Algunos aspectos de los basaltos y andesitas cuaternarios de Michoacán oriental
The Quaternary eruptive dynamics from northeastern Michoacan allowed the identification of two types of events. The first one is widespread and it is represented by cinder cones and flows; the second one was found to have a local distribution (Valle de Santiago region) and it is characterized by the presence of explosion craters Xalapascos or maars.
The rock mineralogy is essentially homogeneous. It is constituted by plagioclase, olivine, orthopyroxene, clinopyroxene and oxides of Fe-Ti. These lavas exhibit a variable microscopic texture that led to the large petrographic diversity in these rocks.
Major elements show the predominante of basic terms, which has permitted the identification of three groups with a chemical character as follows: 50-58%. 48-55%, and 56% of SiO2. This aspect agrees with the petrographic variability defined herein, the two first terms are the most abundant in the field... In order to continue, download the full paper in PDF.
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