Institute Dom Luiz

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Interactive computational modelling to improve teaching of physics and mathematics in marine geophysics

Publication . Neves, Rui Gomes; C. Neves, Maria; Simos, T.; Tsitouras, C.

This study discusses the implementation of a learning sequence with interactive computational modelling activities in the context of introductory marine geophysics university courses. The application of two computer modelling systems, Modellus and Mirone, is considered for the introduction of mathematical physics models of interest in marine geophysics to students having only basic level knowledge of physics and mathematics and no prior knowledge of scientific computation. Modellus is used to compute the theoretical depth of the seafloor predicted using the plate cooling model, while is used to manipulate and display actual bathymetric data in the region of mid-ocean ridges. The combination of both software systems is illustrative and insightful of functionalities suitable to develop other computational modelling activities for marine geophysics as well as for other areas of the geosciences.

2020Conference object

Open access

Links between extremes in GRACE TWS and climate patterns across iberia

Publication . Neves, Maria C.

The Iberian region relies heavily on groundwater and is highly vulnerable to climate variability, making it crucial to understand factors influencing water availability. The aim of this research was to assess how large-scale climate patterns affect total water storage anomalies (TWSAs) in Iberia, particularly in relation to persistent droughts and floods. To address this, I analyzed TWSAs derived from a reconstructed dataset (GRACE-REC) spanning from 1980 to 2019, first at the scale of the entire Iberian Peninsula and then across its main river basins. The links between the North Atlantic Oscillation (NAO), East Atlantic (EA) and Scandinavian (SCAND) patterns, TWSAs, and hydrological extremes were quantified using wavelet and principal component analysis. The results reveal that the NAO exerts the strongest multiyear influence on TWSAs, with periodicities of approximately 10 and 6.5 years, particularly in the southern river basins (Tagus, Guadiana, and Guadalquivir). EA and SCAND have stronger influences in the northern basins (Douro, Minho, and Ebro), driving 2- to 3.5-year cycles. Coupled phases of climate patterns, such as NAO+ and EA- (or SCAND-), correspond to extreme droughts, whereas NAO- and EA+ (or SCAND+) correspond to wet conditions.

2025-04-08Journal article

Open access

A glycymeris-rich unit as evidence of a late pleistocene tsunami event from NW algeria: a biostratigraphic, taphonomic, and sedimentological approach

Publication . Doukani, Mohamed Amine; Satour, Linda; Ozer, Caner Kaya; Belkebir, Lahcene; Voelker, Antje; Tedjeddine, Hassane; Landau, Bernard; Uchman, Alfred; Bessedik, Mostefa; Johnson, Markes E.; Hipólito, Ana; Madeira, José; Ávila, Sérgio P.

Compared to the extensive research carried out on the Neogene deposits of the Lower Chelif Basin, the Pleistocene series is still poorly studied, with no detailed lithological succession published to date. This study focuses on the Glycymeris-rich Unit (GRU) along the coastal area of the Hachacha Plateau in Northwestern Algeria. This unit unconformably overlies Miocene, Pliocene, and Pleistocene basements. The latter was identified for the first time in this work using a biostratigraphic approach based on calcareous nannofossils and planktonic foraminifera. The GRU is interpreted as a tsunami-related deposit, formed in a coastal environment (foreshore/backshore) during the upper Pleistocene, corresponding to the Last Interglacial period, i.e., Marine Isotopic Substage 5e (MIS 5e). This interpretation provides a first multidisciplinary description of a tsunami deposit in Algeria that is supported by distinctive biotic, taphonomic, and sedimentological features. The deposits contain a mixture of marine organisms from different ecological zones (supralittoral to shallow circalittoral biocenoses), including molluscan assemblages such as the so-called Senegalese fauna (bivalves and gastropods), sponges, serpulids, coralline algae and corals. Occasionally, rare terrestrial snails are also found mixed with the marine fauna. Taphonomic analysis reveals low percentages of boring, absence of encrustation, and excellent shell preservation, suggesting that powerful waves eroded sediment masses and transported them inland from deeper areas beneath the taphonomic active zone. The predominance of sharp-edged fragmented shells, chaotic arrangements with oblique to vertical shell orientations and the good shell sorting, indicates transport by mass flows and rapid deposition during an extreme event – a tsunami –, distinguishing these deposits from those associated with gradual and oscillatory flows, such as storm events. Sedimentological characteristics, including irregular erosive base, lateral facies variations, wide grain size ranges (clay to boulders), normal and inverse grading, and diagnostic structures (both fragile and hard-rock rip-up clasts, high-energy flow features such as horizontal and oblique laminations, and hummocky cross-stratification, injection of sediment into the substrate, imbrication of large angular boulders and soft sediment deformation structures), combined with the active tectonic context of Northwestern Algeria support the interpretation as a seismically triggered tsunami and enhances the understanding of this type of deposits in similar coastal settings.

2025-11Journal article

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