Geochemical Characteristics And Metallogenic Potentiality Of The Baqiuyan Group In Shiquanhe,Tibet

The Shiquanhe area is located on the Shiquanhe ophiolitic mélange belt in the western part of the Bangonghu-Nujiang metallogenic belt.It is closely related to the Bangonghu-Nujiang suture zone,and its tectonic setting is very complicated,while the Baqiuyan Formation volcanic rocks.It is widely distributed in the Shiquanhe ophiolitic mélange belt,which is of great significance for understanding the tectonic evolution of the Shiquanhe joint zone.In this paper,the volcanic rocks of the Baqiuyan Formation in Shiquanhe,Tibet are selected as the research objects.After analyzing the volcanic rocks of the Baqiuyan Formation and combining the Rock geochemistry,we can determine the family of rocks.This article discusses the source of volcanic magma in the Baqiuyan Formation.The diagenesis mechanism of rocks and rocks,and the interpretation of the tectonic setting of the Baqiuyan Formation,in order to restore the original tectonic environment and evolutionary process formed by the volcanic rocks of the Baqiuyan Formation.The Baqiuyan Formation is a metamorphic volcanic rock with a Si O₂ content between 44.5%and 55.56%,combined with the main elemental analysis results and corresponding diagrams.It is known that the original rock should be a medium-basic volcanic rock?Andesite and Basalt?,belonging to the Ca-alkaline series.The metamorphic volcanic rocks of the Baqiuyan Formation as a whole have intermediate-basic magmatic rocks,volcanic rocks?basalts?are characterized by low-potassium tholeiitic basalts,and metamorphic rocks are characterized by medium-low-potassium,medium-basic calc-alkaline magmatic rocks.In the analysis of trace elements,the rocks are relatively enriched in the main body of Ba,K,Sr and other large ion lithophile elements,while the Nb,Ti,P,Ta and other high field strength elements have obvious negative anomalies,Zr shows a slight negative Anomalies imply that the formation of volcanic rocks in the Baqiuyan Formation was affected by the subduction of oceanic plates.The total amount of rare earth in the two types of rare earth element analysis is relatively low,which is obviously different from the OIB characteristics.Both types of rocks are characterized by the enrichment of light rare earth elements and the loss of heavy rare earth elements.The REE curves of basalt and metamorphic rocks are different from the REE curves.The N-MORB pattern,which is similar to the IAB,shows that the volcanic rocks of the Baqiuyan Formation should be similar to those of the island-arc basalt.From the aspect of physicochemical parameters,the magma temperature is in the temperature range of 1025°C-1225°C of the basic magmatic lava flow.From the Ol?-Ne?-Q?triangular diagram,the pressure value is between 1-2GPa.It is estimated that the depth of the magma source area is between 33-60km.It is shown that the volcanic rock of the Baqiuyan Formation has a paleo-Tethys ocean basin.At the time of south subduction and subduction,the northern arc of the Gangdese stretched back to form a post-arc basin environment.From the analysis of trace element characteristics,the magma should be derived from the mantle.The volcanic rocks of the Baqiuyan Formation are controlled by partial melting and segregation crystallization.The main melting is mainly partial melting.Volcanic magma is mixed in the source area to form new magma,and the magma is During the upwelling,it experienced a partial remelting process and finally ejected the surface.The measurement of water sediments and corresponding work combined with metallogenic geological conditions show that the Cu element in the study area has an abnormally high concentration of Cu,with obvious concentration zoning and corresponding copper mineralization points are found,suggesting that the study area has a good prospecting potential.