Lamprófiro das Proximidades do Cerro Tupanci, Quadrícula de Arroio São Sepé, São Sepé, Rio Grande do Sul

Abstract

The present paper deals with some petrographical observations on a lamprophyre taht occurs in the vicinity of outerops of acid volcanic rocks – Cerro Tupanci. The geographical setting is to the north of Arroio São Sepé Quadrangue. With the exception of texture detaisl the rock is composed fundamentally by hornblende and plagioclase within a mesostasis of plagioclase, hornblende, quartz a apatite. The secondary formation of chlorite, carbonate, sphene, epidote and opaque minerals was observe.