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The impact of avulsion on groundwater level and peat

Apr 19, 2017 Basal peat samples come from strata that directly overlie sandy aeolian sediments, minimizing compaction effects in the curves. The basal peats sampled for these reconstructions are swamp peat and fen-edge peat (Alnus peat, that is, alder peat), which form approximately at or slightly below the annual mean groundwater table (Charman, 2002).

Effects of peat compaction on delta evolution: A review on

Jan 01, 2009 Peat compaction and formation potentially influence avulsion as 1) a decrease in accommodation space created by peat compaction underneath a channel causes superelevation and/or an increase in lateral migration, 2) the high cohesiveness of peat banks inhibits lateral migration, which increases bed aggradation, decreases sediment transport

Effects of peat compaction on delta evolution: A review on

Peat is most compressible of all natural soils. Compaction of peat layers potentially leads to substantial amounts of land subsidence. Peat is common

Peat compaction in deltas : implications for Holocene

Jun 16, 2010 Moreover, regional gradients are low in peatlands, which inhibits a crevasse splay to evolve into an avulsion, as is usually the mechanism of avulsion initiation. Only if the maximum peat compaction potential at a certain location has been reached, while at a nearby location on the floodplain rates of subsidence due to peat compaction are still

Peat compaction in deltas : implications for Holocene

Request PDF Peat compaction in deltas : implications for Holocene delta evolution Many deltas contain substantial amounts of peat, which is the most compressible soil type. Therefore, peat

Causes of Avulsion: An Overview Fluvial Sedimentology VI

Avulsion, i.e. the relatively sudden displacement of a river channel, has an important effect on sediment distribution and on architecture of fluvial deposits because avulsion is a primary control on channel location on a floodplain. Depositional record of an avulsive fluvial system controlled by peat compaction (Neogene, Most Basin, Czech

Peat compaction in deltas : implications for Holocene

Therefore, peat compaction potentially leads to high amounts of subsidence in deltas. The main objective of this research was to quantify subsidence due to peat compaction in Holocene fluvial-deltaic settings and to evaluate effects of peat read more compaction on delta evolution.

Causes of Avulsion: An Overview Fluvial Sedimentology VI

Avulsion, i.e. the relatively sudden displacement of a river channel, has an important effect on sediment distribution and on architecture of fluvial deposits because avulsion is a primary control on channel location on a floodplain. Depositional record of an avulsive fluvial system controlled by peat compaction (Neogene, Most Basin, Czech

Effects of peat compaction on delta evolution: A review on

Peat is most compressible of all natural soils. Compaction of peat layers potentially leads to substantial amounts of land subsidence. Peat is common

Peat compaction in deltas : implications for Holocene

Moreover, regional gradients are low in peatlands, which inhibits a crevasse splay to evolve into an avulsion, as is usually the mechanism of avulsion initiation. Only if the maximum peat compaction potential at a certain location has been reached, while at a nearby location on the floodplain rates of subsidence due to peat compaction are still

Peat compaction in deltas : implications for Holocene

Request PDF Peat compaction in deltas : implications for Holocene delta evolution Many deltas contain substantial amounts of peat, which is the most compressible soil type. Therefore, peat

© The Author(s) 2017 level and peat formation in delta

The impact of avulsion on groundwater level and peat formation in delta floodbasins during the middle-Holocene transgression in the Rhine-Meuse delta, minimizing compaction effects in the curves. The basal peats sampled for these reconstructions are swamp peat and fen-edge peat (Alnus peat, that is,

Effects of peat compaction on delta evolution: A review on

However, in the Tullock Member, in contrast to the avulsion process in fluvial systems mainly composed of clastic material, compaction of underlying peat layers in response to channel infill

Peat compaction in deltas : implications for Holocene

Therefore, peat compaction potentially leads to high amounts of subsidence in deltas. The main objective of this research was to quantify subsidence due to peat compaction in Holocene fluvial-deltaic settings and to evaluate effects of peat read more compaction on delta evolution.

Contribution of peat compaction to relative sea‐level rise

Plot of the percentage of peat compaction and final average subsidence rate vs. final overburden thickness, in a peat sequence with an uncompacted thickness (i.e., base‐level rise multiplied by time of peat accumulation) of 4 m (Situation 1), and 100 years of constant aggradation of 0.001 m/yr during Situation 2 (symbol list in Text S1). The

The influence of peat compaction on river channel

Aim: (1) determine the magnitude and rate of compaction using field data from the Holocene Rhine-Meuse delta and other sources, (2) determine how compaction influences topographic slopes, (3) examine avulsion sites and river courses in order to determine if compaction has had an influence, (4) make a numerical model of compaction, (5) incorporate a compaction module into a next generation

Contribution of peat compaction to relative sea-level rise

understanding peat compaction over a range of temporal and spatial scales, which is fundamental to comprehending modern environmental problems within deltaic settings, in particular relative sea-level rise, which may result in damage to wetland ecosystems and increased flooding risk [e.g., Day

A new soil mechanics approach to quantify and predict land

Peat is a fibrous, waterlogged, highly organic substance composed of plant remains, and is highly compressible. Overburden increases the effective stress in a peat layer; the pore water contained within the peat is expelled, and the peat becomes more compact with a more dense packing of the peat fibers.

FACTORS CONTROLLING PEAT COMPACTION IN ALLUVIAL

current avulsion belt, these sediments are typically found about 2 to 4 m below the surface mainly as stiff, well-compacted, gray silt and silty clay The amount of peat compaction was

Crevasse Splays Versus Avulsions: A Recipe for Land

Apr 19, 2018 To simulate compaction we developed a routine in Delft3D that dynamically lowers the floodplain surface in response to sediment deposition. In some model experiments we observe an avulsion, where floodplain erosion exceeds deposition and discharge increases beyond model stability. for instance because of thicker peat beds in the

Depositional record of an avulsive fluvial system

Furthermore, peat compaction may influence the occurrence of avulsion (Michaelsen et al., 2000; Rajchl and Uličný, 2005). Avulsion, the partial or full abandonment of a channel in favour of a

Peat compaction in deltas : implications for Holocene

Therefore, peat compaction potentially leads to high amounts of subsidence in deltas. The main objective of this research was to quantify subsidence due to peat compaction in Holocene fluvial-deltaic settings and to evaluate effects of peat read more compaction on delta evolution.

Effects of peat compaction on delta evolution: A review on

However, in the Tullock Member, in contrast to the avulsion process in fluvial systems mainly composed of clastic material, compaction of underlying peat layers in response to channel infill

Avulsion: The relative roles of autogenic and allogenic

Jun 01, 2007 Compaction of peat, underlying natural levees, may also result in higher local aggradation rates, but this is especially important in the western part of the delta (west of coordinate x = 130). Download : Download full-size image; Fig. 7. Local and regional aggradation rates plotted in a W–E section versus time. Left: 14 C yr BP, right: cal

Contribution of peat compaction to relative sea-level rise

understanding peat compaction over a range of temporal and spatial scales, which is fundamental to comprehending modern environmental problems within deltaic settings, in particular relative sea-level rise, which may result in damage to wetland ecosystems and increased flooding risk [e.g., Day

Crevasse Splays Versus Avulsions: A Recipe for Land

Apr 19, 2018 To simulate compaction we developed a routine in Delft3D that dynamically lowers the floodplain surface in response to sediment deposition. In some model experiments we observe an avulsion, where floodplain erosion exceeds deposition and discharge increases beyond model stability. for instance because of thicker peat beds in the

The contribution of peat compaction to total basin

Apr 01, 2011 The observed variability in compaction within one peat sequence derives from variations in organic content and fibre structure, which is mainly determined by the plant species composition and degree of degradation. 8 The average percentage of compaction of a peat sequence (average of all 5‐cm‐thick peat layers; vertical lines indicate the

A new soil mechanics approach to quantify and predict land

Peat is a fibrous, waterlogged, highly organic substance composed of plant remains, and is highly compressible. Overburden increases the effective stress in a peat layer; the pore water contained within the peat is expelled, and the peat becomes more compact with a more dense packing of the peat fibers.

Peat accumulation on a drowned coastal braidplain: the

Oct 01, 1999 Peat distribution was apparently influenced by differential compaction of facies associated with the tectonic subsidence of the underlying fault blocks . The presence of a stable platform composed of non-compactible fluvial sand may have promoted the accumulation of thick, high-quality peat, as noted for other peat- and coal-bearing regions by

Contribution of peat compaction to relative sea‐level rise

Apr 28, 2013 Contribution of peat compaction to relative sea‐level rise within Holocene deltas Contribution of peat compaction to relative sea‐level rise within Holocene deltas Asselen, S.; Karssenberg, D.; Stouthamer, E. 2013-04-28 00:00:00 Modern and forecasted flooding of deltas is accelerated by subsidence of Holocene deposits. Subsidence caused by tectonics, isostasy, sediment compaction

A relationship between alluvial backswamps and avulsion

Apr 15, 2001 Compaction ratios for organic-rich fine-grained sediments are on the order of 4:1–8:1 (Collinson and Thompson, 1989). For the basal carbonaceous shale, which was not a true peat and contains only thin stringers of lignite, an average compaction ratio of about 6:1 probably gives a fair approximation of the actual compaction that occurred.

Peat layer accumulation and post‐burial deformation during

Abstract Peat horizons are characteristic features of delta plains worldwide. In this study, we tested the use of peat‐based correlations to assess the deformation of Holocene strata in the Po coastal plain (Northern Italy). The Holocene stratigraphy, about 30 km inland from the modern coastline consists of a peat‐bearing, estuarine and deltaic succession, up to 23 m thick.

Chapter 2 Conceptual models for short-eccentricity-scale

autogenic avulsion model is widely adopted in studies on coal-bearing fluvial successions. It considers differential peat compaction as a major autogenic control on channel avulsion resulting in diagonally stacked channel sandstones over time (e.g. Fielding, 1984). However, in many cases,

Avulsions, channel evolution and floodplain sedimentation

The avulsion history within the transect was deduced from these data, and morphological stages in channel development were recognized. Additionally, floodplain sedimentation rates were established. Depositional record of an avulsive fluvial system controlled by peat compaction (Neogene, Most Basin, Czech Republic), Sedimentology

Conceptual models for short-eccentricity-scale climate

In model 1, orbitally forced climate change controls the timing of peat compaction, leading to enhancement of autogenic channel avulsions. In model 2, orbitally forced climate change controls upstream sediment supply and clastic influx determining the persistence of peat-forming conditions.