Geologia Marinha e Costeira - GMC
Permanent URI for this community
Browse
Browsing Geologia Marinha e Costeira - GMC by Title
Now showing 1 - 10 of 235
Results Per Page
Sort Options
- 3D facies architecture and dynamics of a beach barrier-lagoon complex (Ría de Vigo, Galicia, Spain)Publication . Clemente, F.; Pérez-Arlucea, Marta; Alejo, Irene; Nombela, Miguel Ángel; González, D.; Costas, Susana; Bernárdez, Patrícia; González, R.; González Villanueva, Rita
- Abrupt sea surface temperature changes during The Last Glacial-Interglacial Transition in the Iberian margin: sea level implicationsPublication . Rodrigues, Teresa; Grimalt, Joan O.; Abrantes, Fátima; Naughton, Filipa; Flores, José-Abel
- Active faults and geomorphology in the seafloor between the Gibraltar straits and the Tore-Madeira RisePublication . Terrinha, Pedro; Duarte, João; Valadares, Vasco; Rosas, Filipe M.; Matias, L.; Batista, L.; Gonçalves, João Noiva; Cunha, T.; Silva, S.; Gràcia, Eulàlia; Zitellini, N.Apresenta-se um mapa tectónico das falhas activas e um mapa geomorfologico entre a Crista Tore-Madeira e o estreito de Gibraltar. Classificam-se as falhas do ponto de vista geométrico, cinemático e cronológico. Apresentam-se resultados de modelação numérica e análoga para a interferência de falhas de desligamento dextrógiro (próximas de WNW-ESE/90º) e cavalgamento (NE-SW/SE) e ainda para a interferência destas falhas de desligamento com o prisma acrecionário do Golfo de Cádis. Os resultados experimentais sugerem que no primeiro caso de interferência simulado se formam falhas de coalescência entre os desligamentos e os cavalgamentos, locais onde se concentra a sismicidade registada durante 12 meses por 25 OBS (2006-07). As experiências sugerem ainda que o prisma acrecionário e os desligamentos são ambos activos no presente. Discute-se a partição da deformação e a migração da frente de deformação ao longo da Margem Ocidental Ibérica.
- Alterações recentes nas razões isotópicas de Pb em sedimentos do Canhão Submarino de Cascais, PortugalPublication . Mil-Homens, Mário; Caetano, M.; Lebreiro, Susana; Costa, A. M.; Richter, T.; Cesário, R.; Brito, Pedro Oliveira; De Stigter, H.; Boer, Wim; Trancoso, Maria Ascensão; Mouro, F.Temporal variations in lead concentrations and stable lead isotopic ratios in two sediment cores from the Cascais Canyon shows changes in sources of Pb during the last two centuries. The increase of total Pb contents wIth the evolution of Pb ratio recorded in both cores reveals the Increase of Pb from industrial sources. Nevertheless, this increase is lower in deeper core location (252-32) due to dilution and mixing with uncontaminated marine materials. An isotopic shift towards lower Pb/Pb in the shallower core (252-35) during the 1970s may reflect the increasing number of vehicles in the Lisboa area during that time.
- An examination of potential controls on shell Mn-Ca ratios in the calcite of the bivalve Mytilus edulisPublication . Freitas, Pedro Seabra; Clarke, Leon J.; Kennedy, H. A.; Richardson, Christopher A.
- Análisis genético y morfométrico en el cangrejo Liocarcinus depurator en la transición Atlanto-MediterraneaPublication . Pascual, M.; García-Merchán, V. H.; Robainas-Barcía, A.; Palero, F.; Rufino, Marta M.; Calabria, G.; Ordóñez, V.; Schunter, C.; Balanyà, J.; Mestres, F.; Macpherson, E.; Abelló, P.
- Application of factor analysis for the characterization of major and trace elements in surface sediments of the Minho estuaryPublication . Mil-Homens, Mário; Costa, Ana Novo; Fonseca, S.; Trancoso, Maria Ascensão; Lopes, Cristina Isabel; Serrano, R.; Sousa, R.
- Assessing landslide movements in volcanic islands using near-shore marine geophysical data : south Pico Island, AzoresPublication . Mitchell, Neil C.; Quartau, Rui; Madeira, José
- Assessment of sea surface temperature changes in the Gulf of Cadiz during the last 30 ka : implications for glacial changes in the regional hydrographyPublication . Penaud, Aurélie; Eynaud, Frédérique; Voelker, Antje H. L.; Kageyama, M.; Marret, Fabienne; Turon, Jean-Louis; Blamart, D.; Mulder, Thierry; Rossignol, L.
- Atlantic circulation changes across a stadial-interstadial transitionPublication . Waelbroeck, Claire; Tjiputra, Jerry; Guo, Chuncheng; Nisancioglu, Kerim H.; Jansen, Eystein; Riveiros, Natalia Vazquez; Toucanne, Samuel; Eynaud, Frédérique; Rossignol, Linda; Dewilde, Fabien; Marches, Elodie; Lebreiro, Susana; Nave, SilviaABSTRACT: We combine consistently dated benthic carbon isotopic records distributed over the entire Atlantic Ocean with numerical simulations performed by a glacial configuration of the Norwegian Earth System Model with active ocean biogeochemistry in order to interpret the observed Cibicides delta C-13 changes at the stadial-interstadial transition corresponding to the end of Heinrich Stadial 4 (HS4) in terms of ocean circulation and remineralization changes. We show that the marked increase in Cibicides delta C-13 observed at the end of HS4 between similar to 2000 and 4200 m in the Atlantic can be explained by changes in nutrient concentrations as simulated by the model in response to the halting of freshwater input in the high-latitude glacial North Atlantic. Our model results show that this Cibicides delta C-13 signal is associated with changes in the ratio of southern-sourced (SSW) versus northern-sourced (NSW) water masses at the core sites, whereby SSW is replaced by NSW as a consequence of the resumption of deep-water formation in the northern North Atlantic and Nordic Seas after the freshwater input is halted. Our results further suggest that the contribution of ocean circulation changes to this signal increases from similar to 40 % at 2000 m to similar to 80 % at 4000 m. Below similar to 4200 m, the model shows little ocean circulation change but an increase in remineralization across the transition marking the end of HS4. The simulated lower remineralization during stadials compared to during interstadials is particularly pronounced in deep subantarctic sites, in agreement with the decrease in the export production of carbon to the deep Southern Ocean during stadials found in previous studies.