Clay resources in the Nelas region (Beira Alta), Portugal: A contribution to the characterization of potential raw materials for prehistoric ceramic production

R. Marques (Corresponding Author), Ana Jorge, D. Franco, M. I. Dias, M. I. Prudencio

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Mineralogical and chemical compositions of residual and sedimentary clays (bulk and <2 µm fraction) from the Nelas region (schist, aplite-pegmatites, granites and Tertiary sediments from both Mondego River margins), Portugal, were studied, aiming to establish indicators for raw materials in ancient ceramic provenance studies. The mineralogy of bulk material does not provide a clear distinction between samples. Among clay minerals, kaolinite dominates, except in the aplite-pegmatites where illite prevails. Smectite was only found in sediments of the left river bank.

A more successful result was the geochemical differentiation of clay types. The weathered schist presents greater enrichment in Cr, whereas the clay fraction of aplite-pegmatites shows enrichment in all the chemical elements studied. The sediments and weathered granites are not easy to differentiate; the best geochemical indicators are U (lower contents in clay-size fraction of sediments) and REE patterns in both bulk and clay-size fraction.

Mineralogical and chemical compositions of residual and sedimentary clays (bulk and <2 µm fraction) from the Nelas region (schist, aplite-pegmatites, granites and Tertiary sediments from both Mondego River margins), Portugal, were studied, aiming to establish indicators for raw materials in ancient ceramic provenance studies. The mineralogy of bulk material does not provide a clear distinction between samples. Among clay minerals, kaolinite dominates, except in the aplite-pegmatites where illite prevails. Smectite was only found in sediments of the left river bank.

A more successful result was the geochemical differentiation of clay types. The weathered schist presents greater enrichment in Cr, whereas the clay fraction of aplite-pegmatites shows enrichment in all the chemical elements studied. The sediments and weathered granites are not easy to differentiate; the best geochemical indicators are U (lower contents in clay-size fraction of sediments) and REE patterns in both bulk and clay-size fraction.
Original languageEnglish
Pages (from-to)353-370
Number of pages18
JournalClay Minerals
Volume45
Issue number3
DOIs
Publication statusPublished - 1 Sep 2010

    Fingerprint

Keywords

  • clay minerals
  • geochemistry
  • rare earth elements
  • mineralogy
  • archaeometry
  • Nelas Region
  • Portugal

Cite this