgite and pyroxenite), gabbro and diabasic dikes (mostly rudenginized). Chromite lenses are generally covered by a few centimeters to several meters of ultramafic rocks mainly of dunite. Primary disseminated and massive textures are abundant in chromite ores and secondary brecite, pulapart and kataclastic textures are present. These textures and dunite pods are confirming that chromite deposits of investigated area are in syngenetic type. Tectonic activities and specially NE-SE direction faults are the major factor for dispersion of chromite lenses. Geochemical analysis indicate that Kuhi chromite deposits samples have an average values of Cr₂O₃ (49.54%), MgO (20.29%), TiO₂ (19.0%) and Al₂O₃ (2.44 to 7.9%), as well as the ratio of Cr / Cr + Al ranges from 0.86 to 0.95 (average 0.81). These indicate that chromite samples are high in Cr & low in Al type.  The percentage of Cr₂O₃ and MgO in the chromite samples, indicate high partial melting in magma crystallization. Lower amounts of Al₂O₃ and TiO₂ in chromite deposits with their stratigraphic positions in ophiolitic sequence indicate deep chromite zones of the upper mantle- origin of magma. Due to the amounts of major oxides, Kuhi chromite deposits are in Podiform shape which are probably derived from island arc and boninite magmatic series which are associated with Supra-Subduction zones (SSZ). Depletion in Ti and enrichments in Th of samples conform that magma source is related to subduction zone.

---

Trachyandesites, trachytes and latites associated with ignimbrite and pyrocalstic rocks, characterized by shoshonitic affinity are the main Plio-Quaternary volcanic rocks in the Sabalan region (Ardabil). Plagioclase, K-feldspar, biotite associated with clinopyroxene and glass are the main constituents of these lavas. Plagioclases are andesine to labradorite while clinopyroxenes have augitic composition. The Sabalan volcanic rocks show enrichment in LREE relative to HREE and are characterized by enrichment in LILE and depletion in HFSE. Petrological observations along with geochemistry of rare earth and trace elements of these lavas suggest shoshonitic affinity and derivation from a subduction zone. The Sabalan volcanic rocks are isotopically characterized by derivation from an enriched mantle source (with/without crustal influence) with tendency to plot in a field defined by island-arc basalts (IAB) and OIBs (in εNd vs. ⁸⁷Sr/⁸⁶Sr diagram). The geochemical and isotopic signatures of the Sabalan lavas suggest that their magma has been issued via low degree partial melting of a subduction-metasomatized continental lithospheric mantle. The formation of these lavas is linked to slab steepening and break-off in a post-collisional regime.

---

This study has focused on provenance of Eslamlu metapelites, NW Iran. Whole rock chemistry analysis has revealed that these metapelites are rich in Iron and Aluminum and as a result the modal abundance of garnet (Almandine) is high. But those samples which are rich in SiO₂ are poor in Al₂O₃, therefore, Eslamlu metapelites have less cordierite and aluminosilicates. The position of different samples in AFM compatibility diagrams is similar, as a result, bulk rock chemistry variable was constant and parageneses are produced due to changes in P and T of metamorphism. Further studies has unraveled that parent sedimentary rocks have been Fe-shale and graywacke. The high concentration of Al₂O₃ and Fe₂O₃ shows that the rocks are Laterite.  PIA, CIA and CIW indexes are high showing intense weathering conditions; hence the aluminum content is very high. According to major element composition of metapelites, tectonic environment of igneous parent of sediments, not Ruteh sediments, has been active continental margin.

---

The Band-e-Hezarchah granitoids mainly include alkali granite and granite. that intruded in Late Neoproterozoic metamorphic rocks. Orthoclase, microcline, plagioclase, quartz and biotite are the main rock-forming minerals. Plagioclase is mostly albite and oligoclase with Si = 2.57-2.7 a.p.f.u. and An_0.4–12.6. Biotite is mostly siderophyllite, with Si = 4.30-6.22 a.p.f.u. and X_Mg= 0.025 - 0.859. Chlorite with Si = 4-5.53 a.p.f.u. and X_Fe= 0.84-0.91 is mostly daphnite and pseudothuringite. Field and geochemical evidences show the BHG is S type and their magmas seem to have originated from melting meta-pelitic and metagraywacky metamorphic rocks in the active continental marginal above a subduction zone. These rocks are thought to be formed in acontinental arc setting, related to the oblique subduction of Proto-Tethys oceanic lithosphere beneath the northern margin of Gondwanan supercontinent during Ediacaran- Early Cambrian time.

---

Northeast  of Meshkinshahr, Eocene igneous rocks are exposed and are composed mainly of andesite, basalt, andesitic basalt, tephrite and is sometimes analcimite. The chemical composition of the rocks are in the range of alkaline rocks with high potassium and shoshsonitic affinity. Two main hypotheses are that they are either primary analcite or replacement pseudomorphous of leucite. Analcime crystals are usually large and eohedral to subhedral shaped phenocrysts coexisting with clinopyroxene in most rocks of this area. The presence of Ca-clinopyroxene and plagioclase rather than their sodic equivalents, presence of anhydrous mineral phases and lack of Na differentiation trend as well as partial alteration of the rocks likely supports the secondary growth of analcime either during cooling or after magma solidification.

---

The studied diabase rocks of the Hormuz Formation have undergone a variety of secondary processes and greenschist facies to amphibolite facies metamorphism. These rocks are metasomatized due to the effect of infiltrating metasomatism and hydrothermal alteration and are metamorphed due to CO₂-rich aqueous fluids and rock-fluid interaction. Feldespat, pyroxene, olivine, apatite, rutile, magnetite and pyrite are the primary magmatic minerals present in these rocks and other minerals, are products of the transformation of the primary minerals due to metasomatism and thermal metamorphism. Feldspars are labrador, albite and orthoclase. Labrador and albite were crystalized at tempretures of <700 and pressures of <6 kbar which is their recrystallization tempreture. Orthoclase was crystalized at tempretures and pressures of 700, 6 kbar and >1000, >7 kbar and is a magmatic mineral. Clinopyroxens are augite and diopside and were crystalized at 1100 to 1300 and are magmatic minerals. Pyroxenes are subalkaline to alkaline and were formed within plate tholleitic basalt or oceanic floor basalt environment. Plagioclase and pyroxene minerals show oxidation conditions. According to the analyzed zircons from Band-e Moullem (539/4 ± 6/4 Ma) and Champeh (543/5 ± 6/1 Ma) salt dome diabase, these rocks have been crystalized and formed during Early Cambrian time. In addition, most of these zircons have a magmatic origin. This estimated age suggests that the intrusion of these diabase, occurred during and/or after the Neoproterozoic to Early Cambrian rifting of the northern part of the Arabian plate and the sedimentation of the Hormuz Formation in the Persian Gulf Basin.

---

In the eastern part of the Sabzevar ophiolite, southeast of Soleymanieh, there are white to pale greenish veins of diopsidite with 1–15 cm width inside mantle serpentinized harzburgites. The center of these veins is rather homogeneous and includes a monomineralic clinopyroxen with granular texture. The contact between the pure clinopyroxene and its host peridotite is always progressive and characterised by replacement textures and minerals. The host harzburgite has also been affected by diopsidization. There are patches of cores grain altered plagioclase and clinopyroxen with inclusions of serpentine in the host harzburgite. The mineral assemblage, field relationships and mineral chemistry of the mantle diopsidites in the eastern part of the Sabzevar ophiolite indicate that they are product of circulation of very high temperature hydrothermal fluids (550–900 °C) rich in Si, Ca, Mg, CO₄^2–, SO₄^2– and Cl^– in the upper mantle. These fluids leached plagioclase rich lithologies before penetrating the mantle.

---

The clinopyroxene composition of two types of alkaline and calc-alkaline gabbros at Piranshahr pluton was investigated in this study. The major oxides variations are similar in all clinopyroxenes of two types of gabbros and are classified as diopside- augite; but trace element compositions are very different in these two groups. The clinopyroxenes of alkaline gabbros are rich in high field strength elements (HFSE) and rare earth elements (ΣREE= 34- 64 ppm) and have high ⁸⁷Sr/⁸⁶Sr ratios. In other side, the clinopyroxenes in calc-alkaline samples have high Sr, Rb and Ba and elevated ⁸⁷Sr/⁸⁶Sr; but are depleted in HFSE and rare earth elements (ΣREE= 9.4- 21.6 ppm). Calculation of equilibrated melts from trace elements composition of clinopyroxenes using partition coefficients between clinopyroxene and the basaltic melt show that they are formed by different sources which is consistent with whole-rock geochemical data of gabbros.

---

The sedimentary copper mineralization of the Sorkheh area is located about 20 km northwest of Marand, East-Azarbaidjan Province, northwest Iran. The most important lithologic units in this area include sandstones and red-color shales, with the Late Miocene age, that are intruded by lamprophyric dike. The copper mineralization in the study area occurred as stratiform laminations and disseminations hosted by sandstones and shales and as open-space filling textures within lamprophyric dike. The ore mineralization in the sandstones consists of chalcopyrite, bornite, chalcocite, tetrahedrite, covellite, native copper, and cuprite. This study showed that mineralization is associated with weathering and leaching of the lamprophyric dike. Also, deposition of copper in sandstone units can be related to trapping of organic matters. Activity of the hydrothermal fluids,  presence of abundant organic matters, function of diagenetic processes, existance of the geochemical barriers (organic matter and silicification), and the active tectonic in the area played crucial roles in this ore mineralization.

---

Mehdiabad zinc-lead-barite deposit is located in the Central Iran structural zone and about 116 km southeast of Yazd. The host rock of this deposit is Lower Cretaceous dolomitic limestone of the Taft Formation . The main ore minerals in the Mehdiabad East Ridge ore zone include hemimorphite, hydrozincite, cerussite, and chalcophanite. Ore textures are mainly replacement, brecciated, and open-space filling. As a result of supergene and weathering processes, the sulfide minerals (sphalerite and galena) have been changed to non-sulfide minerals such as hemimorphite, hydrozincite, and cerussite. Statistical analysis of geochemical data indicates that the elements in the ore could be divided into three groups: terrigenous, host rock-forming, and ore-forming elements. Formation of iron-rich dolomite, ankerite, and siderite indicates high concentrations of iron and manganese in the mineralizing fluid. Based on this study, the characteristics of the Mehdiabad deposit are very similar to the Mississippi-Valley type deposits.
 

---

In the south and south east of Kaleybar city, lamprophyric dykes associated with basanitic and andesitic dykes intruded in the Cretaceous-Paleocene flysch-type and volcanic rocks. The lamprophyric dykes show typical lamprophyric texture with biotite and pseudomorphs of clinopyroxene phenocrysts. According to mineralogy and geochemistry, the studied lamprophyres belong to calc-alkaline group and are minette. The studied lamprophyres show enrichment in the large ion lithophile and light rare elements and depletion in the high field strength elements. Geochemical features of the studied lamprophyres confirm that they are originated from 1-3 % partial melting of a garnet lherzolite mantle source with phlogopite veinlets that previously have been metsomatized by subduction related melts. According to biotite crystals Ar-Ar dating, the studied lamprophyres emplaced during Middle Oligocene (31-32 Ma.) in a volcanic arc tectonic setting.  

---

The Guydash Fe deposit is located in the south of East Azarbaijan Province, about 27 km southwest of Qara Aghaj city at the northwestern parts of the Sanandaj-Sirjan zone. This research was conducted to study the mineralogy of the ore and the geochemistry of the intrusive bodies producing skarn mineralization. A set of granitoids with porphyry diorite-monzodiorite and porphyry granodiorite-monzogranite compositions have intruded  into the Jurassic carbonate rocks and caused iron skarn mineralization. The ore is composed dominantly of magnetite with subordinate minerals including hematite, pyrite, chalcopyrite, tetrahedrite, tennantite and goethite. The skarn zone includes various minerals of garnet (grossular and andradite), pyroxene, chlorite, epidote, actinolite, calcite and quartz. This mineral assemblage indicates that the skarn is calcic. In the geochemical diagrams, skarn-producing igneous rocks locate in granite and monzodiorite fields. All of these rocks are calc-alkaline, diorite rocks are meta-aluminous, and granodiorite rocks are per-aluminous in nature. Granodioritic rocks are adakite-type with high silica, and dioritic rocks are ordinary calc-alkaline type. The enrichment of Rb, Th, Ba and U, and the depletion of Nb and Ti elements in these rocks relative to the primitive mantle is comparable to the rocks derived from subduction zones. The chondrite-normalized REE patterns are almost similar for the studied rocks, indicating their richness in light rare earth elements (LREE) compared to heavy rare earth elements (HREE). The La_N/Yb_N ratio in these rocks indicates the absence of garnet at the source site and the shallow depth of magma formation. Granodiorite-producing magma is obtained by melting of the thinned lower crust. The Nb/Zr and Sr/Ce ratios in these rocks reveal that magma was formed by melting of the subducted crust and the sediments on it. The studied rocks fall in the category of igneous intrusions relating to magmatic activity in the active continental margin, in a continental arc.