Characteristics of Volcanic Rock In The Bualemo Area, North Gorontalo District Based On Petrographic Analysis

Abstract

The research was conducted in Bualemo Area, Kwandang District, North Gorontalo Regency. The aim of this study was to analyze the petrogenesis of volcanic rocks in the Bualemo Area, North Gorontalo Regency. A mapping technique was utilized in this work to assess the geological conditions of the research site, and petrographic analysis was used to assess the mineral content and rock texture. The findings revealed the stratigraphy of the research region, including an altered andesite unit, an andesite unit, and an alluvial deposit unit, when sorted from old to new. The results of the petrographic analysis show that the rock has a cumoloporphyritic texture, with phenocryst (25%) consisting of plagioclase (60%), k-feldspar (30%), and pyroxene (7%). Pyroxene minerals are all present as phenocrysts, measuring 0.5-0.8 mm, in subhedral-anhedral shape, measuring 0.5-1.5 mm, phenocrysts are starting to turn into secondary minerals, and some are present as relict minerals. The groundmass (75%) consists of predominant plagioclase and minor K-feldspar. The rock is basaltic andesite.