scholarly journals Channel incision into a submarine landslide: an exhumed Carboniferous example from the Paganzo Basin, San Juan, Argentina

2021 ◽  
Author(s):  
David Hodgson ◽  
Jeff Peakall ◽  
Charlotte Allen ◽  
Luz Gomis Cartesio ◽  
Juan Pablo Milana
Keyword(s):  
Sediment Transport ◽  
Large Scale ◽  
Submarine Landslide ◽  
Geological Mapping ◽  
Transport Systems ◽  
Submarine Landslides ◽  
Dispersal Patterns ◽  
Paganzo Basin ◽  
Mass Transport Deposits ◽  
Erosion Surface

Emplacement of submarine landslides, or mass transport deposits, can radically reshape the physiography of continental margins, and strongly influence subsequent sedimentary processes and dispersal patterns. The irregular relief they generate creates obstacles that force reorganisation of sediment transport systems. Subsurface and seabed examples show that channels can incise directly into submarine landslides. Here, we use high-resolution sedimentological analysis, geological mapping and photogrammetric modelling to document the evolution of two adjacent, and partially contemporaneous, sandstone-rich submarine channel-fills (NSB and SSB) that incised deeply (>75 m) with steep lateral margins (up to 70°) into a 200 m thick debrite. The stepped erosion surface mantled by clasts, ranging from gravels to cobbles, points to a period of downcutting and sediment bypass. A change to aggradation is marked by laterally-migrating sandstone-rich channel bodies that is coincident with prominent steps in the large-scale erosion surface. Two types of depositional terrace are documented on these steps: one overlying an entrenchment surface, and another located in a bend cut-off. Above a younger erosion surface, mapped in both NSB and SSB, is an abrupt change to partially-confined tabular sandstones with graded caps, interpreted as confined lobes. The lobes are characterised by a lack of compensational stacking and increasingly thick hybrid bed deposits, suggesting progradation of a lobe complex confined by the main erosion surface. The incision of adjacent and partially coeval channels into a thick submarine landslide, and sand-rich infill including development of partially confined lobes, reflects the complicated relationships between evolving relief and changes in sediment gravity flow character, which can only be investigated at outcrop. The absence of channel-fills in bounding strata, and the abrupt and temporary presence of coarse sediment infilling the channels, indicates that the submarine landslide emplacement reshaped sediment transport systems, and established conditions that effectively separated sand- from mud-dominated deposits.

scholarly journals SUBSTRATE ENTRAINMENT, DEPOSITIONAL RELIEF, AND SEDIMENT CAPTURE: IMPACT OF A SUBMARINE LANDSLIDE ON FLOW PROCESS AND SEDIMENT SUPPLY

2021 ◽  
Author(s):  
Ander Martínez-Doñate ◽  
Aurelia Privat ◽  
David Hodgson ◽  
Chris Jackson ◽  
Ian Kane ◽  
...  
Keyword(s):  
Large Scale ◽  
Submarine Landslide ◽  
Sediment Supply ◽  
Submarine Landslides ◽  
Dispersal Patterns ◽  
Flow Process ◽  
Growth Strata ◽  
Shallow Marine ◽  
Depositional Processes ◽  
Stratal Architecture

Submarine landslides can generate complicated patterns of seafloor relief that influence subsequent flow behaviour and sediment dispersal patterns. While the large-scale morphology of submarine landslide deposits, or mass transport deposits (MTDs), can be resolved in seismic data, the nature of their upper surface, and its impact on facies distributions and stratal architecture of overlying deposits, is rarely resolvable. MTD is a commonly used term in subsurface studies, covering a range of processes and resultant deposits that can not be resolved in seismic or core-based datasets. However, field-based studies often allow a more detailed characterisation of the deposit. The early post-rift Middle Jurassic deep-water succession of the Los Molles Formation is exceptionally well-exposed along a dip-orientated WSW-ENE outcrop belt in the Chacay Melehue depocentre, Neuquén Basin, Argentina. We correlate 27 sedimentary logs constrained by marker beds to document the sedimentology and architecture of a >47 m thick and at least 9.6 km long mud-rich debrite. The debrite overlies ramps and steps, indicating erosion and substrate entrainment. Megaclasts sourced from shallow-marine environments support a shallow marine origin of the mass failure. Two distinct sandstone-dominated units overlie the debrite. The lower sandstone unit is characterised by: i) abrupt thickness changes, wedging and progressive rotation of laminae in sandstone beds associated with growth strata; and ii) detached sandstone load balls within the underlying debrite. The combination of these features suggests syn-sedimentary foundering processes due to density instabilities at the top of the fluid-saturated mud-rich debrite. The debrite relief controlled the spatial distribution of foundered sandstones. The upper sandstone unit is characterised by thin-bedded deposits, locally overlain by medium- to thick-bedded lobe axis/off-axis deposits. The thin-beds show local thinning and onlapping onto the debrite, where it develops its highest relief. Facies distributions and stacking patterns record the progradation of submarine lobes and their complex interaction with long-lived debrite-related topography. These characteristics can help us understand post-depositional processes above MTDs and predict facies distributions and palaeoenvironments in subsurface datasets. The emplacement of a kilometre-scale debrite in an otherwise mud-rich basinal setting and accumulation of overlying sand-rich deposits suggests a genetic link between the mass-wasting event and transient coarse clastic sediment supply to an otherwise sand-starved part of the basin.

scholarly journals Substrate Entrainment, Depositional Relief, and Sediment Capture: Impact of a Submarine Landslide on Flow Process and Sediment Supply

2021 ◽  
Vol 9 ◽  
Author(s):  
A. Martínez-Doñate ◽  
A. M-L. J. Privat ◽  
D. M. Hodgson ◽  
C. A-L. Jackson ◽  
I. A. Kane ◽  
...  
Keyword(s):  
Large Scale ◽  
Submarine Landslide ◽  
Sediment Supply ◽  
Submarine Landslides ◽  
Dispersal Patterns ◽  
Flow Process ◽  
Seismic Reflection Data ◽  
Growth Strata ◽  
Reflection Data ◽  
Stratal Architecture

Submarine landslides can generate complicated patterns of seafloor relief that influence subsequent flow behaviour and sediment dispersal patterns. In subsurface studies, the term mass transport deposits (MTDs) is commonly used and covers a range of processes and resultant deposits. While the large-scale morphology of submarine landslide deposits can be resolved in seismic reflection data, the nature of their upper surface and its impact on both facies distributions and stratal architecture of overlying deposits is rarely resolvable. However, field-based studies often allow a more detailed characterisation of the deposit. The early post-rift Middle Jurassic deep-water succession of the Los Molles Formation is exceptionally well-exposed along a dip-orientated WSW-ENE outcrop belt in the Chacay Melehue depocentre, Neuquén Basin, Argentina. We correlate 27 sedimentary logs constrained by marker beds to document the sedimentology and architecture of a >47 m thick and at least 9.6 km long debrite, which contains two different types of megaclasts. The debrite overlies ramps and steps, indicating erosion and substrate entrainment. Two distinct sandstone-dominated units overlie the debrite. The lower sandstone unit is characterised by: 1) abrupt thickness changes, wedging and progressive rotation of laminae in sandstone beds associated with growth strata; and 2) detached sandstone load balls within the underlying debrite. The combination of these features suggests syn-sedimentary foundering processes due to density instabilities at the top of the fluid-saturated mud-rich debrite. The debrite relief controlled the spatial distribution of foundered sandstones. The upper sandstone unit is characterised by thin-bedded deposits, locally overlain by medium-to thick-bedded lobe axis/off-axis deposits. The thin-beds show local thinning and onlapping onto the debrite, where it develops its highest relief. Facies distributions and stacking patterns record the progradation of submarine lobes and their complex interaction with long-lived debrite-related topography. The emplacement of a kilometre-scale debrite in an otherwise mud-rich basinal setting and accumulation of overlying sand-rich deposits suggests a genetic link between the mass-wasting event and transient coarse clastic sediment supply to an otherwise sand-starved part of the basin. Therefore, submarine landslides demonstrably impact the routing and behaviour of subsequent sediment gravity flows, which must be considered when predicting facies distributions and palaeoenvironments above MTDs in subsurface datasets.

scholarly journals SUBSTRATE ENTRAINMENT, DEPOSITIONAL RELIEF, AND SEDIMENT CAPTURE: IMPACT OF A SUBMARINE LANDSLIDE ON FLOW PROCESS AND SEDIMENT SUPPLY

2021 ◽  
Author(s):  
Ander Martínez-Doñate ◽  
Aurelia Privat ◽  
David Hodgson ◽  
Chris Jackson ◽  
Ian Kane ◽  
...  
Keyword(s):  
Large Scale ◽  
Submarine Landslide ◽  
Sediment Supply ◽  
Submarine Landslides ◽  
Dispersal Patterns ◽  
Flow Process ◽  
Growth Strata ◽  
Shallow Marine ◽  
Depositional Processes ◽  
Stratal Architecture

Submarine landslides can generate complicated patterns of seafloor relief that influence subsequent flow behaviour and sediment dispersal patterns. While the large-scale morphology of submarine landslide deposits, or mass transport deposits (MTDs), can be resolved in seismic data, the nature of their upper surface, and its impact on facies distributions and stratal architecture of overlying deposits, is rarely resolvable. MTD is a commonly used term in subsurface studies, covering a range of processes and resultant deposits that can not be resolved in seismic or core-based datasets. However, field-based studies often allow a more detailed characterisation of the deposit. The early post-rift Middle Jurassic deep-water succession of the Los Molles Formation is exceptionally well-exposed along a dip-orientated WSW-ENE outcrop belt in the Chacay Melehue depocentre, Neuquén Basin, Argentina. We correlate 27 sedimentary logs constrained by marker beds to document the sedimentology and architecture of a >47 m thick and at least 9.6 km long mud-rich debrite. The debrite overlies ramps and steps, indicating erosion and substrate entrainment. Megaclasts sourced from shallow-marine environments support a shallow marine origin of the mass failure. Two distinct sandstone-dominated units overlie the debrite. The lower sandstone unit is characterised by: i) abrupt thickness changes, wedging and progressive rotation of laminae in sandstone beds associated with growth strata; and ii) detached sandstone load balls within the underlying debrite. The combination of these features suggests syn-sedimentary foundering processes due to density instabilities at the top of the fluid-saturated mud-rich debrite. The debrite relief controlled the spatial distribution of foundered sandstones. The upper sandstone unit is characterised by thin-bedded deposits, locally overlain by medium- to thick-bedded lobe axis/off-axis deposits. The thin-beds show local thinning and onlapping onto the debrite, where it develops its highest relief. Facies distributions and stacking patterns record the progradation of submarine lobes and their complex interaction with long-lived debrite-related topography. These characteristics can help us understand post-depositional processes above MTDs and predict facies distributions and palaeoenvironments in subsurface datasets. The emplacement of a kilometre-scale debrite in an otherwise mud-rich basinal setting and accumulation of overlying sand-rich deposits suggests a genetic link between the mass-wasting event and transient coarse clastic sediment supply to an otherwise sand-starved part of the basin.

The Río Grío–Pancrudo Fault Zone (central Iberian Chain, Spain): recent extensional activity revealed by drainage reversal

2021 ◽  
pp. 1-16
Author(s):  
Alba Peiro ◽  
José L. Simón
Keyword(s):  
Fault Zone ◽  
Large Scale ◽  
Hanging Wall ◽  
Slip Rate ◽  
Vertical Displacement ◽  
Geological Mapping ◽  
Fault Segment ◽  
Iberian Chain ◽  
Basin Margin ◽  
Erosion Surface

Abstract The NNW–SSE-trending extensional Río Grío–Pancrudo Fault Zone is a large-scale structure that obliquely cuts the Neogene NW–SE Calatayud Basin. Its negative inversion during the Neogene–Quaternary extension gave rise to structural and geomorphological rearrangement of the basin margin. Geological mapping has allowed two right-relayed fault segments to be distinguished, whose recent extensional activity has been mainly characterized using a deformed planation surface (Fundamental Erosion Surface (FES) 3; 3.5 Ma) as a geomorphic marker. Normal slip along the Río Grío–Lanzuela Fault Segment has induced hanging-wall tilting, subsequent drainage reversal at the Güeimil valley after the Pliocene–Pleistocene transition, as well as morphological scarps and surficial ruptures in Pleistocene materials. In this sector, an offset of FES3 indicates a total throw of c. 240 m, resulting in a slip rate of 0.07 mm a–1, while retrodeformation of hanging-wall tilting affecting a younger piedmont surface allows the calculation of a minimum throw in the range of 140–220 m after the Pliocene–Pleistocene transition, with a minimum slip rate of 0.07–0.11 mm a–1. For the late Pleistocene period, vertical displacement of c. 20 m of a sedimentary level dated to 66.6 ± 6.5 ka yields a slip rate approaching 0.30–0.36 mm a–1. At the Cucalón–Pancrudo Fault Segment, the offset of FES3 allows the calculation of a maximum vertical slip of 300 m for the last 3.5 Ma, and hence a net slip rate close to 0.09 mm a–1. Totalling c. 88 km in length, the Río Grío–Pancrudo Fault Zone could be the largest recent macrostructure in the Iberian Chain, probably active, with the corresponding undeniable seismogenic potential.

Tectonic and geomorphic controls on the distribution of submarine landslides across active and passive margins, eastern New Zealand

2020 ◽  
Author(s):  
Sally Watson ◽  
Joshu Mountjoy ◽  
Gareth Crutchley
Keyword(s):  
New Zealand ◽  
Mass Transport ◽  
Submarine Landslide ◽  
Sediment Supply ◽  
Submarine Landslides ◽  
Mass Wasting ◽  
Active Margin ◽  
Eastern Margin ◽  
Marine Habitats ◽  
Mass Transport Deposits

<p>Submarine landslides occur on continental margins globally and can have devastating consequences for marine habitats, offshore infrastructure and coastal communities due to potential tsunamigenic consequences. Evaluation of the magnitude and distribution of submarine landslides is central to marine and coastal hazard planning. Despite this, there are few studies that comprehensively quantify the occurrence of submarine landslides on a margin-wide scale.</p><p> </p><p>We present the first margin-wide submarine landslide database along the eastern margin of New Zealand comprising >2200 landslide scars and associated mass-transport deposits. Analysis of submarine landslide distribution reveals 1) locations prone to mass-failure, 2) spatial patterns of landslide scale and occurrence, and 3) the potential preconditioning factors and triggers of mass wasting across different geologic settings.</p><p> </p><p>Submarine landslides are widespread on the eastern margin of New Zealand, occurring in water depths from ~300 m to ~4,000 m. Landslide scars and mass transport deposits are more prevalent, and on average larger, on the active margin, compared the passive margin. We attribute higher concentrations of landslides on the active margin to the prevalence of deforming thrust ridges, related to active margin processes including oversteepening, faulting and seamount subduction. Higher sediment supply on the northernmost active margin is also likely to be a key preconditioning factor resulting in the concentration of large landslides in this region.</p><p> </p><p>In general, submarine landslide scars are concentrated around canyon systems and close to canyon thalwegs. This suggests that not only does mass wasting play a major role in canyon evolution, but also that slope undercutting in canyons may be a fundamental preconditioning factor for slope failure.</p><p> </p><p>Results of this study offer unique insights into the spatial distribution, magnitude and morphology of submarine landslides across different geologic settings, providing a better understanding of the causative factors for mass wasting in New Zealand and around the world.</p><p> </p>

Formation of excess fluid pressure, sediment fluidization and mass-transport deposits in the Plio-Pleistocene Boso forearc basin, central Japan

2018 ◽  
Vol 477 (1) ◽  
pp. 255-264 ◽  
Author(s):  
Nana Kamiya ◽  
Masayuki Utsunomiya ◽  
Yuzuru Yamamoto ◽  
Junichi Fukuoka ◽  
Feng Zhang ◽  
...  
Keyword(s):  
Mass Transport ◽  
Large Scale ◽  
Fluid Pressure ◽  
High Porosity ◽  
Submarine Landslides ◽  
Forearc Basin ◽  
Central Japan ◽  
Pressure Interval ◽  
The Stability ◽  
Mass Transport Deposits

AbstractAnalyses of consolidation state, fabrics and physical properties were conducted on rock samples from the Plio-Pleistocene Boso forearc basin, central Japan. Consolidation tests identified that the trend in consolidation yield stress was systematically 8 MPa smaller than expected for the overburden from the sediment thickness of the Kazusa Group. An excess fluid pressure interval was also identified in the lower part of the basin fill, where several large-scale (several kilometres in length and several tens of metres thick) mass-transport deposits (MTDs) are intercalated. This interval is characterized by high porosity and small consolidation yield stresses, indicating that consolidation had been retarded by the excess fluid pressure. The estimated excess fluid pressure was c. 5–7 MPa. In addition, outcrop-scale fluidization and minor liquefaction features were identified within and below the high fluid pressure interval. The excess fluid pressure reduced the effective stress in the Boso forearc basin and, subsequently, the stability of the slope, allowing small tectonic events to generate submarine landslides. Therefore, the formation of these large-scale MTDs was probably related to the excess fluid-pressure generation.

Megaclasts within mass-transport deposits: their origin, characteristics and effect on substrates and succeeding flows

2020 ◽  
Vol 500 (1) ◽  
pp. 515-530 ◽  
Author(s):  
Jefferson Nwoko ◽  
Ian Kane ◽  
Mads Huuse
Keyword(s):  
Mass Transport ◽  
Seismic Reflection ◽  
Radial Flow ◽  
Submarine Landslide ◽  
Submarine Landslides ◽  
3D Seismic ◽  
Seafloor Topography ◽  
Basal Surface ◽  
Mass Transport Deposits ◽  
Substrate Influence

AbstractMegaclasts transported within submarine landslides can erode the substrate, influence the flow that transports them and, if they form seafloor topography, can influence subsequent flows and their deposits. We document grooves up to 40 km long formed by megaclasts carried in submarine landslides that scoured tens of metres deep into the contemporaneous substrate of the deep-water Taranaki Basin, New Zealand. A 1925 km2 3D seismic reflection survey records six mass transport deposits (MTDs) interbedded with turbidites. Here, we focus on three MTDs, labelled A (oldest), B and C (youngest). MTD-A features megaclasts that internally have coherent parallel strata, and formed striations 4–15 km long and 2–3 km wide, with protruding megaclasts that are onlapped by younger sediments. The seafloor expression of these megaclasts partially obstructed the submarine landslide that created MTD-B. MTD-B contains megaclasts that incised through the rugose topography of the underlying MTD-A, and formed divergent grooves on the basal surface of MTD-B (8–40 km long and 200–250 m wide), which suggest radial flow expansion where flows exited topographic confinement. MTD-C features grooves 2–6 km long and 100–200 m wide that terminate at megaclasts and which internally are characterized of highly deformed reflectors surrounded by a chaotic matrix. This study directly links megaclasts to the grooves they form, and demonstrates that markedly different styles of scouring and resultant grooves can occur in closely related MTDs.

Line length balancing to evaluate multi-phase submarine landslide development: an example from the Storegga Slide, Norway

2019 ◽  
Vol 500 (1) ◽  
pp. 531-549 ◽  
Author(s):  
Suzanne Bull ◽  
Joseph A. Cartwright
Keyword(s):  
Seismic Data ◽  
Large Scale ◽  
Line Length ◽  
Proximal Region ◽  
Submarine Landslide ◽  
Landslide Development ◽  
Multi Phase ◽  
Storegga Slide ◽  
2D And 3D ◽  
3D Seismic Data

AbstractThis study shows how simple structural restoration of a discrete submarine landslide lobe can be applied to large-scale, multi-phase examples to identify different phases of slide-lobe development and evaluate their mode of emplacement. We present the most detailed analysis performed to date on a zone of intense contractional deformation, historically referred to as the compression zone, from the giant, multi-phase Storegga Slide, offshore Norway. 2D and 3D seismic data and bathymetry data show that the zone of large-scale (>650 m thick) contractional deformation can be genetically linked updip with a zone of intense depletion across a distance of 135 km. Quantification of depletion and accumulation along a representative dip-section reveals that significant depletion in the proximal region is not accommodated in the relatively mild amount (c. 5%) of downdip shortening. Dip-section restoration indicates a later, separate stage of deformation may have involved removal of a significant volume of material as part of the final stages of the Storegga Slide, as opposed to the minor volumes reported in previous studies.

Simulation of tsunami waves generated by submarine landslides in the Black Sea

2015 ◽  
Vol 30 (4) ◽  
Author(s):  
Gayaz S. Khakimzyanov ◽  
Oleg I. Gusev ◽  
Sofya A. Beizel ◽  
Leonid B. Chubarov ◽  
Nina Yu. Shokina
Keyword(s):  
Surface Waves ◽  
Black Sea ◽  
Numerical Technique ◽  
Submarine Landslide ◽  
The Black Sea ◽  
Submarine Landslides ◽  
Hydrodynamic Approximation ◽  
Tsunami Waves ◽  
Dispersive Model ◽  
Shallow Water Models

AbstractNumerical technique for studying surface waves appearing under the motion of a submarine landslide is discussed. This technique is based on the application of the model of a quasi-deformable landslide and two shallow water models, namely, the classic (dispersion free) one and the completely nonlinear dispersive model of the second hydrodynamic approximation. Numerical simulation of surface waves generated by a large model landslide on the continental slope of the Black Sea near the Russian coast is performed. It is shown that the dispersion has a significant impact on the picture of propagation of tsunami waves on sufficiently long paths.

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