“Granitos colgados”

A practical term for studying weathering profiles in the south of the Cedeño municipality, Venezuela

Abstract

This study explains the formation mechanisms of “granitos colgados” (literal translation in Spanish), a practical and informal term that describes the rock boulders with a spherical or ellipsoidal shape that resist weathering and remain isolated within a matrix of more altered material. These rock remnants, referred to in the geological literature as residual boulders or their Anglo-Saxon synonyms: corestone and woolsacks, are commonly observed in the Los Pijiguaos bauxite mine, Bolívar State, Venezuela, in the saprolite within the leaching zone or washing zone of the weathering profile of the Parguaza Granite. The formation of granitos colgados is a multifactorial process driven by spheroidal weathering, influenced by two key factors: the structural geological history, with its fractures (joints and faults), and the humid tropical climate typical of present-day Guayana. Knowledge of these processes is essential to understanding the practical and informal term granitos colgados that is proposed to describe these occurrences throughout the vast area of ​​the Lower Parguaza river basin, Cedeño municipality, Bolívar state.