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Basal Control of Supraglacial Meltwater Catchments on the Greenland Ice Sheet
The Cryosphere, 12, 3383–3407, 2018 https://doi.org/10.5194/tc-12-3383-2018 © Author(s) 2018. This work is distributed under the Creative Commons Attribution 4.0 License. Basal control of supraglacial meltwater catchments on the Greenland Ice Sheet Josh Crozier1, Leif Karlstrom1, and Kang Yang2,3 1University of Oregon Department of Earth Sciences, Eugene, Oregon, USA 2School of Geography and Ocean Science, Nanjing University, Nanjing 210023, China 3Joint Center for Global Change Studies, Beijing 100875, China Correspondence: Josh Crozier ([email protected]) Received: 5 April 2018 – Discussion started: 17 May 2018 Revised: 13 October 2018 – Accepted: 15 October 2018 – Published: 29 October 2018 Abstract. Ice surface topography controls the routing of sur- sliding regimes. Predicted changes to subglacial hydraulic face meltwater generated in the ablation zones of glaciers and flow pathways directly caused by changing ice surface to- ice sheets. Meltwater routing is a direct source of ice mass pography are subtle, but temporal changes in basal sliding or loss as well as a primary influence on subglacial hydrology ice thickness have potentially significant influences on IDC and basal sliding of the ice sheet. Although the processes spatial distribution. We suggest that changes to IDC size and that determine ice sheet topography at the largest scales are number density could affect subglacial hydrology primarily known, controls on the topographic features that influence by dispersing the englacial–subglacial input of surface melt- meltwater routing at supraglacial internally drained catch- water. ment (IDC) scales ( < 10s of km) are less well constrained. Here we examine the effects of two processes on ice sheet surface topography: transfer of bed topography to the surface of flowing ice and thermal–fluvial erosion by supraglacial 1 Introduction meltwater streams. -
Calving Processes and the Dynamics of Calving Glaciers ⁎ Douglas I
Earth-Science Reviews 82 (2007) 143–179 www.elsevier.com/locate/earscirev Calving processes and the dynamics of calving glaciers ⁎ Douglas I. Benn a,b, , Charles R. Warren a, Ruth H. Mottram a a School of Geography and Geosciences, University of St Andrews, KY16 9AL, UK b The University Centre in Svalbard, PO Box 156, N-9171 Longyearbyen, Norway Received 26 October 2006; accepted 13 February 2007 Available online 27 February 2007 Abstract Calving of icebergs is an important component of mass loss from the polar ice sheets and glaciers in many parts of the world. Calving rates can increase dramatically in response to increases in velocity and/or retreat of the glacier margin, with important implications for sea level change. Despite their importance, calving and related dynamic processes are poorly represented in the current generation of ice sheet models. This is largely because understanding the ‘calving problem’ involves several other long-standing problems in glaciology, combined with the difficulties and dangers of field data collection. In this paper, we systematically review different aspects of the calving problem, and outline a new framework for representing calving processes in ice sheet models. We define a hierarchy of calving processes, to distinguish those that exert a fundamental control on the position of the ice margin from more localised processes responsible for individual calving events. The first-order control on calving is the strain rate arising from spatial variations in velocity (particularly sliding speed), which determines the location and depth of surface crevasses. Superimposed on this first-order process are second-order processes that can further erode the ice margin. -
Seismic Model Report.Pdf
Scientific Report GEFSC Loan 925 The Character and Extent of subglacial Deformation and its Links to Glacier Dynamics in the Tarfala Basin, northern Sweden Jeffrey Evans, David Graham, and Joseph Pomeroy Polar and Alpine Research Group, Loughborough University ABSTRACT A pilot passive seismology experiment was conducted across the main overdeepening of Storglaciaren in the Tarfala Basin, northern Sweden, in July 2010, to see whether basal microseismic waveforms could be detected beneath a small polythermal arctic glacier and to investigate the spatial and temporal distribution of such waveforms in relation to known glacier flow dynamics. The high ablation rate made it difficult to keep geophones buried and well- coupled to the glacier during the experiment and reduced the number of days of good quality data collection. Event counts and the subsequent characterisation of typical and atypical waveforms showed that the dominant waveforms detected were from near-surface events such as crevassing. Although basal sliding is known to occur in the overdeepening, no convincing examples of basal waveforms were detected, which suggests basal microseismic signals are rare or difficult to detect beneath polythermal glaciers like Storglaciaren, a finding that is consistent with results from alpine glaciers in Switzerland. The data- set could prove useful to glaciologists interested in the dynamics of near-surface events such as crevassing, the opening and closing of englacial water conduits, or temporal and spatial changes in the glacier’s stress field. Background Smith (2006) found that pervasive soft-bed deformation characterised parts of the Rutland Ice Stream in West Antarctica and produced 6 times fewer basal microseismic signals than regions where basal sliding or stick slip movement dominated. -
COLD-BASED GLACIERS in the WESTERN DRY VALLEYS of ANTARCTICA: TERRESTRIAL LANDFORMS and MARTIAN ANALOGS: David R
Lunar and Planetary Science XXXIV (2003) 1245.pdf COLD-BASED GLACIERS IN THE WESTERN DRY VALLEYS OF ANTARCTICA: TERRESTRIAL LANDFORMS AND MARTIAN ANALOGS: David R. Marchant1 and James W. Head2, 1Department of Earth Sciences, Boston University, Boston, MA 02215 [email protected], 2Department of Geological Sciences, Brown University, Providence, RI 02912 Introduction: Basal-ice and surface-ice temperatures are contacts and undisturbed underlying strata are hallmarks of cold- key parameters governing the style of glacial erosion and based glacier deposits [11]. deposition. Temperate glaciers contain basal ice at the pressure- Drop moraines: The term drop moraine is used here to melting point (wet-based) and commonly exhibit extensive areas describe debris ridges that form as supra- and englacial particles of surface melting. Such conditions foster basal plucking and are dropped passively at margins of cold-based glaciers (Fig. 1a abrasion, as well as deposition of thick matrix-supported drift and 1b). Commonly clast supported, the debris is angular and sheets, moraines, and glacio-fluvial outwash. Polar glaciers devoid of fine-grained sediment associated with glacial abrasion include those in which the basal ice remains below the pressure- [10, 12]. In the Dry Valleys, such moraines may be cored by melting point (cold-based) and, in extreme cases like those in glacier ice, owing to the insulating effect of the debris on the the western Dry Valleys region of Antarctica, lack surface underlying glacier. Where cored by ice, moraine crests can melting zones. These conditions inhibit significant glacial exceed the angle of repose. In plan view, drop moraines closely erosion and deposition. -
Inferred Basal Friction and Surface Mass Balance of the Northeast
The Cryosphere, 8, 2335–2351, 2014 www.the-cryosphere.net/8/2335/2014/ doi:10.5194/tc-8-2335-2014 © Author(s) 2014. CC Attribution 3.0 License. Inferred basal friction and surface mass balance of the Northeast Greenland Ice Stream using data assimilation of ICESat (Ice Cloud and land Elevation Satellite) surface altimetry and ISSM (Ice Sheet System Model) E. Larour1, J. Utke3, B. Csatho4, A. Schenk4, H. Seroussi1, M. Morlighem2, E. Rignot1,2, N. Schlegel1, and A. Khazendar1 1Jet Propulsion Laboratory – California Institute of Technology, 4800 Oak Grove Drive MS 300-323, Pasadena, CA 91109-8099, USA 2University of California Irvine, Department of Earth System Science, Croul Hall, Irvine, CA 92697-3100, USA 3Argonne National Lab, Argonne, IL 60439, USA 4Department of Geological Sciences, University at Buffalo, Buffalo, NY, USA Correspondence to: E. Larour ([email protected]) Received: 5 April 2014 – Published in The Cryosphere Discuss.: 8 May 2014 Revised: 9 September 2014 – Accepted: 30 September 2014 – Published: 15 December 2014 Abstract. We present a new data assimilation method within 1 Introduction the Ice Sheet System Model (ISSM) framework that is capa- ble of assimilating surface altimetry data from missions such Global mean sea level (GMSL) rise observations show an as ICESat (Ice Cloud and land Elevation Satellite) into re- overall budget in which freshwater contribution from the po- constructions of transient ice flow. The new method relies on lar ice sheets represents a significant portion (Church and algorithmic differentiation to compute gradients of objective White, 2006, 2011; Stocker et al., 2013), which is actually functions with respect to model forcings. -
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. -
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 -
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. -
Navigating Troubled Waters a History of Commercial Fishing in Glacier Bay, Alaska
National Park Service U.S. Department of the Interior Glacier Bay National Park and Preserve Navigating Troubled Waters A History of Commercial Fishing in Glacier Bay, Alaska Author: James Mackovjak National Park Service U.S. Department of the Interior Glacier Bay National Park and Preserve “If people want both to preserve the sea and extract the full benefit from it, they must now moderate their demands and structure them. They must put aside ideas of the sea’s immensity and power, and instead take stewardship of the ocean, with all the privileges and responsibilities that implies.” —The Economist, 1998 Navigating Troubled Waters: Part 1: A History of Commercial Fishing in Glacier Bay, Alaska Part 2: Hoonah’s “Million Dollar Fleet” U.S. Department of the Interior National Park Service Glacier Bay National Park and Preserve Gustavus, Alaska Author: James Mackovjak 2010 Front cover: Duke Rothwell’s Dungeness crab vessel Adeline in Bartlett Cove, ca. 1970 (courtesy Charles V. Yanda) Back cover: Detail, Bartlett Cove waters, ca. 1970 (courtesy Charles V. Yanda) Dedication This book is dedicated to Bob Howe, who was superintendent of Glacier Bay National Monument from 1966 until 1975 and a great friend of the author. Bob’s enthusiasm for Glacier Bay and Alaska were an inspiration to all who had the good fortune to know him. Part 1: A History of Commercial Fishing in Glacier Bay, Alaska Table of Contents List of Tables vi Preface vii Foreword ix Author’s Note xi Stylistic Notes and Other Details xii Chapter 1: Early Fishing and Fish Processing in Glacier Bay 1 Physical Setting 1 Native Fishing 1 The Coming of Industrial Fishing: Sockeye Salmon Attract Salters and Cannerymen to Glacier Bay 4 Unnamed Saltery at Bartlett Cove 4 Bartlett Bay Packing Co. -
Download the Program and Abstracts
PROGRAM AND ABSTRACTS 47TH ANNUAL INTERNATIONAL ARCTIC WORKSHOP March 23-25, 2017 Buffalo, New York Sponsored and Hosted by: University at Buffalo Center for GeoHazards Studies College of Arts and Sciences Department of Geology The RENEW Institute Organizing Committee: Jason Briner Barbara Catalano Beata Csatho Avriel Schweinsberg Elizabeth Thomas Greg Valentine 1 2 Introduction Overview and history The 47th Annual International Arctic Workshop will be held March 23-25, 2017, on the campus of the University of Buffalo. The meeting is sponsored and hosted by the University at Buffalo, Center for GeoHazard Studies, College of Arts and Sciences, Department of Geology, and the RENEW Institute. This workshop has grown out of a series of informal annual meetings started by John T. Andrews and sponsored by INSTAAR and other academic institutions worldwide. 2017 Theme “Polar Climate and Sea Level: Past, Present & Future” Website https://geohazards.buffalo.edu/aw2017 Check-In / Registration Please check in or register on (1) Wednesday evening at the Icebreaker/Reception between 5:00 – 7:00 pm in the Davis Hall Atrium (UB North Campus), or (2) Thursday morning between 8:00 – 8:45 am in the Davis Hall Atrium. At registration those who have ordered a print version will also receive their printed high-resolution volume. Davis Hall Davis Hall is located between Putnam Way and White Road on the UB North Campus. Davis Hall is directly north of Jarvis Hall and east of Ketter Hall. To view an interactive map of North Campus, please visit this webpage: https://www.buffalo.edu/home/visiting- ub/CampusMaps/maps.html Wi-Fi Wireless internet access is available (“UB_Connect”). -
4 Ecological Environmental Effects Assessment Methods for Deterministic Oil Spill Modelling
CA PDF Page 105 of 1038 Part B: Deterministic Modelling of the Ecological and Energy East Project Human Health Consequences of Marine Oil Spills Volume 24: Ecological and Human Health Risk Section 4: Ecological Environmental Effects Assessment Assessment for Oil Spills in the Marine Environment Methods for Deterministic Oil Spill Modelling 4 ECOLOGICAL ENVIRONMENTAL EFFECTS ASSESSMENT METHODS FOR DETERMINISTIC OIL SPILL MODELLING 4.1 Introduction This section provides details for the approach to the deterministic assessment of physically or toxicologically induced changes in health of ecological receptors exposed to spilled crude oil, or chemical constituents of spilled crude oil. Results of the assessment are provided for three spill scenarios: (i) a grounding in Saint John Harbour; (ii) a collision in the Bay of Fundy; and (iii) a grounding south of Grand Manan) (see Sections 6, 7 and 8). This ecological risk assessment (ERA) follows accepted risk assessment methodologies and follows guidance published and endorsed by regulatory agencies, including CCME (1996, 1997), Government of Canada (2012a) and the U.S. EPA (1989, 1998). 4.2 Ecological Risk Assessment Problem Formulation Problem formulation is the initial information gathering and interpretation stage that focuses the assessment on areas of primary concern within the study area for marine accidents and malfunctions (SAMAM). The problem formulation defines the nature and scope of the work to be conducted, and enables practical boundaries to be placed on the overall scope of work, -
Glacial Geomorphological Mapping a Review of Approaches And
Earth-Science Reviews 185 (2018) 806–846 Contents lists available at ScienceDirect Earth-Science Reviews journal homepage: www.elsevier.com/locate/earscirev Glacial geomorphological mapping: A review of approaches and frameworks for best practice T ⁎ Benjamin M.P. Chandlera, , Harold Lovellb, Clare M. Bostonb, Sven Lukasc, Iestyn D. Barrd, Ívar Örn Benediktssone, Douglas I. Bennf, Chris D. Clarkg, Christopher M. Darvillh, David J.A. Evansi, Marek W. Ewertowskij, David Loiblk, Martin Margoldl, Jan-Christoph Ottom, David H. Robertsi, Chris R. Stokesi, Robert D. Storrarn, Arjen P. Stroeveno,p a School of Geography, Queen Mary University of London, Mile End Road, London E1 4NS, UK b Department of Geography, University of Portsmouth, Portsmouth, UK c Department of Geology, Lund University, Lund, Sweden d School of Science and the Environment, Manchester Metropolitan University, Manchester, UK e Institute of Earth Sciences, University of Iceland, Reykjavík, Iceland f Department of Geography and Sustainable Development, University of St Andrews, St Andrews, UK g Department of Geography, University of Sheffield, Sheffield, UK h Geography, School of Environment, Education and Development, University of Manchester, Manchester, UK i Department of Geography, Durham University, Durham, UK j Faculty of Geographical and Geological Sciences, Adam Mickiewicz University, Poznań, Poland k Department of Geography, Humboldt University of Berlin, Berlin, Germany l Department of Physical Geography and Geoecology, Charles University, Prague, Czech Republic m Department