Development of Rheological Heterogeneity in Clay-Rich High-Density Turbidity Currents: Aptian Britannia Sandstone Member, U.K. Continental Shelf

2008 ◽  
Vol 78 (2) ◽  
pp. 45-68 ◽  
Author(s):  
S. P. Barker ◽  
P. D.W. Haughton ◽  
W. D. McCaffrey ◽  
S. G. Archer ◽  
B. Hakes
Keyword(s):  
Continental Shelf ◽  
High Density ◽  
Turbidity Currents ◽  
Rheological Heterogeneity

Prevalence of small high-density microplastics in the continental shelf and deep sea waters of East Asia

2021 ◽  
pp. 117238
Author(s):  
Soeun Eo ◽  
Sang Hee Hong ◽  
Young Kyoung Song ◽  
Gi Myung Han ◽  
Seongbong Seo ◽  
...  
Keyword(s):  
Continental Shelf ◽  
East Asia ◽  
Deep Sea ◽  
High Density

scholarly journals Data-Driven, Multi-Model Workflow Suggests Strong Influence from Hurricanes on the Generation of Turbidity Currents in the Gulf of Mexico

2020 ◽  
Vol 8 (8) ◽  
pp. 586
Author(s):  
Courtney Harris ◽  
Jaia Syvitski ◽  
H.G. Arango ◽  
E.H. Meiburg ◽  
Sagy Cohen ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Continental Shelf ◽  
Numerical Models ◽  
Ocean Dynamics ◽  
Turbidity Currents ◽  
Regional Ocean Modeling System ◽  
Transport Pathway ◽  
Seabed Sediment ◽  
Continental Scale ◽  
Sediment Routing

Turbidity currents deliver sediment rapidly from the continental shelf to the slope and beyond; and can be triggered by processes such as shelf resuspension during oceanic storms; mass failure of slope deposits due to sediment- and wave-pressure loadings; and localized events that grow into sustained currents via self-amplifying ignition. Because these operate over multiple spatial and temporal scales, ranging from the eddy-scale to continental-scale; coupled numerical models that represent the full transport pathway have proved elusive though individual models have been developed to describe each of these processes. Toward a more holistic tool, a numerical workflow was developed to address pathways for sediment routing from terrestrial and coastal sources, across the continental shelf and ultimately down continental slope canyons of the northern Gulf of Mexico, where offshore infrastructure is susceptible to damage by turbidity currents. Workflow components included: (1) a calibrated simulator for fluvial discharge (Water Balance Model - Sediment; WBMsed); (2) domain grids for seabed sediment textures (dbSEABED); bathymetry, and channelization; (3) a simulator for ocean dynamics and resuspension (the Regional Ocean Modeling System; ROMS); (4) A simulator (HurriSlip) of seafloor failure and flow ignition; and (5) A Reynolds-averaged Navier–Stokes (RANS) turbidity current model (TURBINS). Model simulations explored physical oceanic conditions that might generate turbidity currents, and allowed the workflow to be tested for a year that included two hurricanes. Results showed that extreme storms were especially effective at delivering sediment from coastal source areas to the deep sea, at timescales that ranged from individual wave events (~hours), to the settling lag of fine sediment (~days).

Facies and provenance of deep marine sediment gravity flows with fragments of coalified land plants at Lipowica, the Cergowa Beds (Oligocene), Outer Carpathians of Poland

2021 ◽  
Author(s):  
Joanna Pszonka ◽  
Marek Wendorff ◽  
Magdalena Zielińska ◽  
Paweł Godlewski
Keyword(s):  
Organic Matter ◽  
High Density ◽  
Turbidity Currents ◽  
Terrestrial Plants ◽  
Terrestrial Organic Matter ◽  
Fine Grained ◽  
Lower Stage ◽  
Gravity Flows ◽  
Facies Associations ◽  
Outer Carpathians

<p>Facies analysis of the Cergowa Beds of the Polish and Slovak Outer Carpathians shows that this deep-marine siliciclastic unit was deposited by a spectrum of gravity flows ranging from high to low density, which deposited three facies associations (A, B and C). Association A consists of very fine- to medium-grained sandstones with mudstone and coal clasts, granules and rich in coalified organic matter fragments. Sandstones beds reach 8 m in thickness, are massive and subordinately parallel laminated (Ta and Tab). They are interpreted as resulting from incremental, rapid deposition from collapse of a near-bed layer (Ta, Tab) and laterally sheared near-bed layer (Tb) below high-density, turbulent flows and steady turbidity currents or, in case of mud-rich sandstones, en masse deposition by debris flows. Association B comprises very fine- and fine-grained sandstones with mud and coal clasts, granules and coalified plant fragments and detritus. They are massive, parallel- and ripple cross-laminated (Tab, Tabc, Tbc), reach 2 m in thickness and contain mudstone intercalations up to 50 cm. These sandstones seem to have originated from a combination of incremental deposition by high-density turbidity currents (Tab, Tb), low-amplitude bedload waves at the upper stage planar lamination in more dilute turbidity current (Tb) and suspension of fully turbulent and dilute turbidity currents (Tbc, Tc). Association C consists of very fine- to fine-grained sandstones and siltstones with fine organic detritus and minor mud clasts. Parallel- and ripple cross-lamination (Tbc, Tbcd) dominate, bed thickness of sandstones and siltstones amounts to 1-50 cm and mudstones reaches 200 cm. Association C was deposited by transformation of waning, dilute and fully turbulent turbidity currents from ripples into lower stage planar lamination.</p><p>Sandstone and mudstone beds at Lipowica (Poland) contain three types of coalified terrestrial organic matter. Based on their morphology and size these are: (i) coalified plant detritus dispersed in B and C associations, (ii) coalified plant fragments forming elongated lenses in A and B associations and (iii) coalified fragments of tree trunks occurring in A and B facies. Petrographic components of organic matter represented by collotelinite, telinite, gelinite and fusinite with co-occuring framboidal pyrite indicate terrestrial plants affected by fast gelification and burial processes of varying intensity. The size of the plant fragments supplied to the Dukla basin is positively correlated with indicators of hydrodynamic regimes suggested by their hosting sediments. Namely, the larger the fragments, the higher flow energy and steadier and longer lasting sustained sediment delivery.</p><p>Sedimentary features of the Cergowa Beds suggest deposition out of gradually aggrading sustained turbulent sandy gravity flows primarily controlled by hyperpycnal effluents from a delta. Palaeocurrent data and comparison of mineral composition of sandstone infilling a hollow coalified tree trunk at Lipowica quarry with sandstone beds of the hosting succession suggest provenance from shelf fringing the emergent Silesian Ridge, which acted as a source area to the west of the basin. The depositional age NP23 and NP24 during the Oligocene eustatic sea-level fall implies that the delta supplying the Cergowa basin was located at the edge of this shelf.</p>

Stratigraphy and depositional setting of the Lagrelius Point Formation from the Lower Cretaceous of James Ross Island, Antarctica

1993 ◽  
Vol 5 (4) ◽  
pp. 379-388 ◽  
Author(s):  
Luis A. Buatois ◽  
Francisco J. Medina
Keyword(s):  
Sedimentary Facies ◽  
High Density ◽  
Coarse Grained ◽  
Turbidity Currents ◽  
North West ◽  
The North ◽  
Braided Channel ◽  
James Ross Island ◽  
Siliciclastic Rocks ◽  
Sandstone Facies

The Lagrelius Point Formation (?Barremian–Aptian) is the basal unit of the Gustav Group and crops out on the north-west coast of James Ross Island. It consists of about 250 m of coarse-grained siliciclastic rocks. The type section of the Lagrelius Point Formation is defined here from just south of Lagrelius Point. The measured section comprises the uppermost 80 m of the unit and mainly consists of clast-supported, boulder, cobble to pebble conglomerates; very coarse to medium-grained sandstones occur rarely. Four sedimentary facies are recognized. A disorganized conglomerate facies (1) is interpreted as having been deposited from non-cohesive debris flows and high density gravelly turbidity currents. Inversely graded conglomerate facies (2) and normally graded to graded stratified conglomerate and pebbly sandstone facies (3) reflect sedimentation from high density gravelly turbidity currents. Massive and parallel stratified sandstone facies (4) is thought to record deposition from high density sandy turbidity currents. Two types of facies assemblages have been recognized. A major channel assemblage, represented by the lower part of the measured section and the minor channel assemblage forming the upper part of the section. The total succession is thought to represent the aggradation of a major submarine braided channel followed by the establishment and subsequent infill of a series of minor channels in a marginal terrace.

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