Geomorphology
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1 Recognising Glacial Features. Examine the Illustrations of Glacial Landforms That Are Shown on This Page and on the Next Page
1 Recognising glacial features. Examine the illustrations of glacial landforms that are shown on this C page and on the next page. In Column 1 of the grid provided write the names of the glacial D features that are labelled A–L. In Column 2 indicate whether B each feature is formed by glacial erosion of by glacial deposition. A In Column 3 indicate whether G each feature is more likely to be found in an upland or in a lowland area. E F 1 H K J 2 I 24 Chapter 6 L direction of boulder clay ice flow 3 Column 1 Column 2 Column 3 A Arête Erosion Upland B Tarn (cirque with tarn) Erosion Upland C Pyramidal peak Erosion Upland D Cirque Erosion Upland E Ribbon lake Erosion Upland F Glaciated valley Erosion Upland G Hanging valley Erosion Upland H Lateral moraine Deposition Lowland (upland also accepted) I Frontal moraine Deposition Lowland (upland also accepted) J Medial moraine Deposition Lowland (upland also accepted) K Fjord Erosion Upland L Drumlin Deposition Lowland 2 In the boxes provided, match each letter in Column X with the number of its pair in Column Y. One pair has been completed for you. COLUMN X COLUMN Y A Corrie 1 Narrow ridge between two corries A 4 B Arête 2 Glaciated valley overhanging main valley B 1 C Fjord 3 Hollow on valley floor scooped out by ice C 5 D Hanging valley 4 Steep-sided hollow sometimes containing a lake D 2 E Ribbon lake 5 Glaciated valley drowned by rising sea levels E 3 25 New Complete Geography Skills Book 3 (a) Landform of glacial erosion Name one feature of glacial erosion and with the aid of a diagram explain how it was formed. -
Jökulhlaups in Skaftá: a Study of a Jökul- Hlaup from the Western Skaftá Cauldron in the Vatnajökull Ice Cap, Iceland
Jökulhlaups in Skaftá: A study of a jökul- hlaup from the Western Skaftá cauldron in the Vatnajökull ice cap, Iceland Bergur Einarsson, Veðurstofu Íslands Skýrsla VÍ 2009-006 Jökulhlaups in Skaftá: A study of jökul- hlaup from the Western Skaftá cauldron in the Vatnajökull ice cap, Iceland Bergur Einarsson Skýrsla Veðurstofa Íslands +354 522 60 00 VÍ 2009-006 Bústaðavegur 9 +354 522 60 06 ISSN 1670-8261 150 Reykjavík [email protected] Abstract Fast-rising jökulhlaups from the geothermal subglacial lakes below the Skaftá caul- drons in Vatnajökull emerge in the Skaftá river approximately every year with 45 jökulhlaups recorded since 1955. The accumulated volume of flood water was used to estimate the average rate of water accumulation in the subglacial lakes during the last decade as 6 Gl (6·106 m3) per month for the lake below the western cauldron and 9 Gl per month for the eastern caul- dron. Data on water accumulation and lake water composition in the western cauldron were used to estimate the power of the underlying geothermal area as ∼550 MW. For a jökulhlaup from the Western Skaftá cauldron in September 2006, the low- ering of the ice cover overlying the subglacial lake, the discharge in Skaftá and the temperature of the flood water close to the glacier margin were measured. The dis- charge from the subglacial lake during the jökulhlaup was calculated using a hypso- metric curve for the subglacial lake, estimated from the form of the surface cauldron after jökulhlaups. The maximum outflow from the lake during the jökulhlaup is esti- mated as 123 m3 s−1 while the maximum discharge of jökulhlaup water at the glacier terminus is estimated as 97 m3 s−1. -
Analysis of Groundwater Flow Beneath Ice Sheets
SE0100146 Technical Report TR-01-06 Analysis of groundwater flow beneath ice sheets Boulton G S, Zatsepin S, Maillot B University of Edinburgh Department of Geology and Geophysics March 2001 Svensk Karnbranslehantering AB Swedish Nuclear Fuel and Waste Management Co Box 5864 SE-102 40 Stockholm Sweden Tel 08-459 84 00 +46 8 459 84 00 Fax 08-661 57 19 +46 8 661 57 19 32/ 23 PLEASE BE AWARE THAT ALL OF THE MISSING PAGES IN THIS DOCUMENT WERE ORIGINALLY BLANK Analysis of groundwater flow beneath ice sheets Boulton G S, Zatsepin S, Maillot B University of Edinburgh Department of Geology and Geophysics March 2001 This report concerns a study which was conducted for SKB. The conclusions and viewpoints presented in the report are those of the authors and do not necessarily coincide with those of the client. Summary The large-scale pattern of subglacial groundwater flow beneath European ice sheets was analysed in a previous report /Boulton and others, 1999/. It was based on a two- dimensional flowline model. In this report, the analysis is extended to three dimensions by exploring the interactions between groundwater and tunnel flow. A theory is develop- ed which suggests that the large-scale geometry of the hydraulic system beneath an ice sheet is a coupled, self-organising system. In this system the pressure distribution along tunnels is a function of discharge derived from basal meltwater delivered to tunnels by groundwater flow, and the pressure along tunnels itself sets the base pressure which determines the geometry of catchments and flow towards the tunnel. -
Ice-Stream Flow Switching by Up-Ice Propagation of Instabilities Along Glacial Marginal Troughs
Ice-stream flow switching by up-ice propagation of instabilities along glacial marginal troughs Etienne Brouard1* & Patrick Lajeunesse1 5 1 Centre d’études nordiques & Département de géographie, Université Laval, Québec, Québec Correspondence to: Etienne Brouard ([email protected]) Abstract. Ice stream networks constitute the arteries of ice sheets through which large volumes of glacial ice are rapidly delivered from the continent to the ocean. Modifications in ice stream networks have a major impact on ice sheets mass balance and global sea level. Reorganizations in the drainage network of ice streams have been reported in both modern and palaeo- 10 ice sheets and usually result in ice streams switching their trajectory and/or shutting down. While some hypotheses for the reorganization of ice streams have been proposed, the mechanisms that control the switching of ice streams remain poorly understood and documented. Here, we interpret a flow switch in an ice stream system that occurred prior to the last glaciation on the northeastern Baffin Island shelf (Arctic Canada) through glacial erosion of a marginal trough, i.e., deep parallel-to-coast bedrock moats located up-ice of a cross-shelf trough. Shelf geomorphology imaged by high-resolution swath bathymetry and 15 seismostratigraphic data in the area indicate the extension of ice streams from Scott and Hecla & Griper troughs towards the interior of the Laurentide Ice Sheet. Up-ice propagation of ice streams through a marginal trough is interpreted to have led to the piracy of the neighboring ice catchment that in turn induced an adjacent ice stream flow switch and shutdown. -
Glacier Mass Balance Bulletin No. 11 (2008–2009)
GLACIER MASS BALANCE BULLETIN Bulletin No. 11 (2008–2009) A contribution to the Global Terrestrial Network for Glaciers (GTN-G) as part of the Global Terrestrial/Climate Observing System (GTOS/GCOS), the Division of Early Warning and Assessment and the Global Environment Outlook as part of the United Nations Environment Programme (DEWA and GEO, UNEP) and the International Hydrological Programme (IHP, UNESCO) Compiled by the World Glacier Monitoring Service (WGMS) ICSU (WDS) – IUGG (IACS) – UNEP – UNESCO – WMO 2011 GLACIER MASS BALANCE BULLETIN Bulletin No. 11 (2008–2009) A contribution to the Global Terrestrial Network for Glaciers (GTN-G) as part of the Global Terrestrial/Climate Observing System (GTOS/GCOS), the Division of Early Warning and Assessment and the Global Environment Outlook as part of the United Nations Environment Programme (DEWA and GEO, UNEP) and the International Hydrological Programme (IHP, UNESCO) Compiled by the World Glacier Monitoring Service (WGMS) Edited by Michael Zemp, Samuel U. Nussbaumer, Isabelle Gärtner-Roer, Martin Hoelzle, Frank Paul, Wilfried Haeberli World Glacier Monitoring Service Department of Geography University of Zurich Switzerland ICSU (WDS) – IUGG (IACS) – UNEP – UNESCO – WMO 2011 Imprint World Glacier Monitoring Service c/o Department of Geography University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland http://www.wgms.ch [email protected] Editorial Board Michael Zemp Department of Geography, University of Zurich Samuel U. Nussbaumer Department of Geography, University of Zurich -
1 Andrews Glacier in August 2016 Tyndall Glacier Lidar Scan in May
Final Report for “Glacier and perennial snowfield mass balance of Rocky Mountain National Park (ROMO): Past, Present, and Future” Task Agreement Number P16AC00826 PI Dr. Daniel McGrath June 28, 2019 Department of Geosciences Colorado State University [email protected] Andrews Glacier in August 2016 Tyndall Glacier LiDAR scan in May 2016 1 Summary of Key Project Outcomes • Over the past ~50 years, geodetic glacier mass balances for four glaciers along the Front Range have been highly variable; for example, Tyndall Glacier thickened slightly, while Arapaho Glacier thinned by >20 m. These glaciers are closely located in space (~30 km) and hence the regional climate forcing is comparable. This variability points to the important role of local topographic/climatological controls (such as wind-blown snow redistribution and topographic shading) on the mass balance of these very small glaciers (~0.1-0.2 km2). • Since 2001, glacier area (for 11 glaciers on the Front Range) has varied ± 40%, with changes most commonly driven by interannual variability in seasonal snow. However, between 2001 and 2017, the glaciers exhibited limited net change in area. Previous work (Hoffman et al., 2007) found that glacier area had started to decline starting in ~2000. • Seasonal mass turnover is very high for Andrews and Tyndall glaciers. On average, the glaciers gain and lose ~9 m of elevation each year. Such extraordinary amounts of snow accumulation is primarily the result of wind-blown snow redistribution into these basins (and to a certain degree, avalanching at Tyndall Glacier) and exceeds observed peak snow water equivalent at a nearby SNOTEL station by 5.5 times. -
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. -
Abrupt Changes in Ice Shelves and Ice Streams
The Pennsylvania State University The Graduate School College of Earth and Mineral Sciences ABRUPT CHANGES IN ICE SHELVES AND ICE STREAMS: MODEL STUDIES A Thesis in Geosciences by Todd K. Dupont c 2004 Todd K. Dupont Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy May 2004 The thesis of Todd K. Dupont has been reviewed and approved∗ by the following: Richard B. Alley Evan Pugh Professor of Geosciences Thesis Advisor Chair of Committee Derek Elsworth Professor of Energy and Geo-Environmental Engineering James F. Kasting Distinguished Professor of Geosciences Raymond G. Najjar Associate Professor of Meteorology & Geosciences Peter Deines Professor of Geochemistry Associate Head for Graduate Programs and Research ∗Signatures are on file in the Graduate School. ii Abstract Ice sheets are among the most important components of the Earth system because of their ability to force changes in climate and sea level. Ice streams are efficient pathways of mass flux from the interior of ice sheets. Thus an understanding of ice-stream dynamics is integral to an understanding of ice sheets and their interplay with sea level and climate. Here a 1-d model of the coupled mass and momentum balance of ice streams and shelves is developed. Longitudinal deviatoric stress is included in the force-balance component model. The mass-balance component model is time-dependent and thus allows simulation of the dynamic consequences of changes in boundary conditions or parameters. An improved, computationally efficient algorithm of the discretization of the mass-balance equation is outlined. All model parameters are non-dimensional. -
VACATION LAND the National Forests in Oregon
VACATION LAND The National Forests in Oregon High up in the mountains, where the timber is scarce and stunted and the only means of transportation is by horseback United States Department of Agriculture::Forest Service 1919 WELCOME TO THE ATIONAL PORESTS U.S.DEPARTVENT OFAGRICULTURE FOREST SIEIRVICE UNITED STATES DEPARTMENT OF AGRICULTURE DEPARTMENT CIRCULAR 4 Contribution from the Forest Service HENRY S. GRAVES. Forester DIRECTORY OF NATIONAL FORESTS IN OREGON. George H. Cecil, District Forester. District Office, Post Office Building, Portland, Oreg. NATIONAL FOREST. FOREST SUPERVISOR. HEADQUARTERS. Cascade C. R. Seitz Eugene, Oreg. 2- Crater H B Rankin Medford, Oreg. Deschutes N. G. Jacobson Bend, Oreg. H Fremont...... Gilbert D. Brown Lakeview, Oreg. -Maiheur Cy J. Bingham John Day, Oreg. L-Milaam R. M. Evans.... Baker, Oreg. - Ochoco.. V. V. Harpham Prineville, Oreg. Oregon H. Sherrard...... Portland, Oreg. Santiam C. C. Hall.. Albany, Oreg. -Siskiyou.... N. F. Macduff Grants Pass, Oreg. Siuslaw R. S. Shelley Eugene, Oreg. \-Umati1la W. W. Cryder Pendleton, Oreg. 13 .Umpqua C. Bartrum Roseburg, Oreg. j Wallowa H. W. Harris Wallowa, Oreg. S'Wenaha J. C. Kulins Walla Walla, Wash. l,Whitman R. M. Evans.... Baker, Oreg. The view on page s of the cover is a reprodtction from a photograph of Mount Jefferson, Sautiam National Forest, showing forest and snow peak. THE NATIONAL VACATION 1 ANDESTS IN OREGON AN IDEAL VACATION LAND HEN, tired of the daily grind, you say to yourself, "I need a vacation," your first thought is to get away from civili- zation and its trammels.Your next is to find interest- ing and health-giving recreation.In the National For- ests in Oregon you may find both, and much besides. -
Distribution, Geometry, Age and Origin of Overdeepened Valleys and Basins in the Alps and Their Foreland
Swiss J Geosci (2010) 103:407–426 DOI 10.1007/s00015-010-0044-y Distribution, geometry, age and origin of overdeepened valleys and basins in the Alps and their foreland Frank Preusser • Ju¨rgen M. Reitner • Christian Schlu¨chter Received: 22 February 2010 / Accepted: 14 June 2010 / Published online: 14 December 2010 Ó Swiss Geological Society 2010 Abstract Overdeepened valleys and basins are commonly and excavated by glaciers during past glaciations. However, found below the present landscape surface in areas that were the age of the original formation of (non-Messinian) over- affected by Quaternary glaciations. Overdeepened troughs deepened structures remains unknown. The mechanisms and their sedimentary fillings are important in applied causing overdeepening also remain unidentified and it can geology, for example, for geotechnics of deep foundations only be speculated that pressurised meltwater played an and tunnelling, groundwater resource management, and important role in this context. radioactive waste disposal. This publication is an overview of the areal distribution and the geometry of overdeepened Keywords Glaciations Á Erosion Á Sediments Á troughs in the Alps and their foreland, and summarises the Overdeepening Á Alps Á Quaternary present knowledge of the age and potential processes that may have caused deep erosion. It is shown that overdee- pened features within the Alps concur mainly with tectonic Introduction structures and/or weak lithologies as well as with Pleisto- cene ice confluence and partly also diffluence situations. In ‘‘Mit Butter hobelt man nicht (Butter is not an abrasive the foreland, overdeepening is found as elongated buried agent)’’. This famous statement by Albert Heim (1919), valleys, mainly oriented in the direction of former ice flow, probably one of the most prominent alpine geologists of the and glacially scoured basins in the ablation area of glaciers. -
Glaciers and Glacial Erosional Landforms
GLACIERS AND GLACIAL EROSIONAL LANDFORMS Dr. NANDINI CHATTERJEE Associate Professor Department of Geography Taki Govt College Taki, North 24 Parganas, West Bengal Part I Geography Honours Paper I Group B -Geomorphology Topic 5- Development of Landforms GLACIER AND ICE CAPS Glacier is an extended mass of ice formed from snow falling and accumulating over the years and moving very slowly, either descending from high mountains, as in valley glaciers, or moving outward from centers of accumulation, as in continental glaciers. • Ice Cap - less than 50,000 km2. • Ice Sheet - cover major portion of a continent. • Ice thicker than topography. • Ice flows in direction of slope of the glacier. • Greenland and Antarctica - 3000 to 4000 m thick (10 - 13 thousand feet or 1.5 to 2 miles!) FORMATION AND MOVEMENT OF GLACIERS • Glaciers begin to form when snow remains Once the glacier becomes heavy enough, it in the same area year-round, where starts to move. There are two types of enough snow accumulates to transform glacial movement, and most glacial into ice. Each year, new layers of snow bury movement is a mixture of both: and compress the previous layers. This Internal deformation, or strain, in glacier compression forces the snow to re- ice is a response to shear stresses arising crystallize, forming grains similar in size and from the weight of the ice (ice thickness) shape to grains of sugar. Gradually the and the degree of slope of the glacier grains grow larger and the air pockets surface. This is the slow creep of ice due to between the grains get smaller, causing the slippage within and between the ice snow to slowly compact and increase in crystals. -
GLACIATION in SNOWDONIA by Paul Sheppard
GeoActiveGeoActive 350 OnlineOnline GLACIATION IN SNOWDONIA by Paul Sheppard This unit can be used These remnants of formerly much higher mountains have since been independently or in Conwy conjunction with OS 1:50,000 eroded into what is seen today. The Bangor mountains of Snowdonia have map sheet 115. N Caernarfon Llanrwst been changed as a result of aerial Llanberis Capel Curig Snowdon Betws y Coed (climatic) and fluvial (water) HE SNOWDONIA OR ERYRI (Yr Wyddfa) Beddgelert Blaenau erosion that always act upon a NATIONAL PARK, established Ffestiniog T Porthmadog landscape, but in more recent SNOWDONIA Y Bala in 1951, was the third National NATIONAL Harlech geological times the effects of ice PARK Park to be established in England have had a major impact upon the and Wales following the 1949 Barmouth Abermaw Dolgellau actual land surface. National Parks and Access to the Cadair Countryside Act (Figure 1). It Idris Tywyn 2 Machynlleth Glaciation covers an area of 2,171 km (838 Aberdyfi 0 25 km square miles) of North Wales and Ice ages have been common in the British Isles and northern Europe, encompasses the Carneddau and Figure 1: Snowdonia National Park Glyderau mountain ranges. It also with 40 having been identified by includes the highest mountain in important to look first at the geologists and geomorphologists. England and Wales, with Mount geological origins of the area, as The most recent of these saw Snowdon (Yr Wyddfa in Welsh) this provides the foundation upon Snowdonia covered with ice as reaching a height of 1,085 metres which ice can act.