Variations of physico-mechanical, mineralogical and geochemical properties of marble under the influence of weathering

N.O. Ogunsola¹, A.I. Lawal¹, M.A. Saliu¹

¹Federal University of Technology Akure, Akure, Nigeria

Min. miner. depos. 2019, 13(1):95-102

https://doi.org/10.33271/mining13.01.095

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ABSTRACT

Purpose. To investigate the physico-mechanical, mineralogical and geochemical properties variations of Igbeti marble, south-western Nigeria under the influence of weathering.

Methods. About twenty representative samples were collected at a varying depth up to a depth of 30 meters from the study area. The samples represented a group of unweathered, slightly weathered, moderately weathered and highly weathered rocks using weathering classification indices. Thin sections were prepared for textural and mineralogical studies of the rock samples. The chemical composition analyses of the rock samples were conducted using X-ray Fluorescence spectrometry (XRF). The physico-mechanical properties were also evaluated.

Findings. The results showed that noticeable mineralogical and chemical changes occur in the rock fabric because of the increase in weathering state. The laboratory tests result also revealed that weathering reduces the strength of the rock.

Originality.The transformation of physical and mechanical properties of rocks because of weathering is a major concern to the geotechnical engineers. These properties have been investigated by the researchers, but the majority of the available researches were conducted on weathered sedimentary and igneous rocks while that of metamorphic rock is very scarce. Hence, this study investigates the influence of weathering on physico-mechanical, mineralogical and geochemical properties of Igbeti marble, south-western Nigeria.

Practical implications. The obtained results show that the transition of selected rock properties as a result of weathering would significantly affect slope stability and performance of the rock in engineering applications.

Keywords: marble, weathering, physico-mechanical properties, mineralogical properties, thin section, XRF, geochemical studies

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