Volume 112 (2025) Fascículo I
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- Identification of saline areas in wetlands using spectral indices and geochemical data. The case of Baixo Vouga Lagunar (Aveiro, Portugal)Publication . Rolo, R. S. V.; Silva, S. M. L.; Medina, Jorge; Patinha, CarlaABSTRACT: The Baixo Vouga Lagoon (BVL) is an important wetland on the Portuguese coastal continent that has been suffering from the destruction of its agricultural fields due to saline intrusion processes. The aim of the research was to identify areas of salinity combining geochemical data and spectral indices obtained from Sentinel 2B satellite images. The methodology was developed using images from July 2023 and February 2024, with samples taken during the same seasonal period. Fourteen spectral indices were calculated: four vegetation indices and ten salinity indices. Pearson's method was used to assess the correlation between geochemical data and the spectral indices. The Canopy Response Salinity Index (CRSI) and Salinity Index 1 (SI 1) showed the highest correlation, at 0.428 and 0.516 respectively. Despite the limitations of using optical sensor in flooded areas, the spectral response of halophyte vegetation in areas of higher salinity was crucial for its differentiation and primary delimitation of the most affected areas.
- The first occurrence of tuna Thunnus sp. (Family Scombridae) in the Miocene fossil record of PortugalPublication . Neto de Carvalho, Carlos; Marrecas, P.; Figueiredo, SilvérioABSTRACT: The fossil record of tunas (tribe Thunnini, family Scombridae) is sparse due to their pelagic lifestyle. Yet such finds are essential for reconstructing evolutionary and biogeographic patterns of these marine apex predators. We report the first occurrence of Thunnus sp. in Portugal, based on a well-preserved caudal vertebra from Burdigalian (Lower Miocene) deposits at Praia da Foz da Fonte (Baixo Tejo Basin, Setúbal Peninsula). The specimen, although recovered ex situ, is confidently attributed to the Lower Miocene shallow-marine succession of the locality. Morphological features—including an amphicoelous centrum, paired lateral foramina, and distinct growth rings—support its assignment to a large scombrid, consistent with the taxon Thunnus. Estimated body length exceeds 284 cm, indicating the presence of large pelagic predators from this genus in Miocene seas of western Iberia. This find represents the earliest tuna record from Portugal and supports a widespread Miocene distribution and diversification of the genus Thunnus across Europe and the Americas.
- Site screening requirements for hydrogen geological storage in saline aquifersPublication . MAZEZO, AUGUSTO; Pereira, Pedro; Al Mala Khudhur, Karwan S AhmadABSTRACT: Underground hydrogen storage (UHS) in deep saline aquifers is a promising solution for large-scale, long-duration energy storage, vital for addressing renewable intermittency and enabling deep decarbonization. This study presents a benchmarking of requirements and a comprehensive framework for site screening of saline aquifers for hydrogen storage. It integrates technical parameters –such as reservoir quality, seal integrity, and geomechanical stability–with non-technical aspects, including economic viability, regulatory readiness, environmental risk, and social acceptance. Particular focus is given to hydrogen-specific challenges affecting storage integrity, especially geochemical and geomechanical factors. Drawing from experience with natural gas and CO2 storage, the study proposes a multidisciplinary screening workflow to support early-stage project assessment. The findings provide a foundation for future pilot projects, policy development, and regulatory frameworks tailored to UHS in porous media, contributing to the strategic expansion of hydrogen infrastructure and energy system resilience.
- Miragaia longicollum MG 4863: New fossil and historical evidence from the most complete stegosaur from EuropePublication . Costa Pinto, Francisco; Maidment, Susannah; Sequero, Cristina; Crespo, Vicente D.ABSTRACT: Additional historical data regarding the original finding and excavation (circa 1958-1959) of the Miragaia longicollum stegosaur MG 4863 has been identified (including field notes and the complete field map), allowing a better understanding of its stratigraphic context. Additionally, osteological material that was previously partially encased in matrix was fully prepared and restored, including anterior and posterior caudal vertebrae, metacarpals, and five semi-complete dorsal vertebrae (the latter being the most significant addition, as these are the only skeletal elements shared by all type specimens of dacentrurine taxa). New anatomical information from these additional elements provides further evidence that M. longicollum is distinct from the closely related Late Jurassic stegosaur Dacentrurus armatus from England (demonstrated mainly by various caudal differences). The newly prepared material further completes what was already the best reference specimen among the Dacentrurinae clade, as well as Stegosauria in Europe during the Late Jurassic, increasing its value to better understand these contexts in future studies.
- Friedrich Welwitsch’s prolegomena of Angolan geologyPublication . Brandão, José Manuel Moraes Vale; Mesquita Soares, SofiaABSTRACT: Recent work at the drill core library of LNEG at Alfragide has brought to light a small collection of rocks and fossils gathered by the Austrian physician and botanist Friedrich Welwitsch during his prolific expedition to Angola (Iter Angolense, 1853-1860) on behalf of the Portuguese crown. The samples were seen and mentioned by Paul Choffat, in 1889, but have remained completely forgotten ever since. Revisiting the samples, this article, which extends the evocation of 150 years of Welwitsch's passing, recalls the scientific partnership with the French naturalist Arthur Morelet, who studied mollusk faunas, and reviews the geological notes taken during the years of herborisations. Considering those notes and samples, it can be said that these pioneering elements in the study of the geology of Angola are, in essence, consistent with the recent knowledge and geological mapping of that territory.
- Zeolites and associated minerals as indicators of post-magmatic hydrothermal alteration in Mesozoic tholeiitic basalts in Northeastern BrazilPublication . Araujo, Lidyane; Castro Jobim Vilalva, Frederico; Franco de Souza, Raquel; Bustamante, Andres; Souza, LaécioABSTRACT: In northeastern Brazil, tholeiitic basalts and microgabbros from the Rio Ceará-Mirim dike swarm and Serra do Cuó basaltic flow experienced post-magmatic hydrothermal alteration, forming secondary minerals that replaced magmatic phases and filled amygdules. Petrographic, X-ray diffraction, thermogravimetric, and chemical analyses identified laumontite, quartz, and calcite as the dominant amygdule minerals in the Rio Ceará-Mirim dikes, formed at temperatures < 150 °C (Stage II) following an earlier low to moderate-temperature (< 150 – 200 ºC) alteration phase (Stage I). In the Serra do Cuó basalts, polymineralic amygdule formation began with mafic phyllosilicates (from < 150 to ~200 °C, Stage I) and proceeded to Ca-Na zeolites (~250 °C, Stage II). These assemblages reflect fluid composition changes due to primary mineral destabilization by heated meteoric fluids. Results indicate fluid composition, rather than temperature, as the primary control on mineral variability, highlighting the role of host-rock chemistry in hydrothermal alteration.
- Oceanos e continentes: no fim dos séculos XV e XX, e no início do século XXIPublication . Ribeiro, AntónioRESUMO: Durante os séculos XV e XVI, os descobridores portugueses substituíram a geografia Mediterrânica pela Atlântica. De algum modo, é possível estabelecer um paralelo com a perspetiva atual da Tectónica de Placas Macias, em que a litosfera oceânica arrasta a litosfera rígida dos escudos pré-câmbricos.