The vale das fontes formation in the alcobaça area (Lusitanian basin, portugal): Organic petrology characterization and thermal maturation [A Formação de Vale das Fontes na área de Alcobaça (Bacia Lusitânica, Portugal): Caracterização petrológica e maturação térmica]

• Tipo: Artigo em Revista Científica Internacional
• Data: 2014

Autores

Pereira, JL (Autor) Outra; Goncalves, PA (Autor) Outra; Mendonca Filho, JG (Autor) Outra; Flores, D (Autor) FCUP

Revista

Título: Comunicações Geológicas

Vol. 101

Páginas: 533-536

ISSN: 0873-948X

Editora: LNEG - Laboratório Nacional de Energia e Geologia

Indexação

ISI Web of Knowledge

Scopus - 2 Citações

Outras Informações

ID Authenticus: P-00G-53P

Abstract (EN): The Lower Jurassic of the Lusitanian Basin (Portugal) is characterized by marly-limestone sedimentary deposits, rich in organic matter (OM). This paper focuses on the study of the Vale das Fontes Formation (Pliensbachian) in the Alcobaça area. Its objectives are the petrographic characterization of the OM and evaluation of the thermal maturation based in organic petrographic analysis, such as vitrinite (%Rr) and solid bitumen reflectances and the identification of maceral groups, and organic geochemistry analyses, such as total organic carbon (TOC) and insoluble residue (IR). The petrographic analysis shows that OM belongs mostly to a type II kerogen. The mean random vitrinite reflectance ranges between 0.56-0.70 %Rr. The interpretation of solid bitumens reflectance and their optical characteristics allowed to distinguish three different families. The solid bitumen family with the lowest reflectance, which values range between 0.39-0.65 %Rr, was classified as grahamite. The solid bitumen families with reflectance values between 0.72-0.85 %Rr and 1.04-1.61%Rr were classified as impsonites. The vitrinite reflectance indicates that the OM is thermally mature. TOC values range between 0.55-2.91 wt.%, pointing out a fair to very good content of organic carbon. IR values lower than 50% confirms the presence of carbonate sediments. © 2014 LNEG ¿ Laboratório Nacional de Geologia e Energia IP.

Idioma: Português

Tipo (Avaliação Docente): Científica