Geochemical Characteristics and Tectonic Significance of Volcanic Rock Blocks in Mianxian Section of Mianlue Tectonic Belt

On the basis of a 1:10000 geological survey of volcanic rock blocks in the Mianxian section of the Mianlue tectonic belt, four types of metamorphic volcanic rock associations are classified based on their rock types, rock association characteristics, and rock geochemical characteristics. Guanyintang volcanic rocks are composed of basic volcanic rocks and acidic volcanoes. The rock combination consists of basalt, dacite rhyolite, rhyolite, etc., belonging to the alkaline rock series volcanic rocks. The rare earth distribution curve of the rock is characterized by a right leaning enrichment of light rare earth elements, with weak δ Eu positive anomaly. The spider web diagram of trace elements shows a rich and uplifted morphology of large ion lithophile elements Ba, U, Sr, and high field strength elements Ta, Zr, Ti, with Th element depletion. The Tudi Temple volcanic rocks are composed of basic volcanic rocks, neutral volcanic rocks, and acidic volcanic rocks. The rock combination includes basalt, basaltic andesite, andesite, coarse andesite, rhyolite, etc., belonging to the tholeiite series, calcium alkaline rock series, and alkaline rock series volcanic rocks. The rare earth curve of the rock is characterized by a strong enrichment of light rare earth elements and a right leaning type, with δ Eu negative anomaly,enriched with large ion lithophile elements Ba, Th, and U, strongly depleted with high field strength elements Nb, Ta, Hf,P, Ti, and trace element spider web with valley peak overlapping morphology. The Xigou volcanic rocks are all composed of medium basic volcanic rocks, with rock combinations such as basalt and basaltic andesite, belonging to the tholeiitic basalt series volcanic rocks. The rare earth curve of the rock leans to the right, with obvious fractionation of light and heavy rare earth elements, not shown δ Eu anomaly, enriched with large ion lithophile elements Sr, Rb, Th, Sm, and some high field strength elements Ta and Zr, but depleted with high field strength elements Nb, Hf, and P. The volcanic rocks in Anzishan are all basic volcanic rocks, belonging to the tholeiitic basalt series volcanic rocks. The rock has a flat rare earth distribution curve, with δ Eu positive anomaly, enriched with large ion lithophile elements Sr, Rb, Ba, characterized by low abundance of high field strength elements Nb, Zr, and Hf, and high abundance of low field strength elements K, Sr, and Rb.Research suggests that they were generated in continental rift environments, continental margin volcanic arc environments,oceanic island environments, and backarc small ocean basin environments, respectively.