The Experts below are selected from a list of 12018 Experts worldwide ranked by ideXlab platform

K T Pickering - One of the best experts on this subject based on the ideXlab platform.

  • architecture and stacking patterns of lower slope and proximal Basin Floor channelised submarine fans middle eocene ainsa system spanish pyrenees an integrated outcrop subsurface study
    Earth-Science Reviews, 2015
    Co-Authors: K T Pickering, Jordi Corregidor, Julian Clark
    Abstract:

    Abstract An integrated outcrop and subsurface study of the Middle Eocene (Lutetian) Ainsa System, Ainsa Basin, Spanish Pyrenees, was undertaken to characterise the proximal depositional environments of sandy channelised submarine fans, interfan and slope deposits, the results of which are presented here for the first time as a coherent synthesis and interpretation. It is unique for any drilling programme in coarse-grained deep-marine clastic sediments as it documents the facies, architecture, and evolution of the proximal parts of three structurally confined and channelised sandy lower-slope and proximal Basin-Floor submarine fans (Ainsa I, II and III fans). Eight wells were drilled through ~ 220–250 m of stratigraphy with typical inter-well spacing of ~ 400–500 m, with seismic lines, wireline logs, essentially continuous coring, sandstone petrography, micropalaeontological and palynomorph analyses. The fans show a lateral stepwise migration away from a growth anticline that formed the lateral Basin margin on the side of the growing Pyrenean orogen. Unlike the Ainsa I Fan, the Ainsa II and III fans appear to have an essentially non-erosive base overlain by at least several metres of relatively unconfined sandy deposits interpreted as pre-channel proximal-lobe deposits. Submarine channels erode into these proximal-lobe deposits, typically 5–30 m deep and hundreds of metres wide (~ 100–600 m). The channels are associated with composite erosional surfaces, local m-scale scouring, and pebbly lag deposits, suggesting substantial sediment bypass in the early stages of channel evolution, but with later channel abandonment and filling by finer-grained deposits. This process of channel incision, bypass and likely backfill appears to have occurred many times during the main growth phase of the sandy submarine fans, and with only one channel active at any time. Well correlations and mapping, including using bio-events, suggest the presence of levee–overbank deposits. Candidate lateral accretion packages suggest that there was an increase in channel sinuosity upwards from the Ainsa I, II and III fans, probably linked to an overall decrease in seaFloor gradients; supported by the presence of many tens of metres of essentially undeformed marlstones of very fine-grained, thin- to very thin-bedded turbidites in the upper parts of the Ainsa System. Depositional architecture was controlled by a combination of syn-sedimentary tectonics fashioned by seaFloor growth structures, climate change (affecting seaFloor environmental conditions that controlled bioturbation intensity) and probably autocyclic (intrafan) processes (that were probably responsible for individual channel elements). Local accommodation was controlled by intra-Basinal tectonics and the interplay between erosional and depositional processes, including irregular seaFloor topography created by cohesive debris flow and slide deposits (MTDs/MTCs). We also show that post-depositional thrusting and folding has created locally complex geometrical relationships within the fans and interfan deposits, which could not have been resolved without careful outcrop and subsurface mapping, logging and correlation.

  • Trace fossils as diagnostic indicators of deep-marine environments, Middle Eocene Ainsa-Jaca Basin, Spanish Pyrenees
    SEDIMENTOLOGY, 2008
    Co-Authors: K T Pickering
    Abstract:

    A quantitative study of trace fossil abundance in the Middle Eocene deep-marine clastic systems, Ainsa-Jaca Basin, Spanish Pyrenees, shows that they are powerful discriminators of submarine fan and related environments. Sixteen fan and related environments are recognized from upper-slope gully to the distal Basin-Floor. For each environment, the degree of bioturbation (density), trace-fossil diversity, number of pre-depositional and post-depositional trace fossils, as well as the number of graphoglyptid ichnospecies were quantified. In the more laterally confined and channel-dominated Ainsa Basin, there is a trend of increasing bioturbation intensity and trace-fossil diversity away from channel-axis to off-axis environments. In the more unconfined and distal Jaca Basin, there is a trend of increasing trace-fossil diversity and number of pre-depositional trace fossils including graphoglyptids from the channel-lobe transition to the fan-fringe. The trace-fossil assemblages of the Ainsa-Jaca Basin are characteristic of a number of sub-ichnofacies of the Nereites ichnofacies. In the distal Jaca Basin, the Paleodictyon sub-ichnofacies occurs in the lobe-fringe and fan-fringe, whereas the distal Basin-Floor has a trace-fossil assemblage typical of the Paleodictyon sub-ichnofacies, but with a high proportion of post-depositional fodinichnia. Trace-fossil assemblages of proximal Basin, axial, environments are characteristic of the Ophiomorpha rudis sub-ichnofacies, whilst proximal off-axis environments, have a mixed Paleodictyon-Ophiomorpha rudis sub-ichnofacies trace-fossil assemblage.

  • mass transport complexes mtcs and tectonic control on Basin Floor submarine fans middle eocene south spanish pyrenees
    Journal of Sedimentary Research, 2005
    Co-Authors: K T Pickering, Jordi Corregidor
    Abstract:

    In many deep-marine clastic systems, mass-transport complexes (MTCs) constitute a major component of the stratigraphy and represent an integral part of the evolution and depositional style. In tectonically active Basins, as is the case in our study of the syntectonic deep-marine Ainsa submarine fans (Eocene of the Ainsa Basin, Spanish Pyrenees), organized, predictable vertical sedimentary sequences provide a testable generic model for submarine fan development in other Basins where tectonic processes provide a first-order driver on fan growth. In the Ainsa Basin, the linear submarine fans were confined by lateral thrust ramps and influenced by intra-Basinal growth anticlines. This study represents an integration of outcrop data from sedimentary logs and mapping, with core data from eight wells and micropaleontological and palynomorph analyses. Mapping shows the lateral stepwise migration of sandy channelized submarine fans, as a foreland-propagating clastic wedge. The stepwise foreland migration of each fan (away from the deformation front), and also the time scales involved (many hundreds of thousands of years for each fan), are interpreted within the context of a primary tectonic control. Three distinct types of MTC are recognized, each of which appears to be characteristic of stratigraphic position in relation to the evolution of individual fans. The deep-marine expression of the inferred tectonic pulses began with the large-scale Basin-slope collapse as sediment slides and debris flows (type I MTCs) that formed much of the seaFloor topography for each fan and contributed to their lateral confinement. The uppermost slope and any shelf edge, including the narrow shelf, then collapsed, redepositing unconsolidated sands and gravels into deep water (type II MTCs). The basal coarse clastics are overlain by an interval of mainly channelized and amalgamated sandy deposits, with major erosional events, including reincision processes associated with channel development, being characterized by pebbly mudstones and sandstones rich in angular, locally derived intraclasts (type III MTCs). The channelized sands pass up into several tens of meters of less confined, non-amalgamated, medium- and thin-bedded, fine-grained sands and marls. These deposits represent the phase of most active fan growth, initially by erosional channel development, sediment bypass, and backfill (in several cycles), giving way to nonchannelized, fine-grained sandy deposition, interpreted as a response to the flushing out of the coarser clastics from the coastal and near-coastal fluvial systems. During this latter stage in active fan growth and when sediment accumulation rates probably remained high, the degraded submarine slope was regraded and healed by fine-grained depositional events. The high amount of woody material and the high nonmarine palynomorph signal in these sandy deposits suggest direct river input as both turbidity currents and hyperpycnal flows for the silty marls. In the upper few meters, a thinning and fining-upward sequence shows a return to background marl deposition, representing fan abandonment. Many sequences are overlain by intraformational sediment slides (typically type I MTCs but, rarely type II MTCs) that attest to the increasing seaFloor gradients associated with the regrading and healing stage in slope development. Our explanation for these vertical sequences provides a readily testable depositional model for other deep-marine clastic systems associated with a tectonically active hinterland and Basin slopes.

  • a new type of bedform produced by backfilling processes in a submarine channel late miocene tabernas sorbas Basin se spain
    Journal of Sedimentary Research, 2001
    Co-Authors: K T Pickering, E S Platzman, Julian David Clark, David M. Hodgson, Clare Stephens
    Abstract:

    The Late Miocene ''Solitary Channel," Tabernas-Sorbas Basin, SE Spain, has been interpreted as a submarine channel fed by sediment gravity flows from the east. In this paper, the channel is reinterpreted as a lower-slope erosional channel fed by sediment gravity flows from the west. The channel shows cobble/pebble lag deposits, including breccias, associated with erosional phases with substantial sediment bypass, and a later infill by episodes of inclined backstepping macroforms (the primary focus in this paper), mainly comprising sands, interpreted here for the first time as channel backfill deposits. These inclined sandy macroforms, typically 2-5 in in height and 3040 in in length, are described in detail for the first time in this paper, and are interpreted as a new large-scale sedimentary structure. We observe that the seeding process for the inclined sandy macroforms appears to have been in the upstream depression immediately behind ridges on the surface directly overlying cohesive debris-How deposits.The internal channel architecture is interpreted in terms of fluctuating relative base levels. A purely local tectonic explanation for the inclined sandy macroforms is discounted because within the bed bundles, dips are essentially constant across the intrachannel disconformities. We speculate that the most likely overall change in base level throughout the history of the channel was driven by regional tectonic change. The higher-frequency variations were probably a consequence of fluctuations in sediment supply/caliber from the source area and/or of cycles of eustatic or regional sea-level changes. The channel was abruptly overlain by about 200 in of marls and then a heterolithic sheet-like turbidite system typical of a confined Basin-Floor setting. This change in depositional style represents a response to a significant overall decrease in Basin-Floor gradient, in which there was a differential change in base level, shown by the coeval development of a major angular unconformity farther east (Sorbas area). The channel history is important for sequence-stratigraphic modeling because it demonstrates that a backstepping fill can be caused by an overall tectonic control on the accommodation space (initiation and abandonment). Higher-frequency source-area changes in sediment flux/caliber and/or eustatic sea level probably exert a strong influence on the detailed depositional architecture in the channel (multiple bypass-backfill events).

  • Basin Floor fans in the north sea sequence stratigraphic models vs sedimentary facies discussion
    AAPG Bulletin, 1997
    Co-Authors: Richard N Hiscott, K T Pickering, Arnold H Bouma, B M Hand, B C Kneller, G Postma, W Soh
    Abstract:

    Original article : Shanmugan, G., R. B. Bloch, S. M. Mitchell, G. W. J. Beamish, R. J. Hodgkinson, J. E. Damuth, T. Straume, S. E. Syvertsen, and K. E. Shields, 1995, AAPG Bulletin, v. 79, p. 477-512.

Stephen S Flint - One of the best experts on this subject based on the ideXlab platform.

  • disconnected submarine lobes as a record of stepped slope evolution over multiple sea level cycles
    Geosphere, 2018
    Co-Authors: Hannah L Brooks, Rufus L Brunt, David M. Hodgson, Jeff Peakall, Miquel Poyatosmore, Stephen S Flint
    Abstract:

    The effects of abrupt changes in slope angle and orientation on turbidity current behavior have been investigated in numerous physical and numerical experiments and examined in outcrop, subsurface, and modern systems. However, the long-term impact of subtle and evolving seabed topography on the stratigraphic architecture of deep-water systems requires fine-scale observations and extensive 3-D constraints. This study focuses on the Permian Laingsburg and Fort Brown formations, where multiple large sand-rich systems (Units A–F) have been mapped from entrenched slope valleys, through channel-levee systems, to Basin-Floor lobe complexes over a 2500 km2 area. Here, we investigate three thinner (typically <5 m in thickness) and less extensive sand-rich packages, Units A/B, B/C, and D/E, between the large-scale systems. Typically, these sand-rich units are sharp-based and topped, and contain scours and mudstone clast conglomerates that indicate deposition from high-energy turbidity currents. The mapped thickness and facies distribution suggest a lobate form. These distinctive units were deposited in similar spatial positions within the Basin-fill and suggest similar accommodation patterns on the slope and Basin Floor prior to the larger systems (B, C, and E). Stratigraphically, these thin units represent the first sand deposition following ­major periods of shut-down in sediment supply, and are interpreted as marking a partial re-establishment of sand delivery pathways creating “disconnected lobes” that are fed mainly by flows sourced from failures on the shelf and upper slope rather than major feeder channel-levee systems. Thickness and facies patterns throughout the deep-water stratigraphy suggest seabed topography was present early in the Basin formation and maintained persistently in a similar area to ultimately form a stepped slope profile. The stepped slope profile evolved through three key stages of development: Phase 1, where sediment supply exceeds deformation rate (likely caused by differential subsidence); Phase 2, where sediment supply is on average equal to deformation rate; and Phase 3, where deformation rate outpaces sediment supply. This study demonstrates that smaller systems are a sensitive record of evolving seabed topography and they can consequently be used to recreate more accurate paleotopographic profiles.

  • depositional architecture and sequence stratigraphy of the karoo Basin Floor to shelf edge succession laingsburg depocentre south africa
    Marine and Petroleum Geology, 2011
    Co-Authors: Stephen S Flint, Rufus L Brunt, David M. Hodgson, D Box, A R Sprague, W Van Der Merwe, J Figueiredo, Amandine Prelat, C Di Celma, John P Kavanagh
    Abstract:

    Abstract The Laingsburg depocentre of the SW Karoo Basin, South Africa preserves a well-exposed 1200 m thick succession of upper Permian strata that record the early filling of a Basin during an icehouse climate. Uniformly fine-grained sandstones were derived from far-field granitic sources, possibly in Patagonia, although the coeval staging and delivery systems are not preserved. Early condensed shallow marine deposits are overlain by distal Basin plain siltstone-prone turbidites and volcanic ashes. An order of magnitude increase in siliciclastic input to the Basin plain is represented by up to 270 m of siltstone with thin sandstone turbidites (Vischkuil Formation). The upper Vischkuil Formation comprises three depositional sequences, each bounded by a regionally developed zone of soft sediment deformation and associated 20–45 m thick debrite that represent the initiation of a major sand delivery system. The overlying 300 m thick sandy Basin-Floor fan system (Unit A) is divisible into three composite sequences arranged in a progradational–aggradational–retrogradational stacking pattern, followed by up to 40 m of Basin-wide hemipelagic claystone. This claystone contains Interfan A/B, a distributive lobe system that lies 10 m beneath Unit B, a sandstone-dominated succession that averages 150 m thickness and is interpreted to represent a toe of slope channelized lobe system. Unit B and the A/B interfan together comprise 4 depositional sequences in a composite sequence with an overall Basinward-stepping stacking pattern, overlain by 30 m of hemipelagic claystone. The overlying 400 m thick submarine slope succession (Fort Brown Formation) is characterized by 10–120 m thick sand-prone to heterolithic packages separated by 30–70 m thick claystone units. On the largest scale the slope stratigraphy is defined by two major cycles interpreted as composite sequence sets. The lower cycle comprises lithostratigraphic Units B/C, C and D while the upper cycle includes lithostratigraphic Units D/E, E and F. In each case a sandy basal composite sequence is represented by an intraslope lobe (Units B/C and D/E respectively). The second composite sequence in each cycle (Units C and E respectively) is characterized by slope channel-levee systems with distributive lobes 20–30 km down dip. The uppermost composite sequence in each cycle (Units D and F respectively) are characterised by deeply entrenched slope valley systems. Most composite sequences comprise three sequences separated by thin (

  • widespread syn sedimentary deformation on a muddy deep water Basin Floor the vischkuil formation permian karoo Basin south africa
    Basin Research, 2009
    Co-Authors: W Van Der Merwe, David M. Hodgson, Stephen S Flint
    Abstract:

    The ∼380-m-thick mudstone–siltstone-dominated Vischkuil Formation represents the initiation phase of a 1.3-km-thick prograding Basin Floor to slope to shelf succession that marks a significant increase in the rate of siliciclastic sediment supply to the early Karoo Basin in the Permian. In the upper Vischkuil Formation three well exposed, widespread (∼3000 km2) 10–70-m-thick intervals of deformed strata are encased within undeformed sediments. Such chaotic mass movement deposits that are mappable over areas comparable with seismic-scale mass transport deposits are commonly associated with submarine slope settings. However, the surrounding lithofacies and the correlation of distinctive marker beds indicate that these deformation intervals developed in a distal low gradient Basin Floor setting. The deformed intervals comprise a lower division of tight down-flow verging folds dissected by thrust planes that sole out onto a highly sheared decollement surface that are interpreted as slides. The lower divisions are overlain by an upper division of chaotic lithofacies with large contorted clasts of sandstone supported by a fine-grained matrix interpreted as a debrite. The juxtaposition of these lithofacies, the distribution of thickness of the divisions, and their close kinematic relationships indicate that the emplacement of the debris-flows triggered and drove the underlying slide, in a low-gradient distal setting. Individual beds in the deformed intervals can be mapped laterally into undeformed strata indicating limited movement of the slide. Therefore, widespread zones of syn-sedimentary deformation in deep-water settings do not necessarily indicate a slope setting and should not be used as single criterion to determine depositional setting. When associated with major debrites they may be developed on a flat Basin Floor.

  • anatomy and stratigraphic development of a Basin Floor turbidite system in the laingsburg formation main karoo Basin south africa
    Journal of Sedimentary Research, 2004
    Co-Authors: P Sixsmith, Stephen S Flint, H De Ville Wickens, Stephen D Johnson
    Abstract:

    ABSTRACT Six individual turbidite systems, informally called Fans A-F, were deposited in the Laingsburg area of the southwestern Karoo Permian foreland Basin. This study concentrates on the lowermost, 300 m thick "Fan A" system. Facies associations include channel fills and correlative lateral overbank deposits consisting of thin sheet-like and rippled sandstones. Massive- and thin-bedded frontal sheet sandstones form down-dip extensions to channel systems. Identification and correlation of mudstone-dominated intervals from field mapping and oblique aerial photostratigraphy delineates a high-resolution internal stratigraphy of the fan system which, coupled with 4000 m of logged section, allows detailed geometrical and architectural analysis. Seven individual depositional units have been mapped within Fan A, and these are interpreted as the deep-Basin sedimentological expressions of high-frequency lowstand systems tracts, separated by high-frequency transgressive and highstand condensed intervals. Stacking patterns of the seven lowstand fan units that make up Fan A record early progradation (units 1 to 3), a backstep (unit 4), followed by further progradation (units 5 and 6). Retrogradation during unit 7 records abandonment of the whole Fan A deposystem. Coupled with facies analysis, paleocurrents reveal unusual paleotransport patterns that are interpreted as a consequence of structural deformation of the Basin Floor. Paleotransport indicators reveal that sediment pathways are strongly parallel to the structural grain, while some point to sediment pathways that crosscut the dominant structural grain.

  • anatomy geometry and sequence stratigraphy of Basin Floor to slope turbidite systems tanqua karoo south africa
    Sedimentology, 2001
    Co-Authors: Stephen S Flint, Stephen D Johnson, David Hinds, H De Ville Wickens
    Abstract:

    The Tanqua area of the Karoo Basin, South Africa, contains five Permian deep-water turbidite fan systems, almost completely exposed over some 640 km2. Reconstruction of the Basin-fill and fan distributions indicates a progradational trend in the 450 m+ thick succession, from distal Basin Floor (fan 1) through Basin-Floor subenvironments (fans 2, 3 and 4) to a slope setting (fan 5). Fans are up to 65 m thick with gradational to sharp bases and tops. Facies associations include Basin plain claystone and distal turbidite siltstone/claystone and a range of fine-grained sandstone associations, including low- and high-density turbidite current deposits and proportionally minor debris/slurry flows. Architectural elements include sheets of amalgamated and layered styles and channels of five types. Each fan is interpreted as a low-frequency lowstand systems tract with the shaly interfan intervals representing transgressive and highstand systems tracts. All fans show complex internal facies distributions but exhibit a high-frequency internal stratigraphy based on fan-wide zones of relative sediment starvation. These zones are interpreted as transgressive and highstand systems tracts of higher order sequences. Sandy packages between these fine-grained intervals are interpreted as high-frequency lowstand systems tracts and exhibit dominantly progradational stacking patterns, resulting in subtle downdip clinoform geometries. Bases of fans and intrafan packages are interpreted as low- and high-frequency sequence boundaries respectively. Facies juxtapositions across these sequence boundaries are variable and may be gradational, sharp or erosive. In all cases, criteria for a Basinward shift of facies are met, but there is no standard ‘motif’ for sequence boundaries in this system. High-frequency sequences represent the dominant mechanism of active fan growth in the Tanqua deep-water system.

Julian Clark - One of the best experts on this subject based on the ideXlab platform.

  • architecture and stacking patterns of lower slope and proximal Basin Floor channelised submarine fans middle eocene ainsa system spanish pyrenees an integrated outcrop subsurface study
    Earth-Science Reviews, 2015
    Co-Authors: K T Pickering, Jordi Corregidor, Julian Clark
    Abstract:

    Abstract An integrated outcrop and subsurface study of the Middle Eocene (Lutetian) Ainsa System, Ainsa Basin, Spanish Pyrenees, was undertaken to characterise the proximal depositional environments of sandy channelised submarine fans, interfan and slope deposits, the results of which are presented here for the first time as a coherent synthesis and interpretation. It is unique for any drilling programme in coarse-grained deep-marine clastic sediments as it documents the facies, architecture, and evolution of the proximal parts of three structurally confined and channelised sandy lower-slope and proximal Basin-Floor submarine fans (Ainsa I, II and III fans). Eight wells were drilled through ~ 220–250 m of stratigraphy with typical inter-well spacing of ~ 400–500 m, with seismic lines, wireline logs, essentially continuous coring, sandstone petrography, micropalaeontological and palynomorph analyses. The fans show a lateral stepwise migration away from a growth anticline that formed the lateral Basin margin on the side of the growing Pyrenean orogen. Unlike the Ainsa I Fan, the Ainsa II and III fans appear to have an essentially non-erosive base overlain by at least several metres of relatively unconfined sandy deposits interpreted as pre-channel proximal-lobe deposits. Submarine channels erode into these proximal-lobe deposits, typically 5–30 m deep and hundreds of metres wide (~ 100–600 m). The channels are associated with composite erosional surfaces, local m-scale scouring, and pebbly lag deposits, suggesting substantial sediment bypass in the early stages of channel evolution, but with later channel abandonment and filling by finer-grained deposits. This process of channel incision, bypass and likely backfill appears to have occurred many times during the main growth phase of the sandy submarine fans, and with only one channel active at any time. Well correlations and mapping, including using bio-events, suggest the presence of levee–overbank deposits. Candidate lateral accretion packages suggest that there was an increase in channel sinuosity upwards from the Ainsa I, II and III fans, probably linked to an overall decrease in seaFloor gradients; supported by the presence of many tens of metres of essentially undeformed marlstones of very fine-grained, thin- to very thin-bedded turbidites in the upper parts of the Ainsa System. Depositional architecture was controlled by a combination of syn-sedimentary tectonics fashioned by seaFloor growth structures, climate change (affecting seaFloor environmental conditions that controlled bioturbation intensity) and probably autocyclic (intrafan) processes (that were probably responsible for individual channel elements). Local accommodation was controlled by intra-Basinal tectonics and the interplay between erosional and depositional processes, including irregular seaFloor topography created by cohesive debris flow and slide deposits (MTDs/MTCs). We also show that post-depositional thrusting and folding has created locally complex geometrical relationships within the fans and interfan deposits, which could not have been resolved without careful outcrop and subsurface mapping, logging and correlation.

Matthieu J.b. Cartigny - One of the best experts on this subject based on the ideXlab platform.

  • Sediment Volume and Grain-Size Partitioning Between Submarine Channel−Levee Systems and Lobes: An Experimental Study
    Journal of Sedimentary Research, 2018
    Co-Authors: Jan W De Leeuw, Maarten S Heijnen, Joris T Eggenhuisen, Yvonne T Spychala, Florian Pohl, Matthieu J.b. Cartigny
    Abstract:

    The width and depth of submarine channels change progressively as the channels evolve. This is inferred to act as an important control on the rate of sediment loss due overbank and in-channel deposition. Understanding the downstream extraction of sediment from turbidity currents is important for the prediction of grain-size trends and volume distribution in the stratigraphy. However, the partitioning of sediment by individual turbidity currents as a function of channel dimensions has not been investigated previously. We present a series of physical experiments studying the link between channel dimensions and the resulting partitioning of sediment volume and grain size between sub-environments. The experimental set-up consists of a slope (11°) with a straight pre-formed channel and a horizontal Basin Floor. An identical flow was released repeatedly into channels with different dimensions, resulting in various styles of overspill, erosion, and deposition under varying degrees of channel confinement. The fraction of sediment that was bypassed through the channel to the Basin Floor varied between 67% and 89%, depending on the amount of levee and in-channel deposition. The volume of levee deposition correlates well with channel depth. A large channel depth relative to flow thickness limits the amount of overspill. The amount of in-channel deposition correlates well with channel width/depth (W/D) ratio, where low-W/D-ratio channels have less deposition. We compare the experiments to natural system to show that the same patterns of volume and grain-size partitioning are present at different scales. The experiments provide snapshots of different phases of evolution of natural submarine channels. Natural submarine channels in an early evolution phase are inferred to be shallow and the experiments demonstrate that this results in significant sediment loss to levee deposition along the channel. The process of levee deposition preferentially extracts the fine-grained sediment fraction, which overspills from the channel. Therefore, we predict that the initial sediment pulse that reaches the Basin Floor is coarse grained and volumetrically small. As the channel matures and deepens, it will bypass more sediment with a mix of grain sizes to the Basin Floor.

  • sediment volume and grain size partitioning between submarine channel levee systems and lobes an experimental study
    Journal of Sedimentary Research, 2018
    Co-Authors: Maarten S Heijnen, Joris T Eggenhuisen, Yvonne T Spychala, Florian Pohl, Jan W De Leeuw, Matthieu J.b. Cartigny
    Abstract:

    The width and depth of submarine channels change progressively as the channels evolve. This is inferred to act as an important control on the rate of sediment loss due overbank and in-channel deposition. Understanding the downstream extraction of sediment from turbidity currents is important for the prediction of grain-size trends and volume distribution in the stratigraphy. However, the partitioning of sediment by individual turbidity currents as a function of channel dimensions has not been investigated previously. We present a series of physical experiments studying the link between channel dimensions and the resulting partitioning of sediment volume and grain size between sub-environments. The experimental set-up consists of a slope (11°) with a straight pre-formed channel and a horizontal Basin Floor. An identical flow was released repeatedly into channels with different dimensions, resulting in various styles of overspill, erosion, and deposition under varying degrees of channel confinement. The fraction of sediment that was bypassed through the channel to the Basin Floor varied between 67% and 89%, depending on the amount of levee and in-channel deposition. The volume of levee deposition correlates well with channel depth. A large channel depth relative to flow thickness limits the amount of overspill. The amount of in-channel deposition correlates well with channel width/depth (W/D) ratio, where low-W/D-ratio channels have less deposition. We compare the experiments to natural system to show that the same patterns of volume and grain-size partitioning are present at different scales. The experiments provide snapshots of different phases of evolution of natural submarine channels. Natural submarine channels in an early evolution phase are inferred to be shallow and the experiments demonstrate that this results in significant sediment loss to levee deposition along the channel. The process of levee deposition preferentially extracts the fine-grained sediment fraction, which overspills from the channel. Therefore, we predict that the initial sediment pulse that reaches the Basin Floor is coarse grained and volumetrically small. As the channel matures and deepens, it will bypass more sediment with a mix of grain sizes to the Basin Floor.

  • morphodynamics of submarine channel inception revealed by new experimental approach
    Nature Communications, 2016
    Co-Authors: Jan W De Leeuw, Joris T Eggenhuisen, Matthieu J.b. Cartigny
    Abstract:

    Submarine channels are ubiquitous on the seaFloor and their inception and evolution is a result of dynamic interaction between turbidity currents and the evolving seaFloor. However, the morphodynamic links between channel inception and flow dynamics have not yet been monitored in experiments and only in one instance on the modern seaFloor. Previous experimental flows did not show channel inception, because flow conditions were not appropriately scaled to sustain suspended sediment transport. Here we introduce and apply new scaling constraints for similarity between natural and experimental turbidity currents. The scaled currents initiate a leveed channel from an initially featureless slope. Channelization commences with deposition of levees in some slope segments and erosion of a conduit in other segments. Channel relief and flow confinement increase progressively during subsequent flows. This morphodynamic evolution determines the architecture of submarine channel deposits in the stratigraphic record and efficiency of sediment bypass to the Basin Floor.

Yvonne T Spychala - One of the best experts on this subject based on the ideXlab platform.

  • Flow‐process controls on grain type distribution in an experimental turbidity current deposit: Implications for detrital signal preservation and microplastic distribution in submarine fans
    'Wiley', 2021
    Co-Authors: Daniel Bell, Yvonne T Spychala, Ian A Kane, Euan L. Soutter, Zoë A. Cumberpatch, Ross A. Ferguson, Joris T Eggenhuisen
    Abstract:

    Abstract Deep‐water depositional systems are the ultimate sink for vast quantities of terrigenous sediment, organic carbon and anthropogenic pollutants, forming valuable archives of environmental change. Our understanding of the distribution of these particles and the preservation of environmental signals, in deep‐water systems is limited due to the inaccessibility of modern systems, and the incomplete nature of ancient systems. Here, the deposit of a physically modelled turbidity current was sampled (n = 49) to determine how grain size and grain type vary spatially. The turbidity current had a sediment concentration of 17%. The sediment consisted of, by weight, 65% quartz sand (2.65 g/cm3), 17.5% silt (2.65 g/cm3), 7.5% clay (2.60 g/cm3) and 5% each of sand‐grade garnet (3.90 g/cm3) and microplastic fragments (1.50 g/cm3). The grain size and composition of each sample was determined using laser diffraction and density separation, respectively. The results show that: (a) bulk grain size coarsened axially downstream on the Basin Floor challenging the notion that Basin Floor deposits fine radially from an apex upon becoming unconfined; (b) no sample composition matched the input composition of the flow, indicating that allogenic signals can be autogenically shredded and spatially variable in sediment gravity flow deposits; and (c) microplastic fragments were concentrated in levee and lateral Basin Floor fringe positions; however, microplastic concentrations in these positions were lower than input, suggesting microplastics bypassed the sampled positions. These findings have implications for: (a) the development of ‘finger‐like’ geometries and facies distributions observed in modern and ancient systems; (b) interpreting environmental signals in the stratigraphic record; and (c) predicting the distribution of microplastics on the sea Floor

  • the influence of Basin setting and turbidity current properties on the dimensions of submarine lobe elements
    Sedimentology, 2020
    Co-Authors: Joris T Eggenhuisen, Yvonne T Spychala, Mike Tilston, Florian Pohl
    Abstract:

    Submarine lobes have been identified within various deep‐water settings, including the Basin‐Floor, the base of slope and the continental slope. Their dimensions and geometries are postulated to be controlled by the topographic configuration of the seabed, sediment supply system and slope gradient. Ten experiments were conducted in a three‐dimensional‐flume to study the depositional characteristics of submarine lobes associated with: (i) different Basin Floor gradients (0 to 4°); (ii) different sediment concentrations of the parent turbidity current (11 to 19% vol); and (iii) varying discharge (25 to 40 m3 h−1). Most runs produced lobate deposits that onlapped onto the lower slope. Deposit length was proportional to Basin‐Floor angle and sediment volume concentration. A higher amount of bypass is observed in the proximal area as the Basin‐Floor angles get steeper and sediment concentrations higher. Deposits of runs with lower discharge could be traced higher upslope while runs with higher discharge produced an area of low deposition behind the channel mouth, i.e. discharge controlled whether lobe deposits were attached or detached from their channel‐levee systems. A particle‐advection‐length scale analysis suggests that this approach can be used as a first order estimation of lobe element length. However, the estimations strongly depend on the average grain size used for calculations (for example, silt is still actively transported after all sand has been deposited) and the method cannot be used to locate the main depocentre. Furthermore, attempted reconstructions of turbidity current velocities from natural systems suggest that the method is not appropriate for use in inversions from more complex composite bodies such as lobes.

  • sediment volume and grain size partitioning between submarine channel levee systems and lobes an experimental study
    Journal of Sedimentary Research, 2018
    Co-Authors: Maarten S Heijnen, Joris T Eggenhuisen, Yvonne T Spychala, Florian Pohl, Jan W De Leeuw, Matthieu J.b. Cartigny
    Abstract:

    The width and depth of submarine channels change progressively as the channels evolve. This is inferred to act as an important control on the rate of sediment loss due overbank and in-channel deposition. Understanding the downstream extraction of sediment from turbidity currents is important for the prediction of grain-size trends and volume distribution in the stratigraphy. However, the partitioning of sediment by individual turbidity currents as a function of channel dimensions has not been investigated previously. We present a series of physical experiments studying the link between channel dimensions and the resulting partitioning of sediment volume and grain size between sub-environments. The experimental set-up consists of a slope (11°) with a straight pre-formed channel and a horizontal Basin Floor. An identical flow was released repeatedly into channels with different dimensions, resulting in various styles of overspill, erosion, and deposition under varying degrees of channel confinement. The fraction of sediment that was bypassed through the channel to the Basin Floor varied between 67% and 89%, depending on the amount of levee and in-channel deposition. The volume of levee deposition correlates well with channel depth. A large channel depth relative to flow thickness limits the amount of overspill. The amount of in-channel deposition correlates well with channel width/depth (W/D) ratio, where low-W/D-ratio channels have less deposition. We compare the experiments to natural system to show that the same patterns of volume and grain-size partitioning are present at different scales. The experiments provide snapshots of different phases of evolution of natural submarine channels. Natural submarine channels in an early evolution phase are inferred to be shallow and the experiments demonstrate that this results in significant sediment loss to levee deposition along the channel. The process of levee deposition preferentially extracts the fine-grained sediment fraction, which overspills from the channel. Therefore, we predict that the initial sediment pulse that reaches the Basin Floor is coarse grained and volumetrically small. As the channel matures and deepens, it will bypass more sediment with a mix of grain sizes to the Basin Floor.

  • Sediment Volume and Grain-Size Partitioning Between Submarine Channel−Levee Systems and Lobes: An Experimental Study
    Journal of Sedimentary Research, 2018
    Co-Authors: Jan W De Leeuw, Maarten S Heijnen, Joris T Eggenhuisen, Yvonne T Spychala, Florian Pohl, Matthieu J.b. Cartigny
    Abstract:

    The width and depth of submarine channels change progressively as the channels evolve. This is inferred to act as an important control on the rate of sediment loss due overbank and in-channel deposition. Understanding the downstream extraction of sediment from turbidity currents is important for the prediction of grain-size trends and volume distribution in the stratigraphy. However, the partitioning of sediment by individual turbidity currents as a function of channel dimensions has not been investigated previously. We present a series of physical experiments studying the link between channel dimensions and the resulting partitioning of sediment volume and grain size between sub-environments. The experimental set-up consists of a slope (11°) with a straight pre-formed channel and a horizontal Basin Floor. An identical flow was released repeatedly into channels with different dimensions, resulting in various styles of overspill, erosion, and deposition under varying degrees of channel confinement. The fraction of sediment that was bypassed through the channel to the Basin Floor varied between 67% and 89%, depending on the amount of levee and in-channel deposition. The volume of levee deposition correlates well with channel depth. A large channel depth relative to flow thickness limits the amount of overspill. The amount of in-channel deposition correlates well with channel width/depth (W/D) ratio, where low-W/D-ratio channels have less deposition. We compare the experiments to natural system to show that the same patterns of volume and grain-size partitioning are present at different scales. The experiments provide snapshots of different phases of evolution of natural submarine channels. Natural submarine channels in an early evolution phase are inferred to be shallow and the experiments demonstrate that this results in significant sediment loss to levee deposition along the channel. The process of levee deposition preferentially extracts the fine-grained sediment fraction, which overspills from the channel. Therefore, we predict that the initial sediment pulse that reaches the Basin Floor is coarse grained and volumetrically small. As the channel matures and deepens, it will bypass more sediment with a mix of grain sizes to the Basin Floor.