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Deep-water fold-and-thrust belt (DWFTB) systems are gravity-driven collapse structures often found in passive margin settings and are comprised of a linked up-dip extensional domain, central transitional/translational domain, and down-dip compressional domain. Many Late Cretaceous DWFTB systems occur along the SW African passive margin with multiple, over-pressurized, seaward-dipping shale detachment surfaces accommodating gravitational slip. In this study we use 3D reflection seismic data to constrain the strato-structural evolution of the translational and compressional domains of a Late Cretaceous DWFTB system and the overlying Cenozoic deposits in the Orange Basin, South Africa. The stratigraphy and structure of the Late Cretaceous DWFTB system is shown to have controlled fundamental sedimentary processes and the stability of the evolving margin. The compressional domain exhibits large-scale landward-dipping DWFTBs with thrust faults detaching the main Turonian shale detachment surface at depth and terminating at the early Campanian surface. A major ∼ 7 km wide seafloor slump scar reflecting margin instability occurs directly above a syncline of the same width from the buried DWFTB system's compressional domain. The translational domain is imaged as a complex region displaying overprinted features of both extensional and compressional tectonics with the downslope translation of sediment comprising listric normal and then thrust and oblique-slip faults distally. Thrust sheets are segmented along strike by extensive oblique-slip faults which extend from the translational domain into the down-dip compressional domain. Smaller, localized fold-and-thrust belts are found directly below the kilometre-scale DWFTB system in the down-dip compressional domain detaching a lower, Albian shale detachment surface which corresponds to an older gravitational collapse. The upward propagation of normal and oblique-slip faults with progressive sedimentation is hindered by the Oligocene or Miocene stratigraphic markers corresponding to mass erosional processes in the Cenozoic. A large (∼ 2.3 km wide), roughly slope-perpendicular Oligocene submarine canyon formed by turbidity currents is attributed to a major sea-level fall at ∼ 30 Ma. Oceanographic circulation is shown to have held a significant control on the deposition of mid-Miocene to present-day sedimentary sequences. Between 1200 to 1500 m water depths along the upper continental slope well-preserved extensive slope-parallel, sinusoidal channel-like features occur on the Miocene stratigraphic marker. The channels are confined within a ∼ 14 km wide zone at the interface of the upper northward-flowing Antarctic Intermediate Water (AAIW) and deeper southward-flowing North Atlantic Deep Water (NADW) currents. The erosive interaction of these oppositely flowing bottom currents combined with the effects of the Benguela Upwelling System (BUS), all of which formed or intensified at ∼ 11 Ma, are responsible for the creation and preservation of the extensive slope-parallel channels. This study shows the difference in structural styles of the translational and compressional domains of a Late Cretaceous DWFTB system and the processes responsible for mass-scale erosion in the Cenozoic. [ABSTRACT FROM AUTHOR]

Modern marine seismic reflection data have allowed for the study of the morphology of submarine channels in a 3D perspective. This study presents a quantitative analysis of continental slope channel complexes morphology within the Canterbury Basin (New Zealand). It aims to characterize the morphology and seismic facies of submarine channels to better understand their formative sedimentary processes, paleoenvironment, and petroleum prospectivity. Submarine channel morphometric parameters are measured at 150 m intervals perpendicular to the axis of channels complexes. Based on the morphology analysis of erosional surfaces and seismic facies of channel complexes filling deposits, four types of continental slope channel complexes are found in the study area. These are vertical migrating channels, lateral migrating channels, V-shaped channels, and U-shaped channels. Furthermore, our work shows that channel morphometry varies over distances of 0.1 to 14 km in this continental slope system. These changes indicate a combination of submarine gravity flow process and channel wall collapse responsible for the development of continental slope channel complexes. Regionally, the evolution of the channels indicated less significant regional plate movement. This quantitative seismic geomorphology approach of characterizing submarine channels system has broader applications for better interpretation of paleoenvironment and petroleum prospectivity within frontier basins. [ABSTRACT FROM AUTHOR]

The Andaman Sea Basin, a well-known back-arc spreading centre and a mature petroliferous basin, presents a unique and complex scenario for understanding the interplay of sedimentary processes and fault tectonics on seafloor geomorphology evolution, particularly in the eastern shelf region. This study, using high-resolution 3D seismic data and published exploratory well-seismic interpretation results, aims to establish a comprehensive stratigraphic framework for the Tanintharyi region, spanning the Lower Miocene, Middle Miocene, Upper Miocene, Pliocene, and Quaternary. A submarine canyon system was identified and investigated along the Tanintharyi continental slope within the East Andaman Basin, comprising thirteen slope-confined canyons arranged predominantly in an east-west vertical slope orientation. By analysing seismic reflection features, five distinct seismic facies have been identified, including basal lag (BL), slump and debris-flow deposits (SDFDs), canyon confined sheets (CCSs), laterally inclined packages (LIPs), and channel-levees (CLs). The evolution of this canyon system, a vital focus of this study, can be categorised into three phases based on the morphology and sedimentary structures observed: canyon initiation, canyon extension, and erosion-sedimentation. The findings of this study highlight the critical controlling role of faults in canyon evolution, with the intensity of fault activity displaying a negative correlation with canyon size, indicating the direct impact of faults on geomorphological changes. In addition, the geomorphological changes induced by fault activity have resulted in changes in sediment supply, dispersal, and sedimentation rates, thus significantly impacting the spatial distribution and dimensions of slope-confined canyons within the East Andaman Basin, with far-reaching implications. [Display omitted] • A matured canyon system exists in the Tanintharyi region of the East Andaman Basin. • Thirteen slope-confined canyons show nearly an east-west vertical slope alignment. • The sedimentary characteristics of these canyons display three stages of evolution. • Geomorphological changes induced by fault activity impacted the canyon's evolution. • Intensity of fault activities displays a negative correlation with canyon extent. [ABSTRACT FROM AUTHOR]

Analysis of multichannel seismic profiles collected on the continental rise off the Sabrina Coast, East Antarctica, has allowed the determination of the acoustic features that are indicative of major evolution steps of the East Antarctic Ice Sheet (EAIS) and highlights the role of meltwater that originated from Totten Glacier in shaping the margin architecture. The arrival of marine-terminating glaciers into the coastal region was recorded by an enhanced sediment input on the continental rise and the nucleation of channel-levees. Downslope sedimentary processes were dominant throughout the Late Cenozoic, testifying to the progressive growth of a highly dynamic, temperate ice sheet on the continent. The last evolutionary step marks the transition to when a full polar glacial regime occurred. The development of a prograding wedge with steeply dipping foresets on the continental shelf and slope exemplifies sedimentation at this time. Other sub-sea-floor observations indicate that downslope fluxes, triggered by glacial meltwater, were still able to deeply erode and deliver sediments to the rise area. This study's findings have led to the identification of expanded and well-preserved sedimentary successions, which we suggest should be considered as priority targets for future International Ocean Discovery Program deep drilling due to the sensitivity of the ice sheet in this area. [ABSTRACT FROM AUTHOR]

Submarine canyons are common features on the northern South China Sea (SCS) continental slope. Three main submarine canyon systems were observed by multi‐beam investigation and evaluated by a pre‐existing sedimentary dataset. They include the Xisha Canyon Zone, Shenhu Canyon Zone, and Taiwan Canyon Zone on the northern SCS continental slope which developed from the middle Miocene to the present‐day. Previous analysis implied that an enriched oil‐gas accumulation formed under this region with distinct gravity anomalies or active tectonic activity. Previous interpretation and geodynamics studies have revealed the detailed sedimentary records and the coupled tectonic‐sedimentary processes. However, the timing and mechanism of formation of the canyons on the northern SCS slope are still poorly constrained and vigorously debated, especially the differences among three submarine canyons from west to east that requires allowances for a variety of conflicting datasets. Here, we adopt the high‐resolution multi‐beam relief map and seismic profiles from these three canyon systems to estimate if the SCS slope controlled geometric segmentation and differentiation of canyon formation mechanisms and times. For this purpose, we ascertained that these canyons were initially controlled by the NE‐ to NW‐trending faults as a better constraint on the sediment flow direction. All the submarine canyons in the northern SCS slope extend in a range from NE‐/N–S‐ to NW‐ and E–W‐trending directions associated with the SCS oceanic spreading and the subsequent subduction‐related deformation along the Manila Trench. Furthermore, the present‐day morphology of these canyons implies a remarkable tectonic jump from west to east in the SCS continental slope and a north‐westward recession of the continental slope. Apart from the neo‐tectonic faults, the sea‐level fluctuation, gas hydrate disassociation, sediment source, and transportation channel also yielded dynamic processes and preservation for the submarine canyons. We finally propose a coupling model of the sedimentary and tectonic processes and confirm the spatial and temporal evolution of mechanisms of these canyons. [ABSTRACT FROM AUTHOR]

The availability of the micronutrient iron (Fe) in surface waters determines primary production, N2 fixation, and microbial community structure in large parts of the world's ocean, and thus it plays an important role in ocean carbon and nitrogen cycles. Eastern boundary upwelling systems and the connected oxygen minimum zones (OMZs) are typically associated with elevated concentrations of redox-sensitive trace metals (e.g., Fe, manganese (Mn), and cobalt (Co)), with shelf sediments typically forming a key source. Over the last 5 decades, an expansion and intensification of OMZs has been observed and this trend is likely to proceed. However, it is unclear how trace-metal (TM) distributions and transport are influenced by decreasing oxygen (O2) concentrations. Here we present dissolved (d; <0.2 µ m) and leachable particulate (Lp; >0.2 µ m) TM data collected at seven stations along a 50 km transect in the Mauritanian shelf region. We observed enhanced concentrations of Fe, Co, and Mn corresponding with low O2 concentrations (<50 µ mol kg -1), which were decoupled from major nutrients and nutrient-like and scavenged TMs (cadmium (Cd), lead (Pb), nickel (Ni), and copper (Cu)). Additionally, data from repeated station occupations indicated a direct link between dissolved and leachable particulate Fe, Co, Mn, and O2. An observed dFe (dissolved iron) decrease from 10 to 5 nmol L -1 coincided with an O2 increase from 30 to 50 µ mol kg -1 and with a concomitant decrease in turbidity. The changes in Fe (Co and Mn) were likely driven by variations in their release from sediment pore water, facilitated by lower O2 concentrations and longer residence time of the water mass on the shelf. Variations in organic matter remineralization and lithogenic inputs (atmospheric deposition or sediment resuspension; assessed using Al as indicator for lithogenic inputs) only played a minor role in redox-sensitive TM variability. Vertical dFe fluxes from O2 -depleted subsurface-to-surface waters (0.08–13.5 µ mol m -2 d -1) driven by turbulent mixing and vertical advection were an order of magnitude larger than atmospheric deposition fluxes (0.63–1.43 µ mol m -2 d -1 ; estimated using dAl inventories in the surface mixed layer) in the continental slope and shelf region. Benthic fluxes are therefore the dominant dFe supply to surface waters on the continental margins of the Mauritanian upwelling region. Overall, our results indicated that the projected future decrease in O2 concentrations in OMZs may result in increases in Fe, Mn, and Co concentrations. [ABSTRACT FROM AUTHOR]

This study uses high‐quality two‐dimensional (2‐D) seismic and well data to analyse seismic stratigraphy and deep‐water Pliocene sediments in the Qiongdongnan Basin (QDNB), South China Sea. Eight major seismic facies were identified based on the amplitude, continuity, configuration, and external geometry of seismic reflections. Among them, sigmoid progradational configurations, oblique progradational configurations, mound‐shaped chaotic configurations, and mound‐shaped hummocky configurations are newly identified seismic facies indicative of provenance and water system significance. They were interpreted as a Pliocene‐aged eastern shelf‐edge delta, a western shelf‐edge delta, and eastern and western submarine fans in QDNB. Consequently, two sets of Pliocene shelf‐edge delta‐continental slope canyon‐submarine fan systems were established in the QDNB. From the approximately NNW–SSE progradation of the shelf‐edge delta, the characteristics of the approximately ENE–WSW distributed continental slope system, and the definition of a source‐to‐sink system, as well as previous heavy mineral research, we conclude the existence of two Pliocene sources from Hainan Island in the northern QDNB, corresponding to the Lingshui River and Wanquan River. Two independent and complete source‐to‐sink systems (S2S‐2, S2S‐3) were distinguished from the northern Hainan Island to the basin area. S2S‐2 is located in the western QDNB, which includes the Lingshui River‐western shelf‐edge delta‐continental slope canyon‐submarine fan. This source‐to‐sink system has more sand‐rich material and better reservoir conditions than S2S‐3 in the eastern basin, predominantly due to a higher quality granite parent rock, abundant provenance, and a large‐scale delta and submarine fan. [ABSTRACT FROM AUTHOR]

The integrated interpretation of high-resolution multibeam bathymetry, seismic profiles and backscatter data in the S. Eufemia Gulf (SEG; Calabro-Tyrrhenian continental margin, south-eastern Tyrrhenian Sea) documents the relationship between postglacial fault activity and morpho-sedimentary processes. Three systems of active normal faults that affect the seafloor or the shallow subsurface, have been identified: 1) the S. Eufemia fault system located on the continental shelf with fault planes mainly oriented N26E-N40E; 2) the offshore fault system that lies on the continental slope off Capo Suvero with fault planes mainly oriented N28E-N60E; 3) the Angitola Canyon fault system located on the seafloor adjacent to the canyon having fault planes oriented N60E-N85E. The faults produce a belt of linear escarpments with vertical displacement varying from a few decimeters to about 12 m. One of the most prominent active structures is the fault F1 with the highest fault length (about 9.5 km). Two main segments of this fault are identified: a segment characterised by seafloor deformation with metric slip affecting Holocene deposits; a segment characterised by folding of the seafloor. A combined tectono-stratigraphic model of an extensional fault propagation fold is proposed here to explain such different deformation. In addition to the seabed escarpments produced by fault deformation, in the SEG, a strong control of fault activity on recent sedimentary processes is clearly observed. For example, canyons and channels frequently change their course in response to their interaction with main tectonic structures. Moreover, the upper branch of the Angitola Canyon shows straight flanks determined by fault scarps. Tectonics also determined different sediment accumulation rates and types of sedimentation (e.g., the accumulation of hanging wall turbidite deposits and the development of contourite deposits around the Maida Ridge). Furthermore, the distribution of landslides is often connected to main fault scarps and fluids are locally confined in the hanging wall side of faults and can escape at the seabed, generating pockmarks aligned along their footwall. • Active faults are imaged by multibeam bathymetry and seismic profiles. • Three main systems of faults affect the continental shelf and slope sectors. • A tectono-stratigraphic model of an extensional fault propagation fold is proposed. • Tectonic activity exerts a strong control on seabed morphology and recent processes. • Margin shaping results from the interplay between tectonic and non-tectonic factors. [ABSTRACT FROM AUTHOR]

Several high-resolution 'SES 2000 deep' seismic profiles and a core of bottom sediments were obtained in cruises 33, 35, and 37 of the R/V Akademik Ioffe in the area of the Columbia channel (continental rise of Brazil, South America). The analysis of seismic facies and direct correlation of acoustic and lithological data indicates that sedimentation in this area is mostly controlled by the contour current of the Antarctic Bottom Water (AABW). The gravity flows from seamounts and continental slope only episodically contributed coarser material to the deposition of the muddy contourites. The mixed gravitite-contourite systems consisting of accumulative bodies (drifts) and erosion channels are the results of interaction of these sedimentation processes. [ABSTRACT FROM AUTHOR]

Recent studies suggest that as much as half of the organic carbon (OC) undergoing burial in the sediments of tectonically active continental margins may be the product of fossil shale weathering. These estimates rely on the assumption that vascular plant detritus spends little time sequestered in intermediate reservoirs such as soils, freshwater sediments, and river deltas, and thus only minimally contributes to the extraneously old 14C ages of total organic matter often observed on adjacent shelves. Here we test this paradigm by measuring the Δ14C and δ13C values of individual higher plant wax fatty acids as well as the δ13C values of extractable alkanes isolated from the Eel River margin (California). The isotopic signatures of the long chain fatty acids indicate that vascular plant material has been sequestered for several thousand years before deposition. A coupled molecular isotope mass balance used to reassess the sedimentary carbon budget indicates that the fossil component is less abundant than previously estimated, with pre-aged terrestrial material instead composing a considerable proportion of all organic matter. If these findings are characteristic of other continental margins proximal to small mountainous rivers, then the importance of petrogenic OC burial in marine sediments may need to be reevaluated. [ABSTRACT FROM AUTHOR]

We present new Sm–Nd isotope data for sediments from a core located on the continental slope of the St. Pierre Bank of Canada’s east coast. The Nd analyses indicate that the sediments were derived from two principal sources: the North American Shield that yields an average early Proterozoic isotopic signature and a younger Proterozoic signature attributed to Appalachian crustal sources. The Appalachian-sourced sediments predominated during the last glacial maximum (LGM) and were associated with low sedimentation rates (<30 cm/ka), with the exception of a strong North American Shield signature present in a detrital carbonate layer that corresponds to Heinrich Layer 1 (H1). The dominance of the Appalachian signature decreased subsequent to H1. The Appalachian signatures closely follow the distribution of sediments interpreted as locally derived glacial tills, while the North American Shield signatures follow the distribution of hemipelagic mud that was likely deposited by the Labrador Current. The Nd data are consistent with the persistence of the Wisconsinan Ice Sheet coverage of Newfoundland and the Grand Banks after the LGM, although the coverage began to wane prior to 12.5 ka as evidenced by the increasing influence of the Labrador Current. However, an increase in the Appalachian isotope signature at the close of the Younger Dryas event likely indicates the final melting of the ice sheet covering the Grand Banks and the Avalon Peninsula, and the initiation of the Labrador Current’s modern circulation pathway. Nous présentons de nouvelles données isotopiques Sm–Nd pour les sédiments provenant d’une carotte prélevée sur la pente continentale du Banc de Saint-Pierre de la Côte Est du Canada. Les analyses de Nd indiquent que les sédiments proviennent surtout de deux sources : le Bouclier nord-américain, lequel fournit une signature isotopique moyenne du Protérozoïque précoce et une signature Protérozoïque plus jeune attribuée aux sources de la croûte appalachienne. Les sédiments provenant de la source appalachienne prédominaient lors du dernier maximum glaciaire et ils sont associés à des taux de sédimentation faibles (< 30 cm/ka), à l’exception d’une forte signature du Bouclier nord-américain présente dans une couche de carbonate détritique qui correspond à l’événement Heinrich 1 (H1). La dominance de la signature appalachienne décroît après le H1. Les signatures appalachiennes suivent de près la distribution des sédiments, lesquels proviendraient de tills glaciaires, alors que les signatures du Bouclier nord-américain suivent la distribution d’une boue hémipélagique qui a fort probablement été déposée par le courant du Labrador. Les données Nd concordent avec la persistance de la couverture de la calotte glaciaire wisconsinienne de Terre-Neuve et des Grands Bancs après le dernier maximum glaciaire, bien que la couverture ait commencé à diminuer il y a plus de 12,5 ka, tel que mis en évidence par l’influence croissante du courant du Labrador. Toutefois, une augmentation de la signature isotopique appalachienne vers la fin de l’événement du Dryas Récent indique probablement la fonte finale de la calotte glaciaire qui recouvrait les Grands Bancs et la presqu'île Avalon et le début du tracé moderne de circulation du courant du Labrador. [ABSTRACT FROM AUTHOR]

Internal solitary wave shoaling is the product of the interaction of internal solitary waves (ISWs) with the seafloor. There will be a series of changes in the waveform of the internal solitary wave when water depth decreases, and it affects the flow near the seafloor. These processes are captured by the seismic oceanography(SO) method. We analyze and summarize water-column reflections characteristics in the Dongsha region of South China Sea(SCS). The interior of the ocean is dominated by high/low frequency internal waves, internal solitary waves and high-mode internal waves. The seismic oceanography profiles record 45 internal solitary waves in the study area, and the depression waves are widely distributed in both deep and shallow water area. During their shoaling process in the Dongsha region, the depression waves gradually come into the transition stage under influence of the topography, and finally convert its polarity to elevation waves in the shallow water area. In addition, the energy dissipation during the internal solitary wave shoaling process, has an important impact on the shaping of the upper continental slope in the northern South China Sea.It is proposed that the computational fluid dynamic (CFD) modelling is combined with seismic forward modelling to study seawater seismic facies. Modelling experiments are focused on internal solitary waves shoaling as well as the formation and evolution of seismic facies over sand dunes. Shoaling internal solitary waves propagating westward in the northeastern South China Sea of depression, transition and elevation types are simulated. The temperature, velocity field and seismic reflection events in forward modelling sections are compared with observed SO data. The shape of isothermal curve is analyzed to study the speed of ISWs and the effect of seafloor fiction. Different Iribarren numbers are discussed to study the diverse types of ISW breaking, including surging and plunging breaking.The depression and elevation internal solitary waves bring about the southeast and northwest direction wave-induced currents respectively. On the one hand these near-bed wave-induced currents resuspend sediment particles into water columns to generate nepheloid layers, and on the other hand they contribute to the bed load, which maintains the very large sand dunes formation and migration. Seawater seismic facies over sand dunes are analyzed, including the coupling of seismic events and morphology, the high frequency oscillating seismic events in both edges of ISWs, and hair reflection configuration seismic events over sand dunes on slope. Modelling results show that the coupling of sand dunes and seismic events may be related to unidirection flow over sand dunes. The high frequency oscillating seismic events in both edges of ISWs are related to ISWs propagating over sand dunes. While the shape of the oscillating seismic events is similar to undulation of sand dunes in the beginning, they are reshaped by ISWs and move toward the same direction of ISW propagation. This study may reveal the relationship among multi-scale movements of seawater, bottom topography and sedimentary processes, which can deepen the understanding of the seafloor interface process. [ABSTRACT FROM AUTHOR]

The Capbreton canyon stands out by its deep incision through continental shelf and slope and its present turbidity activity. The head of the canyon is disconnected from the Adour River since 1310 AD but is located close enough to the coast to allow a direct supply by longshore drifting. Gravity processes in the canyon body are well understand, but many questions remain for the head and the upper part of the Capbreton submarine canyon such as: Which kind of gravity processes provide sediment transfer from the head to the canyon? How these processes interact with the canyon floor morphology: floor shaping and feedback? Our study is based on the analysis and comparison of eight multibeam bathymetric surveys acquired between 1998 and 2018 from a depth of 10 to 320 m below sea level. This data set covers the same area of the upper part of the canyon and allows the comparison and morphologic follow-up of this outstanding dynamic area. This proximal dataset is completed by two distal bathymetric surveys on a meander at 1500m water depth acquired in the canyon in 2013 and 2016. The morphological evolutions in these sites over the last 20 years especially affect the canyon floor and the canyon head. Time of flat floor talweg is observed, succeeded by a period of talweg incision (low lateral terraces and axial narrow talweg). The entrenchment of the narrow talweg is induced by retrogressive erosion and is evidenced by upstream-migrating-knickpoints suggesting a return to the equilibrium profile. The construction process of the low terraces observed here appears to be an analog of the fluvial terraces construction, where axial channel entrenchment follow the sediment filling of the valley. Time of flat shaped talweg (1998) suggests a partial filling of the canyon talweg related to a substantial emptying of the canyon head and significant mass transfer to the proximal part of the canyon. Such flat floor talweg has not been observed again so far (since 2010), suggesting a possible quieter working mode of the canyon. In fact, in the light of currentmeter data (ADCP) recorded during winters 2015 and 2016 (at 555, 900 and 1500m water depth in the canyon), periods of talweg entrenchment (2010 to present day) are subject to gravity flows weaker than 40 cm.s-1. However, first accurate volume quantification on the canyon floor has been undertaken. This underlines an alternation of filling and erosive periods in the canyon axis and an unexpected continuous sediment deposition in the canyon head during the last 20 years. At the present time, the canyon head is filling up and we may fear an important head emptying including costal risks during the upcoming violent event. [ABSTRACT FROM AUTHOR]

Submarine mass movements may have profound effects on the morphology and stratigraphic architecture of continental margins. Furthermore, they can represent a threat to human life and infrastructures, and also have implications for hydrocarbon exploration/production. In polar regions, they are one of the predominant sedimentary processes on the continental slope. Exploration seismology has been widely employed to study masstransport deposits (landslides, glacigenic debris flows, mass flows, etc.), which are usually characterized by chaotic reflections. In this study, we analyse a seismic profile acquired in the southern part of the Storfjorden trough mouth fan (NW Barents Sea margin), showing the presence of two submarine mass-transport deposits (MTDs). A giant MTD (PLS-1) is located on the lower continental slope at 2.6–3 km depth, while a more recent MTD (PLS-2) occurs at 1.9–2.4 km depth. Velocity and attenuation seismic tomography, seismic attributes analyses and rock-physics models reveal distinct petrophysical properties for PLS-1 and PLS-2. Despite the known influence of burial depth(s), fluid flow content, and compaction on the internal character of MTDs, the two deposits studied here, in fact, show distinct petrophysical characteristics that reflect lithological variations - more than to any other control. These results suggest different source areas for the two MTDs. The inferred coarser sediment in PLS-1 indicates provenance from areas with abundant glacigenic debris flows, (such as the Bjørnøya Trough-Mouth Fan). Conversely, the finer, relatively fluid-rich sediments of PLS-2 that underwent little translation could have an origin in the area between trough-mouth fans. Here, slow-moving ice resulted in a relatively scarce release of subglacial debris at the shelf edge and the continental slope was subject to enhanced erosion and degradation with a comparatively higher production of relatively fine-grained turbidite flows. [ABSTRACT FROM AUTHOR]