DOCSLIB.ORG

Glacier Outburst Floods and Outwash Plain Development: Skei Araâ Rsandur, Iceland B

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Glacier Outburst Floods and Outwash Plain Development: Skei Araâ Rsandur, Iceland B Paper 277 Disc Glacier outburst floods and outwash plain development: Skei ara rsandur, Iceland B. Gomez1*, L.C. Smith2, F.J. Magilligan3, L.A.K. Mertes4 and N.D. Smith5 1Geomorphology Laboratory, Indiana State University, Terre Haute, IN 47809, U.S.A., 2Department of Geography, University of California, Los Angeles, CA 90095, U.S.A., 3Department of Geography, Dartmouth College, Hanover, NH 03755, U.S.A., 4Department of Geography, University of California, Santa Barbara, CA 93106, U.S.A., 5Department of Geosciences, University of Nebraska, Lincoln, NE 68508, U.S.A. ABSTRACT Outwash plains, such as Skei ara rsandur, serve as prototypes for from the conditions that prevailed when the ice front was braided river facies and analogs for the Mars Pathfinder and coupled to the sandur, and the November 5±6 1996 outburst Viking 1 landing sites on the margins of the Chryse Basin. Glacier flood from Skei ara rjoÈ kull had little impact on the proximal outburst floods (joÈ kulhlaups) have generated some of the largest surface of Skei ara rsandur beyond the confines of the known terrestrial freshwater flows and recent studies suggest entrenched channels that traverse it. Thus, the point-source that the stratigraphyof outwash plains (sandur) is dominated by dispersal system on Skei ara rsandur maynot provide an exact sedimentarysequences laid down during joÈ kulhlaups, rather than analogue for the pattern of meltwater dispersal responsible for bybraided river facies produced byan ablation-related flow the sediment assemblage laid down during past joÈ kulhlaups, and regime. The modern point-source drainage configuration on caution maybe required when comparing conditions on Skei ara rsandur evolved from a diffuse, multipoint distributary Skei ara rsandur to those presumed to have been experienced system during glacier retreat, when meltwater began to be during massive outburst floods elsewhere. routed parallel to the ice front. The contemporarypattern of water and sediment dispersal across Skei ara rsandur differs Terra Nova, 12, 126±131, 2000 the November 1996 joÈ kulhlaup on dukvõ sl and Seluhu sskvisl, are acti- Introduction Skeiðara rsandur (Figs 1 and 2), pro- vated during joÈ kulhlaups when water Distributary channels on outwash vide a synoptic perspective of the drai- ponds in the proglacial zone. plains, or sandur, are employed as pro- nage network during a large glacier The proglacial zone behind the term- totypes of braided river systems, and outburst flood. This data, together inal moraine complex is widest in the information about fluvial processes and with information derived from the lit- west, where a *1 km wide, CË 25 m deep lithofacies, derived from studies of active erature, sequential aerial photographs ice-marginal depression developed be- sandur, underpins depositional models (1945±97) and a postevent field sur- tween 1931 and 1960 (Fig. 2). The ice of braided alluvium (Rust, 1978). Pat- vey, allow us to develop a conceptual front is CË 15 m lower than the proximal terns of erosion and deposition on san- model to illustrate how the geometry sandur surface, except along Skeiðar- dur also provide analogs for the Martian of the proglacial drainage system has a rjoÈ kull's east-central margin. The surface in the vicinity of the Viking 1 and developed over time. moraine complex also becomes topo- Mars Pathfinder landing sites (Rice and graphically less distinct toward the east, where it is being overridden. No term- Edgett, 1997). Glacier outburst floods, Study area or joÈ kulhlaups, have generated some of inal moraine is preserved beyond the largest known terrestrial freshwater Skeiðara rsandur has an area of 1350 Skeiðara rjoÈ kull's eastern margin, flows,and in locales where large volumes km2 and is the largest active glacial where the ice-marginal depression is of sediment are flushed from beneath outwash plain on Earth. It is being CË 250 m wide and CË 14 m deep. An glaciers they are instrumental in creating constructed by braided rivers that ema- incised braided channel system is pre- outwash plains, or sandur. Sandur ap- nate from Skeiðara rjoÈ kull, an outlet served on the T3 surface east of the ice- pear to be dominated by sediments laid glacier on the southern margin of the marginal depression. Further west, down during joÈ kulhlaups rather than by VatnajoÈ kull ice cap (Fig. 1). Meltwater where the moraine complex is present, braided river facies (Maizels, 1991, emerges through numerous subglacial the T3 surface comprises an apron of 1997). However, field observations have tunnels at the ice front (Rist, 1955; small, coalescing, coarse-grained out- focused on the ablation-related flow re- Churski, 1973). Three large braided wash fans that merge with the sandur gime (cf. Boothroyd and Nummedal, stream systems channel water and sedi- surface at a point CË 4 km beyond the 1978), and little is known about how ment from the glacier onto Skeiðara r- gaps from which the feeder channels the meltwater dispersal system functions sandur (Figs 1 and 2). The Skeiðara and emerge (Klimek, 1973). during joÈ kulhlaups. Nu psvoÈ tn rivers route run off from the Active channels beyond the progla- Satellite synthetic aperture radar glacier margins directly onto the san- cial zone are entrenched and bordered (SAR) images and aerial photographs dur. The Gõ gjukvõ sl River is fed by by a sequence of three terraces. The acquired immediately after and during meltwater from the central and west- (highest) T3 terrace surface lies be- central sections of Skeiðara rjoÈ kull, tween 13 and 20 m above the floors of which collects in the proglacial zone these channels (Fig. 2). The active *Correspondence. before being routed on to the sandur. channel area of the Skeiðara ,NuÂps- E-mail: [email protected] Overflow channels, such as the Ha oÈ l- voÈ tn, and Gõ gjukvõ sl rivers becomes 126 *C 2000 Blackwell Science Ltd Ahed Fig marker Bhed Table marker Ched Ref end Dhed Ref start Ref marker Paper 277 Disc Terra Nova, Vol 12, No. 3, 126±131 Glacier outburst floods and outwash plain development . B. Gomez et al. ............................................................................................................................................................................................................................................. the Gõ gjukvõ sl River is lower than that of: (i) the Skeiðara Rivers (whose melt- water sources are not buffered by the ice-marginal drainage system); (ii) the slope of the main ice-marginal channel within the proglacial zone (where much coarse sediment was deposited); and (iii) the slope of the T3 terrace surface which was active when the ice front was coupled to the sandur (Fig. 4). Despite the high discharge and although the Ha oÈ ldukvõ sl and Selu- hu sskvisl overflow channels were acti- vated, only CË 24% of the proximal zone was inundated (Figs 2 and 3). In effect, the entrenched channels permitted the event to bypass the proximal zone. The geometry of the distributary channels, patterns of erosion and deposition, and presence of inactive surfaces in the proximal zone during the 1996 outburst flood, thus contrast with the historical and stratigraphic evidence for a com- plex braided channel network and sys- tem of coalescing outwash fans coupled to the ice margin (Churski, 1973; Mai- zels, 1991), and require explanation. Fig. 1 ERS-2 SAR intensity (backscatter) image of Skeiðara rsandur, acquired on November 7 1996. The maximum extent of the outbust flood is indicated by high levels of Proglacial drainage evolution radar backscatter, which are probably caused by enhanced surface moisture levels and/ In the case of glaciers flowing over an or frozen floodwater. Flow across the sandur is from North to South. Meltwater supplied from the point-source distributary system can be seen to spread out over an unlithified sediment bed, the potential increasingly large area down-sandur once the channels that traverse the proximal zone, for evacuating large amounts of sedi- which are incised 13 and 20 m below the highest T3 terrace surface (delineated by low ment from beneath the ice front in- levels of radar backscatter), merge with the sandur surface. N = NuÂpsvoÈ tn, creases during joÈ kulhlaups, when the G=Gõ gjukvõ sl, and Sk = Skeiðara rivers. H = Ha oÈ ldukvõ sl and S = Seluhu sskvisl flow in the vicinity of the ice margin is overflow channels. The dashed rectangle delimits the detail of the proximal zone and ice- dispersed across the bed (Rist, 1955; marginal depression shown in Fig. 2. BjoÈ rnsson, 1998). By contrast, during surges, basal drainage beneath Skeiðar- a rjoÈ kull occurs through a distributed progressively wider and less well-de- In two days CË 3.8 km3 of water drained network of passageways (BjoÈ rnsson, fined down-sandur. A complex system from Grõ msvoÈ tn. The cumulative peak 1998). At times when the position of of shifting braid channels develops discharge was CË 4.5 6 104 m3 s71 the ice margin is relatively stable, the within 3±8 km from the ice front, as (Snorrason et al., 1997). Field survey removal of sediment by repeated joÈ - the channels merge with the sandur and correlation mapping using tempor- kulhlaups, in combination with peri- surface, and in the distal zone the flow al sequences of SAR images revealed odic surges, may facilitate lowering of is transformed into a shallow, discon- that during the 1996 joÈ kulhlaup, pat- the ice front and the elevation of melt- tinuous sheet of water. When the three terns of erosion and deposition in the water outlets (Jo nsson, 1955; Gustava- river systems merge during high flows, proglacial zone were highly localized son and Boothroyd, 1987). Once the the intermediate and distal portions of (Russell et al., 1999; Gomez et al.in base of the glacier drops below the Skeiðara rsandur are almost comple- press; Smith et al. 2000). The ice-mar- elevation of the proximal sandur sur- tely inundated (Figs 1 and 3).
Load more

Recommended publications
  • Pleistocene Geology of Eastern South Dakota
    Pleistocene Geology of Eastern South Dakota GEOLOGICAL SURVEY PROFESSIONAL PAPER 262 Pleistocene Geology of Eastern South Dakota By RICHARD FOSTER FLINT GEOLOGICAL SURVEY PROFESSIONAL PAPER 262 Prepared as part of the program of the Department of the Interior *Jfor the development-L of*J the Missouri River basin UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1955 UNITED STATES DEPARTMENT OF THE INTERIOR Douglas McKay, Secretary GEOLOGICAL SURVEY W. E. Wrather, Director For sale by the Superintendent of Documents, U. S. Government Printing Office Washington 25, D. C. - Price $3 (paper cover) CONTENTS Page Page Abstract_ _ _____-_-_________________--_--____---__ 1 Pre- Wisconsin nonglacial deposits, ______________ 41 Scope and purpose of study._________________________ 2 Stratigraphic sequence in Nebraska and Iowa_ 42 Field work and acknowledgments._______-_____-_----_ 3 Stream deposits. _____________________ 42 Earlier studies____________________________________ 4 Loess sheets _ _ ______________________ 43 Geography.________________________________________ 5 Weathering profiles. __________________ 44 Topography and drainage______________________ 5 Stream deposits in South Dakota ___________ 45 Minnesota River-Red River lowland. _________ 5 Sand and gravel- _____________________ 45 Coteau des Prairies.________________________ 6 Distribution and thickness. ________ 45 Surface expression._____________________ 6 Physical character. _______________ 45 General geology._______________________ 7 Description by localities ___________ 46 Subdivisions. ________-___--_-_-_-______ 9 Conditions of deposition ___________ 50 James River lowland.__________-__-___-_--__ 9 Age and correlation_______________ 51 General features._________-____--_-__-__ 9 Clayey silt. __________________________ 52 Lake Dakota plain____________________ 10 Loveland loess in South Dakota. ___________ 52 James River highlands...-------.-.---.- 11 Weathering profiles and buried soils. ________ 53 Coteau du Missouri..___________--_-_-__-___ 12 Synthesis of pre- Wisconsin stratigraphy.
    [Show full text]
  • The Dynamics and Mass Budget of Aretic Glaciers
    DA NM ARKS OG GRØN L ANDS GEO L OG I SKE UNDERSØGELSE RAP P ORT 2013/3 The Dynamics and Mass Budget of Aretic Glaciers Abstracts, IASC Network of Aretic Glaciology, 9 - 12 January 2012, Zieleniec (Poland) A. P. Ahlstrøm, C. Tijm-Reijmer & M. Sharp (eds) • GEOLOGICAL SURVEY OF D EN MARK AND GREENLAND DANISH MINISTAV OF CLIMATE, ENEAGY AND BUILDING ~ G E U S DANMARKS OG GRØNLANDS GEOLOGISKE UNDERSØGELSE RAPPORT 201 3 / 3 The Dynamics and Mass Budget of Arctic Glaciers Abstracts, IASC Network of Arctic Glaciology, 9 - 12 January 2012, Zieleniec (Poland) A. P. Ahlstrøm, C. Tijm-Reijmer & M. Sharp (eds) GEOLOGICAL SURVEY OF DENMARK AND GREENLAND DANISH MINISTRY OF CLIMATE, ENERGY AND BUILDING Indhold Preface 5 Programme 6 List of participants 11 Minutes from a special session on tidewater glaciers research in the Arctic 14 Abstracts 17 Seasonal and multi-year fluctuations of tidewater glaciers cliffson Southern Spitsbergen 18 Recent changes in elevation across the Devon Ice Cap, Canada 19 Estimation of iceberg to the Hansbukta (Southern Spitsbergen) based on time-lapse photos 20 Seasonal and interannual velocity variations of two outlet glaciers of Austfonna, Svalbard, inferred by continuous GPS measurements 21 Discharge from the Werenskiold Glacier catchment based upon measurements and surface ablation in summer 2011 22 The mass balance of Austfonna Ice Cap, 2004-2010 23 Overview on radon measurements in glacier meltwater 24 Permafrost distribution in coastal zone in Hornsund (Southern Spitsbergen) 25 Glacial environment of De Long Archipelago
    [Show full text]
  • Glacial Processes and Landforms-Transport and Deposition
    Glacial Processes and Landforms—Transport and Deposition☆ John Menziesa and Martin Rossb, aDepartment of Earth Sciences, Brock University, St. Catharines, ON, Canada; bDepartment of Earth and Environmental Sciences, University of Waterloo, Waterloo, ON, Canada © 2020 Elsevier Inc. All rights reserved. 1 Introduction 2 2 Towards deposition—Sediment transport 4 3 Sediment deposition 5 3.1 Landforms/bedforms directly attributable to active/passive ice activity 6 3.1.1 Drumlins 6 3.1.2 Flutes moraines and mega scale glacial lineations (MSGLs) 8 3.1.3 Ribbed (Rogen) moraines 10 3.1.4 Marginal moraines 11 3.2 Landforms/bedforms indirectly attributable to active/passive ice activity 12 3.2.1 Esker systems and meltwater corridors 12 3.2.2 Kames and kame terraces 15 3.2.3 Outwash fans and deltas 15 3.2.4 Till deltas/tongues and grounding lines 15 Future perspectives 16 References 16 Glossary De Geer moraine Named after Swedish geologist G.J. De Geer (1858–1943), these moraines are low amplitude ridges that developed subaqueously by a combination of sediment deposition and squeezing and pushing of sediment along the grounding-line of a water-terminating ice margin. They typically occur as a series of closely-spaced ridges presumably recording annual retreat-push cycles under limited sediment supply. Equifinality A term used to convey the fact that many landforms or bedforms, although of different origins and with differing sediment contents, may end up looking remarkably similar in the final form. Equilibrium line It is the altitude on an ice mass that marks the point below which all previous year’s snow has melted.
    [Show full text]
  • Port Jefferson Geomorphology by Danielle Mulch, Gilbert N
    Port Jefferson Geomorphology By Danielle Mulch, Gilbert N. Hanson Figure 1 (Above)A DEM of Long Island with a close-up of the Port Jefferson Valley and Outwash Plain. Adapted from Gilbert Hanson's DEM. Abstract Research was conducted in the Port Jefferson region to determine the origin of the har- bor itself as well as the gentle sloping plain that begins in Port Jefferson Station and slopes southward past the LIE. Surficial analysis and corroborating evidence (including past re- search, mapping projects and well logs) strongly indicate that Port Jefferson was formed during the late Wisconsinan, specifically, that the Port Jefferson valley, including the harbor, is the remnant of a tunnel valley fed by a subglacial lake and that Port Jefferson Station and south is the resulting outwash fan from a catastrophic subglacial discharge. The research strongly supports the initial hypothesis that the origin of Port Jefferson Harbor was incise- ment by a tunnel valley into the Harbor Hill moraine. Research also strongly supports the catastrophic deposition of the outwash fan. However, the research does raise significant questions that require further study. Two important questions are: What is the stratigraphy and depositional history within the harbor, which is a buried tunnel valley? and What is the nature of Grim's Trench (if it exists) just north of the harbor and how does it interact with the buried tunnel valley? 1 Introduction In this paper, we propose that Port Jefferson valley is a tunnel valley created during the Wisconsinan. This valley cuts the Harbor Hill moraine. We also propose that the fan shaped feature immediately south of the valley is in fact a related alluvial fan that was deposited catastrophically when the sediment-rich water left the tunnel valley and lost energy abruptly.
    [Show full text]
  • Pleistocene Geology of the Embarrass Area, St. Louis County
    UNNERSITY OF MINNESOTA This is to certify that I have examined this copy of a master's thesis by James Davis Lehr and have found that it is complete and satisfactory in all respects, and that any and all revisions required by the final examining committee have been made. Charles L. Matsch Name of Faculty Advisor Signature of Faculty Advisor May 12, 2000 Date GRADUATE SCHOOL PLEISTOCENE GEOLOGY OF THE EMBARRASS ST. LOUIS COUNTY, MINNESOTA A THESIS SUBMITTED TO THE FA CUL TY OF THE GRADUATE SCHOOL OF THE UNIVERSITY OF MINNESOTA BY JAMES DA VIS LEHR IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE May,2000 © James Davis Lehr 2000 TABLE OF CONTENTS Page TABLE OF CONTENTS ..................................................................................................... i LIST OF ILLUSTRATIONS .................................................................. ........................... iv ACKNOWLEDGMENTS ................................................................................................ vii INTRODUCTION ............................................................................................................... 1 STUDY AREALOCATION ................................................................................... l STUDY OBJECTIVES ............................................................................................ 3 METHODS OF INVESTIGATION ........................................................................ 3 FIELD METHODS .................................... .................................................
    [Show full text]
  • Esker Habitat Characteristics and Traditional Land Use in the Slave Geological Province
    Re: Esker Habitat Characteristics and Traditional Land Use in the Slave Geological Province STUDY DIRECTOR RELEASE FORM The above publication is the result of a project conducted under the West Kitikmeot / Slave Study. I have reviewed the report and advise that it has fulfilled the requirements of the approved proposal and can be subjected to independent expert review and be considered for release to the public. Study Director Date INDEPENDENT EXPERT REVIEW FORM I have reviewed this publication for scientific content and scientific practices and find the report is acceptable given the specific purposes of this project and subject to the field conditions encountered. Reviewer Date INDEPENDENT EXPERT REVIEW FORM I have reviewed this publication for scientific content and scientific practices and find the report is acceptable given the specific purposes of this project and subject to the field conditions encountered. Reviewer Date BOARD RELEASE FORM The Study Board is satisfied that this final report has been reviewed for scientific content and approves it for release to the public. Chair West Kitikmeot/Slave Society Date Box 2572, Yellowknife, NT, X1A 2P9 Ph (867) 669-6235 Fax (867) 920-4346 e-mail: [email protected] Home Page: http://www.wkss.nt.ca ESKER HABITAT CHARACTERISTICS and TRADITIONAL USE STUDY in the SLAVE GEOLOGICAL PROVINCE FINAL REPORT to the WEST KITIKMEOT / SLAVE STUDY Submitted by: Stephen Traynor Senior Land Specialist – Land Administration Indian and Northern Affairs Canada Yellowknife, NT August 2001 SUMMARY In May of 1996 approval was granted and funding awarded by the West Kitikmeot Slave Study Society (WKSS) for a project to initiate research and information dissemination on eskers in the Slave Geological Province.
    [Show full text]
  • Notes on Coastal Processes and Geomorphology
    Notes on Coastal Processes and Geomorphology An incomplete assortment of digital notes. Handwritten notes and other materials are stored in the Harvard Forest Archives Brouillet MV Geomorphology The highly unstable geologic structure of the south side of the Vineyard enables it to erode at a much faster rate than that predicted by the Bruun rule (Table 17) From 1933 to 2003, trend analyses indicated that sea level was rising at 2.56 mm/yr in Woods Hole (Figure 57A). Similar analyses for Nantucket, from1965 to 2003, indicated a rate of 3.08 mm/year. the IPCC’s projection of 0.59 m by the year 2100, Massachusetts Coastal Zone Management and Thieler et al., (2001) indicated that, from 1851 to 1994A closer look at the individual study sites showed that the south side of Martha’s Vineyard had the highest linear rate of shoreline change per year (-1.71 m/yr) (Table 15), with 90% of the shoreline eroded and 2.6 km2 of land lost to the sea. Clearly, sea levels are rising and Martha’s Vineyard is eroding at a much faster rate on the south side of the island than at the other two study sites with predominantly northeastern and northwestern exposure. The northwest coast takes the brunt of winter winds and the northeastern side of the Vineyard has direct exposure to Northeasters, but both of these study sites appear to be on the low end of the coastal erosion spectrum for this island. In fact, the NE and NWareas are manifesting accretion in some spots. The culmination of these analyses led me to five key conclusions, namely that: 1) the three sites manifested different rates of erosion and accretion, from a loss of approximately 0.1 m/yr at the NE and NW sites to over 1.7 m/yr at the SS site; 2) the NE and NW sites fit the ratio predicted by Bruun for the rate of erosion vs.
    [Show full text]
  • Incision and Aggradation in Proglacial Rivers
    Incision and aggradation in proglacial rivers: Post-Little Ice Age long-profile adjustments of Southern Iceland outwash plains Erwan Roussel, Philip Marren, Etienne Cossart, Jean-Pierre Toumazet, Marie Chenet, Delphine Grancher, Vincent Jomelli To cite this version: Erwan Roussel, Philip Marren, Etienne Cossart, Jean-Pierre Toumazet, Marie Chenet, et al.. Incision and aggradation in proglacial rivers: Post-Little Ice Age long-profile adjustments of Southern Iceland outwash plains. Land Degradation and Development, Wiley, 2018, 10.1002/ldr.3127. hal-01897894 HAL Id: hal-01897894 https://hal.archives-ouvertes.fr/hal-01897894 Submitted on 5 Nov 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Land Degradation & Development INCISION AND AGGRADATION IN PROGLACIAL RIVERS: POST-LITTLE ICE AGE LONG-PROFILE ADJUSTMENTS OF SOUTHERN ICELAND OUTWASH PLAINS Journal: Land Degradation & Development Manuscript ForID LDD-17-1101.R1 Peer Review Wiley - Manuscript type: Special Issue Article Date Submitted by the Author: 05-Jun-2018 Complete List of Authors: Roussel,
    [Show full text]
  • Dating Glacial Landforms I: Archival, Incremental, Relative Dating Techniques and Age- Equivalent Stratigraphic Markers
    TREATISE ON GEOMORPHOLOGY, 2ND EDITION. Editor: Umesh Haritashya CRYOSPHERIC GEOMORPHOLOGY: Dating Glacial Landforms I: archival, incremental, relative dating techniques and age- equivalent stratigraphic markers Bethan J. Davies1* 1Centre for Quaternary Research, Department of Geography, Royal Holloway University of London, Egham Hill, Egham, Surrey, TW20 0EX *[email protected] Manuscript Code: 40019 Abstract Combining glacial geomorphology and understanding the glacial process with geochronological tools is a powerful method for understanding past ice-mass response to climate change. These data are critical if we are to comprehend ice mass response to external drivers of change and better predict future change. This chapter covers key concepts relating to the dating of glacial landforms, including absolute and relative dating techniques, direct and indirect dating, precision and accuracy, minimum and maximum ages, and quality assurance protocols. The chapter then covers the dating of glacial landforms using archival methods (documents, paintings, topographic maps, aerial photographs, satellite images), relative stratigraphies (morphostratigraphy, Schmidt hammer dating, amino acid racemization), incremental methods that mark the passage of time (lichenometry, dendroglaciology, varve records), and age-equivalent stratigraphic markers (tephrochronology, palaeomagnetism, biostratigraphy). When used together with radiometric techniques, these methods allow glacier response to climate change to be characterized across the Quaternary, with resolutions from annual to thousands of years, and timespans applicable over the last few years, decades, centuries, millennia and millions of years. All dating strategies must take place within a geomorphological and sedimentological framework that seeks to comprehend glacier processes, depositional pathways and post-depositional processes, and dating techniques must be used with knowledge of their key assumptions, best-practice guidelines and limitations.
    [Show full text]
  • The Last British Ice Sheet: a Review of the Evidence Utilised in the Compilation of the Glacial Map of Britain
    This is a repository copy of The last British Ice Sheet: A review of the evidence utilised in the compilation of the Glacial Map of Britain . White Rose Research Online URL for this paper: http://eprints.whiterose.ac.uk/915/ Article: Evans, D.J.A., Clark, C.D. and Mitchell, W.A. (2005) The last British Ice Sheet: A review of the evidence utilised in the compilation of the Glacial Map of Britain. Earth-Science Reviews, 70 (3-4). pp. 253-312. ISSN 0012-8252 https://doi.org/10.1016/j.earscirev.2005.01.001 Reuse Unless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version - refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher’s website. Takedown If you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing [email protected] including the URL of the record and the reason for the withdrawal request. [email protected] https://eprints.whiterose.ac.uk/ White Rose Consortium ePrints Repository http://eprints.whiterose.ac.uk/ This is an author produced version of a paper published in Earth-Science Reviews.
    [Show full text]
  • Glaciers of the Canadian Rockies
    Glaciers of North America— GLACIERS OF CANADA GLACIERS OF THE CANADIAN ROCKIES By C. SIMON L. OMMANNEY SATELLITE IMAGE ATLAS OF GLACIERS OF THE WORLD Edited by RICHARD S. WILLIAMS, Jr., and JANE G. FERRIGNO U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1386–J–1 The Rocky Mountains of Canada include four distinct ranges from the U.S. border to northern British Columbia: Border, Continental, Hart, and Muskwa Ranges. They cover about 170,000 km2, are about 150 km wide, and have an estimated glacierized area of 38,613 km2. Mount Robson, at 3,954 m, is the highest peak. Glaciers range in size from ice fields, with major outlet glaciers, to glacierets. Small mountain-type glaciers in cirques, niches, and ice aprons are scattered throughout the ranges. Ice-cored moraines and rock glaciers are also common CONTENTS Page Abstract ---------------------------------------------------------------------------- J199 Introduction----------------------------------------------------------------------- 199 FIGURE 1. Mountain ranges of the southern Rocky Mountains------------ 201 2. Mountain ranges of the northern Rocky Mountains ------------ 202 3. Oblique aerial photograph of Mount Assiniboine, Banff National Park, Rocky Mountains----------------------------- 203 4. Sketch map showing glaciers of the Canadian Rocky Mountains -------------------------------------------- 204 5. Photograph of the Victoria Glacier, Rocky Mountains, Alberta, in August 1973 -------------------------------------- 209 TABLE 1. Named glaciers of the Rocky Mountains cited in the chapter
    [Show full text]
  • A Thesis Entitled the Chronology of Glacial Landforms Near Mongo
    A Thesis entitled The Chronology of Glacial Landforms Near Mongo, Indiana – Evidence for the Early Retreat of the Saginaw Lobe by Thomas R. Valachovics Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Master of Science Degree in Geology ___________________________________________ Timothy G. Fisher, PhD., Committee Chair ___________________________________________ James M. Martin-Hayden, PhD., Committee Member ___________________________________________ Jose Luis Antinao-Rojas, PhD., Committee Member ___________________________________________ Cyndee Gruden, PhD, Dean College of Graduate Studies The University of Toledo August 2019 Copyright 2019 Thomas R. Valachovics This document is copyrighted material. Under copyright law, no parts of this document may be reproduced without the expressed permission of the author. An Abstract of The Chronology of Glacial Landforms Near Mongo, Indiana – Evidence for the Early Retreat of the Saginaw Lobe by Thomas R. Valachovics Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Master of Science Degree in Geology The University of Toledo August 2019 The Saginaw Lobe of the Laurentide Ice Sheet occupied central Michigan and northern Indiana during the last glacial maximum. Evidence exists that the Saginaw Lobe retreated earlier than its neighboring lobes but attempts to constrain this retreat using radiocarbon dating methods has led to conflicting results. Optically stimulated luminescence dating (OSL) offers an alternative methodology to date deglacial deposits. The Pigeon River Meltwater Channel (PRMC) was formed by a large, erosional pulse of meltwater that exited the ice sheet and eroded through the deglaciated landscape previously occupied by the Saginaw Lobe. Sediments that partially fill the PRMC were dated using OSL. Minimum ages for the retreat of the Saginaw Lobe were acquired to test the hypothesis that the Mongo area is ice free by 23 ka.
    [Show full text]