Browsing by Author "Cerrillo-Escoriza, Javier"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
- Incised valleys on the Algarve inner shelf, northern Gulf of Cadiz margin: stratigraphic architecture and controlling factors in a low fluvial supply settingPublication . Carrión-Torrente, Álvaro; Lobo, Francisco José; Puga-Bernabéu, Ángel; Luján, María; Mendes, Isabel; Hanebuth, Till J. J.; Lebreiro, Susana; García, Marga; Reguera, María Isabel; Antón, Laura; Van Rooij, David; Cerrillo-Escoriza, JavierA network of cross-shelf paleovalleys has been recognized over the paleo-inner shelf off the Gila & SIM;o-Almargem Estuary, a small fluvial drainage system that presently receives minor sediment supply in the eastern Algarve shelf, northern margin of the Gulf of Cadiz (SW Iberian Peninsula). This study is aimed at determining the driving controls that triggered substantially different paleohydrological conditions and sedimentary dynamics of ancient fluvial systems in this margin. We focus on evidences of secondary controls on valley genesis and evolution, superimposed to primary glacio-eustatic control such as antecedent geology, low fluvial supply and changing hydrodynamic regimes. The architecture and spatial distribution of these paleovalleys were interpreted based on a grid of seismic profiles with different resolutions. Likewise, a sediment core obtained in a distal position of the paleovalley system provided information about sedimentary processes during the most recent stage of valley infilling. The chronostratigraphic framework was constructed based on regional seismic horizons defined in previous studies and complemented with two AMS 14C dates obtained from bivalve shells.The inner shelf paleovalley system is composed of several incised valley features which exhibit a remarkable similar internal architecture. These inner valley features exhibit two major incision phases (from oldest to youngest; IP 2 and IP 1) that are thought to constitute a simple paleovalley system formed during the last glacial cycle. The origins of the incision are considered to be different. The older one is related to fluvial incision during the sea-level fall leading into the Last Glacial Maximum, whereas the recent one is interpreted as the result of tidal scour during the postglacial transgression. Their corresponding infillings are interpreted, respectively, as estuarine bay-fill deposits and estuary-mouth sands. Overlying the paleovalley infilling, a distinctive reflective unit is in agreement with the generation of coastal barriers and related depositional systems.The formation of the paleo-inner-shelf paleovalley system was strongly conditioned by antecedent geology, which strongly limited the generation of wide incised valleys and determined the amount of incision landward of a well-defined break of slope. Its postglacial infilling was mainly estuarine in nature, likely involving the development of a dendritic system, with numerous barriers interrupted by tidal inlets and channels in a mixed estuarine system with low fluvial supply.
- Origin and driving mechanisms of marine litter in the shelf-incised Motril, Carchuna, and Calahonda canyons (northern Alboran Sea)Publication . Cerrillo-Escoriza, Javier; Lobo, Francisco José; Puga-Bernabéu, Ángel; Rueda, José Luis; Bárcenas, Patricia; Sánchez-Guillamón, Olga; Serna Quintero, José Miguel; Pérez Gil, José Luis; Murillo, Yelvana; Caballero-Herrera, José Antonio; López-Quirós, Adrián; Mendes, Isabel; Pérez-Asensio, José NoelIntroduction and methodsMarine litter density, distribution and potential sources, and the impact on canyon seafloor habitats were investigated in the Motril, Carchuna and Calahonda canyons, located along the northern margin of the Alboran Sea. During the ALSSOMAR-S2S oceanographic survey carried out in 2019, canyon floor imagery was collected by a Remotely Operated Vehicle along 5 km in the Motril Canyon, 10 km in the Carchuna Canyon, and 3 km in Calahonda Canyon, together with 41 surficial sediment samples. Additionally, coastal uses, maritime traffic and fishing activity data were analyzed. A 50 m resolution multibeam bathymetry served as base map. ResultsIn the Motril and Calahonda canyons, the density of marine litter was low and the material was dispersed, very degraded and partially buried. In contrast, the Carchuna Canyon contained a greater amount and variety of litter. The Carchuna Canyon thalweg exhibited a density of marine litter up to 8.66 items center dot 100 m(-1), and litter hotspots with a density of up to 42 items center dot m(2) are found along the upper reaches of the canyon thalweg. DiscussionLow litter abundances found in the studied canyons most likely reflect low population densities and the absence of direct connections with streams in the nearby coasts. The high shelf incision of the Carchuna Canyon and its proximity to the coastline favor littoral sediment remobilization and capture as well as the formation of gravity flows that transport the marine litter along the thalweg toward the distal termination of the channel. Litter hotspots are favored by the canyon morphology and the occurrence of rocky outcrops. Most debris is of coastal origin and related to beach occupation and agricultural practices in the adjacent coastal plain. A third origin was represented by fishing gear in the study area. Fishing activity may be producing an impact through physical damage to the skeletons of the colonial scleractinians located in the walls of the Carchuna Canyon. In contrast, the Motril and Calahonda canyons can be considered passive systems that have mainly acted as depositional sinks in the recent past, as evidenced by buried marine litter.
- Western Mediterranean shelf-incised submarine canyons: multi-proxy evidence of Late Holocene natural and human-induced environmental changesPublication . López-Quirós, Adrián; Puga-Bernabéu, Ángel; José Lobo, Francisco; Ruíz-Caballero, Elvira; Cerrillo-Escoriza, Javier; Pérez-Asensio, José N.; Mendes, Isabel Maria de Paiva Pinto; Mena, Anxo; Puche-Polo, Natalia; Alberjón-Peñas, Tomás; Wacker, LukasSubmarine canyons play a critical role in continental margin sediment transport, functioning both as sediment traps and conduits. This study examines the depositional dynamics of the Motril, Carchuna, and Calahonda canyons in the northern Alboran Sea (western Mediterranean) to assess their role in Holocene sediment storage and transfer. Comprehensive sedimentological and elemental geochemical analyses reveal distinct sedimentation patterns driven by geomorphology, diverse transport mechanisms, and hydroclimatic variability. The Motril Canyon primarily functioned as a river-fed sediment trap, accumulating fine-grained terrigenous material from the Guadalfeo River. At the same time, the Carchuna Canyon was dominated by longshore drift and turbidity currents mobilizing coarse-grained sediments. In contrast, the Calahonda Canyon displays an intermediate behavior, influenced by alongshore drift and fluvial inputs. The Late Holocene sedimentary record from the Motril Canyon provides a high-resolution sedimentary archive of paleoenvironmental changes over the last similar to 2000 years Current Era, reflecting both climatic variability and human-induced landscape alterations. Four phases are identified based on the relationships between sediment physical and mineral-chemical characteristics: the Iberian Roman Humid Period (2600-1600 cal. yr Before Present), characterized by diminished terrigenous input despite increased late-phase humidity; the Dark Ages (1500-1000 cal. yr BP), marked by elevated sedimentation linked to soil erosion and intensified land use; the Medieval Climate Anomaly (1050-650 cal. yr BP), where persistent fine-grained deposition was driven largely by anthropogenic land degradation; and the Little Ice Age (650-150 cal. yr BP), which witnessed heightened sedimentation due to increased rainfall and river discharge. A decline in fluvial-derived material during the Industrial Period indicates a shift towards overall drier conditions, associated with changes in precipitation patterns and land use. These findings underscore the interplay between natural climatic fluctuations and human activities influencing western Mediterranean margin sedimentation. While the Motril Canyon does not serve as a direct conduit to deep waters, it nonetheless records the progressive aridification and anthropogenic impacts experienced in southern Iberia. Furthermore, the contrasting sediment dynamics observed in the Carchuna and Calahonda canyons highlight the inherent complexity of shelf-to-slope sediment transfer. This complexity underlines the necessity to consider human influences when interpreting Late Holocene paleoenvironmental records.