Development of shallow-water contourite deposits on the muddy continental shelf off southeastern Korea DOI Creative Commons
Jong‐Hwa Chun, Jiho Ha, Jungkyun Shin

et al.

Research Square (Research Square), Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 6, 2024

Abstract On the southeastern continental shelf of Korea, within Korea Strait Shelf Mud deposit, seafloor undulations trending north-northwest‒south-southwest have been identified offshore Ulsan. This study utilized multibeam echo sounding, two- and three-dimensional (3D) high-resolution CHIRP seismic surveys, piston core analysis to investigate formation timing these on muddy shelf. The data revealed irregular aligned with bathymetric contours, sea-bottom reflected amplitude 3D profiles elongated mounds this region. surface extend approximately 30 km at a depth 46‒56 m, running parallel contours. These features vary laterally in width from 50 400 m including small, elongate mounds. Core 20MAP-P05, which is located closer coast, contains coarse-grained typhoon deposits high-energy environment above storm wave base, dating 225‒287 cal yr BP. However, interval absent 20MAP-P04, was sampled undulating 51.2 m. vertical burrows, 10‒20 mm diameter, around 183 BP 220 cm, suggesting rapid redeposition resuspended sediments. results indicate an area off Ulsan, that sudden re-sedimentation occurred due influence contourite currents beneath base.

Language: Английский

On depositional processes governing along‐strike facies variations of fine‐grained deposits: Unlocking the Little Ice Age subaqueous clinothems on the Adriatic shelf DOI Creative Commons
Claudio Pellegrini,

Irene Sammartino,

Jüergen Schieber

et al.

Sedimentology, Journal Year: 2023, Volume and Issue: 71(3), P. 941 - 973

Published: Nov. 16, 2023

ABSTRACT Depositional processes recorded by shelf deposits may vary widely along‐strike, depending largely on the mode of delivery and deposition sediments to basin. In fine‐grained systems in particular, depositional are difficult reconstruct with standard facies analysis sediment cores due ostensibly featureless homogenous appearance muds. this study, sedimentological, palaeontological, geochemical, oceanographic data were combined a detailed characterization conditions via sedimentary structures, type organic matter, trace‐metal geochemistry, benthic fauna assemblages (foraminifera ostracods) along 600 km long delta clinothems West Adriatic (Italy). Processes inferred from micro‐structures then considered context modern regime. Specific attention was given Little Ice Age stratigraphic unit (1500–1850 ce ), which contains continuum genetically related strata. The deposit offers opportunity examine source‐to‐sink system high resolution typical analogues, at time interval when Apennine rivers not yet hydraulically engineered man‐made traps their trunks. Individual beds within muddy prodelta form hectometre kilometre‐wide bedsets that reflect interplay between energetic meteo‐ocean (storm‐dominated beds), flood supply (river‐dominated or hyperpycnites) along‐shelf bottom‐current dispersion (drift‐dominated beds). multidisciplinary approach applied different scales observations helped understanding provenance relative timing transport before final burial strongly promoted matter oxygen exposure loss carbon microbial degradation. Overall, distinctive acted concert slope produced subtle lateral heterogeneity preserved faunal associations, composition laterally‐continuous lithostratigraphic deposited centennial scale. These findings have implications forcing ultimately control location nature both ancient, mud‐dominated systems.

Language: Английский

Citations

10
The fourth slope: A fundamental new classification of continental margins DOI Creative Commons
Ingrid Anell

Basin Research, Journal Year: 2024, Volume and Issue: 36(2)

Published: March 1, 2024

Abstract Continental margins develop long submarine slopes, linking the shallow shelves along continental landmasses to deep abyssal plain. They are results of a complex interaction between destructive and constructive processes, although by large they sites deposition. There is great amount variation length, height, smoothness, gradient thereof slope profiles; however, there also recurring similarity in their shape. The similitude has suggested systematic relationships shape processes forming them, led studies on geomorphological categorisation based curvatures. potential for prediction along‐strike variations connection morphology sedimentary process herein approached through broadening mathematical functions used, detailed measurement, observation curve‐fitting over 150 passive margins. Previously, three have been used categorise slopes. present study finds that four closely match slopes: Linear, Gaussian, exponential quadratic (positive negative/inverse), reveals fourth slope, quadratic, far most common. While slopes similar crucial difference way which angle changes. This suggests represent systematically decreasing sediment deposition with distance, previously attributed Exponential meanwhile, readjustment profiles upper bypass lower aggradation. Linear form longest low‐angle response high input. Abrupt shelf‐edges shallower water longer aprons, suggesting formation from erosional processes. implies quintessential sigmoidal (s‐shaped, Gaussian function) smooth rollover, represents fundamental depositional profile.

Language: Английский

Citations

2
The quintessential s-shape in sedimentology: A review on the formation and controls of clinoform shape DOI Creative Commons
Ingrid Anell

Earth-Science Reviews, Journal Year: 2024, Volume and Issue: 254, P. 104821 - 104821

Published: May 25, 2024

Clinoforms are ubiquitous depositional surfaces in sedimentary systems. The quintessential shape, with a flat or gentle topset, sloping foreset, and to bottomset, is recognizable the smallest ripple kilometer high edges of continents. Essentially shape one which develops differential sedimentation away from source. Systematic decay transport competence and/or sediment amount site favouring deposition, generates loading typically lens-shaped body. lithology, grain size, water depth, hydrodynamic factors, mechanisms, antecedent topography, relative sea level rate all interact create different sizes, slopes shapes. Meanwhile there several fundamental similarities between clinoforms, even bedwave features (ripples dunes), despite forming under very conditions. All clinoforms some extent governed by accommodation energy limiting factors (water agitation flow regime), controls their height, proxy influences slope angle. Lithology exerts control, can build angle repose, higher for coarser non-cohesive sediment, while cohesive gentler slopes, also fail at lower angles. Sediment repose steep linear segments, but conversely on continental margins extremely low angle, probably reflecting little along-slope contrast mud-dominance. clinothems similar lithology display wide range foreset angles, indicating numerous additional controls. Sedimentation appears exert significant control steepness, limited promoting steeper related basinward thinning deposits. observation greater depth response deepening environments generating effect comparatively less sedimentation. Processes important controlling as tidal wave reworking, debris flows, overpressure failure, Turbidity currents meanwhile part dynamic system both steepen slope. There four basic clinoform shapes: concave, linear, convex, sigmoidal. These develop variations along profile driven erosion/bypass/factors deposition/accumulation/waning supply. Curvature tends be an indication contrast, such erosional sandier muddier Sigmoidal clinothems, associated more trajectories, shorter than concave clinothems. Decaying shear-zone reworking erosion shapes rounded rollover. carrying capacity ensuing curvature. Concave lacking topsets sharp rollovers often longer sigmoidal forms. Their formation likely closely linked increased accumulation through bypass, turbidity currents, suspension-dominated deposition smaller clinoforms. In this ripples differ, transition rounding crest, unlike larger

Language: Английский

Citations

2
Holocene paleoenvironmental history of Jackson Lake (Grand Teton National Park, USA) deduced from CHIRP seismic reflection and radiocarbon-dated sediment cores DOI
J.R. Dilworth, Michael M. McGlue,

R.J. Thigpen

et al.

Quaternary Science Reviews, Journal Year: 2024, Volume and Issue: 336, P. 108748 - 108748

Published: June 19, 2024

Language: Английский

Citations

1
Development of shallow-water contourite deposits on the muddy continental shelf off southeastern Korea DOI Creative Commons
Jong‐Hwa Chun, Jiho Ha, Jungkyun Shin

et al.

Research Square (Research Square), Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 6, 2024

Abstract On the southeastern continental shelf of Korea, within Korea Strait Shelf Mud deposit, seafloor undulations trending north-northwest‒south-southwest have been identified offshore Ulsan. This study utilized multibeam echo sounding, two- and three-dimensional (3D) high-resolution CHIRP seismic surveys, piston core analysis to investigate formation timing these on muddy shelf. The data revealed irregular aligned with bathymetric contours, sea-bottom reflected amplitude 3D profiles elongated mounds this region. surface extend approximately 30 km at a depth 46‒56 m, running parallel contours. These features vary laterally in width from 50 400 m including small, elongate mounds. Core 20MAP-P05, which is located closer coast, contains coarse-grained typhoon deposits high-energy environment above storm wave base, dating 225‒287 cal yr BP. However, interval absent 20MAP-P04, was sampled undulating 51.2 m. vertical burrows, 10‒20 mm diameter, around 183 BP 220 cm, suggesting rapid redeposition resuspended sediments. results indicate an area off Ulsan, that sudden re-sedimentation occurred due influence contourite currents beneath base.

Language: Английский

Citations

0