Amanda Owen

University of Glasgow

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Co-Authors

Adrian J. Hartley

University of Aberdeen

Gary S. Weissmann

University of New Mexico

Gary Nichols

University of Portsmouth

John Howell

University of Aberdeen

Trevor Hoey

Brunel University of London

L. A. Scuderi

University of New Mexico

Richard Williams

University of Glasgow

Octria Adi Prasojo

University of Indonesia

Francyne Bochi do Amarante

Universidade Federal do Rio Grande do Sul

Adriano Domingos dos Reis

Universidade Federal do Rio Grande do Sul

Cooperative Institutions

University of Aberdeen

Universidade Federal do Rio Grande do Sul

University of Glasgow

Universitat de Barcelona

University of New Mexico

Instituto de Geociencias

King's College Hospital

Institute of Geology and Geophysics

Universidade Federal do Rio de Janeiro

University of Birmingham

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Uranium distribution as a proxy for basin-scale fluid flow in distributive fluvial systems

Journal of the Geological Society (2016)

Amanda Owen Adrian J. Hartley Gary S. Weissmann Gary Nichols

We infer system-scale fluid flow in the Late Jurassic Salt Wash fluvial succession (SW USA) by plotting uranium deposit distribution against sedimentological data, using uranium distribution as a proxy for subsurface fluid flow. More than 90% of uranium deposits in the Salt Wash occur where sandstone forms 40–55% and sand-rich channel-belts form 20–50% of the succession, which coincides with changes in channel-belt connectivity and gross-scale architecture. The paucity of uranium below these cut-off values suggests that fluid flow is related directly to predictable downstream fining and facies variations in distributive fluvial systems. Supplementary material: A summary table of location data, key trends and the amalgamation ratio method is available at https://doi.org/10.6084/m9.figshare.c.2849581 .

Proxy (statistics)

10.1144/jgs2016-007

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Citations (12)

Fluvial sedimentation and its reservoir potential at foreland basin margins: A case study of the Puig-reig anticline (South-eastern Pyrenees)

Sedimentary Geology (2021)

Xiaolong Sun Juan Alcalde Enrique Gomez‐Rivas Amanda Owen Albert Griera

Fluvial fans represent one of the dominant sedimentary systems at the active margins of non-marine foreland basins. The Puig-reig anticline at the north-eastern margin of the Ebro Foreland Basin (SE Pyrenees, Spain) exposes continuous outcrops of Late Eocene-Early Oligocene fluvial deposits, from proximal to medial fluvial fan environments. The proximal deposits are found in the north limb of the anticline, especially in the northwest zone. These deposits are characterised by conglomerates with minor interbedded sandstones, with thick and wide sheet-like geometries with unscoured or variably scoured basal surfaces. These are interpreted to be the deposits of unconfined flash floods and wide-shallow channel streams. The medial deposits, covering the rest of the anticline, consist of interbedded conglomerates, sandstones and claystones. These are interpreted to have been deposited from braided to meandering channel streams and overbank areas. Distal deposits are found towards the south, beyond the anticline, and are characterised by sandstone and clay deposits of terminal lobes and lacustrine deltas. This study assesses the impact of the primary depositional characteristics, diagenesis and deformation of the most heterolithic portion of the system, with implications for increasing our understanding of folded fluvial reservoirs. Diagenetic processes, mainly mechanical compaction and calcite cementation, resulted in overall low intergranular porosity, with limited relatively high porosity developed in sandstone lithofacies in the medial deposits. Deformation associated with thrusting and fold growth resulted in the formation of abundant fractures, with relatively high fracture intensities observed in sandstone lithofacies in the anticline crest. This study shows that post-depositional processes can both improve and diminish the reservoir potential of basin proximal fluvial deposits, through the development of fracture networks and by compaction-cementation. The comparison of the Puig-reig anticline with other similar settings worldwide indicates that foreland basin margin locations may be potential areas for effective reservoirs, even in the case of low intergranular porosity.

Anticline

Arenite

Syncline

Outcrop

10.1016/j.sedgeo.2021.105993

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Citations (10)

Paleohydraulic analysis of an ancient distributive fluvial system

Journal of Sedimentary Research (2022)

Adrian J. Hartley Amanda Owen

ABSTRACT Reconstructing the paleohydraulics of ancient fluvial systems has important implications when determining channel-body dimensions in the subsurface as well as aiding source-to-sink studies and quantitatively determining the impact of changing climatic conditions. We undertake a paleohydraulic analysis of the Upper Jurassic Salt Wash distributive fluvial system (DFS) of the Morrison Formation, SW USA, to determine if downstream trends such as decreasing channel size and discharge, inferred in studies of DFS, are present. Channel depth was estimated using cross-set height values and preserved bar thickness. Nine localities across the exposed part of the Salt Wash system were studied. In total, 49 bars were measured, full bar thickness was determined from 12 complete bars, and average cross-set height was calculated for 37 bars. Estimates of maximum bankfull channel depth were derived from measured bar thicknesses. Bar height was then obtained and converted to mean bankfull channel depth using a shape adjustment factor of 0.65. The bar-derived mean bankfull channel depths were then used to derive a factor for which dune cross-set heights could be converted to mean bankfull channel depth (4.6) and maximum bankfull channel depth (7.1). These factors were then applied to localities where only cross-set height data were available, thus allowing consistent comparison and extrapolation of mean bankfull channel depth over the preserved DFS area. The use of measured bar thicknesses to calibrate estimates of mean channel depth from reconstructed dune heights is considered a useful approach, with the factor of 4.6 estimated here being lower than that (6 to 10) commonly used in comparable studies. The datasets for the Salt Wash DFS record systematic downstream trends in cross-set height, bar thickness, calculated channel depth, estimated channel width, and estimated Q, with variability and overlap between the proximal to medial, and medial to distal parts. The variability superimposed on the regional downstream trends is attributed to a combination of autocyclic processes such as variations in discharge, depth of scour, and avulsion as well as more regional-scale channel-belt switching together with allocyclic controls. The wide spatial distribution of the dataset in this study allows distinction between local autocyclic controls and regional downstream trends. Formative discharge shows no downstream trend across the entire Salt Wash DFS, with a wide range in coefficient of variation of preserved cross set thickness (CV(dst) values of 0.1 to 1.1) indicative of flashy (variable) discharge. The spatial distribution of the Salt Wash dataset allows extrapolation of trends upstream to the unexposed part of the system that allows insights into the characteristics of the channel system in the apex area (∼ 150 km to the southwest and removed by post depositional erosion). The fluvial system would have a mean depth of 9 m, and a bankfull-depth discharge of around 1450 m3/s with mean cross-set heights of between 50 and 70 cm. These estimates are in line with those from present-day DFSs in the Himalayan and Andean foreland basins that have a scale similar to that estimated for the Salt Wash system.

Bar (unit)

10.2110/jsr.2021.062

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Meandering rivers in modern desert basins: Implications for channel planform controls and prevegetation rivers

Sedimentary Geology (2019)

Maurício G. M. Santos Adrian J. Hartley Nigel P. Mountney Jeff Peakall Amanda Owen

Meander (mathematics)

10.1016/j.sedgeo.2019.03.011

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Citations (47)

Vertical trends within the prograding Salt Wash distributive fluvial system, SW United States

Basin Research (2015)

Amanda Owen Gary Nichols Adrian J. Hartley Gary S. Weissmann

Abstract Progradation is an important mechanism through which sedimentary systems fill sedimentary basins. Although a general progradational pattern is recognized in many basins, few studies have quantified system scale spatial changes in vertical trends that record fluvial system progradation. Here, we provide an assessment of the spatial distribution of vertical trends across the Salt Wash distributive fluvial system ( DFS ), in the Morrison Formation SW , USA . The vertical distribution of proximal, medial and distal facies, and channel belt proportion and thickness, are analysed at 25 sections across approximately 80 000 km 2 of a DFS that spanned approximately 100 000 km 2 . The stratigraphic signature of facies stacking patterns that record progradation varies depending on location within the basin. An abrupt and incomplete progradation succession dominates the proximal region, whereby proximal deposits directly overlie distal deposits. A more complete succession is preserved in the medial region of the DFS . The medial to distal region of the DFS are either simple aggradational successions, or display progradation of medial over distal facies. Spatial variations in facies successions patterns reflects preservation changes down the DFS . A spatial change in vertical trends of channel belt thickness and proportion is not observed. Vertical trends in channel belt proportion and thickness are locally highly variable, such that systematic up‐section increases in these properties are observed only at a few select sites. Progradation can only be inferred once local trends are averaged out across the entire succession. Possible key controls on trends are discussed at both allocyclic and autocyclic scales including climate, tectonics, eustasy and avulsion. Eustatic controls are discounted, and it is suggested that progradation of the Salt Wash DFS is driven by upstream controls within the catchment.

Progradation

Aggradation

10.1111/bre.12165

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Citations (40)

Quantification of a Distributive Fluvial System: The Salt Wash DFS of the Morrison Formation, SW U.S.A.

Journal of Sedimentary Research (2015)

Amanda Owen Gary Nichols A. J. Hartley Gary S. Weissmann L. A. Scuderi

Recent analysis of modern aggradational continental sedimentary basins reveals that sedimentation patterns are dominated by distributive fluvial systems (DFSs).The Salt Wash Member of the Late Jurassic Morrison Formation has previously been described as a fan-shaped fluvial system.This study characterizes facies variations across the Salt Wash DFS to qualitatively test predicted trends in conceptual DFS models.Notable proximal-to-distal trends include a change in total thickness of the fluvial succession from 174 m to 40 m, and in average grain size from coarse sand to silt, while the percentage of sand decreased from 70% in the proximal region to 8% in the distal region.The proportion of amalgamated channel-belt deposits decreased from 67% to 0%, while floodplain facies and lacustrine deposits increase (38% to 94% and 0.1% to 7% respectively).A downstream decrease in average channel belt thickness (15 m to 3.8 m, from thickest to thinnest) and average story thickness (7.7 m to 2.3 m, from thickest to thinnest) is also recorded.Significant downstream changes in deposit architecture were also noted, with proximal regions dominated by stacked channel belt deposits with a high degree of amalgamation.Distal deposits are dominated by floodplain muds and sheet sandstones and sparse ribbon channels, with little to no amalgamation of channel deposits.This study provides quantified information for an ancient DFS with the aim of providing a dataset that can be used for objective comparison between different DFSs, as well as providing numerical data to aid resource exploration and modelling efforts.

Distributed File System

10.2110/jsr.2015.35

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Citations (106)

A quantitative depositional model of a large distributive fluvial system (Megafan) with terminal aeolian interaction: The Upper Jurassic Guará DFS in southwestern Gondwana

Journal of Sedimentary Research (2022)

Adriano Domingos dos Reis Claiton Marlon dos Santos Scherer Amanda Owen Francyne Bochi do Amarante João Pedro Formolo Ferronatto

ABSTRACT Recent studies have shown that distributive fluvial systems are the dominant fluvial forms in modern continental sedimentary basins, thus composing a large part of the stratigraphic record. This study provides a basin-scale architectural analysis of the Guará Formation, from the Upper Jurassic record of southwestern Gondwana, and attempts to compare the formation's depositional model to those developed for distributive fluvial system (DFS) successions. This time interval is significant because it was a period of intense tectonic activity related to the Paraná–Etendeka plume and the Gondwana breakup. Quantitative analyses were performed on stratigraphic sections at 17 locations (exposing a total of 720 m of stratigraphy) located in southern Brazil and northern Uruguay, from a larger dataset of 64 locations (comprising a total of 1070 m of stratigraphy). Four facies associations were identified: perennial fluvial channel fills, ephemeral fluvial channel fills, floodplain deposits, and aeolian deposits, indicating a dryland climate. Spatial trends were analyzed along a downstream-oriented transect (NNE–SSW) across the system. Grain size, channel-body thickness, number of stories, and bar thickness decrease downstream, indicating a reduction in channel depth, flow capacity, and channelization of the fluvial system, interpreted to be associated with downstream-increasing bifurcation, infiltration, and evapotranspiration. Based on spatial trends and distribution of facies associations, the deposits are interpreted to have been accumulated from a large DFS which can be divided into four zones, from proximal to distal: Zone 1, dominated by perennial fluvial channels; Zone 2, a mixture of perennial and ephemeral channels; Zones 3 and 4, deposits situated externally of the fluvial channel belts dominated by aeolian and floodplain deposits prevailing in each zone, respectively. The Guará Formation likely records the stratigraphic signature of the largest distributive fluvial systems reconstructed from both modern and ancient datasets, and one of the first where fluvio–aeolian interaction is quantified. The Guará Formation DFS model presented herein is key to understanding paleoenvironmental, paleoclimatic, and geotectonic changes related to Gondwanan fragmentation.

10.2110/jsr.2021.040

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Citations (11)

Sedimentology of the proximal portion of a large-scale, Upper Jurassic fluvial-aeolian system in Paraná Basin, southwestern Gondwana

Journal of South American Earth Sciences (2019)

Adriano Domingos dos Reis Claiton Marlon dos Santos Scherer Francyne Bochi do Amarante Marcos de Magalhães May Rossetti Carrel Kifumbi

10.1016/j.jsames.2019.102248

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Citations (23)

Review for "The interactions of volcanism and clastic sedimentation in rift basins: insights from the Palaeogene‐Neogene Shaleitian uplift and surrounding sub‐basins, Bohai Bay Basin, China"

Amanda Owen

Paleogene

Neogene

Sedimentation

10.1111/bre.12651/v1/review3

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The role of the topset slope in autogenically controlling avulsion and bifurcation timescales in river deltas

Octria Adi Prasojo Trevor Hoey Amanda Owen Richard Williams

Earth and Space Science Open Archive This preprint has been submitted to and is under consideration at Journal of Geophysical Research - Earth Surface. ESSOAr is a venue for early communication or feedback before peer review. Data may be preliminary.Learn more about preprints preprintOpen AccessYou are viewing the latest version by default [v1]The role of the topset slope in autogenically controlling avulsion and bifurcation timescales in river deltasAuthorsOctria AdiPrasojoiDTrevor B.HoeyAmandaOwenRichard DavidWilliamsiDSee all authors Octria Adi PrasojoiDCorresponding Author• Submitting AuthorUniversity of GlasgowiDhttps://orcid.org/0000-0003-3404-3925view email addressThe email was not providedcopy email addressTrevor B. HoeyBrunel University Londonview email addressThe email was not providedcopy email addressAmanda OwenUniversity of Glasgowview email addressThe email was not providedcopy email addressRichard David WilliamsiDUniversity of GlasgowiDhttps://orcid.org/0000-0001-6067-1947view email addressThe email was not providedcopy email address

Preprint

10.1002/essoar.10512273.1

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