New petrological data on the volcanic rocks of the Chichinautzin region: The sources of the magmatic melts and the origin of the Trans-Mexican volcanic belt

Abstract

New petrographic, isotopic-geochemical, and mineralogical data are presented for the volcanic rocks of the Chichinautzin region of the Trans-Mexican volcanic belt (TMVB). The geological setting and the peculiarities of the composition of the volcanic rocks from different regions of the belt are compared to the plume-related volcanic rocks from the areas of the Gulf of California, Central America, and the Galapagos hot spot. It was concluded that the composition of the intraplate rocks from the western and eastern parts of the TMVB was subjected to the Californian and Galapagos plumes, respectively. In its turn, the ascending mantle plumes provoke melting of the subcontinental lithospheric mantle related to the formation of islandarc rocks. The model of the consecutive propagating rifting in the eastward direction suggested by some researchers (Marquez et al., 1999; Verma, 2001) instead of the subduction hypothesis is in agreement with the geological and geophysical data and the isotopic-geochemical peculiarities of the volcanic rocks within the TMVB.