CONTROLLING FACTORS AND SIGNIFICANCE OF EARLY CRETACEOUS VOLCANOSTRATIGRAPHIC FRAMEWORK IN NORTHERN DAXINGANLING REGION: A case study of Kuxi volcanotectonic depression

Huge area of acid-intermediate volcanic rocks, most of which belong to Early Cretaceous Guanghua age, are distributed in Northern Daxinganling region. Because of heavy coverage, the division of strata is difficult. This paper, taking Kuxi volcanotectonic depression as example, discusses the forming and evolution of the volcanotectonic depression, the magmatic evolution and its control to the voicanostratigraphic sequence. The magmatism and the evolution of volcanotectonic depression are both continuous and irreversible. The lithochemistry and geochemistry vary with the volcanostratigraphy, which is controlled by the magmatism and the evolution of volcanotectonic depression. The forming and evolving process of magma is quantitatively simulated using lithochemical inverse method. Based on such result, combining with the control of the volcanotectonic depression to volcanic facies in different forming stages and correlation of different areas, the superimposition regularity of the volcanostratigraphy is determined. The regional volcanostratigraphic framework of Northern Daxinganling region in Early Cretaceous Guanghua age is established.