Writers : Vatanpour, Hamid Reza; Khakzad, Ahmad; Vosooghi Abedini, Mansoor; Alavi, Ahmad; Ghaderi, Magid; Usefi, Abbas
Refference : Proceeding of the first applied geological congress of Iran(volume.2)
Publishing Year : 1386

Abstract :
The Sabzevar ophiolitic belt covers a tectonic zone of 200 km length in NE Iran. The northern part of the Sabzevar zone is limited to Alborz and Binaloud mountains and its southern border ends to to the main Kavir Fault. The study area covers Gaft and Foroumad villages in westernmost part of the Sabzevar ophiolite and is situated about 80 km NW of Sabzevar. The main geological units of the area are ophiolitic and non-ophiolitic rocks. The major rock units of the ophiolitic series are serpentinized harzburgite, dunite, gabbro, diabase and some late upper Cretaceous acidic rocks. Tertiary volcanic rocks are the main non-ophiolitic units of the area. The ultrabasic rocks are rich in MgO and have tholeiitic affinity. Other rock types are mainly calk-alkaline.
Chemical composition of the chromite lenses and their host rock do not show significant differences, and this similarity has been observed in the whole area. Generally, chromite lenses are enriched in Cr (>40 % Cr2O3) and poor in Al and Fe. Therefore, their chemical composition is within the range of podiform chromites in known ophiolite complexes.
Chemical composition of the chromite layers indicates that they have been formed by high degree of partial melting. Furthermore, the composition of chromite layers in the area is similar to those found in some neighboring countries such as Turkey, Russia, Greece and Pakistan.
The similarity between geochemical composition, structures and textures of chromite lenses shows that the present broken lenses have been single magmatic layers.
Chemical analysis of alluvial deposits is a good geochemical guide for chromite prospecting. Furthermore, Al2O3 and Cl are the most important indicator elements for prospecting chromite lenses.
Subject List : Chromite