Dissected paleotopography and base-level changes in a Triassic fluvial sequence

Kraus, Mary J.; Middleton, Larry T.

doi:10.1130/0091-7613(1987)15<18:dpabci>2.0.co;2

Cited by 71 publications

(58 citation statements)

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“…between 110-150m on Figure 5), or erosional with Lithofacies C infilling broad, shallow channel scours that range between 14-25m width and 3m depth (Figure 4k; 94-144m on Figure 5). These relationships are consistent with rapid burial of Lithofacies B by sediment-laden traction currents leading to localised scouring and incision (Miall, 1985;Kraus & Middleton, 1987). A number of broad (upto 55m and relatively shallow (<3m) sand and gravel-filled channels can be observed (e.g.…”

Section: 3supporting

confidence: 73%

Sedimentary and structural evolution of a relict subglacial to subaerial drainage system and its hydrogeological implications: an example from Anglesey, north Wales, UK

Lee

Wakefield

Phillips

et al. 2015

Quaternary Science Reviews

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Subglacial drainage systems exert a major control on basal-sliding rates and glacier dynamics. However, comparatively few studies have examined the sedimentary record of subglacial drainage. This is due to the paucity of modern analogues, the limited recognition and preservation of upper flow regime deposits within the geological record, and the difficulty of distinguishing subglacial meltwater deposits from other meltwater sediments (e.g. glacier outburst flood deposits). Within this study, the sedimentological and structural evolution of a subglacial to subaerial (ice-marginal / proglacial) drainage system is examined. Particular emphasis is placed upon the genetic development and preservation of upper flow regime bedforms and specifically recognising them within a subglacial meltwater context. Facies attributed to subglacial meltwater activity record sedimentation within a confined, but progressively enlargening, subglacial channel system produced under dune to upper flow regime conditions. Bedforms include rare large-scale sinusoidal bedding with syn-depositional deformation produced by current-induced traction and shearing within the channel margins. Subglacial sedimentation culminated with the abrupt change to a more ephemeral drainage regime indicating channel-abandonment or a seasonal drainage regime. Retreat of the ice margin, led to the establishment of subaerial drainage with phases of sheet-flow punctuated by channel incision and anastomosing channel development under diurnal, ablation-related, seasonal discharge. The presence of extensive hydrofracture networks demonstrate that proglacial groundwater-levels fluctuated markedly and this may have influenced later overriding of the site by an ice stream.

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Section: 3supporting

confidence: 73%

Sedimentary and structural evolution of a relict subglacial to subaerial drainage system and its hydrogeological implications: an example from Anglesey, north Wales, UK

Lee

Wakefield

Phillips

et al. 2015

Quaternary Science Reviews

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“…The stacking of multiple fining-upward cycles in the thickened terraces reflects the rapid aggradation that took place in the subsiding areas and suggests frequent changes in the channel path (Schumm, 1986(Schumm, , 1993Schumm et al, 2000). In spite of the subsidence, the dominant light orange colour of floodplain fines reveals that most of the floodplain was well-drained apart from some subsidence depressions in which greenish and grey marls were deposited (Kraus and Middleton, 1987;Kraus, 1992). Additionally, differential subsidence and changes in the location of the most-subsiding areas would control the trajectory of the channel and its position (migration and avulsion) (Leeder and Alexander, 1987) as revealed by the frequent association between synformal structures (subsidence paleodepressions) and gravel channels.…”

Section: Evolution Of the Huerva River Terracesmentioning

confidence: 92%

Impact of halite dissolution subsidence on Quaternary fluvial terrace development: Case study of the Huerva River, Ebro Basin, NE Spain

2008

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“…A common interpretation of the stratigraphic record in such fills is that detailed layering reflects discrete external (allogenic) forcing mechanisms, including high frequency climate change, (low amplitude) high frequency tectonic movement, eustatic sea level and lake level fluctuations, and local faulting (Kraus and Middleton 1987;Bromely 1991; LopezGomez and Arche 1993;Blum and Tornqvist 2000). The question of whether there are other mechanisms that could potentially produce the same geomorphic and stratigraphic signatures as these external factors is difficult to address from field data alone.…”

Section: Incised Valley Evolution and Preservationmentioning

confidence: 99%

Fluvial Landscapes and Stratigraphy in a Flume

Strong¹,

Paola²

2006

TSR

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We use data from an experiment conducted in the Experimental EarthScape (XES) facility, National Center for Earth-surface Dynamics (NCED), St.Anthony Falls Laboratory (SAFL), University of Minnesota, to demonstrate why incised valleys preserved in the stratigraphic record probably bear little resemblance to the actual valleys as they appeared in the paleolandscape. In an experiment designed to study fluvial response to changes in sea level, we find that preserved incised-valley structures are typically broader and have more gentle side slopes, than the topographic features from which they develop. Also, because of widening driven by valley wall erosion during both relative sea-level rise and fall, there is virtually no remnant of terraces formed during falling relative sea level preserved in the stratigraphic record.The process of filling an incised valley due to rising relative sea level is not a passive depositional process that simply buries and preserves the original shape of the valley; rather, it includes an energetic erosional component that substantially reshapes the original valley form. INCISED VALLEY EVOLUTION AND PRESERVATIONThe geological community has long recognized the significance of identifying incised valleys in the stratigraphic record as well as understanding the relationships between the filling of incised-valleys and their geomorphologic evolution. Incised valley geometries and fill are often used to infer the record and effects of sea level change on coastal environments, both as a tool in petroleum exploration (e.g. Van Wagoner et al. 1988, 1990Posamentier and Allen 1999) and to better understand the environmental consequences of sea level change (Warrick et al. 1993; Nicholls and Leatherman 1994). Furthermore, incised valleys typically comprise basin scale erosional unconformities that can be identified in seismic sections, well logs, and outcrops, and thus are used to correlate stratigraphic facies and time (e.g., Van Wagoner et al. 1990).Previous work on both modern and preserved incised valleys has illustrated the complexity of incised valley fill. A common interpretation of the stratigraphic record in such fills is that detailed layering reflects discrete external (allogenic) forcing mechanisms, including high frequency climate change, (low amplitude) high frequency tectonic movement, eustatic sea level and lake level fluctuations, and local faulting (Kraus and Middleton 1987;Bromely 1991; LopezGomez and Arche 1993;Blum and Tornqvist 2000). The question of whether there are other mechanisms that could potentially produce the same geomorphic and stratigraphic signatures as these external factors is difficult to address from field data alone. Here we use experimental data to illustrate the role of autogenic (internal) processes in producing this complexity. EXPERIMENTAL FACILITIESThe experimental data presented in this paper come from an experiment conducted in the Experimental EarthScape (XES) facility, National Center for Earth-surface Dynamics, St. Anthony Falls Laboratory,...

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Dissected paleotopography and base-level changes in a Triassic fluvial sequence

Cited by 71 publications

References 0 publications

Sedimentary and structural evolution of a relict subglacial to subaerial drainage system and its hydrogeological implications: an example from Anglesey, north Wales, UK

Sedimentary and structural evolution of a relict subglacial to subaerial drainage system and its hydrogeological implications: an example from Anglesey, north Wales, UK

Impact of halite dissolution subsidence on Quaternary fluvial terrace development: Case study of the Huerva River, Ebro Basin, NE Spain

Fluvial Landscapes and Stratigraphy in a Flume

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