Geological and Structural Controls on Marble Quarrying and Aesthetic Patterns: Espírito Santo State (Brazil)

Abstract

The purpose of this study was the geological characterization of Pit 9 quarry, located in the district of Itaoca, State of Espírito Santo (Brazil). The methodology integrates petrographic, mineralogical, and structural studies. Different types of brittle and ductile structures were surveyed. Structural data were collected at one-meter intervals at the base of the rock slopes, serving as the basis for developing conceptual 3D geological models. Three varieties of marble were identified: calcite, dolomite, and banded. The metamorphic banding is heterogeneous and discontinuous, varying from centimeters to meters in thickness. Its mineralogy consists of carbonates, tremolite, and diopside. The metamorphic banding may also contain disintegrable schistose lenses rich in phlogopite, with a modal attitude of 122/52. Two folding phases were identified, consistent with those described regionally. The marbles are cut by granite and metamafic dikes. These bodies exhibit thin halos of contact metamorphism. Thick felsic dikes cause fracturing of the surrounding rock. At the investigated mining level, the rock mass is poorly fractured and fissures, and non-persistent, tight joints predominate. It can be concluded that the varieties of marble are controlled by the folding pattern, and the intrusive igneous rocks generally degrade rock quality by compromising block physical integrity.