The FORUMAD OPHIOLITE in the northwestern part of the Sabzevar region has embraced the large depleted harzburgites and dunitic bodies associated with podiform chromitites. In some deposits, chromite grains have segregated as nodules. The stretched shape along with high Cr2O3 and TiO2 contents are the characteristics of the nodules. Compared to the other Tethyan nodular chromites, the FORUMAD nodular chromites show high Cr content. The nodules formation seems to be the result of turbulent picritic magma flows accompanied by the water rich fluids.

FORUMAD area is located in NW of Sabzevar, in NE of central Iran structural zone and in western part of Sabzevar OPHIOLITE suite. The mantle section of FORUMAD OPHIOLITE consists mainly of harzburgites, dunites, pyroxenitic dikes and choromititic lenses that contain brown to black Cr-spinels. The content of Cr2O3 and Al2O3 of Cr-spinels in harzburgites are between 32. 6-53. 1 and 15. 6-34. 8 wt%, respectively, and their Cr# ([100 × Cr/(Cr + Al]) atomic ratio]) is between 39-69%. Relationship between Cr# of Cr-spinels and Fo of coexisting olivine (Fo=91-92%), and orthopyroxene and low contents of TiO2 (<0. 06 wt%) indicating that harzburgites fall whitin the olivine-spinel mantle array (OSMA), and plot in abyssal and forearc peridotites fields and are residual of moderate degrees of partial melting (about 15 to 26%) from moderately depleted mantle. But, the content of Cr# in Cr-spinels of dunites, chromitites and pyroxenites are high (between 81-. 85%), and associated to boninitic melts and indicate that formed by high degrees of partial melting. Consequently, minerals chemistry of Cr-spinel, clinopyroxene, orthopyroxene and olivine of mantle section from FORUMAD OPHIOLITE indicate that genesis of this OPHIOLITE have been involved in a suprasubduction zone, and developed as a result of northward subduction of the sea/ocean of the Neo-Tethys in response to the convergence between the Central-east Iranian microcontinent and Alborz (Turan) plates.

The FORUMAD OPHIOLITE pillow lavas crop out at west of Sabzevar and at the periphery of north central Iran microcontinent. These lavas include Upper Cretaceous pelagic limestone with microfossils and are classified in two Late Turonian-Santonian and Coniacian-Late Campanian groups. These basaltic pillow lavas have tubular and flattened forms, with external (vitrified), medial (variolite) and internal (intergranuler) parts. Each part has its own texture with mineral composition of clinopyroxene ± plagioclase ± olivine. The medial part is characterized by formation of skeletal crystals of olivine and lesser extend of plagioclase, indicating high nucleation rate. The nature of Late Turonian-Santonian lavas is tholeiitic and Coniacian-Late Campanian lavas are tholeiitic and calc-alkaline. Despite of enrichment in LILE, relative depletion of HFSE, different enrichment in LREE and various linear trends of HREE which suggest the formation of pillow lavas in the arc environment and the heterogeneous mantle with varying degrees of partial melting, but low ratios of Th/ Yb, La/ Nb, Ce/ Nb and Ce/ Th indicate that they are more inclined to intermediate between IAB and MORB environments. Unlike Late Turonian – Santonian lavas, high ratios of La/Yb, Nb/ Yb in Late Coniacian – Late Campanian lavas represent mantle fertility and decrease of Nb/ Ta ratios as well as relative increase of Th exhibit the effect of partial melting of subducted slab in genesis of these lavas. The depth of partial melting was 40 to 70 km in the spinel lherzolite stability zone. It seems that the formation of FORUMAD ophiolitic pillow lavas is accrued in a marginal basin to a back arc basin of a supra-subduction zone.

Tested water samples taken from the OPHIOLITE region of FORUMAD show that most of the concentrations of calcium, magnesium, sodium, sulfate, potassium, bicarbonate, and nitrate elements are in the standard range. Hydrogeochemical studies of the water samples show the existence of magnesium sulfate, chloromagnesium, and chlorosodium. Results of measuring the physical properties of the water shows that the above values were lower than the 1053 standard of Iran and water hardness is higher than the standard in only some cases. Water pH in the studied region is within the alkaline range. Assessing the distribution of heavy metals through statistical methods (Pearson coefficient and cluster graph), two different origins (anthropogenic and lithological origins) have been identified that are responsible for the entry of heavy metals into the water resources of the studied region. The anthropogenic origin of the distribution of heavy metals in the region is due to local mining of the chromite and ophiolitic rocks and the lithological origin is a result of local mining of conglomerate and volcanic rocks. Evaluating the metal index of MI and HPI shows the water contamination by heavy metals. The zoning map shows that the metallic contamination surrounding FORUMAD village is low and reaches its maximum amount around the chromite FORUMAD mine. The qualitative index of GQI (non-metallic cations and anions including calcium, sodium, chlorine, magnesium, sulfate, and dissolved solids in water) shows that the water quality is within the acceptable range. Based on the zoning map, the water quality GQI index is higher in the downstream around FORUMAD village.

The FORUMADophiolitic rocks as a part of Iran marginal microcontinentOPHIOLITEs have been situated in the western part of SabzevarOPHIOLITE. Field study shows extrusive sequence in this area with Late Cretaceous in age. This sequence has included basaltic pillow lavas with radiolarian chert related to Late Turonian-Santonian, in contrast to Coniacian- Late Campanian age, when this sequence has composed of basaltic pillow lavas in lower - middle part and various tuffs in upper part. Sheet flows, hyaloclasticbreccias and pelagic limestone are intercalations between lavas and tuffs.Abundantly, pillow lavas with phyric texture are most predominant feature contrast with sheet flows. Whereas enrichment of LILE and depletion of some HFSE (Nb, Ta) exhibit subduction environment (island arcs) for pillow lavas of FORUMAD, and different enrichment in LREE to HREE displays unhomogenous mantle in the generation of them; the presence of two magmatic nature in lavas (tholeiitic and calc-alkaline), their positions in tectonomagmatic diagrams and clear enrichment of Th element in Late Turonian –Santonian lavas which are generally exhibition of ophiolitic extrusive sequence in FORUMAD area have been generated in a supra-subduction environment and back-arc basin.

Background: The FORUMAD chromite area from Sabzevar OPHIOLITE belt, Northeastern Iran, is an environment with high concentration of heavy metals, particularly chromite and magnesite minerals, containing chromium and magnesium.Objectives: In this study for the first time, we analyzed and report the diversity of microbial (bacterial and archaeal) community inhabiting in FORUMAD chromite mine environment using metagenomics approach.Materials and Methods: Samples were obtained from different areas of the mine, and total DNA was extracted from water and soil samples. 16S rDNA was amplified using universal primers and the PCR products were cloned in pTz57R/T plasmid. Then, 43% of the positive clones were randomly sequenced. BLAST program in NCBI and EzTaxon databases were used to identify similar 16S rDNA sequences. Phylogenetic analysis was performed using the MEGA5 software and multiple alignments of sequences.Results: In the phylogenetic analyses, proteobacteria, which contains many heavy metals tolerant bacteria especially chromium, were the dominant population in bacterial libraries with Rheinheimera and Cedecaeas the most abundant genuses. Other phyla were Bacteroidetes, Firmicutes, Verrucomicrobia, Chloroflexi, Actinobacteria, Acidobacteria, Cyanobacteria, Gemmatimonadetes, and Planctomycetes. In the archaeal clone library, all the sequences were related to the phylum Thaumarchaeota. Further, 68.6% of the sequences had less than 98.7℅ similarity with the recorded strains which could represent new taxons.Conclusions: The results showed that there was a high microbial diversity in the FORUMAD chromite area. These results can be used for detoxification and bioremediation of regions contaminated with heavy metals, although more studies are needed.

The Siah-Cheshmeh OPHIOLITEs at the north-northwest part of the Khoy OPHIOLITEs show a dismembered pile of metamorphic units, mantle sequence, and basaltic-andesitic lavas associated with Late Cretaceous pelagic limestones and cherts. The basaltic-andesitic lavas can be divided into alkaline and calc-alkaline varieties. The presence of Ti-rich amphibole prisms and Ti-bearing clinopyroxenes is characteristic of these lavas. The calc-alkaline lavas are characterized by enrichment in LREE and depletion in HFSE while the alkaline lavas display positive LREE and HFSE anomalies. The interaction between mantle plumes with a spreading center can be considered for generation of alkaline basalts while a subduction zone is responsible for the genesis of calc-alkaline basalts.

The Khoy OPHIOLITE with Precambrian basement rock is located in north western of Iran.The tectonite peridotites are most formed by clinopyroxene harzburgites. These harzburgites characterized by protogranular, porphyroclastic and transformation textures, and composed of olivine (with kink band), orthopyroxene (with wavy extinction and exsolution clinopyroxene), spinel (like Holly – Leaf and shaped) and less than 10% of clinopyroxene. Two stages of alteration occur in these rocks, including static and dynamic. These peridotites are partial melting residual of spinel lherzolites.The Khoy taconite periodontitis show the U-form pattern in the REEs. These patterns are probably related to the partial melting procedures and the process following the partial melting such as influence of felsic magmas after emplacement of OPHIOLITEs.

Sabzevar OPHIOLITE Zone (SOZ) is located in northern Central Iran (north of Great Kavir fault and south of Miamey fault) and separates Kopp e Dagh sedimentary basin (in the north) from the Central Iran plateau (in the South). The evolution and replacement time of this OPHIOLITE complex has been in the Upper Cretaceous) Santonian – Campanian) and the Middle Campanian to Upper Maastrichtian respectively. This OPHIOLITE belt contains a high amount of ultramafic rocks, small masses of gabbros and a thick sequence of submarine basaltic lavas with Upper Cretaceous pelagic limestone and radiolarite, which are angular unconformable and have a base of conglomerates of volcanic and sedimentary rocks. This study examines the brittle structures of SOZ and carries out a geometrical analysis. The purpose of this study is to obtain a suitable structural model consistent with the area structures. In this paper, the geometrical condition is compared with all the area structures and a logical relationship between fractures has been identified. Also the relationship between the regional macro-structures and area fractures has been identified. For this purpose during the field visits and study of the satellite imagery, structures and exposure which make the base of a structural map of the area have been provided.. Then with the surveyed data and provided rose and contour diagrams the main direction of fractures and the pattern of orientation were obtained. This direction is N59W, the same trend as the Miamey fault. The structures in the region are affected by this fault. If this direction is considered the main right-lateral shear trend, other trends are consistent with pattern of fractures orientations Related to fault cutting. Generally the fractures with N14E, N68E, N86E, N77W, N59W and N41W trend, respectively are consistent with type X, R', T, R, D and P fractures.

Ali abad chromites mines (north east of FORUMAD) are as a part of chromites assemblage dependent on OPHIOLITE Sabzevar that are located in NW Sabzevar city. Chromitites deposits in these mines have been located as irregular lenses and layered or banded along with pods of dunite in depleted harzburgite. In attention to mineralogy observation, incongruent melting of orthopyroxenes and exsolution lamellae of clinopyroene in the orthopyroxenes, indicate that these rocks were originally formed at mantle pressures and temperatures conditions. Mineralography study on the textures and structures of Ali abad chromites indicate two types main textures that are primary and secondary. The primary textures and structures include massive and disseminated or separated grain. The milonitic, brecciated and tensional textures are from secondary types in chromites. On the basis of geochemical results the structural formula are calculated as the chromite minerals [(Mg, Fe2+)O (Cr, Al, Fe3+)2O3]. These studies represent height percent Cr2O3 chromite mineral in disseminated texture than massive textures. Geochemical study on the chromitite area, site them in height Cr types and associated to podiform type that are originated from a parent melt with boninitic character resulting from high degree of partial melting of mantle peridotite in Supra Subduction Zone (SSZ).