Geochemical Characteristics of Metamorphic Basic Volcanic Rocks of the Tanyaokou Ore District,Inner Mongolia and Its Tectonic Significance

In order to investigate the geochemical characteristics of metamorphic basic volcanic rocks of Tanyaokou ore district and its tectonic significance,the occurrence characteristics,petrology,petrochemistry and geochemistry characteristics of metamorphic volcanic rocks are studied.The results show that the primary part of metamorphic basic volcanic rocks is potassic spilite.Geochemical analyses demonstrate that metamorphic basic volcanic rocks are strongly enriched in LREE and incompatible elements and depleted in HREE and other compatible elements,such as Nb,Ta and Ti,and have the similar geochemical characteristics with the volcanic arc basic volcanic rocks.The model of rare earth element(REE) of the basic volcanic rocks shows that its rock-forming elements came from mantle.Based on the research of rock-forming environment and the regional geological researches,it can be confirmed that the metamorphic basic volcanic rocks of Tanyaokou ore district is formed in continental marginal volcanic arc orogenic belt environment.