- The University of Manchester, SEAES, Department Memberadd
- A marine geoscientist interested in the geomorphology of the oceans and underlying structures, from mid-ocean ridge to coasts.edit
The northern Red Sea coastal ecosystem is one of the most diverse coastal ecosystems in the world. Fortunately, it has shown extraordinary resilience against climate change and is predicted to survive global warming during the coming... more
The northern Red Sea coastal ecosystem is one of the most diverse coastal ecosystems in the world. Fortunately, it has shown extraordinary resilience against climate change and is predicted to survive global warming during the coming decades. However, with warming waters, increased sediment and pollutants, and other human impacts, the ecosystem and consequently thriving reef tourism which forms a pillar of the ongoing economic diversification policies of the northern Red Sea region are under threat. A variety of evidence indicates significant damage has already been done to terrestrial and ocean ecosystems on both sides of the northern Red Sea. Expenditures on ecosystem protection and research lag behind Egypt's billions in USD revenue from tourism. Unfortunately, the economic drive to generate profit has resulted in sprawling touristic, industrial, and mixed development without careful planning or assessment of the fragility and sustainability of the natural ecosystem. As a result, the future of coastal urban growth is murky. Given its natural, social, and touristic value, the northern Red Sea system requires a special ecological security system with detailed analysis, inclusive development, and proactive governance across coastal cities and their adjacent inland secondary cities. This study identifies the geological research gaps, human-ecological interactions, inclusive urban development challenges, and related literature pertaining to the northern Red Sea. We propose immediate, targeted, multidisciplinary research
Research Interests:
Research Interests:
Research Interests: Geology and Sedimentary
The northern Red Sea coastal ecosystem is one of the most diverse coastal ecosystems in the world. Fortunately, it has shown extraordinary resilience against climate change and is predicted to survive global warming during the coming... more
The northern Red Sea coastal ecosystem is one of the most diverse coastal ecosystems in the world. Fortunately, it has shown extraordinary resilience against climate change and is predicted to survive global warming during the coming decades. However, with warming waters, increased sediment and pollutants, and other human impacts, the ecosystem and consequently thriving reef tourism which forms a pillar of the ongoing economic diversification policies of the northern Red Sea region are under threat. A variety of evidence indicates significant damage has already been done to terrestrial and ocean ecosystems on both sides of the northern Red Sea. Expenditures on ecosystem protection and research lag behind Egypt's billions in USD revenue from tourism. Unfortunately, the economic drive to generate profit has resulted in sprawling touristic, industrial, and mixed development without careful planning or assessment of the fragility and sustainability of the natural ecosystem. As a result, the future of coastal urban growth is murky. Given its natural, social, and touristic value, the northern Red Sea system requires a special ecological security system with detailed analysis, inclusive development, and proactive governance across coastal cities and their adjacent inland secondary cities. This study identifies the geological research gaps, human-ecological interactions, inclusive urban development challenges, and related literature pertaining to the northern Red Sea. We propose immediate, targeted, multidisciplinary research
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
As the largest ocean, the Pacific is intricately linked to major changes in the global climate system that took place during the Cenozoic. Throughout the Cenozoic the Pacific plate has had a northward component. Thus, the Pacific is... more
As the largest ocean, the Pacific is intricately linked to major changes in the global climate system that took place during the Cenozoic. Throughout the Cenozoic the Pacific plate has had a northward component. Thus, the Pacific is unique, in that the thick sediment bulge of biogenic rich deposits from the currently narrowly focused zone of equatorial upwelling is slowly moving away from the equator. Hence, older sections are not deeply buried and can be recovered by drilling. Previous ODP Legs 138 and 199 were designed as transects across the paleo-equator in order to study the changing patterns of sediment deposition across equatorial regions, while this proposal aims to recover an orthogonal “age-transect” along the paleo-equator. Both previous legs were remarkably successful in giving us new insights into the workings of the climate and carbon system, productivity changes across the zone of divergence, time dependent calcium carbonate dissolution, bio- and magnetostratigraphy, the location of the ITCZ, and evolutionary patterns for times of climatic change and upheaval. Together with older DSDP drilling in the eastern equatorial Pacific, both Legs also helped to delineate the position of the paleo-equator and variations in sediment thickness from approximately 150°W to 110°W. As we have gained more information about the past movement of plates, and where in time “critical” climate events are located, we now propose to drill an age-transect (“flow-line”) along the position of the paleo-equator in the Pacific, targeting selected time-slices of interest where calcareous sediments have been preserved best. Leg 199 enhanced our understanding of extreme changes of the calcium carbonate compensation depth across major geological boundaries during the last 55 million years. A very shallow CCD during most of the Paleogene makes it difficult to obtain well preserved sediments, but we believe our siting strategy will allow us to drill the most promising sites and to obtain a unique sedimentary biogenic carbonate archive for time periods just after the Paleocene- Eocene boundary event, the Eocene cooling, the Eocene/Oligocene transition, the “one cold pole” Oligocene, the Oligocene-Miocene transition, and the Miocene, contributing to the objectives of the IODP Extreme Climates Initiative, and providing material that the previous legs were not able to recover.
Research Interests: Geology, Oceanography, Paleontology, Paleomagnetism, QE, and 4 moreCenozoic, Transect, Upwelling, and Equator
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Assimilation of roof material into mid-ocean ridge magma chambers may play an important role in the overall flux of heat and mass through the ridge system at intermediate- and fast-spreading rates. Field studies in ophiolites provide... more
Assimilation of roof material into mid-ocean ridge magma chambers may play an important role in the overall flux of heat and mass through the ridge system at intermediate- and fast-spreading rates. Field studies in ophiolites provide evidence for assimilation in the form of numerous doleritic and gabbroic xenoliths in the uppermost gabbros. However, owing to the rapid dissolution and/or disagregation
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
It is clear that the Miocene is a key interval to understand how earth systems interact to maintain global warmth, especially since carbon-based greenhouse gases may not have been extremely elevated at that time. It is also much easier,... more
It is clear that the Miocene is a key interval to understand how earth systems interact to maintain global warmth, especially since carbon-based greenhouse gases may not have been extremely elevated at that time. It is also much easier, potentially, to study the Miocene than earlier intervals of global warmth because more complete sedimentary sections exist. To be studied, however, the sediment sections need to be sampled. In the oceans, the Miocene is sampled by the Integrated Ocean Drilling Program and its predecessors (Ocean Drilling Program and Deep Sea Drilling Project). Marine sedimentary records need to be gathered from the oceans at a scale to resolve the temperature evolution of the major surface water masses and transition regions. New drilling targeted to study the Miocene must occur to achieve this distribution. With existing ODP and DSDP cores it is possible to sample and study general trends over the Miocene, but it is only possible to study the early and middle Miocene in high resolution for a few ocean areas. Pelagic Miocene sections as a rule tend to be buried deeply below the surface and have not been cored adequately to make composite sediment columns needed for detailed studies. In the Pacific, for example, there is relatively good coverage to the middle-late Miocene boundary (~12Ma) but continuous sedimentary sections that cover the early and middle Miocene are relatively rare. Ironically, there are relatively good new data from the Pacific subtropical gyres, but information from the equatorial region and the high latitudes is lacking. A new site survey (AMAT-03) and a scheduled IODP drilling program have produced a strategy to measure a continuous 50 million year record of the equatorial Pacific Ocean. Similar programs are needed for other representative regions of the ocean and ocean gateways.
Research Interests:
Research Interests:
Research Interests:
ABSTRACT Knowledge of how carbonates are produced on shelves is needed for working out how these “carbonate factories” generate stratigraphy by providing particles for potential export or local deposition. Production rates can be derived... more
ABSTRACT Knowledge of how carbonates are produced on shelves is needed for working out how these “carbonate factories” generate stratigraphy by providing particles for potential export or local deposition. Production rates can be derived straightforwardly in low-energy environments from one-dimensional analysis (age–depth variations) but rates are less easily derived for high-energy hydrodynamical environments where particles are transported away from their sites of production. This particularly affects knowledge of spatial variations in production rates, needed for working out controlling influences of light, hydrodynamics, and nutrient availability. We show here that, if a non-carbonate component of the sediment, such as terrigenous particles arising from coastal and subaerial erosion, is conserved and thus acts as a tracer, rates of carbonate production can in principle be derived from carbonate content data, if sediment transport fluxes can also be constrained. In the equation developed here, the spatial rate of change of carbonate content is caused by dilution of the terrigenous component by the newly produced carbonate and depends on the sediment transport flux. We investigate this idea using data from Santa Maria Island, Azores, an inactive volcanic island in a temperate environment. Geochemical, X-ray diffraction (XRD), and X-ray fluorescence (XRF) data of surface–sediment grab samples indicate nearly simple mixing trends between two components (volcanic rock and marine carbonate), as needed for our simple dilution-based equation to apply. High-resolution boomer seismic data reveal thicker (> 1 m) deposits in the mid- to outer shelf of the island, which we interpret as having been emplaced during the Holocene. These effectively provide time-averaged depositional fluxes and, assuming conservation of mass, can be used to constrain transport fluxes. The derived equation is used to predict the observed deposit thicknesses into the mid-shelf alongside coincident increasing carbonate percentages. The thicknesses are replicated only if carbonate production rates increase with depth and distance away from the coastline into the mid-shelf, quantifying the variation of production of such a nearshore environment for the first time. We speculate that mollusks dominating the production have a preference for sand that is less frequently or strongly agitated by waves, although nutrient availability from occasional upwelling may also regulate growth to create this trend.
Research Interests:
Research Interests:
Research Interests: Cryobiology, Earth Sciences, Geology, Geochemistry, Informatics, and 15 moreAsteroids, Comets, Natural Hazards, Permafrost, Marine geology and geophysics, Other, Physical sciences, Biogeosciences, Landslide, Cryosphere, Mathematical Geophysics, Lava, Bathymetry, Earthquake Hazards, and Landslide hazard
Research Interests:
Research Interests:
SUMMARYThe axial region of the Central Red Sea has been shown to be floored by oceanic crust, but this leaves the low amplitudes of off-axis magnetic anomalies to be explained. Furthermore, if seafloor spreading occurred in the late... more
SUMMARYThe axial region of the Central Red Sea has been shown to be floored by oceanic crust, but this leaves the low amplitudes of off-axis magnetic anomalies to be explained. Furthermore, if seafloor spreading occurred in the late Miocene, it is unclear how that occurred as widespread evaporites were being deposited then and may have covered the spreading centre. In this study, we derive crustal magnetization for a constant-thickness source layer within the uppermost basement by inverting aeromagnetic anomalies using basement depths derived from seismic reflection and gravity data. Peak-to-trough variations in magnetization away from the axis are found to be slightly less than half of those of normal oceanic crust, but not greatly diminished, and hence the magnetic anomalies are mostly reduced by the greater depth of basement, which is depressed by isostatic loading by the evaporites (kilometres in thickness in places). There is no relationship between seafloor spreading anomali...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Abstract This study describes the emplacement of the Nesjahraun, a basaltic lava flow that entered the lake Þingvallavatn, SW Iceland. High-resolution remotely sensed data were combined with fieldwork to map the flow field. Onshore, the... more
Abstract This study describes the emplacement of the Nesjahraun, a basaltic lava flow that entered the lake Þingvallavatn, SW Iceland. High-resolution remotely sensed data were combined with fieldwork to map the flow field. Onshore, the Nesjahraun exhibits a variety ...
Research Interests:
Research Interests:
Research Interests:
Bathymetry data collected with a multibeam echo-sounder around Pico Island, Azores (Portugal) reveal a remarkable series of lava flows on the island's shelf with a variety of pristine structures. Many flows are dendritic in... more
Bathymetry data collected with a multibeam echo-sounder around Pico Island, Azores (Portugal) reveal a remarkable series of lava flows on the island's shelf with a variety of pristine structures. Many flows are dendritic in plan-view, some with channels and tumuli. Dendritic geometries are reminiscent of lava with more viscous rheology than expected for subaerial flows of these basaltic-Hawaiitic compositions, consistent with viscosity increased by enhanced cooling in water. Screens of elongated flow fingers also occur, with individual fingers of comparable diameters to the largest known megapillows. Some flows have wide transverse clefts, in some cases separating flows into segments. They are interpreted as caused by the flow upper surfaces having solidified, while their still-fluid cores allowed the surfaces to extend. A number of flows moved onto the shelf as large bodies, stopped, and then sourced smaller lobes forming the dendritic patterns. This two-stage evolution and the tumuli (which lie adjacent to a steep near-shore gradient) suggest that, after initial emplacement and development of a crust by cooling, some flows pressurized. Once movements ceased and viscous stresses were dissipated, magmastatic pressure developed from the weight of flow interiors passing over coastal cliffs and near-shore submarine slopes. One group of flows traverses the submarine slope of the island, so direct supply of lava to the slopes is possible, although volumetrically how important such flows are to building the island's internal structure is difficult to tell from these data. Based on observed strong surf erosion of historical flows, these delicate structures could not have survived passage through a moving sea level so they are not pre-Holocene subaerial flows. They were formed in the Holocene from flows penetrating sea level or possibly some from near-shore tube openings or vents. Such flows and abundant sand deposits are ephemeral features that probably become remobilized by surf during times of lowering sea level. The shelves of active volcanic islands are therefore active geologically and are far from being simple products of erosional truncation as was once envisaged. The finding of lava extending below sea level also has implications for assessing the hazards of volcanic islands.
Research Interests:
ABSTRACT Submarine continental slopes are landscapes characterized by large variety of relief from rills and gullies to large canyon net systems, but how these features develop is still not well understood. Marine-geoscientists suspect... more
ABSTRACT Submarine continental slopes are landscapes characterized by large variety of relief from rills and gullies to large canyon net systems, but how these features develop is still not well understood. Marine-geoscientists suspect that sediments delivered from the adjacent land might be the ultimate "driver" for these landscapes, for example, by supplying erosive sedimentary flows. However, it is difficult to prove an intimate cause for submarine system formation as along most coasts the shelf is too wide to allow us to assign individual canyons to rivers and we have poor idea of the sediment supply. The coasts of NE Sicily and SW Calabria have narrow shelves and their uplift rates are well quantified. As the Sicilian coast landscape in particular is mature, the long term sediment flux can be assessed from the uplift rates and their drainage catchment areas. The marine geophysical dataset, used for the present study, reaches to within 100m water depth around the coast. As, according to estimates, local relative sea level was depressed by 120m, the data represents areas that were exposed during the Last Glacial Maximum. This allows an assessment of sediment transport paths during glacial times. Spectacular underwater landscape is observed from the data with developing rills, gullies and deeply incised canyons. Our findings suggest that channels lying offshore large rivers are characterized by canyons with broad channels and channels that lie offshore small rivers are characterized by small relief channels.
Research Interests:
ABSTRACT The landscapes of southern Italy provide an opportunity to observe the response of drainage systems in a Mediterranean climate to variations in bedrock erodibility and uplift rate. The area of NE Sicily studied is mainly composed... more
ABSTRACT The landscapes of southern Italy provide an opportunity to observe the response of drainage systems in a Mediterranean climate to variations in bedrock erodibility and uplift rate. The area of NE Sicily studied is mainly composed of granite, high-grade gneiss, limestone and meta-pellite. Published Late Pleistocene to Holocene uplift rates from bedrock terraces and erosional notches in the study area were compiled to characterise the pattern of uplift. Drainage basins were extracted from a 90m DEM and consequent longitudinal channel profiles were prepared. The profiles show generally concave upward trends with many locally steep reaches (knickpoints). Some of the large scale knickpoints (150-200 m height), at drainage areas less than 106 m2, are interpreted to lie above the critical drainage area representing the transition from debris-flow dominated colluvial channels to stream-flow dominated fluvial channels. Log-log plots of gradient versus area were used to characterise the concavity and steepness indices of the channels. Pervious workers have suggested that in both detachment- and transport-limited erosion, steepness indices of the longitudinal profile are effected by the uplift rates. Provisional results found here suggest a positive but weak correlation between channel steepness and uplift rates. When channels are subdivided into segments along their length, a strong positive correlation between steepness and uplift rate near the drainage divide was revealed, followed by weaker correlation for the segments downstream. Field studies revealed a major shear zone near and parallel to the coast, which generally reduces the bedrock resistance irrespective of its lithology. This is corroborated by Schmidt Hammer readings. Furthermore, the higher uplift rate areas appeared to be associated with unstable hillslopes. Recent enhanced supply to channels by landsliding has infilled valley outlets and is developing coastal deltas of deposited material.
Research Interests:
ABSTRACT The Sicilian and Calabrian coasts either side of the Strait of Messina in southern Italy provide an opportunity to observe the response of subaerial drainage systems to variations in bedrock erodibility and uplift rate. Offshore... more
ABSTRACT The Sicilian and Calabrian coasts either side of the Strait of Messina in southern Italy provide an opportunity to observe the response of subaerial drainage systems to variations in bedrock erodibility and uplift rate. Offshore processes include hyperpycnal currents derived from onshore drainages, as well as longitudinal flow along the Messina Channel. The narrow continental shelves allow a direct connection between these onshore and offshore processes. NE Sicily and SW Calabria are mainly composed of granite, high-grade gneiss, limestone and meta-pelite. Published Late Pleistocene to Holocene uplift rates from bedrock terraces and erosional notches indicate that uplife rates increase away from the Strait, on both sides. Digital topographic analyses reveal that, on the Sicilian side, longitudinal channel profiles exhibit generally concave upward trends with many locally steep reaches (knickpoints). Many of the large scale knickpoints (150-200 m in height) occur at drainage areas below the transition from debris-flow dominated colluvial channels to stream-flow dominated fluvial channels. There is a positive but weak correlation between channel steepness and uplift rate. This correlation is strongest near the drainage divide, with a weaker correlation downstream, where a major shear zone generally reduces the bedrock resistance, irrespective of lithology. The distribution of landslides has been mapped on both sides of the Strait of Messina using aerial photography, revealing contrasting controls on landslide distribution. In Sicily, landslides are most frequent where uplift rates are most rapid and rainfall heaviest. The Calabrian landscape is less incised, so landslides are confined to valley sides, with low-relief interfluves free of landslides. Offshore, geomorphic features have been characterised from multi-beam bathymetric and Chirp data. The central feature is the Messina Channel, which runs north-south. Although the channel does not meander prominently, alterations of its course due to slumping and mass wasting are inferred from the arcuate surfaces bounding it. The Chirp data suggest undermining of the channel wall by sedimentary flows passing down the channel. The continental slopes are heavily gullied with prominent converging patterns of rills and gullies forming confluences at canyon heads. Our findings suggest that submarine channels associated with large, rapidly-uplifting, landslide-prone rivers receive higher sediment fluxes, and are characterised by canyons with broad channels and graded longitudinal profiles. In contrast, submarine channels that lie offshore small rivers (nearer the Strait) are characterised by low relief channels with steep gradients. The combination of multi-beam bathymetry and Chirp data allows us to evaluate the interaction between active tectonics, large currents descending the Messina Canyon, and sediments derived from the Sicilian and Calabrian coasts in shaping the evolving morphology of the Ionian Sea floor.
Research Interests:
Research Interests:
To evaluate paleoceanographic conditions from chemical and physical records in pelagic sediments more accurately, it is imperative to understand how the sediment has been transported, deposited and eroded. To date, few researchers have... more
To evaluate paleoceanographic conditions from chemical and physical records in pelagic sediments more accurately, it is imperative to understand how the sediment has been transported, deposited and eroded. To date, few researchers have studied how these processes have affected seafloor topography over time, and the works were limited to near surface data or to narrow geographic regions (e.g., Laguros and
Research Interests:
A major step in the "Wilson Cycle"... more
A major step in the "Wilson Cycle" is the splitting of a continent and the birth of a new ocean, with the consequent formation of passive plate margins. The transition from a continental to an oceanic rift can be observed today nowhere better than in the Red Sea/Gulf of Aden system. We have carried out during several years a number