Enrichmen And Occurrence Of Scandium Of Tiema Rock In Chengde

This article relies on“The Research on The Occurrence of Three Rare Minerals in Chengde,Hebei Province”from Hebei Geological and Mineral On the basis of previous studies,the research on the Tiema rock mass of petrology,mineralogy and petrogeochemistry was carried out by means of thin section examination,electron probe,X-ray diffraction,whole rock analysis,which attempts to explore the occurrence status,enrichment regularities and source of metallogenic material of Sc in the Tiema-rock mass.The research results are as follows:?1?the study results of the lithofacies of the Tiema rock body indicate that the lithology of the Sc-bearing rock body is amphibolite,and its main mineral is hornblende.Microscopically,it can be found that there is slight greenolitization at the boundary of the amphibole speckle,and that the amphibole belongs to the leucite series,and derived from mantle source.Accessory minerals are mainly apatite,magnetite,pyrite and so on.There were no isolated scandium minerals such as scandium yttrisite and beryllium yttrisite both in the hand specimens of amphibolite and under the microscope??2?the geochemical characteristics of the Tiema rock body show that the rock body belongs to the ultrabasic-basic rock type,which is rich in CaO,Al₂O₃ and MgO.The standardized diagram of the rare earth elements chondrite meteorites is generally right-sided,with light rare earth accumulation and heavy rare earth loss.The original standardized cobweb diagram of the mantle shows the characteristics of enrichment of Rb,Ba,Sr and Sc,and relative loss of K,Ti and P.The amphibole is the mantle source amphibole and the magmatic source area is the mantle.Mg^#=0.45.36-0.60,the samples that should have been put into MORB in the t-hf-ta diagram were put into the CAB region.The above two features indicated that the magma experienced separation and crystallization,and was mixed with crustal material.?3?the results of the study on the occurrence status of Scandium in Tiema rock show that Scandium are mainly distributed uniformly in amphibole,and Scandium are distributed in amphibole in the form of homogeneous image.The analysis results of XRD showed that the parameters of amphibolite crystal cells were increased,indicating that Sc replaced elements with bigger ion radius.The clustering analysis results showed that only Mg and Sc were primary affinity factors,and SiO₂,Al₂O₃ and TiO₂ were secondary affinity factors.In summary,mass isomorphism occurs when Sc³⁺and Al³⁺enter the lattice,replacing Mg²⁺and Si⁴⁺in the M1,M2 and M3 positions.Its isomorphism expression is:Sc³⁺+Al³⁺=Ti⁴⁺/Si⁴⁺+Mg²⁺?4?combined with the previous dating data and the results of the tectonic identification map in this paper,it can be seen that the Tiema rock body was formed in the late devonian,and its tectonic background was the tensile envTiemament.Therefore,the Tiema rock body was formed in this period of the north China craton arc-continent impact post-arc extension of the basin.Sc deposit was also formed in this period.The magma from the enriched lithosphere mantle migrated upward under stress,and was mixed with crustal materials,and separated and crystallized to form a clear facies belt.Sc3+occurred in amphibolite in the manner of isomorphism in accordance with goldschmidt's law and enriched ore formation.?5?the research results of the enrichment regularities of Sc show that both the basic level too high or too low are detrimental to Sc enrichment,Compared with analysis in Panzhihua rock mass,Dianzhong rock mass and Tiema rock mass,we found that this kind of ultrabasic containing scandium miscellaneous was formed from different diagenetic ages and origins of rock mass,but had similar magma source area and geochemical characteristics,it is worth noting that that although containing scandium rock lithology is different,but containing scandium rock mass are miscellaneous dark mineral crystallization in the late of rock mass which means that it is crystalline order deciding whether there is scandium,but not the rock lithology.The enrichment mechanism is:in early times scandium ore spread out in the dark mineral grid work,the amount of Sc in dark mineral grid work of this period is large,but Sc is relative dispersed,and when the scandium crystallized in residal solution,the selection of the dark minerals is less,so although the total content of Sc ion in the dark mineral crystal lattice is low,the Sc is relatively concentrated,so as for the ultrabasic complex of mantle magma source area of rock mass,as long as good differentiation occurs,all of the rock masses formed in late crystallization of dark mineral possibly have a certain amount of Sc,likewise,in the complex rock mass known of containing scandium,Sc is more easily concentrated in the basic components.