Friction- and Inertia-Dominated Effluents In A Lacustrine, River-Dominated Deltaic Succession (Pliocene Upper Valdarno Basin, Italy)

Fidolini, Francesco; Ghinassi, Massimiliano

doi:10.2110/jsr.2016.65

Cited by 21 publications

(33 citation statements)

References 48 publications

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“…The overall convex-up geometries, the downstream migration and the absence of major channels in facies association FA2.1 point to a distal delta mouthbar environment (Fielding et al 2005;Lee et al 2007;Fabbricatore et al 2014). Stable terminal distributary channels allowed for the deposition of laterally persistent downstream migrating mouthbars, which were initiated by bedload sedimentation from inertia-dominated jets (Wright 1977;Postma 1990;Olariu & Bhattacharya 2006;Fidolini & Ghinassi 2016). The slightly landward dipping laterally extensive bounding surfaces of foresetbed packages (Fig.…”

Section: Shoal-water Deltas (Fa2)mentioning

confidence: 95%

“…The formation of V-shaped scours and intraclasts may be related to the formation of cyclic steps during supercritical flow conditions . Laterally overlapping delta lobes and a high dispersion of flow directions point to a proximal delta-front environment (Olariu & Bhattacharya 2006;Lee et al 2007;Fidolini & Ghinassi 2016) gravel with sharp non-erosive basal contacts (facies Gmg; Fig. 6A).…”

Section: Delta Topsetsmentioning

confidence: 96%

“…The ripples partly form climbing bedsets. Laterally overlapping delta lobes and a high dispersion of flow directions point to a proximal delta-front environment (Olariu & Bhattacharya 2006;Lee et al 2007;Fidolini & Ghinassi 2016) gravel with sharp non-erosive basal contacts (facies Gmg; Fig. These deposits are arranged into metre-scale (1.5 -2.5 m) fining-upward or coarsening-upward successions, bounded by major subhorizontal or slightly concave-up erosional surfaces.…”

Section: Delta Topsetsmentioning

confidence: 99%

“…The slightly landward dipping laterally extensive bounding surfaces of foresetbed packages (Fig. Fidolini & Ghinassi 2016). Fidolini & Ghinassi 2016).…”

Section: Shoal-water Deltas (Fa2)mentioning

confidence: 99%

“…Laterally overlapping coarse-grained, poorly sorted shoal-water delta lobe deposits and a high dispersion of flow directions point to frequent autocyclic lobe switching and channel avulsion in a proximal delta-front environment (Olariu & Bhattacharya 2006;Lee et al 2007;Fidolini & Ghinassi 2016). Initial mouthbars formed close to the channel axis, leading to flow splitting and the formation of new terminal distributary channels at different scales.…”

Section: Shoal-water Deltas (Fa2)mentioning

confidence: 99%

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Ice‐marginal forced regressive deltas in glacial lake basins: geomorphology, facies variability and large‐scale depositional architecture

Winsemann

Lang

Polom

et al. 2018

Boreas

130

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Brandes, C. 2018 (October): Ice-marginal forced regressive deltas in glacial lake basins: geomorphology, facies variability and large-scale depositional architecture.This study presents a synthesis of the geomorphology, facies variability and depositional architecture of ice-marginal deltas affected by rapid lake-level change. The integration of digital elevation models, outcrop, borehole, groundpenetrating radar and high-resolution shear-wave seismic data allows for a comprehensive analysis of these delta systems and provides information about the distinct types of deltaic facies and geometries generated under different lake-level trends. The exposed delta sediments record mainly the phase of maximum lake level and subsequent lake drainage. The stair-stepped profiles of the delta systems reflect the progressive basinward lobe deposition during forced regression when the lakes successively drained. Depending on the rate and magnitude of lake-level fall, fanshaped, lobate or more digitate tongue-like delta morphologies developed. Deposits of the stair-stepped transgressive delta bodies are buried, downlapped and onlapped by the younger forced regressive deposits. The delta styles comprise both Gilbert-type deltas and shoal-water deltas. The sedimentary facies of the steep Gilberttype delta foresets include a wide range of gravity-flow deposits. Delta deposits of the forced-regressive phase are commonly dominated by coarse-grained debrisflow deposits, indicating strong upslope erosion and cannibalization of older delta deposits. Deposits of supercritical turbidity currents are particularly common in sand-rich Gilbert-type deltas that formed during slow rises in lake level and during highstands. Foreset beds consist typically of laterally and vertically stacked deposits of antidunes and cyclic steps. The trigger mechanisms for these supercritical turbidity currents were both hyperpycnal meltwater flows and slope-failure events. Shoal-water deltas formed at low water depths during both low rates of lake-level rise and forced regression. Deposition occurred from tractional flows. Transgressive mouthbars form laterally extensive sand-rich delta bodies with a digitate, multi-tongue morphology. In contrast, forced regressive gravelly shoal-water deltas show a high dispersion of flow directions and form laterally overlapping delta lobes. Deformation structures in the forced-regressive ice-marginal deltas are mainly extensional features, including normal faults, small graben or half-graben structures and shear-deformation bands, which are related to gravitational delta tectonics, postglacial faulting during glacial-isostatic adjustment, and crestal collapse above salt domes. A neotectonic component cannot be ruled out in some cases. facies and the larger-scale depositional architecture. The results are compared with other marine and lacustrine delta examples from the literature, and provide information about the distinct types

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Section: Shoal-water Deltas (Fa2)mentioning

confidence: 95%

Section: Delta Topsetsmentioning

confidence: 96%

Section: Delta Topsetsmentioning

confidence: 99%

“…The slightly landward dipping laterally extensive bounding surfaces of foresetbed packages (Fig. Fidolini & Ghinassi 2016). Fidolini & Ghinassi 2016).…”

Section: Shoal-water Deltas (Fa2)mentioning

confidence: 99%

Section: Shoal-water Deltas (Fa2)mentioning

confidence: 99%

See 3 more Smart Citations

Ice‐marginal forced regressive deltas in glacial lake basins: geomorphology, facies variability and large‐scale depositional architecture

Winsemann

Lang

Polom

et al. 2018

Boreas

130

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Internal mouth‐bar variability and preservation of subordinate coastal processes in low‐accommodation proximal deltaic settings (Cretaceous Dakota Group, New Mexico, USA)

Yperen

Poyatos‐Moré

Holbrook

et al. 2020

The Depositional Record

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Mouth bars are the fundamental architectural elements of proximal deltaic successions. Understanding their internal architecture and complex interaction with coastal processes (fluvial, tide and wave‐dominated) is paramount to the interpretation of ancient deltaic successions. This is particularly challenging in low‐accommodation systems, because they are commonly characterized by thin, condensed and top‐truncated sections. This study analyses the exhumed Cenomanian Mesa Rica Sandstone (Dakota Group, Western Interior Seaway, USA), a fluvio‐deltaic system covering a ca 450 km depositional dip‐parallel profile. The study targets the proximal deltaic expression of the system, using 22 sedimentary logs (total of 390 m) spatially correlated within a ca 25 km2 study area at the rim of the Tucumcari Basin. Analysis of facies distributions, depositional architecture and spatial extent of stratigraphic surfaces reveals a 6–10 m thick, sharp‐based and sand‐prone deltaic package, comprising several laterally extensive (>1.4 km width) mouth bars. Composite erosional surfaces infilled with multi‐storey fluvial and marine‐influenced channel deposits (12–20 m thick, 100–250 m wide) scour locally into the deltaic package. Based on differences in sedimentary structures, bed thicknesses, occurrence of interflood beds and bioturbation indexes, four different sub‐environments within single mouth bars were distinguished. These range from mouth‐bar axis, off‐axis, fringe to distal‐fringe deposits, which reflect waning depositional energy with increasing distance from the distributary channel mouth. The interpreted mouth‐bar components also show internal variability in dominant process regime, with overall river dominance but local preservation of tide influence in the fringe and distal fringe components. Mouth‐bar deposits amalgamate to form an extensive sand‐rich sheet body throughout the study area, in which interflood mudstone to very‐fine grained sandstone beds are nearly absent. These features reflect successive coalescence of mouth bars in a low accommodation/supply (A/S) setting. These conditions promoted recurrent channel avulsion/bifurcation and thus the potential reworking of previously deposited mouth‐bar fringe and distal‐fringe sediments, where time and background processes are better recorded. Results of this study evidence internal process‐regime variability within mouth‐bar components. They also caution against the possible loss of preservation of subordinate coastal processes (e.g. tidal indicators), and consequent underestimation of the true mixed influence in low‐accommodation deltaic settings.

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Kontinentale Fazies

Schäfer¹

2019

Klastische Sedimente

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Friction- and Inertia-Dominated Effluents In A Lacustrine, River-Dominated Deltaic Succession (Pliocene Upper Valdarno Basin, Italy)

Cited by 21 publications

References 48 publications

Ice‐marginal forced regressive deltas in glacial lake basins: geomorphology, facies variability and large‐scale depositional architecture

Ice‐marginal forced regressive deltas in glacial lake basins: geomorphology, facies variability and large‐scale depositional architecture

Internal mouth‐bar variability and preservation of subordinate coastal processes in low‐accommodation proximal deltaic settings (Cretaceous Dakota Group, New Mexico, USA)

Kontinentale Fazies

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