The present paper reports on a laboratory investigation of the erosion deltaic front induced by removal dam. We built model dam, and observed both sedimentation in reservoir due to downstream propagation delta during dam removal, including measurement channel morphology flow field. experiments provide detailed view phenomenon that has not been described detail date: erosional narrowing. After sudden incises into deposit, first rapidly then more slowly. During initial period rapid incision...

This paper is devoted to a morphodynamic model of incision into reservoir deposit driven by partial or total removal the associated dam. The considers erosional processes upstream position former dam, rather then deposition that occurs downstream. A theory developed predict evolution both width and depth incisional channel develops as erosion progresses. implemented in numerical model, which tested against verified with flume experiments on sudden, complete In these given initial allowed...

In this work we present direct numerical simulations (DNS) of sediment‐laden channel flows. contrast to previous studies, where the flow has been driven by a constant, uniform pressure gradient, our flows are excess density imposed suspended sediment. This configuration provides simplified model turbidity current and is thus called with roof configuration. Our calculations elucidate DNS for first time several fascinating features flows, which may be summarized as follows. First, presence...

As a river-carrying sediment mixture aggrade, it creates stratigraphic signature that records this evolution. This stratigraphy is characterized by the vertical/horizontal variation of substrate grain size distribution. If river degrades, mines stratigraphy, and transfers so accessed farther downstream. Although several numerical models tracking creation/consumption are available, none has been tested against experiments under plane bed regime conditions. Here nine physical modelling...

The interaction of flow with an erodible bed in alluvial rivers and deep-sea channels gives rise to a wide range self-formed morphologies, including channels, ripples, dunes, antidunes, alternate bars, multiple-row meandering braiding. As the is invariably turbulent field manifestations these there has been tendency assume that turbulence necessary for them form. While undoubtedly important influence when it present, not any features. Indeed, all features can be formed by morphodynamic...

Abstract This paper reports on a laboratory study that aims to reproduce tidal channel network, in order enhance the understanding of morphodynamic evolution characteristics as network expands and finally reaches equilibrium. A high‐resolution laser system scanned bed topography at different time steps creating multiple digital elevation models network. Two hundred seventy individual segments are analyzed cross‐correlated terms their width, depth length. The results show positive linear...

In the present work, we use a three‐dimensional numerical model to simulate turbidity currents in large‐scale submarine environment. The solves Reynolds Averaged Navier–Stokes equations, along with two‐equation turbulence closure model, sediment conservation equations for multiple grain‐size classes and Exner equation of bed conservation. Four different (30, 64, 125, 250 μ m) are considered. is applied modern seafloor environment continental slope Niger Delta where bathymetric data seven...

Abstract The formative mechanisms of many geologic features attributed to the passage turbidity currents are still obscure due difficulties in documenting dynamics field. Submarine channels and lobes have been extensively documented using seismic tools outcrops. actual morphodynamics their emplacement remain, however, only poorly understood. In this paper we present experimental research that documents morphodynamic stratigraphic evolution self-channelized subaqueous fans emplaced by...

Abstract. Knickpoints often form in bedrock rivers response to base-level lowering. These knickpoints can migrate upstream without dissipating. In the case of alluvial rivers, an impulsive lowering base level due to, for example, a fault associated with earthquake or dam removal commonly produces smooth, upstream-progressing degradation; knickpoint suddenly lowered quickly dissipates. Here, however, we use experiments demonstrate that under conditions Froude-supercritical flow over bed,...

Abstract The widespread distribution of tidal creeks and channels that undertake meandering behaviour in modern coasts contrasts with their limited documentation the fossil record, where point‐bar elements arising from interaction between a mix both fluvial currents are mainly documented. sedimentary products channel‐bend evolution relatively poorly known, few studies have focused previously on specific facies models for point bars present settings. This study improves understanding channel...

Research Article| January 01, 2017 High-resolution, millennial-scale patterns of bed compensation on a sand-rich intraslope submarine fan, western Niger Delta slope Zane R. Jobe; Jobe † 1Shell International Exploration and Production, Inc., Houston, Texas 77082, USA §Present address: Department Geology, Colorado School Mines, Golden, 80401, USA. †zanejobe@gmail.com Search for other works by this author on: GSW Google Scholar Zoltán Sylvester; Sylvester #Present Chevron Energy Technology...

The passage of turbidity currents over submarine fans often results in intense channelization. channels are typically bounded by levees, and they vary from mildly to strongly meandering. process self-channelization remains, however, somewhat obscure. Preliminary experiments reported here demonstrate for the first time that subaqueous can be reproduced at laboratory scale. same also illustrate dilute mudflows. resulting weakly sinuous predominantly depositional, erosional, or some combination...

Abstract Incised valleys are critical stratigraphic features for unraveling long-term Earth-surface processes and depositional history, commonly exhibit attributes that make them desirable fluid reservoirs. While there is much descriptive documentation on architecture of incised-valley fills paleoenvironmental regimes, relatively little work has focused quantitative modeling the dynamics evolution. Here we use well-constrained observations incised in experiments field to explore controls...

Abstract High‐resolution bathymetry, seismic reflection, and piston core data from a submarine channel on the western Niger Delta slope demonstrate that thick, coarse‐grained, amalgamated sands in thalweg/axis transition to thin, fine‐grained, bedded muds margin. Radiocarbon ages indicate axis margin deposits are coeval. Core show bed thickness, grain size, deposition rate strongly decrease with increasing height above thalweg and/or distance centerline. A 5 times thickness 1–2 ψ size...

A series of large-scale experiments on nonchannelized, depositional turbidity currents show the evolution and complex stratigraphy channel-lobe systems developed updip downdip a break in slope.Two different sets experimental with sediment concentrations were run.The results provided comparative picture gross structure fans, information their surfaces, growth sequences, times activity incised channels lobed features.In particular, data analysis focused on: (a) velocity suspended-sediment...

Abstract Regional and detailed seismic stratigraphic analyses of Early Cretaceous (Aptian) presalt carbonate sections from offshore Brazil reveal the complex architecture late- post-rift lacustrine systems. The lateral vertical distribution calibrated facies within this framework highlights evolution through time system bathymetry host basin. Despite simple, largely abiotic microbial components, accumulations formed geometries that closely resemble those observed marine systems, suggesting a...

Intricately meandering channels of various scales constitute a major morphological feature the submarine slope and fan systems. These act as conduits density‐driven gravity underflows in turn are shaped by these underflows. The relationship between channel curvature dynamics sediment‐laden commonly known turbidity current has been an enigma, recently, subject controversy. This contribution unravels flow field at bends captured from large scale laboratory experiments. experimental results...

This study focuses on a numerical model of turbidity currents with reversing buoyancy, i.e., flows that are rendered heavier than the ambient water due to presence suspended sediment but as sedimentation progresses become lighter difference in temperature or salinity. The considered here may be either pulsed events continuous flows. It is well known these subject buoyancy reversal. Flows issuing upstream sufficient load and thus form bottom underflow. As deposits downstream direction,...

Abstract Laboratory studies are commonly used to improve our understanding of physical processes that very difficult or almost impossible investigate in their natural settings. Erosion impacts on large-scale submarine morphology good examples. We present the results a preliminary laboratory study focused knickpoints, which bed depressions bounded by steep walls upstream and gentle slope downstream, originated passage turbidity current over an erodible bed. Eight experiments using different...

Deposits of turbidity currents induced by subaqueous volcanic eruptions are increasingly recognized in settings ranging from lakes to the deep sea. These "eruption‐fed density currents" have high current temperatures and low‐density particles, which affect dynamics deposit features. Field data indicate that thickness grain size decrease downflow at a changing rate. This trend is similar for deposits noneruptive currents, but with activity, often exhibit break slope profile distribution. Here...