Caracterização mineralógica do regolito do kimberlito Limeira 1 (Perdizes 4), Monte Carmelo, Minas Gerais

Abstract

Kimberlites are ultrabasic igneous rocks formed by the crystallization of magmas deep in the Earth's mantle, which, as they ascend rapidly, incorporate diverse materials. This study focuses on the mineralogical and textural characterization of the weathering and pedogenesis horizons of the Limeira 1 kimberlite, located in the municipality of Monte Carmelo, Minas Gerais. The methodology adopted consists of: a literature review on kimberlitic magmatism in the Upper Paranaíba, olivine alteration products, and the evolution of the paleoclimate at the site since the Late Cretaceous; the identification and collection of fresh samples, saprolite, and soils related to the Limeira I kimberlite; and the analysis and interpretation of the mineralogy, texture, and chemistry of the grains. Samples from three horizons above the fresh rock were separated into distinct particle size fractions, in which the mineralogy and texture of the different fractions were identified using a bench magnifying glass, an optical microscope, and SEM. The results allowed us to identify the alteration and pedogenetic materials generated from a fresh kimberlite well- known in literature. This information contributes to the understanding of rock and landscape transformation in western Minas Gerais since the Late Cretaceous, the age of kimberlite settlement.