Characterization of "Xisto" as a Way to Promote its Use as Natural Stone

Abstract

The main objective of this work was to contribute to the knowledge of the geological resources of Trás-os-Montes and Alto Douro (TMAD) region, in particular of its “Xisto” (Portuguese word for “schist”, lato sensum), considering its economic and social impact. The target area is characterized by the abundant occurrence of different types of “schist”, belonging to the Variscan basement. This work is a contribution to improve the knowledge about mineralogy, fabric, chemistry and technology of the “schist”, in order to promote its exploitation and use as a natural stone. It was possible to identify the main factors that have an influence on the characteristics of all types of “schist”, conditioning its use as natural stone.

"Schist" from Trás-os-Montes and Alto Douro (NE of Portugal): Potential Use as Natural Stone

“…Method A Wide Wheel Abrasion Test (Capon machine) Very high (1) Public use ≤ 0.8mm ≤ 18.0mm High (2) (1) Includes traffic of heavy vehicles and other cargo transport vehicles. (2) Includes occasional traffic of emergency vehicles and cargo transport vehicles.…”

“…For flexural strength obtained with the load applied perpendicularly to the schistosity planes, the requirements indicated in Table 4 should be considered. (1) Public use (3) ≤ 0.8mm ≤ 18.0mm…”

“…Collective use (4) ≤ 5.5mm ≤ 24.5mm Low Private use ≤ 9.5mm ≤ 30.0mm (1) Includes traffic of heavy vehicles and other cargo transport vehicles. (2) Includes occasional traffic of emergency vehicles and cargo transport vehicles.…”

“…The project was coordinated by the Geology Centre of Oporto University and carried out for about four years between 2007 and 2011. The first task was the selection of the target areas [1]. Afterwards the lithologies to be studied were set up.…”