Study on the direction effect of terrane accretive orogeny and biological evolution during the Jinning–Chengjiang period in the northwestern margin of the Yangtze block

Abstract

In the various stages from life chemistry to biological evolution, major geological events are usually accompanied by the extinction of species and the gestation of new life, which are important factors that determine the direction of ecological evolution. The study of the terrane accretive orogeny during the Jinning–Chengjiang period has had a great impact on the crustal rock composition, the atmospheric environment and the water circulation system, etc. The living environment of the primitive biological community has undergone tremendous changes; for example, the crust produced a superimposed contraction and extensional rift effect, resulting in collisional magmatic activity and strong earthquakes, and a large number of species became extinct. In turn, biological activity and organic matter also contributed significantly to migration. Given the periodic cycle of geological processes, and being fully utilized by nature, the origin and evolution of life grow in a spiral. Based on the analysis of the petrochemical composition characteristics of metamorphic volcanic–sedimentary rock series and intermediate-acid intrusive rocks in Pengguan terrane, this paper proposes that the subduction mechanism of oceanic crust in the study area is formed by the NW subduction of the Longmenshan–Anning oceanic crust on the SE side. The relationship between the average change of chemical composition of the diabase in the Masongling and Xinkaidong areas and around the world, ion radius and compressibility, shows that when the element ion compressibility is less than 4.46 compared with the average world value, the oxide content of Si, Ti, Al and P is markedly lower, while when it is equal to or greater than 4.46, the oxide content of Fe, Mn, Mg and K increases, as opposed to that of Ca and Na.