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Browsing by Author "Rocha, Pedro Ferrara Pires da"

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  • Characterization of the sedimentary deposit of the Costa da Caparica inner shelf as a tool to support coastal management
    Publication . Rocha, Pedro Ferrara Pires da; Veiga-Pires, C.; Drago, Teresa
    Currently 60% of the global population is concentrated in the coastal zone and 75% of the coast is dominated by sandy beaches, thus, the susceptibility of these environments to anthropogenic impact as coastal erosion increases is unquestionable. One common and effective measure for minimizing beach erosion, which has global appeal, is artificial sand nourishment. However, locating a good sediment borrow area especially inland, has become very difficult. Offshore sediments are identified as a good solution. Hence, this study had the objective to do the characterization and definition of sedimentary units of 12 cores (3 meters long each) located between the water depths of 21 m to 27 m of the offshore borrow area of Costa da Caparica, aiming to be used for beach nourishment. Mean grain-size, carbonate content, kurtosis, sorting, skewness and the textural composition are used to characterize and define the sedimentary units of each core. The 3 meters length cores were analyzed with a resolution of 25 cm. A multivariate statistical (PERMANOVA, MDS, Cluster, SIMPER and PCA) approach was used to support the definition of the sedimentary units. The results showed four different sedimentary units. The Unit 1 characterized by medium and fine sand, the Unit 2 by coarse sand, the Unit 3 by fine sand and the Unit 4 by fine and medium sand. Unit 2 is the most observed unit, followed by the units 1, 3 and 4. The PERMANOVA showed significant difference (p < 0,05) between the sedimentary units corroborating with the units definition. The PCA showed correlation to medium and coarse sand with the Units 1, 2 and 4 and to fine sand with the Unit 3. The borrow area shows 3 compatible sedimentary Units, the Unit 1, 2 and 4 which can be used in future nourishment projects in Costa da Caparica.
    2020-12-15Master thesis Open access Show more