DOCSLIB.ORG

Deformation of Glacial Materials: Introduction and Overview

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Deformation of Glacial Materials: Introduction and Overview Downloaded from http://sp.lyellcollection.org/ by guest on September 25, 2021 Deformation of glacial materials: introduction and overview ALEX J. MALTMAN, BRYN HUBBARD & MICHAEL J. HAMBREY Institute of Geography and Earth Sciences, University of Wales, Aberystwyth, Ceredigion SY23 3DB, UK (e-mail. [email protected]; [email protected]; [email protected]) The flow of glacier ice can produce structures Milnes 1977; Hooke & Hudleston 1978; Lawson that are striking and beautiful. Associated sedi- et al. 1994). However, these concepts remain to be ments, too, can develop spectacular deformation applied to deformation at the scale of ice sheets, structures and examples are remarkably well where analogous structures are at least an order preserved in Quaternary deposits. Although such of magnitude larger. Significantly, these struc- features have long been recognized, they are now tures may well contain information with the the subject of new attention from glaciologists potential for assessing the long-term dynamic and glacial geologists. However, these workers behaviour and stability of their host ice masses. are not always fully aware of the methods for Striking deformation structures are also pro- unravelling deformation structures evolved in duced at a wide variety of scales in the sediments recent years by structural geologists, who them- associated with ice. Fine examples appear, selves may not be fully aware of the opportu- for example, in the works of Brodzikowski (e.g. nities offered by glacial materials. This book, and in Jones & Preston 1989) and in the volumes by the conference from which it stemmed, were Ehlers et al. (1995a, b). In fact, of all the vari- conceived of as a step towards bridging this ous kinds of geological deformation structures, apparent gap between groups of workers with among the very first to be described were fea- potentially overlapping interests. tures ascribed to the action of ice. Two great Glaciologists have long been aware of the geological pioneers were involved: both Sir remarkable structures developed in flowing ice. Charles Lyell (1840) and the visionary Henry Nineteenth century Alpine mountaineers and Sorby (1859) interpreted the disturbance of natural scientists, such as the Swiss naturalist, deposits on the coast of eastern England as Agassiz ('The Father of Ice Ages'), and Forbes being due to the movement of icebergs. Lyell and Tyndall from Britain, described a range of (1840) then expanded his ideas on the deforma- structures in glaciers, and were clearly impressed tion of the glacial deposits of Norfolk, and by the by the similarity with deformation structures in end of the century a variety of structures in rocks. The first half of the twentieth century Europe and North America had been interpreted saw few advances in glaciological thinking, but as the result of glacial processes. A history of renewed interest in structures followed the these early studies of deformation of sediments formulation of a flow law for ice (e.g. Nye 1953; by glaciers is given in Aber et al. (1989). Glen 1955) and its application to glaciers (e.g. Despite this long pedigree of research, there is Nye 1957). Since then, as outlined by Hambrey commonly disagreement on the actual mechan- & Lawson (this volume), there have been numer- isms involved in generating glacigenic struc- ous studies of deformation in glaciers. Many of tures. The dominant concept this century, until a these studies link glacier structures to measured decade or so ago, involved the notion of ice deformation rates, notably in the classic case bulldozing into sediments and generating vari- studies of Allen et al. (1960) and Meier (1960) in ous 'ice-thrust' structures as a result. Thus, most North America. However, few glaciologists have deformation of glacial sediment was envisaged applied the structural geological concepts of as being 'made at or near glacial termini' (Flint progressive and cumulative deformation to gla- 1971, p. 121). It was the discovery that some ciers. Where such an approach has been adopted glaciers and parts of major ice-sheets rest not (primarily within valley glaciers and ice caps), on bedrock, but on a layer of sediment (e.g. new insights have emerged concerning ice defor- Engelhardt et al. 1978; Boulton 1979) that mation in relation to the development of folia- launched the 'deformable bed' hypothesis and tion, folds, and crevasses and other faults (e.g. a new significance to deformation structures in Hudleston 1976; Hambrey 1977; Hambrey & glacial sediments. From: MALTMAN, A. J., HUBBARD, B. & HAMBREY, M. J. (eds) Deformation of Glacial Materials. Geological Society, London, Special Publications, 176, 1-9. 0305-8719/00/$15.00 9 The Geological Society of London 2000. Downloaded from http://sp.lyellcollection.org/ by guest on September 25, 2021 2 A.J. MALTMAN ET AL. Even so, a common approach today among aware that something of a schism continues. Our Quaternary specialists is to see the structures as aim is that by collecting together papers on an aid to deducing glacial environments and similar subjects from workers with a range of directions of ice movement (e.g. Evans et al. backgrounds and approaches, new possibilities 1999), risky though this is without a knowledge and collaborations may open. We hope the of the geometries, kinematics, and physical mixture presented here will provide a basis for conditions of the deformation. On the other more integrated approaches in the future. hand, understanding such aspects of deforma- tion has been a growing theme of structural Ice deformation geology over the last 50 years or so, as the subject has become less descriptive (e.g. Twiss The volume opens with four papers concerned & Moores 1992). These efforts, however, have with processes of ice deformation (relation- almost exclusively been restricted to rocks. As ships between ice deformation and structural noted above, few structural geologists have development being considered in the second taken an interest in structures in glaciers. The section). Despite the small number of papers same is largely true for glacial sediments, and in this section, a broad range of approaches concerted efforts at com-bining ideas developed to investigating ice deformation is presented. for rocks with glacial sediments, such as those of These include results from large- and small-scale Banham (1975), Aber et al. (1989), Warren & ice coring projects, laboratory analysis of ice Croot (1994) and Harris et al. (1997), are sparse. character (including isotopic, gas and chemical Yet analysing structures in Quaternary sedi- composition and ice crystallography), and lab- ments can have an important practical advan- oratory analysis of ice rheology, using both tage over studying those in lithified rock: the triaxial deformation apparatus and a novel cen- sediment can readily be scraped away to reveal trifuge apparatus. the full three-dimensional arrangement of the The first paper in the section, by Souchez structures. Indeed, some of the most spectac- et aL, addresses a complex picture of ice for- ular structures appear in working sand and mation by freeze-on and deformation near the gravel pits, where large-scale sections are con- base of the Greenland Ice Sheet as revealed in a stantly changing. number of basal-ice core sections. Souchez and Because of the importance of sub-glacial his team at Brussels are ideally placed to write deforming sediments to the motion of many ice such a review (based on both published and new masses, it is appropriate to examine the defor- information), since they have been working for mation of ice and glacial sediments together. some years on the physical properties of the In some cases, sediments shearing beneath an ice basal sections of many of the world's most sheet are best regarded as being in continuum important ice cores. The data summarised in this with overlying debris-rich ice (e.g. Hart 1998). contribution relate mainly to the basal sections Thus the division of the papers included in this of 3 cores located in central Greenland (Dye 3 volume into separate sections on ice and GRIP and GISP2). Interpretation of the gas, sediments is largely for convenience. We have stable isotope and chemical composition of these attempted to head each section with a paper that core sections indicates that their silt-laden basal provides some insight and overview. Some ice layers are largely composed of ice that was papers deal with the linkage between ice and formed prior to ice-sheet advance. Souchez et al. sediments, and there are other papers that could argue that such silt-rich ice is incorporated have been placed in more than one group. While without a phase change into the advancing ice some of the papers are explicitly contemporary sheet, and that it is subsequently distributed and reviews, others combine review with new find- mixed tectonically with clean (firn-derived) ings or point strongly to future work. glacier ice over some metres to tens of metres In many ways, the papers included here con- at the base of the ice sheet. firm the continuing existence of a gap between The second paper in the section, by Tison & different groups of workers - especially in terms Hubbard, presents new information based on a of approaches, methods and terminology. Some series of eight short ice cores recovered from papers that were refereed by, say, a Quaternary along a flow-line at Glacier de Tsanfleuron, specialist and a structural geologist received Switzerland. This paper supplements an earlier conflicting reviews, with contrasting opinions on classification of the ice facies present in these the practices used and the clarity of the terms. cores (Hubbard et al. 2000) with a wealth Hence, a number of articles herein represent a of ice crystallographic data. Significantly, the working compromise. We have attempted to locations of the ice cores allow a glacier-wide produce a balanced volume, but are keenly flow-line model of crystallographic evolution to Downloaded from http://sp.lyellcollection.org/ by guest on September 25, 2021 INTRODUCTION AND OVERVIEW 3 be reconstructed.
Load more

Recommended publications
  • LESSON PLAN #2: Creating the Driftless: a Study in Glacial Movement
    LESSON PLAN #2: Creating the Driftless: A Study in Glacial Movement Overview: Glaciers are moving mountains of ice. They move like slow rivers and actually flow. Gravity and the sheer weight of the ice mass are the causes of glacial motion. Ice is softer than rock so is easily deformed by the pressure of its own weight. Movement at the underside of a glacier is slower than movement along the top. Glaciers retreat and advance, depending on snow accumulation, evaporation, or ice melt. Glaciers transport materials as they move. They also sculpt and carve the land beneath them. A glacier’s weight combined with gradual movement, reshapes the land over hundreds to thousands of years. The ice erodes the land surface and carries broken rock and soil debris far from their original places, resulting in some interesting glacial landforms. Due to the nature of land formations, some areas in northwest Illinois along with southwest Wisconsin, southeast Minnesota, and northeast Iowa were missed by the four glaciers that at different times covered the rest of these states. This area not covered by glaciers and the resulting glacial drift is called “The Driftless Area.” This Driftless Area is rich with historic and geological information free from glacial impact. Duration: 30 minutes Subject Areas: Earth Science, Physical Science, Geography Standards Addressed: 4-PS3-1 4-PS3-4 5-ESS3-1 MS-ESS3-1 MS-ESS2-5 MS-ESS2-3 MS-ESS1-C MS-PS2-4 Objectives: Gain an understanding of how glaciers move Understand the types of landforms created from glacial movement and glacial scraping Define what is meant by The Driftless Area Teacher Background: Glaciers are made up of fallen snow that, over many years, compresses into large, thickened ice masses.
    [Show full text]
  • Gradient Approach to INSAR Modelling of Glacial Dynamics and Morphology
    Gradient approach to INSAR modelling of glacial dynamics and morphology A. I. Sharov Institute of Digital Image Processing, Joanneum Research, Wastiangasse 6, A - 8010 Graz, Austria E-mail: [email protected] Keywords: differential interferometry, phase gradient, change detection, glacier velocity, geodetic survey ABSTRACT: This paper describes the development and testing of an original gradient approach (GINSAR) to the reconstruction of glacial morphology and ice motion estimation from the interferometric phase gradient that does not involve the procedure of interferometric phase unwrapping, thus excluding areal error propagation and improving the modelling accuracy. The global and stringent GINSAR algorithm is applicable to unsupervised glacier change detection, ice motion estimation and glacier mass balance measurement at regional scale. Experimental studies and field surveys proved its efficacy and robustness. Some algorithmic singularities and limitations are discussed. 1 INTRODUCTION detect and to measure quite small glacier motions and ice deformations in the centimetre range from There is a close interrelation between glacier motion spaceborne SAR interferograms with a nominal and glacial topography. Irregularities in the glacier ground resolution of several tens of meters. Accurate width, thickness, slope or direction alter the reconstruction of the configuration and external character of ice flow. On the other hand, glacial structure of the glacier surface from INSAR data is topography is dynamically supported by the moving also possible. Differential interferometry (DINSAR) ice (Fatland & Lingle 1998). Both, glacier dynamic based on differencing between two different SAR quantities and topographic variables are essential interferograms of the same glacier allows the parameters for studying the glacier mass balance and impacts of glacial topography and surface monitoring actual and potential glacier changes.
    [Show full text]
  • Glacial Processes and Landforms
    Glacial Processes and Landforms I. INTRODUCTION A. Definitions 1. Glacier- a thick mass of flowing/moving ice a. glaciers originate on land from the compaction and recrystallization of snow, thus are generated in areas favored by a climate in which seasonal snow accumulation is greater than seasonal melting (1) polar regions (2) high altitude/mountainous regions 2. Snowfield- a region that displays a net annual accumulation of snow a. snowline- imaginary line defining the limits of snow accumulation in a snowfield. (1) above which continuous, positive snow cover 3. Water balance- in general the hydrologic cycle involves water evaporated from sea, carried to land, precipitation, water carried back to sea via rivers and underground a. water becomes locked up or frozen in glaciers, thus temporarily removed from the hydrologic cycle (1) thus in times of great accumulation of glacial ice, sea level would tend to be lower than in times of no glacial ice. II. FORMATION OF GLACIAL ICE A. Process: Formation of glacial ice: snow crystallizes from atmospheric moisture, accumulates on surface of earth. As snow is accumulated, snow crystals become compacted > in density, with air forced out of pack. 1. Snow accumulates seasonally: delicate frozen crystal structure a. Low density: ~0.1 gm/cu. cm b. Transformation: snow compaction, pressure solution of flakes, percolation of meltwater c. Freezing and recrystallization > density 2. Firn- compacted snow with D = 0.5D water a. With further compaction, D >, firn ---------ice. b. Crystal fabrics oriented and aligned under weight of compaction 3. Ice: compacted firn with density approaching 1 gm/cu. cm a.
    [Show full text]
  • Integración De Modelos Numéricos De Glaciares Y Procesado De Datos De Georradar En Un Sistema De Información Geográfica Tesis Doctoral
    Universidad Politécnica de Madrid Escuela Técnica Superior de Ingenieros de Telecomunicación Integración de modelos numéricos de glaciares y procesado de datos de georradar en un sistema de información geográfica Tesis Doctoral por Ricardo Rodríguez Cielos Ingeniero de Telecomunicación Ingeniero Técnico en Topografía, Geodesia y Cartografía Año 2014 Departamento de Matemática Aplicada a las Tecnologías de la Información Escuela Técnica Superior de Ingenieros de Telecomunicación Integración de modelos numéricos de glaciares y procesado de datos de georradar en un sistema de información geográfica Autor: Ricardo Rodríguez Cielos Ingeniero de Telecomunicación Ingeniero Técnico en Topografía, Geodesia y Cartografía Directores: Francisco José Navarro Valero Javier Jesús Lapazaran Izargain Doctor en Ciencias Físicas Doctor Ingeniero de Telecomunicación Año 2014 III IV Tribunal nombrado por el Mgfco. y Excemo. Sr. Rector de la Uni- versidad Politécnica de Madrid, el día ____ de __________ de 2014. Presidente D. Vocal D. Vocal D. Vocal D. Vocal Secretario D. Realizado el acto de defensa y lectura de la Tesis el día ____ de __________ de 2014, en ____________. Calificación: ________________________ EL PRESIDENTE LOS VOCALES EL VOCAL SECRETARIO V A mis hijos, a ella, a mis padres, a mi familia, a mis compañeros, a mis profesores y a mis alumnos. VII Resumen Resumen Los modelos de termomecánica glaciar están definidos mediante sistemas de ecuaciones en derivadas parciales que establecen los principios básicos de conservación de masa, momento lineal y energía, acompañados por una ley constitutiva que define la relación entre las tensiones a las que está sometido el hielo glaciar y las deformaciones resultantes de las mismas. La resolución de estas ecuaciones requiere la definición precisa del dominio (la geometría del glaciar, obtenido a partir de medidas topográficas y de georradar), así como contar con un conjunto de condiciones de contorno, que se obtienen a partir de medidas de campo de las variables implicadas y que constituyen un conjunto de datos geoespaciales.
    [Show full text]
  • Glaciers and Glaciation
    M18_TARB6927_09_SE_C18.QXD 1/16/07 4:41 PM Page 482 M18_TARB6927_09_SE_C18.QXD 1/16/07 4:41 PM Page 483 Glaciers and Glaciation CHAPTER 18 A small boat nears the seaward margin of an Antarctic glacier. (Photo by Sergio Pitamitz/ CORBIS) 483 M18_TARB6927_09_SE_C18.QXD 1/16/07 4:41 PM Page 484 limate has a strong influence on the nature and intensity of Earth’s external processes. This fact is dramatically illustrated in this chapter because the C existence and extent of glaciers is largely controlled by Earth’s changing climate. Like the running water and groundwater that were the focus of the preceding two chap- ters, glaciers represent a significant erosional process. These moving masses of ice are re- sponsible for creating many unique landforms and are part of an important link in the rock cycle in which the products of weathering are transported and deposited as sediment. Today glaciers cover nearly 10 percent of Earth’s land surface; however, in the recent ge- ologic past, ice sheets were three times more extensive, covering vast areas with ice thou- sands of meters thick. Many regions still bear the mark of these glaciers (Figure 18.1). The basic character of such diverse places as the Alps, Cape Cod, and Yosemite Valley was fashioned by now vanished masses of glacial ice. Moreover, Long Island, the Great Lakes, and the fiords of Norway and Alaska all owe their existence to glaciers. Glaciers, of course, are not just a phenomenon of the geologic past. As you will see, they are still sculpting and depositing debris in many regions today.
    [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]
  • Short-Lived Ice Speed-Up and Plume Water Flow Captured by a VTOL UAV
    Remote Sensing of Environment 217 (2018) 389–399 Contents lists available at ScienceDirect Remote Sensing of Environment journal homepage: www.elsevier.com/locate/rse Short-lived ice speed-up and plume water flow captured by a VTOL UAV give insights into subglacial hydrological system of Bowdoin Glacier T Guillaume Jouveta,*, Yvo Weidmanna, Marin Kneiba, Martin Deterta, Julien Seguinota,c, Daiki Sakakibarab, Shin Sugiyamab a ETHZ, VAW, Zurich, Switzerland b Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan c Arctic Research Center, Hokkaido University, Sapporo, Japan ARTICLE INFO ABSTRACT Keywords: The subglacial hydrology of tidewater glaciers is a key but poorly understood component of the complex ice- Unmanned Aerial Vehicle ocean system, which affects sea level rise. As it is extremely difficult to access the interior of a glacier, our Structure-from-Motion photogrammetry knowledge relies mostly on the observation of input variables such as air temperature, and output variables such Feature-tracking as the ice flow velocities reflecting the englacial water pressure, and the dynamics of plumes reflecting the Particle Image Velocimetry discharge of meltwater into the ocean. In this study we use a cost-effective Vertical Take-Off and Landing (VTOL) Calving glaciers Unmanned Aerial Vehicle (UAV) to monitor the daily movements of Bowdoin Glacier, north-west Greenland, and Meltwater plume Ice flow the dynamics of its main plume. Using Structure-from-Motion photogrammetry and feature-tracking techniques, we obtained 22 high-resolution ortho-images and 19 velocity fields at the calving front for 12 days in July 2016. Our results show a two-day-long speed-up event (up to 170%) – caused by an increase in buoyant subglacial forces – with a strong spatial variability revealing that enhanced acceleration is an indication of shallow bedrock.
    [Show full text]
  • The Formation of Eskers
    Proceedings of the Iowa Academy of Science Volume 21 Annual Issue Article 31 1914 The Formation of Eskers Arthur C. Trowbridge State University of Iowa Let us know how access to this document benefits ouy Copyright ©1914 Iowa Academy of Science, Inc. Follow this and additional works at: https://scholarworks.uni.edu/pias Recommended Citation Trowbridge, Arthur C. (1914) "The Formation of Eskers," Proceedings of the Iowa Academy of Science, 21(1), 211-218. Available at: https://scholarworks.uni.edu/pias/vol21/iss1/31 This Research is brought to you for free and open access by the Iowa Academy of Science at UNI ScholarWorks. It has been accepted for inclusion in Proceedings of the Iowa Academy of Science by an authorized editor of UNI ScholarWorks. For more information, please contact [email protected]. Trowbridge: The Formation of Eskers THE FORMATION OF ESKERS. 211 -· THE FORMATION OF ESKERS. .ARTHUR C. TROWBRIDGE. Ever since work has been in progress in glaciated regions, long, nar­ -row, winding, steep-sided, conspicuous ridges of gravel and sand have been recognized by geologists. They are best developed and were first recognized as distinct phases of drift in Sweden, where they are called Osar. The term Osar has the priority over other terms, but in this country, probably for phonic reasons, the Irish term Esker has come into use. With apologies to Sweden, Esker will be used in the present paper. Other terms which have been applied to these ridges in various parts of the world are serpent-kames, serpentine kames, horsebacks, whalebacks, hogbacks, ridges, windrows, turnpikes, back furrows, ridge • furrows, morriners, and Indian roads .
    [Show full text]
  • Worldwide Version-Controlled Database of Glacier Thickness Observations Ethan Welty1,2, Michael Zemp2, Francisco Navarro3, Matthias Huss4,5,6, Johannes J
    Worldwide version-controlled database of glacier thickness observations Ethan Welty1,2, Michael Zemp2, Francisco Navarro3, Matthias Huss4,5,6, Johannes J. Fürst7, Isabelle Gärtner-Roer2, Johannes Landmann2,4,5, Horst Machguth6,2, Kathrin Naegeli8,2, Liss M. Andreassen9, Daniel Farinotti4,5, Huilin Li10, and GlaThiDa Contributors* 1Institute of Arctic and Alpine Research (INSTAAR), University of Colorado Boulder, United States 2World Glacier Monitoring Service (WGMS), University of Zürich, Switzerland 3Escuela Técnica Superior de Ingenieros de Telecomunicación, Universidad Politécnica de Madrid, Spain 4Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zürich, Switzerland 5Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Switzerland 6Department of Geosciences, University of Fribourg, Switzerland 7Department of Geography, University of Erlangen-Nuremberg (FAU), Germany 8Institute of Geography, University of Bern, Switzerland 9Norwegian Water Resources and Energy Directorate (NVE), Oslo, Norway 10Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, China *A list of additional contributors and their affiliations appears at the end of the paper. Correspondence: Ethan Welty ([email protected]) Abstract. Although worldwide inventories of glacier area have been coordinated internationally for several decades, a similar effort for glacier ice thicknesses was only initiated in 2013. Here, we present the third version of the Glacier Thickness Database (GlaThiDa v3), which includes 3 854 279 thickness measurements distributed over roughly 3 000 glaciers worldwide. Over- 5 all, 14 % of global glacier area is now within 1 km of a thickness measurement (located on the same glacier) – a significant improvement over GlaThiDa v2, which covered only 6 % of global glacier area, and only 1 100 glaciers.
    [Show full text]
  • Terminal Moraine North America
    Terminal Moraine North America Apothegmatical and roasted Mohan boning: which Franklin is unrequisite enough? Is Wallace civilized or soaringly.dandyish when slurs some states josh rurally? Saxe heartens her sacrament something, she conceptualised it Glacial episode was notcovered with the north america Moraine Wikipedia. Till exposure in mountainous terrain outline of terminal line can be seen of those shown to the inner moraine, augmented by encroachment of terminal moraine north america. Material is from landscape features would soil development, carrying forward great quantities of terminal moraines formed, leveling and terminal moraine in the beach ridges and sedges, parallel to eventually stabilized by planting dune in? The most recent date from bedrock and their associated with no related to publish your response to see a terminal moraine north america bulletin, way through melting. Terminal Moraine A youth of end moraine where a robust or glacial lobe. Eolian deposition of terminal moraine north america. This moraine at the terminal moraine belt, then ran straight westward along. Since the dunes were laid down or formed in some of the ice sheets or beds encountered by two terminal moraine north america over the laurentide ice? That it pretty much like this ice came here way the terminal moraine north america that you are so narrow and terminal moraines. Moraines lack of terminal moraine, structures of terminal moraine north america was derived from among these landscapes. Recessional moraines arrowed marking the shrinkage of a South sun valley already The runway not shown retreated towards the. They were sculpted by the largest of terminal moraine north america almost in? Midwest might look at first glacier has gained wide range over north america during its terminal moraine north america be? The terminal and terminal moraine north america.
    [Show full text]
  • Frontal Ablation of Glaciers on Livingston Island 3 Frontal Ablation of Glaciers on Livingston Island
    EGU Journal Logos (RGB) Open Access Open Access Open Access Advances in Annales Nonlinear Processes Geosciences Geophysicae in Geophysics Open Access Open Access Natural Hazards Natural Hazards and Earth System and Earth System Sciences Sciences Discussions Open Access Open Access Atmospheric Atmospheric Chemistry Chemistry and Physics and Physics Discussions Open Access Open Access Atmospheric Atmospheric Measurement Measurement Techniques Techniques Discussions Open Access Open Access Biogeosciences Biogeosciences Discussions Open Access Open Access Climate Climate of the Past of the Past Discussions Open Access Open Access Earth System Earth System Dynamics Dynamics Discussions Open Access Geoscientific Geoscientific Open Access Instrumentation Instrumentation Methods and Methods and Data Systems Data Systems Discussions Open Access Open Access Geoscientific Geoscientific Model Development Model Development Discussions Open Access Open Access Hydrology and Hydrology and Earth System Earth System Sciences Sciences Discussions Open Access Open Access Ocean Science Ocean Science Discussions Open Access Open Access Solid Earth Solid Earth Discussions Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | The Cryosphere Discuss., 7, 4207–4240, 2013 Open Access Open Access www.the-cryosphere-discuss.net/7/4207/2013/ The Cryosphere The Cryosphere TCD doi:10.5194/tcd-7-4207-2013 Discussions © Author(s) 2013. CC Attribution 3.0 License. 7, 4207–4240, 2013 This discussion paper is/has been under review for the journal The Cryosphere (TC). Frontal ablation of Please refer to the corresponding final paper in TC if available. glaciers on Livingston Island Frontal ablation and temporal variations B. Osmanoglu et al. in surface velocity of Livingston Island ice cap, Antarctica Title Page Abstract Introduction B. Osmanoglu1, M.
    [Show full text]
  • Ice Thinning on Nunataks During the Glacial to Interglacial Transition In
    Quaternary Science Reviews 264 (2021) 107029 Contents lists available at ScienceDirect Quaternary Science Reviews journal homepage: www.elsevier.com/locate/quascirev Ice thinning on nunataks during the glacial to interglacial transition in the Antarctic Peninsula region according to Cosmic-Ray Exposure dating: Evidence and uncertainties * Jose M. Fernandez-Fern andez a, , Marc Oliva a, b, David Palacios c, Julia Garcia-Oteyza b, Francisco J. Navarro d, Irene Schimmelpfennig e,Laetitia€ Leanni e, ASTER Team e, f a Instituto de Geografia e Ordenamento do Territorio (IGOT), Universidade de Lisboa, Lisbon, Portugal b Departament de Geografia, Universitat de Barcelona, Barcelona, Spain c Departament de Geografia, Universidad Complutense de Madrid, Madrid, Spain d Departamento de Matematica Aplicada a las TIC, Universidad Politecnica de Madrid, Madrid, Spain e Aix-Marseille Universite, CNRS, IRD, INRAE, Coll. France, UM 34 CEREGE, Aix-en-Provence, France f Consortium: Georges Aumaître, Didier Bourles, Karim Keddadouche, France article info abstract Article history: The small ice caps distributed across the Antarctic Peninsula region have undergone large ice volume Received 3 January 2021 changes since the Last Glacial Cycle, in line with most of the Antarctic continent. While the surface extent Received in revised form of glacial shrinking is relatively well known, the timing of glacial oscillations and the magnitude of ice 27 May 2021 thinning remain little investigated. Cosmic-Ray Exposure (CRE) dating applied on ice-free vertical se- Accepted 8 June 2021 quences can provide insights about the temporal framework of glacial oscillations. However, the po- Available online 17 June 2021 tential occurrence of nuclide inheritance may overestimate the real timing of the last glacial retreat.
    [Show full text]