DOCSLIB.ORG

Published Version

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Published Version PUBLISHED VERSION Lewis, Megan Mary; White, Davina Cherie; Gotch, Travis Bruce (eds.) 2013, Allocating water and maintaining springs in the Great Artesian Basin. Volume IV. Spatial survey and remote sensing of artesian springs of the western Great Artesian Basin, Canberra, National Water Commission © Commonwealth of Australia 2013 This work is copyright. The Copyright Act 1968 permits fair dealing for study, research, news reporting, criticism or review and the National Water Commission supports and encourages the dissemination and exchange of its information. Selected passages, tables or diagrams may be reproduced for such purposes provided you attribute the National Water Commission as the source. Reproduction for commercial use or sale requires prior written permission from the National Water Commission. Requests and enquiries concerning reproduction and rights should be addressed to the Communication Director, National Water Commission, 95 Northbourne Avenue, Canberra ACT 2600 or email [email protected] PERMISSIONS This document is made available with special permission from the National Water Commission. 14.05.2013. The full report is available at the National Water Commission’s Archive site: http://archive.nwc.gov.au/library/topic/groundwater/allocating-water-and-maintaining- springs-in-the-great-artesian-basin ‘Allocating Water and Maintaining Springs in the GAB’ http://hdl.handle.net/2440/77601 Volume IV: Spatial Survey and Remote Sensing of Artesian Springs of the Western Great Artesian Basin Allocating Water and Maintaining Springs 6 in the Great Artesian Basin Evaluation of remote sensing approaches Megan M Lewis School of Earth and Environmental Sciences, The University of Adelaide Davina White School of Earth and Environmental Sciences, The University of Adelaide Volume IV: Spatial Survey and Remote Chapter 6: Evaluation of Sensing of Artesian Springs of the remote sensing approaches Western Great Artesian Basin Allocating Water and Maintaining Springs in the Great Artesian Basin 6 6. Evaluation of remote sensing approaches 6�1� Evaluation 6�2� Imagery This chapter provides an evaluation of the Figure 6.1 illustrates the spatial and temporal types of remote sensing data and approaches domains of the spring environments, in relation that were employed in this study to further to the spatial and temporal resolutions of the understanding of the springs along the western sensors employed in this study. The selection margin of the Great Artesian Basin (GAB). During of imagery for specific GAB spring mapping the study, careful consideration was given to the and monitoring purposes was influenced by the most appropriate choice of sensors and image spatial coverage and repeat frequency of the analyses for detecting GAB Springs and their imagery, as outlined in Table A2.1, Appendix 2. various surface expressions in space and time. Table 6.1 summarises the study components, MODIS imagery, with its moderate spatial remote sensing instruments and image analyses resolution, broad spatial coverage and high used for each application, as well as providing temporal frequency (16-day composites a rationale for selection of sensors and an were used in this study) and long archive of evaluation of the effectiveness of the approaches continuous measurements (since 2000), was adopted. ideally suited to monitoring change at the spring complex scale. MODIS imagery was used to This evaluation is best considered in relation to determine long-term trends in wetland extent for the nature of the spring environments including spring complexes and demonstrate the influence their spatial extent, temporal variability and of climatic conditions. It was also capable surface expressions. The study covered a of determining interseasonal variability and wide range of spatial scales of relevance to phenology in several dominant spring vegetation the GAB Springs, from spring complexes communities. MODIS normalised difference down to spring groups and individual springs. vegetation index (NDVI) was suitable for tracking It spanned time scales ranging from seasons trends at the largest of the spring complexes, and years to the past decade through new but its spatial resolution limits its utility for acquisitions and use of archival imagery. A smaller or more geographically dispersed range of ecological units were targeted, from spring complexes. This high temporal frequency total plant growth in the landscape and precise information was also useful for informing measurements of wetland area, to community optimal times for capturing higher resolution and species discrimination. In addition, spring airborne and satellite imagery for more detailed surface characteristics were differentiated characterisation of the springs. and documented, including vegetation, soil moisture and evaporite crusts related to diffuse groundwater discharge. Photograph on facing page: Megan M Lewis 103 Broad Continuous Spring complexes Spring groups Tasked Tasked Spatial scale of study aquisition aquisition (repeated (repeated at selected at selected intervals) intervals) Individual springs Fine Season Year Decade > Timescale Chapter 6: Evaluation of remote sensing approaches 6 Monthly rainfall (mm) Figure 6.1: Spatial and temporal Year scales of studies of springs in the Broad western margin of the GAB, in relation to spatial and temporal resolutions of sensors used in this report Continuous Spring complexes Legend WorldView-2 and QuickBird very high resolution satellites Spring groups Tasked Tasked HyMap airborne hyperspectral Spatial scale of study aquisition aquisition MODIS 16 day composites (repeated (repeated at selected at selected intervals) intervals) Individual springs Fine Season Year Decade > Timescale QuickBird and WorldView-2 satellite images documentation of wetland change over time, as combine very high spatial resolution with demonstrated by the Dalhousie Springs 2006– extensive spatial coverage, both required for 2010 study. Although these very high resolution precise delineation of wetlands at the spring sensors are a relatively new technology, with Monthly rainfall (mm) complex, spring group and individual spring limited historical archives, they can provide scales. Springs of differing spatial extent, from useful baseline records for future detection of tens to hundreds of hectares, as well as entire spring changes over time.Year spring complexes were well documented with this imagery. These images provided precise With high spatial resolution, airborne delineation of perennial and ephemeral wetland hyperspectral imagery is especially suited to from surrounding dryland vegetation associated detailed detection and mapping of a wide range with the springs, and were used to quantify of spring surface characteristics. The imagery detailed changes in the wetlands over time in was used to target specific study areas (e.g. response to rainfall, spring flow and ecological Eagle image swaths over Dalhousie) or provide processes.Legend comprehensive coverage over large areas (e.g. WorldView-2 and QuickBird HyMap image mosaics of spring complexes), The opportunityvery to task high resolutionimages atsatellites selected times providing information at both spring group and allowed for coincidentHyMap airbornefield data hyperspectral collection and spring complex scales. validation activities,MODIS and 16 studyday composites of change over time, as was undertaken at the Big Blyth Bore The levels of ecological differentiation and and Freeling Springs. The high spatial accuracy focus in this volume range from assessments of the imagery and well-documented radiometric of average total vegetation greenness across characteristics made it very suitable for objective the landscape to differentiation of wetlands 104 Volume IV: Spatial Survey and Remote Chapter 6: Evaluation of Sensing of Artesian Springs of the remote sensing approaches Western Great Artesian Basin Allocating Water and Maintaining Springs in the Great Artesian Basin 6 Spatial scale Sensors Methods Ecological information Spectral scale Figure 6.2: Levels of ecological of study of study differentiation of the springs Broad in the western GAB, in relation NDVI time series to remote sensing data and NDVI Total wetland greenness approaches used in this report Time series Wetlands vs. dryland Wetland phenology MODIS satellite Spring complexes Wetland extent NDVI Precise delineation and Thresholds quantification of wetlands Wetland area-spring flow Very high resolution multispectral satellite relationships Spring groups Vegetation species Indices Standing water Spectral angle Surface moisture mapping Evaporite crust HyMap airborne Mixture-tuned Vegetative communities hyperspectral matched filtering and species Individual springs Spectral library Individual plants Plant spectra and canopies Field Plants spectroradiometer Fine from arid vegetation and understanding of 6�1�2� Analysis wetland function, to more precise delineation A range of analytical approaches were applied and quantification of wetlands (Figure 6.2). At to these rich sources of remote sensing data the broadest landscape and spring complex to extract new information about the spring scales, MODIS NDVI time-series provided ecosystems and their function. The NDVI, information about total wetland greenness and applied to MODIS, multispectral satellite and penology, while very high resolution multispectral airborne hyperspectral imagery was highly satellite imagery was ideally suited to the precise suitable for defining and characterising the delineation
Load more

Recommended publications
  • Holocene Progradation and Retrogradation of the Central Texas Coast Regulated by Alongshore and Cross-Shore Sediment Flux Variability
    Received: 4 May 2020 | Revised: 8 October 2020 | Accepted: 15 October 2020 DOI: 10.1002/dep2.130 ORIGINAL RESEARCH ARTICLE Holocene progradation and retrogradation of the Central Texas Coast regulated by alongshore and cross-shore sediment flux variability Christopher I. Odezulu1 | Travis Swanson2 | John B. Anderson1 1Department of Earth, Environmental and Planetary Science, Rice University, Abstract Houston, TX, USA Fifteen transects of sediment cores located off the central Texas coast between 2Department of Geology and Geography, Matagorda Peninsula and North Padre Island were investigated to examine the off- Georgia Southern University, Statesboro, shore record of Holocene evolution of the central Texas coast. The transects extend GA, USA from near the modern shoreline to beyond the toe of the shoreface. Lithology, grain *Correspondence size and fossil content were used to identify upper shoreface, lower shoreface, ebb- Christopher I. Odezulu, Department tidal delta and marine mud lithofacies. Interpretations of these core transects show of Earth, Environmental and Planetary Science, Rice University, Houston, TX, a general stratigraphic pattern across the study area that indicates three major epi- USA. sodes of shoreface displacement. First, there was an episode of shoreface prograda- Email: [email protected] tion that extended up to 5 km seaward. Second, an episode of landward shoreline Funding information displacement is indicated by 3–4 km of marine mud onlap. Third, the marine muds Rice University Shell Center for Sustainability. are overlain by shoreface sands, which indicates another episode of shoreface pro- gradation of up to 5 km seaward. Radiocarbon ages constrain the onset of the first episode of progradation to ca 6.5 ka, ending at ca 5.0 ka when the rate of sea-level rise slowed from an average rate of 1.6–0.5 mm/yr.
    [Show full text]
  • Resilience of River Deltas in the Anthropocene
    manuscript submitted to JGR: Earth Surface 1 Resilience of river deltas in the Anthropocene 1 2 3 4 2 A.J.F. Hoitink , J.A. Nittrouer , P. Passalacqua , J.B. Shaw , E.J. 5 6 6 3 Langendoen , Y. Huismans & D.S. van Maren 1 4 Wageningen University & Research, Wageningen, The Netherlands 2 5 Rice University, Houston, Texas USA 3 6 University of Texas at Austin, Austin, Texas USA 4 7 Department of Geosciences, University of Arkansas, Fayetteville, Arkansas USA 5 8 National Sedimentation Laboratory, United States Department of Agriculture, Oxford, Mississippi USA 6 9 Deltares, Delft, The Netherlands 10 Key Points: 11 • The predictive capacity of morphodynamic models needs to improve to better an- 12 ticipate global change impacts on deltas 13 • Information theory and dynamical system theory offer complementary analysis frame- 14 works to improve understanding of delta resilience 15 • The sediment balance in a delta channel network needs to be closed such that pre- 16 dictions match with independent observations Corresponding author: Ton Hoitink, [email protected] {1{ manuscript submitted to JGR: Earth Surface 17 Abstract 18 At a global scale, delta morphologies are subject to rapid change as a result of direct and 19 indirect effects of human activity. This jeopardizes the ecosystem services of deltas, in- 20 cluding protection against flood hazards, facilitation of navigation and biodiversity. Di- 21 rect manifestations of delta morphological instability include river bank failure, which 22 may lead to avulsion, persistent channel incision or aggregation, and a change of the sed- 23 imentary regime to hyperturbid conditions. Notwithstanding the in-depth knowledge de- 24 veloped over the past decades about those topics, existing understanding is fragmented, 25 and the predictive capacity of morphodynamic models is limited.
    [Show full text]
  • The Stratigraphic Architecture and Evolution of the Burdigalian Carbonate—Siliciclastic Sedimentary Systems of the Mut Basin, Turkey
    The stratigraphic architecture and evolution of the Burdigalian carbonate—siliciclastic sedimentary systems of the Mut Basin, Turkey P. Bassanta,*, F.S.P. Van Buchema, A. Strasserb,N.Gfru¨rc aInstitut Franc¸ais du Pe´trole, Rueil-Malmaison, France bUniversity of Fribourg, Switzerland cIstanbul Technical University, Istanbul, Turkey Received 17 February 2003; received in revised form 18 November 2003; accepted 21 January 2004 Abstract This study describes the coeval development of the depositional environments in three areas across the Mut Basin (Southern Turkey) throughout the Late Burdigalian (early Miocene). Antecedent topography and rapid high-amplitude sea-level change are the main controlling factors on stratigraphic architecture and sediment type. Stratigraphic evidence is observed for two high- amplitude (100–150 m) sea-level cycles in the Late Burdigalian to Langhian. These cycles are interpreted to be eustatic in nature and driven by the long-term 400-Ka orbital eccentricity-cycle-changing ice volumes in the nascent Antarctic icecap. We propose that the Mut Basin is an exemplary case study area for guiding lithostratigraphic predictions in early Miocene shallow- marine carbonate and mixed environments elsewhere in the world. The Late Burdigalian in the Mut Basin was a time of relative tectonic quiescence, during which a complex relict basin topography was flooded by a rapid marine transgression. This area was chosen for study because it presents extraordinary large- scale 3D outcrops and a large diversity of depositional environments throughout the basin. Three study transects were constructed by combining stratal geometries and facies observations into a high-resolution sequence stratigraphic framework. 3346 m of section were logged, 400 thin sections were studied, and 145 biostratigraphic samples were analysed for nannoplankton dates (Bassant, P., 1999.
    [Show full text]
  • 1 Cyclical Shoreline Erosion: the Impact of a Jettied River Mouth on the Downdrift Barrier Island
    CYCLICAL SHORELINE EROSION: THE IMPACT OF A JETTIED RIVER MOUTH ON THE DOWNDRIFT BARRIER ISLAND ANDREW R. FALLON1, CHRISTOPHER J. HEIN2, PETER S. ROSEN3, HALEY L. GANNON4 1. Virginia Institute of Marine Science, College of William and Mary, 1375 Greate Rd, Gloucester Point, Virginia 23062, [email protected] 2. Virginia Institute of Marine Science, College of William and Mary, 1375 Greate Rd, Gloucester Point, Virginia 23062, [email protected] 3. Northeastern University, 360 Huntington Ave, Boston Massachusetts, 02115, [email protected] 4. College of William and Mary, 200 Stadium Drive, Williamsburg, VA 23186, [email protected] Abstract: Beaches and inlets throughout the U.S. have been stabilized for purposes of navigation, erosion mitigation, and economic resilience, commonly leading to changes in shoreline dynamics and downdrift erosion/accretion patterns. The developed beach of Plum Island, Massachusetts is highly dynamic, experiencing regular complex erosion / accretion patterns along much of the shoreline. We analyzed > 100 years of high-water line positions derived from satellite imagery, t-sheets, historical maps, and aerial photography. Unlike most beaches, the river-proximal sections of Plum Island are not uniformly retreating. Rather, the beach undergoes short-term erosion, followed by periods of accretion and return to a long-term mean stable shoreline position. These cycles occur over different timeframes and in different segments of the beach, creating an ephemeral erosion ‘hotspot’ lasting as briefly as one year. The highly dynamic and spatially diverse nature of erosion along Plum Island provides insight into the complex nature of coupled inlet-beach dynamics over multiple timescales. Introduction Coastlines throughout the world have been highly developed, creating high risk areas due to the dynamic nature of beaches, tidal inlets and barrier islands.
    [Show full text]
  • Zellman Mines 0052E 11720.Pdf (6.993Mb)
    INVESTIGATING LINKS BETWEEN CLIMATE PERTURBATIONS, RIVER DISCHARGE VARIABILITY AND FLUVIAL FANS IN THE PALEOGENE SAN JUAN BASIN, NEW MEXICO, USA by Kristine L. Zellman © Copyright by Kristine L. Zellman, 2019 All Rights Reserved A thesis submitted to the Faculty and the Board of Trustees of the Colorado School of Mines in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Geology). Golden, Colorado Date Signed: Kristine L. Zellman Signed: Dr. Piret Plink-Bj¨orklund Thesis Advisor Golden, Colorado Date Signed: Dr. M. Stephen Enders Professor and Head Department of Geology and Geological Engineering ii ABSTRACT The San Juan Basin in New Mexico preserves the southernmost sedimentary record of the Paleocene and early-Eocene in North America, and thus represents a critical point for comparison for climatic and biotic change during the Paleogene. This dissertation combines basin-scale 3D outcrop analyses of fluvial architecture and preliminary stable carbon isotope records from the Paleocene upper Nacimiento Formation and the early-Eocene San Jose Formation to investigate the link between Paleogene climate perturbations and depositional trends. Through these investigations, we 1) identify the succession as deposits of variable dis- charge river systems, 2) observe a long-term stratigraphic trend toward increasingly well- drained floodplain deposits, and thus successively more arid conditions from Paleocene into the early-Eocene that we suggest may indicate a long-term shift from a monsoonal climate in the Paleocene to fluctuating humid and arid subtropical and then semi-arid/arid conditions in the early Eocene, 3) identify the Paleocene uppermost Nacimiento Formation and early- Eocene Cuba Mesa and Regina Members of the San Jose Formation as deposits of a large fluvial fan and identify at least two vertical packages of fan progradation, and 4) identify at least two negative carbon isotope excursions that may record the Paleocene-Eocene Thermal Maximum (PETM) and one or more post-PETM hyperthermal events.
    [Show full text]
  • Deciphering the Origin of Cyclical Gravel Front and Shoreline Progradation and Retrogradation in the Stratigraphic Record
    Deciphering the origin of cyclical gravel front and shoreline progradation and retrogradation in the stratigraphic record John J. Armitage1, Peter A. Burgess2, Gary J. Hampson3, and Philip A. Allen3 1Department of Earth Science, Royal Holloway, University of London, Egham, UK; Now at Institut de Physique du Globe de Paris, 1 rue Jussieu, Paris, 75005, France; e-mail: [email protected] 2Department of Earth Science, Royal Holloway, University of London, Egham, UK 3Department of Earth Science and Engineering, Imperial College London, London, UK May 4, 2016 1 1 Abstract 2 Nearly all successions of near-shore strata exhibit cyclical movements of the shoreline, which 3 have commonly been attributed to cyclical oscillations in relative sea level (combining eustasy 4 and subsidence) or, more rarely, to cyclical variations in sediment supply. It has become accepted 5 that cyclical change in sediment delivery from source catchments may lead to cyclical movement 6 of boundaries such as the gravel front, particularly in the proximal segments of sediment routing 7 systems. In order to quantitatively assess how variations in sediment transport as a consequence 8 of change in relative sea-level and surface run-off control stratigraphic architecture, we develop a 9 simple numerical model of sediment transport and explore the sensitivity of moving boundaries 10 within the sediment routing system to change in upstream (sediment flux, precipitation rate) and 11 downstream (sea level) controls. We find that downstream controls impact the shoreline and sand 12 front, while the upstream controls can impact the whole system depending on the amplitude of 13 change in sediment flux and precipitation rate.
    [Show full text]
  • Little Ambergris Cay, a Case Study for Ooid Rich Island Development on the Turks and Caicos Carbonate Platform
    Little Ambergris Cay, a Case Study for Ooid Rich Island Development on the Turks and Caicos Carbonate Platform By Drew G. Brown Geological Sciences, University of Colorado at Boulder Defense Date (November 4th, 2020) Thesis Advisor: Dr. Elizabeth Trower, Geology Defense Committee: Dr. Elizabeth Trower, Geological Sciences Dr. Brian Hynek, Geological Sciences Dr. Julia Moriarty, Atmospheric and Oceanic Sciences 1 Abstract: Little Ambergris Cay (LAC) within the Turks and Caicos is a useful field site to examine the accumulation of a carbonate island, within a typical carbonate platform environment, because it does not follow the typically accepted modes of island accretion. There are several methods used to describe carbonate island formation after Schlager (2003), who described carbonate “factories” in reference to the modern analogues of Florida and the Bahamas. The Turks and Caicos, and specifically Little Ambergris Cay, offers a field side that differs from the comparison analogues in sediment composition, energy flux, and Holocene development. Little Ambergris Cay is unusual in that it formed during a period of sea level rise (Figure 2, Toscano & Macintyre, 2003), and thus presents an opportunity for research on how modern carbonate platform environments accumulate through time. This paper presents an argument for eastward direction of island accumulation of Little Ambergris Cay. Based on the research of Trower et al. (2018), Dravis & Wanless (2008), and Schlager (2003), I interpret that Little Ambergris Cay formed via eastward accumulation based on the influence of wind-wave current energy as means of supplying ample sediment to a zone of accumulation; in other words, in this system, sediment supply outpaces accommodation space.
    [Show full text]
  • Sea Level Change
    Sea Level Change Outline Causes of sea level change Temporal (time) scales of sea level changes Climate-related sealevel change and oxygen isotope stages Eustatic and relative sea levels Evidence of sealevel change Sedimentary records of sealevel changes Causes of sea level change Why does the sea level change? Changes in the relative volumes of seawater and polar ice caps and ice sheets a) Formation and melting of ice caps e.g., if Antarctic ice cap and Greenland ice sheets melted completely the sealevel would rise 60-80 m. b) Thermal expansion of seawater 10ºC increase in seawater temperature would cause 10 m increase in sea level These processes are a function of climate: external earth process Changes in the volume of ocean basins containing seawater The ocean basins changing in size and shape: Increase in length of the ocean ridges and rate of seafloor spreading would decrease the volume of ocean basins, causing a sealevel rise. The main process is Plate Tectonics (internal forces) Temporal scale of sea level change Sealevel fluctuations occur on time scales of: Millions of years Thousands of years Diurnal variations: Tides and weather Tides: Diurnal variations is the result of gravitational attraction between Earth, Moon, Sun and rotation of Earth. The times and amplitude of tides at a locale are influenced by: • Alignment of Sun and Moon, • Pattern of tides in the deep ocean • The amphidromic (zero amplitude) systems of the oceans creating waves, tidal currents • The shape of the coastline and near-shore bathymetry Tides Neap tides occur during quarter Moon Spring tides occur during full and new Moon Tidal amplitude Mid-spring range: 14.5 m Extreme range: 16.3 m Amphidromic system and points These occur because of the Coriolis effect and interference within oceanic basins, seas and bays creating a wave pattern Tide amplitude indicated by color.
    [Show full text]
  • Carbonate Platform Evolution: from a Bioconstructed Platform Margin to a Sand-Shoal System (Devonian, Guilin, South China)
    Sedimentology (2002) 49, 737–764 Carbonate platform evolution: from a bioconstructed platform margin to a sand-shoal system (Devonian, Guilin, South China) DAIZHAO CHEN*, MAURICE E. TUCKER , JINGQUAN ZHU* and MAOSHENG JIANG* *Institute of Geology and Geophysics, Chinese Academy of Sciences, PO Box 9825, Beijing 100029, China (E-mail: [email protected]) Department of Geological Sciences, University of Durham, Durham DH1 3LE, UK (E-mail: [email protected]) ABSTRACT The depositional organization and architecture of the middle–late Devonian Yangdi rimmed carbonate platform margin in the Guilin area of South China were related to oblique, extensional faulting in a strike-slip setting. The platform margin shows two main stages of construction in the late Givetian to Frasnian, with a bioconstructed margin evolving into a sand-shoal system. In the late Givetian, the platform margin was rimmed with microbial buildups composed mainly of cyanobacterial colonies (mostly Renalcis and Epiphyton). These grew upwards and produced an aggradational (locally slightly retrogradational) architecture with steep foreslope clinoforms. Three depositional sequences (S3–S5) are recognized in the upper Givetian strata, which are dominated by extensive microbialites. Metre-scale depositional cyclicity occurs in most facies associations, except in the platform-margin buildups and upper foreslope facies. In the latest Givetian (at the top of sequence S5), relative platform uplift (± subaerial exposure) and associated rapid basin subsidence (probably a block-tilting effect) caused large-scale platform collapse and slope erosion to give local scalloped embayments along the platform margin and the synchronous demise of microbial buildups. Subsequently, sand shoals and banks composed of ooids and peloids and, a little later, stromatoporoid buildups on the palaeohighs, developed along the platform margin, from which abundant loose sediment was transported downslope to form gravity-flow deposits.
    [Show full text]
  • Unusual Development of Sandur Sedimentary Succession, an Example from the Pleistocene of S Poland
    Geologos, 2010, 16 (2): 83–99 doi: 10.2478/v10118-009-0007-9 Unusual development of sandur sedimentary succession, an example from the Pleistocene of S Poland Tomasz Salamon1, Tomasz Zieliński2 1 Department of Earth Sciences, University of Silesia, Będzińska Str. 60, 41-200 Sosnowiec, Poland; e-mail: [email protected] 2 Institute of Geology, Adam Mickiewicz University, Maków Polnych Str. 16, 61-606 Poznań, Poland; e-mail: [email protected] Abstract An atypical lithological development of outwash deposits in the Carpathians Foreland (S Poland) shows lower and middle parts of the sedimentary succession that are characterized by sinuous palaeochannels. This channel facies con- sists of laterally accreted sands derived from side bars. The sedimentary environment was a proglacial system of ana- branching channels, presumably of anastomosed type. The outwash channel pattern was most probably controlled by the raising base level of the fluvial system. Both proglacial and extraglacial waters were dammed by a sandur within a small upland valley. Aggradation and progradation of the glaciofluvial deposits resulted in progressive rising of the dammed lake level. The low hydraulic gradient of the outwash streams resulted in a sinuous planform as well as a low- energy style of deposition. Afterwards, the rising lake water was drained off through a low watershed and the entire valley became filled with outwash sediments. The bedrock morphology thus became buried and a typical unconfined sandur with a braided channel network developed during the last phase of the glaciomarginal sedimentation (upper part of the sedimentary succession under study). Keywords: outwash deposits, sedimentology, Pleistocene, Poland Introduction ser, 1993; Marren, 2005) worked this out into a depositional model: the sandur is nowadays Sandurs (outwash plains) are, as a rule, rec- the best example of a braided fluvial system.
    [Show full text]
  • Controls on Turbidite Sedimentation: Insights from a Quantitative Approach of Submarine Channel and Lobe Architecture (Late Quaternary Congo Fan)
    1 Marine and Petroleum Geology Achimer April 2016, Volume 72, Pages 423-446 http://dx.doi.org/10.1016/j.marpetgeo.2016.02.004 http://archimer.ifremer.fr http://archimer.ifremer.fr/doc/00312/42285/ © 2016 Elsevier Ltd. All rights reserved. Controls on turbidite sedimentation: Insights from a quantitative approach of submarine channel and lobe architecture (Late Quaternary Congo fan) Picot Marie 1, *, Droz Laurence 1, Marsset Tania 2, Dennielou Bernard 2, Bez M. 3 1 Laboratoire Domaines Océaniques, UMR6538, Institut Universitaire Européen de la Mer, Place Nicolas Copernic, 29280 Plouzané, France 2 Laboratoire Environnements Sédimentaires, UR GM, IFREMER, BP 70, 29280 Plouzané, France 3 Centre Scientifique et Technique Jean Feger, Total, Avenue Larribau, 64018 Pau, France * Corresponding author : Marie Picot, Tel.: +33 (0)2 98 49 87 17 ; email address : [email protected] [email protected] ; [email protected] ; [email protected] ; [email protected] Abstract : The role of internal and external forcing of sedimentation in turbidite systems remains a subject of debate. Here we propose new insights from the quantitative analysis of architectural parameters of the Congo Axial Fan. Fifty-two channel-levee-lobe systems, spanning the last ca. 200 ka, are visible on the seafloor, most of them having slightly elongated lobe complexes at their termination. Volumes of lobe complexes (usually 3 to 196 km3) are highly variable in time and space. The cumulative volume of the lobe complexes represents approximately 30% of the volume of the Axial Fan. The Axial Fan is sequentially divided into periods of increasing/decreasing channel lengths and basinward/landward migrations of avulsion points, representing successive prograding/retrograding architectural patterns called architectural cycles.
    [Show full text]
  • Coastal Impacts Due to Sea-Level Rise
    Coastal Impacts Due to Sea-Level Rise Duncan M. FitzGerald1, Michael S. Fenster2, Britt A. Argow3, and Ilya V. Buynevich4 1Department of Earth Sciences, Boston University, Boston, Massachusetts 02215, [email protected] 2Environmental Studies Program, Randolph-Macon College, Ashland, Virginia 23005, [email protected] 3Geosciences Department, Wellesley College Wellesley, MA 02481, [email protected] 4Geology and Geophysics Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, [email protected] Key Words barrier islands, tidal inlets, saltmarsh, wetlands, inundation, estuaries, equilibrium slope Abstract Recent estimates by Intergovermental Panel on Climate Change (2007) are that global sea level will rise from 0.18 to 0.59 m by the end of this century. Rising sea level not only inundates low-lying coastal regions, but it also contributes to the redistribution of sediment along sandy coasts. Over the long-term, sea-level rise (SLR) causes barrier islands to migrate landward while conserving mass through offshore and onshore sediment transport. Under these conditions, coastal systems adjust to SLR dynamically while maintaining a characteristic geometry that is unique to a particular coast. Coastal marshes are susceptible to accelerated SLR because their vertical accretion rates are limited and they may drown. As marshes convert to open water, tidal exchange through inlets increases, which leads to sand sequestration on tidal deltas and erosion of adjacent barrier shorelines. INTRODUCTION Many scientists consider global warming-forced climatic change as the most serious environmental threat facing the world today (IPCC 2007). Global warming has the potential to affect many humans dramatically and adversely as a consequence of both natural and anthropogenic changes to temperature, precipitation, sea level, storms, air quality, and other climatic conditions.
    [Show full text]