The barite and the behavior of REE in its crystallo-chemical structure have been a major category of research done by scientists for a long time. There are various barite mineralization in Northwest Iran. These sediment-hosted resources as a type of tectonic-controlled-vein mineralization bear unconformity to their shale host rocks at Precambrian age (Riphean). The REE geochemical studies are carried out with the aims to investigate the behavior of REE in barite and galena crystal chemistries and to compare them with respect to their host rocks and some certain standards to reach the aims, Eu, Ce, La anomalies, chondorite normalized ratios, and other standards are used. REE evidences revealed discrepancy between barite-galena mineralization and host rocks. Barite crystallized at oxidized environment, but galena at reduction environment; moreover, barite originated from volcanic sources. Finally it seems that the mineralizations are formed under brine and hydrothermal fluid mixing condition.

Delbar metamorphic complex composed of schists, amphibolites and gneisses with migmatitic views belong to Neoprotrozoiec (Precambrian) is located in southeast of Shahrood. Debar metamorphic complex crosscut by at least three series of mafic dikes, with different ages (Precambrian, Jurassic and Tertiary). Jurassic dikes intruded in Precambrian metamorphic complex and upper Triassic - lower Jurassic metamorphosed detrital sedimentary rocks (equivalent to the Shemshak Formation), but not continue in the middle Jurassic sandy limestone and lower Cretaceous (Neocomian) limestones. Amphiboles of the mafic dikes are Edenite type Ca group amphiboles. Barometry based on the Al⁺³ content of the amphiboles indicated 4-5 Kbar presuers equivalent to the final equilibrium of amphiboles, illustrated 14-15 Km depths to the implacement of the studied dikes in the crust. U-Pb Age dating on apatites from the mafic dikes, indicated 152± 35 Ma age which completely confirmed field and stratigraphic relationships. The mafic dikes have alkaline to calc-alkaline nature based on the geochemical characteristics. The parental magma produced from 15% partial melting of a spinel lherzolite mantle source. These mafic dikes generated in a back arc extentional setting related to the continental crust extentions of central Iran caused by Neotethys plate subduction under it. This event is related to the magmatism of early Cimmerian orogeny.