Volcanics Geochemical Analysis In Yingcheng 3 Formationin Of Anda Subsag

In this paper, Based on a great quantity of petrographic thin section analysis,geochemical analysis,and previous research results, and other information on the Anda Subsag conducted a series of three sections of volcanic rocks and classified into named. Studies have shown that the purpose of the group of igneous rocks in the layer of business development with lava and pyroclastic igneous rock two categories. Lava type according to the base nature of the basic and neutral can be divided into basalt, basaltic andesite, andesite and trachyte stomata six types, pyroclastic rocks can be divided into narrow pyroclastic rocks, Shen pyroclastic rocks, since the broken pyroclastic rocks ,pyroclastic lava, sub-diabase porphyry and sub-diabase. six categories, according to neutral, basic and further divided into 14 different rock types. According to geochemical data for igneous rock samples representative of the study area were full analysis of silicate, SiO₂ content of up to 64.4%, the lowest 41.2%, with an average of 49.4%. According to SiO₂ content available in the region, the basic igneous rock mainly. By the relationship between the SiO₂ and K2O volcanic rock series of the study area divided in order to calc-alkaline series of volcanic rocks in the area mainly volcanic rock containing a small amount of high-K calc-alkaline series of volcanic rocks and the very small amount of potassium series, very few for the shoshonitic series. The main elements in volcanic rocks in this area SiO₂ and K₂O, Al₂O₃ was an indisputable positive correlation, and Na₂O, MgO, P₂O₅, CaO, MnO, Fe₂O₃ radiate a negative correlation. Sr content of trace elements in there is a positive anomaly. Similar outbreak in this area, overflow compared to development; seismic profiles has obvious Yamaguchi lit dome shape, with the phase axis poor continuity of its internal brought to arch clutter reflection structure. Composite lithology, lithofacies analysis of the volcanic eruption pattern in this area as the center-type eruption. According to core observation description, microscopic identification, logging curves, seismic reflection characteristics, etc., will sag Anda sub-volcanic rocks in the region is divided into six sub-phase 18-phase. In the area mainly come from the crust and mantle magma mixing and mantle-derived melt; basic volcanic rocks formed in island arc and active continental margin environment.