Ornamental stone potential areas for land use planning: a case study in a limestone massif from Portugal

ABSTRACT: Nowadays, the difficulties of the mining sector in accessing the territory are mostly related to inadequate land use plans. Mineral potential maps have become quite relevant for the land use planning authorities as a decision support tool. This work's goal is to present a methodology based on geological criteria, for the delimitation of potential areas for ornamental stones production in a limestone area of Portugal known as Macico Calcario Estremenho. This is one of the world's most important regions producing limestone blocks for ornamental purposes. The methodology, applied at a scale similar to the commonly used in land use planning, considers two main geological-based criteria for the definition of potential areas, namely the homogeneity criterion, related to the textural and chromatic homogeneity of the potentially productive lithologic units, and the dimension criterion, which refers to the thickness of the productive unit, to the volume of the deposit and to its spatial layout. Based on the criteria, two main types of potential areas for ornamental stones' production were delimited: specific areas, where the lithostratigraphic units demonstrate ornamental suitability at a very local scale due to highly appreciated particular features, and areas corresponding to the entire outcrop area of some of the lithostratigraphic units, which due to the resource volume are the most relevant potential areas.info:eu-repo/semantics/publishedVersio

Rochas ornamentais do Maciço Calcário Estremenho : breve caraterização dos recursos, dos centros de produção e delimitação preliminar de áreas potenciais

O Maciço Calcário Estremenho é uma unidade geomorfológica do país onde afloram em grande extensão rochas de idade jurássica. Particularmente as do Jurássico Médio têm sido alvo de intensa exploração de blocos para fins ornamentais. Tendo como base uma apresentação sucinta de todos os núcleos extrativos desta região do país, mas com ênfase nas particularidades respeitantes às unidades litostratigráficas alvo de exploração em cada um deles, apresenta-se uma demarcação preliminar de áreas potenciais para a produção deste tipo de recursos. Essas áreas, sendo de âmbito regional, servem de apoio à decisão política e estratégica de atuação no território e constituem base fundamental de trabalho a estudos de maior pormenor que visem determinar a sua efetiva aptidão a nível local

Potencialidades das rochas graníticas no concelho de Nisa

O presente texto visa dar a conhecer os resultados obtidos a respeito das potencialidades das rochas graníticas existentes na área do município. Estes resultados foram obtidos no âmbito de um trabalho mais vasto de inventariação, caracterização e avaliação das potencialidades em recursos minerais do concelho de Nisa, o qual foi objecto de um protocolo de colaboração com carácter pioneiro entre a autarquia e o LNEG

The "Alpalhão Granite" (Alentejo, Portugal) as a potential ornamental stone

“Alpalhão granite”, also called SPI, is used as a high quality ornamental stone for interior and exterior applications. It is fine grained and equigranular, and has disseminated feldspar phenocrysts showing a homogeneous bluish grey colour. The SPI was mapped and scanlines (14) and drill cores (4) were carried out for lithofacies and joints characterization, besides petrographical study. Three of the 5 granite outcrops were studied regarding their potential for ornamental blocks exploitation (Carvalhal, Pinheiral and Ribeira de Sor). The Carvalhal area has generally no potential, due to intense fracturing and frequent heterogeneities except for drill core SCA1 area. The Pinheiral area has been exploited in all its extent, but still assures 368,800m3 estimated resources of good granite at depth. Ribeira de Sor area presents a good potentiality for commercial blocks in the eastern zone and a limited potential in the western area due to subsurface fracturing and chromatic changes.</jats:p

Typological classification of clayey raw materials for ceramics manufacture, in the Tábua region (central Portugal)

Mapping of clay resources in the Cenozoic deposits of the Tábua region (central Portugal) has been carried out, together with the chemical, mineralogical and technological characterization of seventeen clay samples. The study was undertaken to relate the lithostratigraphic units and the typology of raw materials with regard to the manufacture of ceramics. The sedimentary succession comprises two units with different suitability for the manufacture of ceramics: an upper unit, with clays that present technological restrictions; and a lower unit with a much greater potential. A small set of parameters has been identified which differentiate the typological units. These parameters allow a realistic estimation to be made of the ceramic properties of any clay layer sampled in the study area. It is anticipated that with minor field work and sampling, the typological column can also be used in adjacent areas

Portuguese ornamental stones

Portugal produces a great diversity of ornamental stones. Besides the internationally known white and pink marbles, also light cream limestones are produced, as well as grey, yellow and pink granites, and dark grey slates. From these, limestones are the most request variety today, especially by the Chinese market