Temporal-spatial analysis of alkaline rocks based on GEOROC

摘要

Alkaline rocks account for a small proportion of magmatic rocks with characteristics of the linear distribution, and can reveal the tectonic setting and in source mantle compositions. Based on the GEOROC global geochemical database, we studied the temporal-spatial evolution of alkaline rocks in the world through GIS spatial analysis and data statistical analysis techniques. The results show an abrupt increase of alkaline volcanic magmatism in the Cenozoic from the Mesozoic and Paleozoic, with the volcanic intensity in the Cenozoic being close to 100 times higher than the Paleozoic. The basalts fall mainly in the basanite and phonolite fields in the Total Alkali-Silica (TAS) discrimination diagram. Spatial analysis suggested that the Cenozoic basalts were usually produced along plate boundary or correlated with mantle-plume-related hot spots.