Centre for Earth and Space Research of the University of Coimbra

Funder

Organizational Unit

Publications

Upper Barremian-lower Aptian charophyte biostratigraphy from Arrifes section (Algarve Basin, Southern Portugal): correlation with dinoflagellate cyst biostratigraphy

Publication . Pérez-Cano, J.; Pereira, H. J. R.; Mendes, Márcia; Pereira, Zélia; Callapez, Pedro M.; Fernandes, Paulo

ABSTRACT: The Arrifes section (Algarve Basin, Southern Portugal) has been studied from the viewpoint of char-ophyte biostratigraphy. The previous sedimentological studies in this section showed that it is built of the interbedding of continental and marine facies that contain both marine and continental palynomorphs (pollen, spores, and dinoflagellates), providing an excellent sedimentary context to perform direct cor-relations between marine and continental domains. In the present work, the identified charophyte biozones have been correlated with dinoflagellate biozones previously recognized in the Arrifes section, being the first time that these two biochronologies can be directly correlated. From the charophyte biostratigraphy viewpoint, two assemblages are distinguished. The older one is found between 65 and 135 m of the stratigraphic section, and it is composed of the species Echinochara lazarii, Atopochara trivolvis var. triquetra, A. trivolvis var. trivolvis, Clavator grovesii var. jiuquanensis, Clavator harrisii var. harrisii, C. harrisii var. reyi, and C. harrisii var. zavialensis. This assemblage belongs to the upper Barremian -lower Aptian Clavator grovesii var. jiuquanensis Eurasian biozone and also to the Ascidiella cruciata-Pseudoglobator paucibracteatus European biozone and it is described in beds with the dinoflagellate cyst Subtilisphaera scabrata (lower to lowermost upper Barremian) and Odontochitina operculata (from upper Barremian upwards). The younger charophyte assemblage is found between 135 and 155 m of the stratigraphic section, and it is composed of the species A. trivolvis var. trivolvis, Clavator grovesii var. corrugatus, Clavator harrisii var. harrisii, C. harrisii var. reyi, and C. harrisii var. zavialensis. This assemblage belongs to Clavator grovesii var. corrugatus biozone, previously assigned to upper Aptian (Clavator grovesii var. lusitanicus biozone). However, in the Arrifes section, this assemblage is found in beds assigned to the dinoflagellate cyst Odontochitina operculata (from upper Barremian-lower Aptian). The direct correlation of the base of the C. grovesii var. corrugatus biozone with the dinoflagellate cyst O. operculata, indicates that the base of the Clavator grovesii var. corrugatus biozone is in the upper lower Aptian, which is slightly older than was previously suggested, and it is extended until the middle Albian.

2023-10Journal article

Open access

Lithostratigraphy and structural setting of the Banda Terrane and Gondwana Sequence on the Northeast of Oecusse Enclave, Timor-Leste

Publication . de Sousa Vicente, Victor Aleluia; Pratas, João; Lopes, Fernando Carlos; Harris, Ronald

ABSTRACT: The limited geological information of the Oecusse enclave, coupled with its geotectonic complexity, makes it difficult to comprehend its geological context. To better understand the lithostratigraphy and tectonics of the northeastern sector of this territory, a new geological map was created, utilizing the interpretation of remote sensing data and field observations. The studied area consists mainly of the Banda terranes of Asian affinity, which partially correspond to metamorphic rocks, with a Jurassic protolith and mostly Eocene metamorphic age, at the base of the Lolotoe Complex, to deposits with basin facies from the Cretaceous (Palelo Group), associated with shallow water limestones from the Eocene (Dartollu Limestones) and to an Eocene-Pliocene volcanic series (Manamas Group). These units constitute of the thrust pile of a duplex of horse thrusts of Australian affinity (Gondwana Sequence), dominated by shallow-water Triassic silts, clays and carbonates. The roof thrusts have a NW-SE orientation and are linked by left lateral tear faults NE-SW oriented.

2025-04Journal article

Open access

Viagem à volta do mundo com a Geologia : análise de 611 questões de exames nacionais (2008-2021)

Publication . Barata, Carlos; Silva Marques, Carla Sofia; da Silva Lopes, Betina; Carvalho Soares, Diana; Abrantes, Isabel; Gomes, Ana; Lopes, Fernando Carlos; Gomes, Elsa; Callapez Tonicher, Pedro Miguel

RESUMO: Este estudo procura compreender a importância dada à georreferenciação de situações reais nas questões de Geologia dos Exames Nacionais (EN) de Biologia e Geologia (BG) portugueses e contextualizá-la com o currículo. Estes exames são obrigatórios para a conclusão da disciplina bienal de BG (10.º e 11.º anos) dos Cursos Científicos e Humanísticos, podendo ainda constituir um requisito obrigatório ou facultativo para o acesso ao ensino superior. Para tal, analisaram-se os grupos de questões de Geologia de 39 EN realizados entre 2008 e 2021, os quais revelaram que a maioria dos grupos de questões de Geologia são enquadrados em cenários científicos georreferenciados (93,6%), sendo os Açores a região citada mais frequentemente. O presente estudo transmite a importância de situações reais, em particular do arquipélago dos Açores, para os conteúdos de Geologia lecionados nos 10.º e 11.º anos, considerando os atributos geológicos desta região e a sua presença frequente nos EN portugueses.

2025-04Journal article

Open access