Marta Ribo | Auckland University of Technology (original) (raw)

Papers by Marta Ribo

2014 American Geophysical Union Fall Meeting, 15-19 december 2014, San FranciscoRecently acquired... more 2014 American Geophysical Union Fall Meeting, 15-19 december 2014, San FranciscoRecently acquired swath bathymetry on the Gulf of Valencia continental margin (NW Mediterranean Sea) allowed characterizing a large-scale sediment wave field which develops on the continental slope, from 250 m in depth to the continental rise, found at 850 m in depth. Geometric parameters as wavelength, wave height, asymmetry index, and steepness were obtained from the analysis of the bathymetric models. The internal structure of the sediment waves was determined using parametric (TOPAS), single-channel (Sparker) and multi-channel (Airgun) seismic reflection profiles. Sediment wavelengths range between 500 and 1000 m, and maximum wave heights of up to 50 m were observed on the upper-slope, decreasing downslope to just 2 m high on the continental rise. These depositional sediment waves over the continental slope are preferentially developed on the foreset region of the prograding margin clinoform, and are preserved in the sediment record since the Early/Lower Pliocene. Contemporary hydrodynamic data have determined the presence of strong near-inertial internal waves interacting with the continental slope, playing an important role in the redistribution of near-bottom suspended particles. Such hydrodynamic process can contribute to the sediment transport and deposition and to the formation of the sediment waves over the Gulf of Valencia continental slope. These morphological features were previously interpreted as a result of gravitational slope failures. However, the use of adequate seafloor mapping techniques, together with oceanographic and sedimentary dynamics measurements, allowed changing the previous interpretation and providing new insights on the seafloor morphology over this part of the NW Mediterranean continental marginPeer Reviewe

International Coastal Symposium, 6-11 March 2016, Sydney, AustraliaDense shelf water cascading (D... more International Coastal Symposium, 6-11 March 2016, Sydney, AustraliaDense shelf water cascading (DSWC) and eastern storms control the off-shelf sediment transport in the northwestern Mediterranean Sea. Previous studies in the Gulf of Lions have shown that most of the sediment transport during these high-energetic events occurs through the Cap de Creus Canyon (Fig 1). However, it is known that part of the bottom currents and the associated sediment transport is advected southwards, channelized between the Cap de Creus promontory and the submarine canyon flank. Recently acquired swath bathymetry and seismic datasets on the Gulf of Roses continental slope, obtained during the FORMED Project (Ref: CGL2012-33989), revealed the presence of large sediment waves (wavelengths of ~ 2000 m and maximum heights of ~ 60 m) developed between 200 and 400 m depth (Fig. 1A). The analysis of seismic profiles showed the general architecture of the late Quaternary deposits over the Gulf of Roses outer shelf and slope, where five unconformity-bounded seismic units are differentiated, with sediment waves developed in all of them (Fig. 1B). The sediment waves over the continental slope are presumably generated by bottom currents intensified during major DSWC events flowing downslope in an oblique angle with respect the main bathymetry, whereas the outer continental shelf is characterized by morphological erosional features that erodes the upper part of the most recent seismic unit. While most observations of sediment dynamics over the study area have focussed in the transfer of sediment from the continental shelf into the deeper areas through the Cap de Creus Canyon, these findings suggest that this transfer also occur across the slope, associated with the overflow of DSWC south of the Cap de Creus coastal promontory, in agreement with the expected hydrodynamic conditions and the morphological configuration of the continental marginPeer Reviewe

Marine Geology, Dec 1, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

International Canyons Workshop, 04-06 September 2012, BrestPeer Reviewe

Particles in Europe (PIE) 2012, 17‐19 October 2012, ICM (Institut de Ciencies del Mar) Barcelona,... more Particles in Europe (PIE) 2012, 17‐19 October 2012, ICM (Institut de Ciencies del Mar) Barcelona, Spain

This study offers new insights on the role of DSWC processes and associated off-shelf sediment tr... more This study offers new insights on the role of DSWC processes and associated off-shelf sediment transport reshaping the morphology of the open-slope regions and contributes to a better understanding of their sedimentary evolution. This study presents new bathymetric and high-resolution seismic data over the Gulf of Roses (GoR) continental slope that allowed re-interpreting the formation processes of large-scale sediment waves.

This thesis offers an extensive perspective of the hydrodynamics and sediment transport of the Gu... more This thesis offers an extensive perspective of the hydrodynamics and sediment transport of the Gulf of Valencia (GoV) continental margin (NW Mediterranean), focussing on the geomorphological and internal structure description of the bedforms observed over the margin. A comprehensive dataset using a wide range of methodologies was used during the project, spanning from hydrographic and hydrodynamic datasets, instrumented moorings, swath bathymetry, sediment sample and seismic profiles. The hydrography of the GoV has been characterized evaluating the relation between currents, water masses and turbidity in the area. Surface circulation is marked by a convergence between the southwestward Northern Current carrying old Atlantic waters (oAW) and the northward intrusions of recent Atlantic waters (rAW) imported through the Ibiza Channel. Below this surface circulation, several water masses were identified: Levantine Intermediate Water mass (LIW); the Western Mediterranean Intermediate Water (WIW) and the Western Mediterranean Deep Water (WMDW). Higher suspended sediment concentrations were observed in the oAW than in the rAW, and an important detachment of particulate matter (nepheloid layer) was observed at the shelf-break depth, extending seawards all across the Ibiza Channel. This indicate a Chapters 4, 6, 7 and 8, including the study area description and methodology used, and also the general discussion and conclusions extracted in each one (Chapter 2 and 3, and 10), correspond to peer-reviewed scientific papers published in journals included in the JCR of ISI. In addition Chapter 5 and 9 are in preparations to be also submitted in 2015.

Dialogue Between Contourite and Oceanography processes International Workshop, 28-26 January 2013... more Dialogue Between Contourite and Oceanography processes International Workshop, 28-26 January 2013, University of Hull, UK.-- 1 page

3rd Annual Hermione Meeting, 11-14 September 2012, Faro, PortugalPeer Reviewe

Atlas of Bedforms in the Western Mediterranean, 2016

A sand ridge field with crests oriented NE–SW (52°) located between 55 and 85 m water depth on th... more A sand ridge field with crests oriented NE–SW (52°) located between 55 and 85 m water depth on the Valencia continental shelf (Spain) was mapped with multibeam swath bathymetry and characterized with high-resolution seismic reflection profiling and sediment sampling. Boundary layer hydrodynamic and suspended sediment concentration measurements conducted over a sand ridge at 66 m depth showed evidence of wave and current sediment resuspension during a major storm event. It is argued that these sand ridges developed in a shallow environment and there is no evidence of present-day ridge migration or morphological degradation.

The Deep-sea & Sub-Seafloor Frontiers Conference project (DS3F), 11-14 March 2012, Sitges, Ba... more The Deep-sea & Sub-Seafloor Frontiers Conference project (DS3F), 11-14 March 2012, Sitges, Barcelona, SpainPeer Reviewe

Resumen: Diversos estudios han descrito la circulación y dinámica en el golfo de Valencia con el ... more Resumen: Diversos estudios han descrito la circulación y dinámica en el golfo de Valencia con el objetivo de entender las interacciones entre masas de agua. Sin embargo, no se ha abordado aún el estudio de la dinámica sedimentaria ni de la distribución de material particulado en suspensión. En la campaña oceanográfica MESO'95 se cubrió esta región con una malla de perfiles verticales de temperatura, salinidad, fluorescencia y turbidez mediante un CTD equipado con un fluorómetro y un transmisómetro. En este artículo se presentan los resultados de estos perfiles hidrográficos. Se observaron varios despegues de capas nefeloides en el talud, entre 400 y 600 m de profundidad, coincidiendo con la capa de Agua Levantina Intermedia (LIW), sugiriendo la existencia de procesos de resuspension del sedimento por ondas internas en el talud intermedio. Capas nefeloides de fondo fueron también observadas en la parte central y sur del golfo de Valencia. Frente al cabo La Nao, a profundidades de borde de plataforma, se identificó un importante despegue de material particulado que se extendía mar adentro cubriendo totalmente el canal de Ibiza. Su presencia indica un transporte preferencial del sedimento de plataforma al sur del golfo de Valencia, donde cambia la orientación del margen continental.

Frontiers in Earth Science

On inner continental shelves, a variety of coarse grained bedforms, such as gravel dunes, are sha... more On inner continental shelves, a variety of coarse grained bedforms, such as gravel dunes, are shaped by hydrodynamic and morphodynamic processes. The formation and evolution of bedforms reflect a balance between seabed and coastal morphology, sediment type and availability, and regional hydrodynamics. Yet, observing bedform evolution directly in the marine environment is rare, mostly due to the lack of repeat seafloor mapping surveys. In this study we use repeat bathymetry from 3 surveys over 4 years from the western Cook Strait/Te Moana-o-Raukawakawa region, New Zealand/Aotearoa. We integrate seabed morphology characterisation with sediment classification and regional hydrodynamic modelling, to investigate the evolution of gravel dunes under multi-directional current conditions. The repeat seafloor mapping reveals morphological changes to plan-view dune geometry and bifurcation of crestlines, with maximum observed vertical changes up to 3 m at water depths between 60 and 80 m. Howe...

Here we present a synthesis of bedforms and sediment types on the shelves surrounding the Iberian... more Here we present a synthesis of bedforms and sediment types on the shelves surrounding the Iberian Peninsula and the Balearic Islands, after the integration several pieces of bathymetric, morphological and sedimentological datasets. The Iberian and Balearic shelves are divided into segments according to the largescale margin configuration, fluvial sediment supply and hydrodynamic regime. Their geological settings and large-scale sedimentation patterns place the investigated shelves into two broad categories: abrupt, steep and narrow sediment-starved shelves, illustrated by the Cantabrian shelf, and gentle, smooth and wide sediment-fed shelves, such as the shelves off some major flivial systems. An in-depth classification was subsequently attempted, based on morpho-sedimentary types. Under this approach, the Iberian and Balearic shelves can be classified as: (1) storm-dominated shelves, with erosional rocky floors, frequent abrasion surfaces and coarse-grained sediments; (2) current-d...

The Palamós and the Cap de Creus submarine canyon heads were instrumented during two consecutive ... more The Palamós and the Cap de Creus submarine canyon heads were instrumented during two consecutive winters to study their respective role in the dynamics of the sediment transport on the northwestern Mediterranean Sea. Several events of dense shelfwater cascading (DSWC) were identified and compared among them. Sediment transport during DSWC at the Palamós canyon is significant during eastern and also northern storm events, but not related with river floods. However, the magnitude of transport events in the Palamós Canyon is one order of magnitude lower than in the Cap de Creus Canyon.

2014 American Geophysical Union Fall Meeting, 15-19 december 2014, San FranciscoRecently acquired... more 2014 American Geophysical Union Fall Meeting, 15-19 december 2014, San FranciscoRecently acquired swath bathymetry on the Gulf of Valencia continental margin (NW Mediterranean Sea) allowed characterizing a large-scale sediment wave field which develops on the continental slope, from 250 m in depth to the continental rise, found at 850 m in depth. Geometric parameters as wavelength, wave height, asymmetry index, and steepness were obtained from the analysis of the bathymetric models. The internal structure of the sediment waves was determined using parametric (TOPAS), single-channel (Sparker) and multi-channel (Airgun) seismic reflection profiles. Sediment wavelengths range between 500 and 1000 m, and maximum wave heights of up to 50 m were observed on the upper-slope, decreasing downslope to just 2 m high on the continental rise. These depositional sediment waves over the continental slope are preferentially developed on the foreset region of the prograding margin clinoform, and are preserved in the sediment record since the Early/Lower Pliocene. Contemporary hydrodynamic data have determined the presence of strong near-inertial internal waves interacting with the continental slope, playing an important role in the redistribution of near-bottom suspended particles. Such hydrodynamic process can contribute to the sediment transport and deposition and to the formation of the sediment waves over the Gulf of Valencia continental slope. These morphological features were previously interpreted as a result of gravitational slope failures. However, the use of adequate seafloor mapping techniques, together with oceanographic and sedimentary dynamics measurements, allowed changing the previous interpretation and providing new insights on the seafloor morphology over this part of the NW Mediterranean continental marginPeer Reviewe

International Coastal Symposium, 6-11 March 2016, Sydney, AustraliaDense shelf water cascading (D... more International Coastal Symposium, 6-11 March 2016, Sydney, AustraliaDense shelf water cascading (DSWC) and eastern storms control the off-shelf sediment transport in the northwestern Mediterranean Sea. Previous studies in the Gulf of Lions have shown that most of the sediment transport during these high-energetic events occurs through the Cap de Creus Canyon (Fig 1). However, it is known that part of the bottom currents and the associated sediment transport is advected southwards, channelized between the Cap de Creus promontory and the submarine canyon flank. Recently acquired swath bathymetry and seismic datasets on the Gulf of Roses continental slope, obtained during the FORMED Project (Ref: CGL2012-33989), revealed the presence of large sediment waves (wavelengths of ~ 2000 m and maximum heights of ~ 60 m) developed between 200 and 400 m depth (Fig. 1A). The analysis of seismic profiles showed the general architecture of the late Quaternary deposits over the Gulf of Roses outer shelf and slope, where five unconformity-bounded seismic units are differentiated, with sediment waves developed in all of them (Fig. 1B). The sediment waves over the continental slope are presumably generated by bottom currents intensified during major DSWC events flowing downslope in an oblique angle with respect the main bathymetry, whereas the outer continental shelf is characterized by morphological erosional features that erodes the upper part of the most recent seismic unit. While most observations of sediment dynamics over the study area have focussed in the transfer of sediment from the continental shelf into the deeper areas through the Cap de Creus Canyon, these findings suggest that this transfer also occur across the slope, associated with the overflow of DSWC south of the Cap de Creus coastal promontory, in agreement with the expected hydrodynamic conditions and the morphological configuration of the continental marginPeer Reviewe

Marine Geology, Dec 1, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

International Canyons Workshop, 04-06 September 2012, BrestPeer Reviewe

Particles in Europe (PIE) 2012, 17‐19 October 2012, ICM (Institut de Ciencies del Mar) Barcelona,... more Particles in Europe (PIE) 2012, 17‐19 October 2012, ICM (Institut de Ciencies del Mar) Barcelona, Spain

This study offers new insights on the role of DSWC processes and associated off-shelf sediment tr... more This study offers new insights on the role of DSWC processes and associated off-shelf sediment transport reshaping the morphology of the open-slope regions and contributes to a better understanding of their sedimentary evolution. This study presents new bathymetric and high-resolution seismic data over the Gulf of Roses (GoR) continental slope that allowed re-interpreting the formation processes of large-scale sediment waves.

This thesis offers an extensive perspective of the hydrodynamics and sediment transport of the Gu... more This thesis offers an extensive perspective of the hydrodynamics and sediment transport of the Gulf of Valencia (GoV) continental margin (NW Mediterranean), focussing on the geomorphological and internal structure description of the bedforms observed over the margin. A comprehensive dataset using a wide range of methodologies was used during the project, spanning from hydrographic and hydrodynamic datasets, instrumented moorings, swath bathymetry, sediment sample and seismic profiles. The hydrography of the GoV has been characterized evaluating the relation between currents, water masses and turbidity in the area. Surface circulation is marked by a convergence between the southwestward Northern Current carrying old Atlantic waters (oAW) and the northward intrusions of recent Atlantic waters (rAW) imported through the Ibiza Channel. Below this surface circulation, several water masses were identified: Levantine Intermediate Water mass (LIW); the Western Mediterranean Intermediate Water (WIW) and the Western Mediterranean Deep Water (WMDW). Higher suspended sediment concentrations were observed in the oAW than in the rAW, and an important detachment of particulate matter (nepheloid layer) was observed at the shelf-break depth, extending seawards all across the Ibiza Channel. This indicate a Chapters 4, 6, 7 and 8, including the study area description and methodology used, and also the general discussion and conclusions extracted in each one (Chapter 2 and 3, and 10), correspond to peer-reviewed scientific papers published in journals included in the JCR of ISI. In addition Chapter 5 and 9 are in preparations to be also submitted in 2015.

Dialogue Between Contourite and Oceanography processes International Workshop, 28-26 January 2013... more Dialogue Between Contourite and Oceanography processes International Workshop, 28-26 January 2013, University of Hull, UK.-- 1 page

3rd Annual Hermione Meeting, 11-14 September 2012, Faro, PortugalPeer Reviewe

Atlas of Bedforms in the Western Mediterranean, 2016

A sand ridge field with crests oriented NE–SW (52°) located between 55 and 85 m water depth on th... more A sand ridge field with crests oriented NE–SW (52°) located between 55 and 85 m water depth on the Valencia continental shelf (Spain) was mapped with multibeam swath bathymetry and characterized with high-resolution seismic reflection profiling and sediment sampling. Boundary layer hydrodynamic and suspended sediment concentration measurements conducted over a sand ridge at 66 m depth showed evidence of wave and current sediment resuspension during a major storm event. It is argued that these sand ridges developed in a shallow environment and there is no evidence of present-day ridge migration or morphological degradation.

The Deep-sea & Sub-Seafloor Frontiers Conference project (DS3F), 11-14 March 2012, Sitges, Ba... more The Deep-sea & Sub-Seafloor Frontiers Conference project (DS3F), 11-14 March 2012, Sitges, Barcelona, SpainPeer Reviewe

Resumen: Diversos estudios han descrito la circulación y dinámica en el golfo de Valencia con el ... more Resumen: Diversos estudios han descrito la circulación y dinámica en el golfo de Valencia con el objetivo de entender las interacciones entre masas de agua. Sin embargo, no se ha abordado aún el estudio de la dinámica sedimentaria ni de la distribución de material particulado en suspensión. En la campaña oceanográfica MESO'95 se cubrió esta región con una malla de perfiles verticales de temperatura, salinidad, fluorescencia y turbidez mediante un CTD equipado con un fluorómetro y un transmisómetro. En este artículo se presentan los resultados de estos perfiles hidrográficos. Se observaron varios despegues de capas nefeloides en el talud, entre 400 y 600 m de profundidad, coincidiendo con la capa de Agua Levantina Intermedia (LIW), sugiriendo la existencia de procesos de resuspension del sedimento por ondas internas en el talud intermedio. Capas nefeloides de fondo fueron también observadas en la parte central y sur del golfo de Valencia. Frente al cabo La Nao, a profundidades de borde de plataforma, se identificó un importante despegue de material particulado que se extendía mar adentro cubriendo totalmente el canal de Ibiza. Su presencia indica un transporte preferencial del sedimento de plataforma al sur del golfo de Valencia, donde cambia la orientación del margen continental.

Frontiers in Earth Science

On inner continental shelves, a variety of coarse grained bedforms, such as gravel dunes, are sha... more On inner continental shelves, a variety of coarse grained bedforms, such as gravel dunes, are shaped by hydrodynamic and morphodynamic processes. The formation and evolution of bedforms reflect a balance between seabed and coastal morphology, sediment type and availability, and regional hydrodynamics. Yet, observing bedform evolution directly in the marine environment is rare, mostly due to the lack of repeat seafloor mapping surveys. In this study we use repeat bathymetry from 3 surveys over 4 years from the western Cook Strait/Te Moana-o-Raukawakawa region, New Zealand/Aotearoa. We integrate seabed morphology characterisation with sediment classification and regional hydrodynamic modelling, to investigate the evolution of gravel dunes under multi-directional current conditions. The repeat seafloor mapping reveals morphological changes to plan-view dune geometry and bifurcation of crestlines, with maximum observed vertical changes up to 3 m at water depths between 60 and 80 m. Howe...

Here we present a synthesis of bedforms and sediment types on the shelves surrounding the Iberian... more Here we present a synthesis of bedforms and sediment types on the shelves surrounding the Iberian Peninsula and the Balearic Islands, after the integration several pieces of bathymetric, morphological and sedimentological datasets. The Iberian and Balearic shelves are divided into segments according to the largescale margin configuration, fluvial sediment supply and hydrodynamic regime. Their geological settings and large-scale sedimentation patterns place the investigated shelves into two broad categories: abrupt, steep and narrow sediment-starved shelves, illustrated by the Cantabrian shelf, and gentle, smooth and wide sediment-fed shelves, such as the shelves off some major flivial systems. An in-depth classification was subsequently attempted, based on morpho-sedimentary types. Under this approach, the Iberian and Balearic shelves can be classified as: (1) storm-dominated shelves, with erosional rocky floors, frequent abrasion surfaces and coarse-grained sediments; (2) current-d...

The Palamós and the Cap de Creus submarine canyon heads were instrumented during two consecutive ... more The Palamós and the Cap de Creus submarine canyon heads were instrumented during two consecutive winters to study their respective role in the dynamics of the sediment transport on the northwestern Mediterranean Sea. Several events of dense shelfwater cascading (DSWC) were identified and compared among them. Sediment transport during DSWC at the Palamós canyon is significant during eastern and also northern storm events, but not related with river floods. However, the magnitude of transport events in the Palamós Canyon is one order of magnitude lower than in the Cap de Creus Canyon.