Abstract The Fariman ophiolite complex is a nickeloferous peridotite and our recent investigations revealed more than 5000 ppm of Ni in Chahrbast area. The nickle deposit associated with ultramafic complexes in the area. This type of deposit is the major source of Ni. The Fariman ophiolite complex in northeastern Iran consists of a well-deformed amphibolite, peridotites (dunite, lherzolite, harzburgite), serpentinized peridotites, gabbros, sheeted dikes, pillow and massive lava and pelagic sedimentary rocks as well as radiolarian chert. The high-grade metamorphic rocks are immediately adjacent to the peridotites and the gabbros. Result suggests that Fariman ophiolite is equivalent to the Sabzevar ophiolite and was formed as a result of closure of the northeastern branch of central Iranian microcontinent. The ultramaphic samples were determined by XRF and XRD to be mixtures of chromite, and Ni-Ti-Cr-Fe oxide/hydroxide compounds. There is still ambiguity about the origin of Ni-Ti-Cr-Fe oxides, but they can be related with Progressive differentiation of liquids residual from basic magma leads to late enrichment in Ni. Typically olivine crystallization results in concentration of Ni. The later alteration will help to more concentration of Ni in the rocks. Primary lithogeochemical haloes in the area quite complex, including both enrichment and depletion zones. These appear to be spatially linked to each other and maybe viewed as a single geochemical system. The forms and sizes of geochemical ore deposit systems vary, ranging from a few hundred square meters to thousands of square meters.

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