The role of mass transport deposits contributing to fluid escape: Neogene outcrop and seismic examples from north Taranaki, New Zealand

Browne, Greg H.; Bull, Suzanne; Arnot, Malcolm J.; Boyes, AF; King, Peter R.; Helle, K.

doi:10.1007/s00367-020-00641-z

Cited by 8 publications

(6 citation statements)

References 71 publications

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“…Bünz et al., 2005; Deville et al., 2020; Elger et al., 2018); however, few studies link MTCs to syn‐ or post‐emplacement release of fluids (e.g. Bøe et al., 2012; Browne et al., 2020; Yang et al., 2013). It is suggested that significant volumes of methane (an important greenhouse gas) may have been emitted during the disaggregation of the 3,000 km 3 Storegga Slide (Paull et al., 2007), and that methane release by widespread submarine landslide activity may have been a contributory mechanism for elevated methane emissions that catalysed the Palaeocene‐Eocene Thermal maximum (Higgins and Schrag, 2006).…”

Section: Discussionmentioning

confidence: 99%

The formation and implications of giant blocks and fluid escape structures in submarine lateral spreads

Jackson

Johnson

et al. 2021

Basin Research

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Lateral spread (or 'spreading') and submarine creep are processes that occur near the headwalls of both terrestrial landslides and submarine mass-transport complexes (MTCs).Both submarine creep and spread deposits may contain giant (km-scale) coherent blocks, but their transport processes remain poorly constrained. Here we use 2D and 3D seismic reflection data to determine the geometry, scale, and origin of an ancient (Late Miocene) mass-transport complex (MTC) located in the Kangaroo Syncline, offshore NW Australia. We show that this large remobilised mass of carbonate ooze is c. 170-300 m thick and covers an area of at least c. 1050 km 2 . The deposit is defined internally by two distinct seismic facies: (i) large, upward-tapering blocks (up to 210-300 m thick, 170-210 m wide, and 800-1200 m long) with negligible internal deformation, which decrease in height and spacing along the transport direction (identical, but in situ, seismic facies forms undeformed slope material immediately updip of the deposit headwall); and (ii) troughs (160-260 m thick, 190-230 m wide and 800-1200 m long) comprising moderately deformed strata, which contain 'v'-shaped, pipe-like structures that extend upwards from the inferred basal shear surface to the top surface of the MTC. The lack of deformation within the blocks, and their correlation to adjacent in-situ deposits, suggests they underwent very limited transport (c. 50 m-70 m). The relatively high degree of deformation within the intervening troughs is attributed to the vertical expulsion of fluids and sediment during hydraulic failure of the sediment mass. We present a hydraulic failure model that accounts for the styles and patterns of intra-MTC deformation process. This model invokes evacuation of the lower slope by a pre-cursor MTC that formed the space to trigger the lateral spread event. Our study provides new insights into the genesis and rheology of subaqueous lateral spreads, enabling improved assessments of the threats posed to critical seafloor infrastructure. The genetic links identified between mass wasting and spatially-focused fluid flow indicate that, as well as disturbing the deep seafloor, submarine landslides may also create important deep-sea biodiversity hotspots.

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Section: Discussionmentioning

confidence: 99%

The formation and implications of giant blocks and fluid escape structures in submarine lateral spreads

Jackson

Johnson

et al. 2021

Basin Research

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“…In contrast, another two hypotheses are deemed more plausible; fluid loss and fault-controlled mechanical subsidence. Fluid loss-controlled evacuation could have promoted differential subsidence of the upper surface of the debrite and overlying units (e.g., Browne et al, 2020). Alternatively, given the early post-rift setting, mechanical subsidence by an east-facing and N-S striking fault (Manceda and Figueroa, 1995) could have generated more accommodation in the western part of the study area (see Cristallini et al, 2006).…”

Section: Dynamic Debrite Topography and Impact On Overlying Stratamentioning

confidence: 99%

“…Butler and McCaffrey, 2010) or secondary mass movements (Sobiesiak et al, 2016). Furthermore, the high water content within newly deposited MTDs promotes active dewatering at their upper surface (Mulder and Alexander, 2001;Talling et al, 2012;Browne et al, 2020) associated with local instabilities and movement (Iverson, 1997;Major and Iverson, 1999;Van der Merwe et al, 2009). Fluids can also generate overpressure along with the interface between MTDs and its sediment cover, exploiting pathways created by internal MTD deformation (Ogata et al, 2012;Migeon et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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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.

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“…Whether it is regional or local is here a matter of speculation. The large-scale fluid escape structures present in the underlying sandstones would result from sudden loading of the mass-wasting products onto the sandstone strata, increasing pore pressure and promoting dewatering (Figure 10k) (Browne et al 2020).…”

Section: Accepted Manuscript Version Published Journal Article Versio...mentioning

confidence: 99%

Contrasting mixed siliciclastic-carbonate shelf-derived gravity-driven systems in compressional intra-slope basins (southern Hikurangi margin, New Zealand)

Claussmann

Bailleul

Chanier

et al. 2021

Marine and Petroleum Geology

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The role of mass transport deposits contributing to fluid escape: Neogene outcrop and seismic examples from north Taranaki, New Zealand

Cited by 8 publications

References 71 publications

The formation and implications of giant blocks and fluid escape structures in submarine lateral spreads

The formation and implications of giant blocks and fluid escape structures in submarine lateral spreads

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

Contrasting mixed siliciclastic-carbonate shelf-derived gravity-driven systems in compressional intra-slope basins (southern Hikurangi margin, New Zealand)

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