DOCSLIB.ORG

Régimes Des Feux Et Dynamique Forestière Post-Feu De Part Et D'autre

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Régimes Des Feux Et Dynamique Forestière Post-Feu De Part Et D'autre UNIVERSITÉ DU QUÉBEC À MONTRÉAL RÉGIMES DES FEUX ET DYNAMIQUE FORESTIÈRE POST-FEU DE PART ET D'AUTRE DE LA LIMITE NORDIQUE DES FORÊTS COMMERCIALES AU QUÉBEC THÈSE PRÉSENTÉE COMME EXIGENCE PARTIELLE DU DOCTORAT EN SCIENCES DE L'ENVIRONNEMENT PAR NICOLAS MANSUY MAI 2013 UNIVERSITÉ DU QUÉBEC À MONTRÉAL Service des bibliothèques Avertissement La diffusion de cette thèse se fait dans le respect des droits de son auteur, qui a signé le formulaire Autorisation de reproduire et de diffuser un travail de recherche de cycles supérieurs (SDU-522 -Rév.ül-2ÜÜG). Cette autorisation stipule que «conformément à l'article 11 du Règlement no 8 des études de cycles supérieurs, [l'auteur] concède à l'Université du Québec à Montréal une licence non exclusive d'utilisation et de publication de la totalité ou d'une partie importante de [son] travail de recherche pour des fins pédagogiques et non commerciales. Plus précisément, [l'auteur] autorise l'Université du Québec à Montréal à reproduire, diffuser, prêter, distribuer ou vendre des copies de [son] travail de recherche à des fins non commerciales sur quelque support que ce soit, y compris l'Internet. Cette licence et cette autorisation n'entraînent pas une renonciation de [la] part [de l'auteur] à [ses] droits moraux ni à [ses] droits de propriété intellectuelle. Sauf entente contraire, [l'auteur] conserve la liberté de diffuser et de commercialiser ou non ce travail dont [il] possède un exemplaire.» Il REMERCIEMENTS La réalisation de ce doctorat a été possible grâce à une collaboration multidisciplinaire entre plusieurs chercheurs affiliés à différents organismes (provinciaux, fédéraux et universitaires) mais aussi grâce à une grande amitié avec les autres étudiants et collègues. Je remercie ma directrice, Sylvie Gauthier du Service Canadien des Forêts et mon codirecteur Yves Bergeron de l'UQAT et l'UQAM, pour m'avoir dirigé et conseillé tout au long de ce projet. Je remercie André Robitaille du MRNFQ, coauteur des articles publiés, qui a bien voulu partager avec moi sa Science des dépôts de surface, Je remercie toute l'équipe de la Direction des inventaires forestiers (projet Limite Nordique) du MRNFQ pour avoir fourni les données cartographiques indispensables à la réalisation du projet. Merci à Julie Fortin du MRNFQ pour les données sur les feux. De plus, je remercie les diverses organismes qui ont participé au support financier de ce doctorat: l'UQAM, la subvention stratégique du CRSNG, la subvention Fonds Forestier du FQRNT et la Commission Régionale sur les Ressources Naturelles et le Territoire de la Baie-James (CRRNTBJ). Je remercie aussi Ressources Naturelles Canada et le Centre de Foresterie des Laurentides pour avoir mis à disposition un bureau ainsi que les ressources matérielles et technologiques nécessaires au bon déroulement de mes recherches. Un gros merci à toute l'équipe du CEF de Montréal (Danielle Charron et Luc Lauzon) et et celle de Québec pour la gestion administrative et logistique. Merci à Mélanie Desrochers et Pierre Racine pour leurs réponses à toutes mes requêtes cartographiques. Je remercie aussi celles qui m'ont permis de publier mes articles en anglais : Pamela Cheers, Alix Rive et Isabelle Lamarre. Je remercie également Rémi Saint-Amant du Centre de Foresterie des Laurentides pour m'avoir fourni les données météorologiques et les données sur les vents, et Marc Mazerolle de 1' UQA T pour ses conseils en statistique. l11 Je tiens à remercier chaleureusement Sylvie Gauthier qui m'a soutenu et écouté dans mon parcours et mes réflexions pendant les six années travaillées ensemble. Elle m'a aussi généreusement accueilli au Centre de Foresterie des Laurentides à partir de 2009 et permis de partager mon quotidien avec des gens reconnus comme expert dans leur domaine comme Louis de Grandpré, Martin Girardin, Dominique Boucher, mais aussi avec des gens un peu moins experts mais tout aussi sympathiques comme Rik Van Bogaert, tout particulièrement Miren Lorente, Yan Boulanger, François Girard et Dave Gervais. Ces trois dernières années de thèse ont été les plus enrichissantes et stimulantes en termes d'expérience professionnelle mais aussi en termes de camaraderie avec les collègues. Sylvie a aussi eu l'audace de me prêter son casque à vélo pour le Se Pentathlon des Neiges. Sans elle, je n'aurais jamais pu finir 32e sur 154 avec un temps de 29'32"58'". Je remercie également les amis qui ont partagé mon quotidien dès le début de cette aventure et ceux et celles rencontrés en cours de route. Quelques noms évocateurs : Emestito et Oscarito (Les deux princes du Chili qui me supportent depuis 6 ans), Amar Etto roi du café (merci pour ta sagesse sétifienne et tes précieux conseils), Maurice un bon rôti, Aurélie pipi, Nicolas popo, Annie-Claude, Dom, Pablo, Taylor, Nanard, Nic T, Jacko, Tim Horton, Jean Coutu. Finalement toute ma gratitude va à ma super famille pour leur support inconditionnel quelque soit l'objectif à atteindre. Merci à Papa, Sylvain, Julie et Nao pour leurs visites. Et bien sûr un gros « MUAH » à ma chérie, Alix, qui n'arrête pas de me faire réfléchir sur tout ... IV AVANT-PROPOS Cette thèse se compose d'une introduction générale, de trois chapitres qui décrivent de façon non exhaustive le travail effectué au cours du doctorat et d'une conclusion générale. Les trois chapitres, qui ne suivent pas l'ordre chronologique de leur réalisation, sont présentés sous forme d'articles scientifiques publiés ou engagés dans le processus de publication. Avec la collaboration des coauteurs, j'ai été le principal responsable des étapes du développement et le rédacteur des trois chapitres. Chaque chapitre répond à un objectif de recherche précis et intègre de façon systématique une introduction qui présente la problématique; les données et méthodes utilisées; les résultats et une discussion qui met en perspective les résultats obtenus. D'autres articles scientifiques et rapports professionnels ont été réalisés au cours du doctorat mais ne sont pas présentés dans le cadre de la thèse. Le premier chapitre, intitulé The effects of surficial deposit- drainage combinations on spatial variations ofjire cycles in the boreal forest of eastern Canada, a été publié en 2010 dans la revue International Journal of Wildland Fire 2010, 19, 1083- 1098. Les coauteurs sont les cosuperviseurs de cette thèse Sylvie Gauthier, Yves Bergeron et André Robitaille. Le deuxième chapitre, intitulé Attributs spatiaux des f eux dans l 'est du Canada. Une approche basée sur la physionomie des paysages, sera soumis dans la revue Landscape Ecology. Les coauteurs sont les cosuperviseurs de cette thèse Sylvie Gauthier, Yves Bergeron ainsi qu'André Robitaille et Yan Boulanger. Le troisième chapitre, intitulé Regional patterns of postfire canopy recovery in the northern boreal forest of Quebec: Interactions between surficial deposit, climate and jire cycle, a été publié en juillet 2012 dans la revue Canadian Journal of Forest v Research. Les coauteurs sont les cosuperviseurs de cette thèse Sylvie Gauthier, Yves Bergeron ainsi que André Robitaille. VI TABLE DES MATIÈRES LISTE DES FIGURES ............................................................................................................. xi LISTE DES TABLEAUX ........................................................................................... .. ......... xiii LISTE DES ANNEXES .. ............... ................ ......... ...... ... ........ ..... ..... ..... ....... xv INTRODUCTION GÉNÉRALE ................... .... ................ .. ...................................................... 1 CHAPITRE I THE EFFECTS OF SURFICIAL DEPOSIT-DRAINAGE COMBINATIONS ON SPATIAL VARIATIONS OF FIRE CYCLES IN BOREAL FOREST OF EASTERN CANADA ...... 12 1. 1 Résumé ...................... ................. ..................................... .................................................. 13 1.2 Abstract .......... .. ...................................... ... .. .... ... ................... .. ............... ... ... ... .... .............. 13 1.3 Introduction .... .. ....... .......................................................................................................... 14 1.4 Materials and Methods ......................................................... .... ........................ ................. 17 1.4.1 Study area ............................................................................................................. 17 1.4.2 Surficial deposit-drainage data ............................................................................. 19 1.4.3 Landscape units data ............................................................................................ 21 1.4.4 Fi re data ..... ... .............................................. ...... ................ .. .. ............................... 22 1.4.5 Random sampling .............................................................................. .................. 22 1.4.6 Estimations offire cycle with the burn rate .... ..................................................... 24 1.4.7 Regionalisation and comparison offire cycle based on survival analysis ........... 24 1.4.8 Explaining spatial variation in fi re cycle at regional scale ................................... 25 1.5.1 Results .. .................. .............................................................................................. 26 1.5.1 SDD fire cycle at the broad scale ......................................................................... 26 1.5 .2 Fi re cycle for the different region .......................................................................
Load more

Recommended publications
  • Ribbed Bedforms in Palaeo-Ice Streams Reveal Shear Margin
    https://doi.org/10.5194/tc-2020-336 Preprint. Discussion started: 21 November 2020 c Author(s) 2020. CC BY 4.0 License. Ribbed bedforms in palaeo-ice streams reveal shear margin positions, lobe shutdown and the interaction of meltwater drainage and ice velocity patterns Jean Vérité1, Édouard Ravier1, Olivier Bourgeois2, Stéphane Pochat2, Thomas Lelandais1, Régis 5 Mourgues1, Christopher D. Clark3, Paul Bessin1, David Peigné1, Nigel Atkinson4 1 Laboratoire de Planétologie et Géodynamique, UMR 6112, CNRS, Le Mans Université, Avenue Olivier Messiaen, 72085 Le Mans CEDEX 9, France 2 Laboratoire de Planétologie et Géodynamique, UMR 6112, CNRS, Université de Nantes, 2 rue de la Houssinière, BP 92208, 44322 Nantes CEDEX 3, France 10 3 Department of Geography, University of Sheffield, Sheffield, UK 4 Alberta Geological Survey, 4th Floor Twin Atria Building, 4999-98 Ave. Edmonton, AB, T6B 2X3, Canada Correspondence to: Jean Vérité ([email protected]) Abstract. Conceptual ice stream landsystems derived from geomorphological and sedimentological observations provide 15 constraints on ice-meltwater-till-bedrock interactions on palaeo-ice stream beds. Within these landsystems, the spatial distribution and formation processes of ribbed bedforms remain unclear. We explore the conditions under which these bedforms develop and their spatial organisation with (i) an experimental model that reproduces the dynamics of ice streams and subglacial landsystems and (ii) an analysis of the distribution of ribbed bedforms on selected examples of paleo-ice stream beds of the Laurentide Ice Sheet. We find that a specific kind of ribbed bedforms can develop subglacially 20 from a flat bed beneath shear margins (i.e., lateral ribbed bedforms) and lobes (i.e., submarginal ribbed bedforms) of ice streams.
    [Show full text]
  • May Be Xeroxed
    CENTRE FOR NEWFOUNDLAND STUDIES TOTAL OF 10 PAGES ONLY MAY BE XEROXED (Without Author's Permiss•on) ,. (J Contemporary Frontal Moraine Formation in the Yoho Valley , Br~tish Columbia . b y Martin J. Batterson B.A. (Hens.) , University of Wales, l978 A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of ~aster of Science . Departmen~ of Geography ~emorial Unlversity or Newroundland 1980 Abstract The northern terminus or Emerald Glacier (510 3 l' N, 116 0 32 ' W) in the Yoho Valley , British Columbia was bordered by a small , actively forming frontal moraine during summer 1979 . Strati- graphic and morphological contrasts existed r ound the ice front , which primarily resulted from a contrast in the distribution of supraglacial debris . Sedimentological and geotechnical techniques were utilised to determine the origin of stratigraphic units within the moraine ridge . Moraine A, at the margin of heavily debris covered ice , exhibited a complex stratigraphy. At most sites a lens of subglacially derived till was evident , between units of supra- glacially derived material . It is proposed that the moraine forming process involved the initial development of an ice- front talus apron , which was subsequently pushed and over- ridden . A plastic subglacial till was squeezed from beneath the supra- morainal ice margin , and overlain by a sorted supraglacial unit during glacier retreat . The moraine was actively advancing during the field season due to the main- tenance of glacier- moraine contact resulting rrom the retardation of ice- melt afforded by the supraglacial debris co':er . Moraine B is located at the margin or debris-free ice .
    [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]
  • Quaternary Geology of Manitoba: Digital Compilation of Point and Line Data, with Updating of the Dataset Using Remotely Sensed (SPOT) Imagery by M.S
    GS-18 Quaternary geology of Manitoba: digital compilation of point and line data, with updating of the dataset using remotely sensed (SPOT) imagery by M.S. Trommelen, G.R. Keller and B.K. Lenton Trommelen, M.S., Keller, G.R. and Lenton, B.K. 2012: Quaternary geology of Manitoba: digital compilation of point and line data, with updating of the dataset using remotely sensed (SPOT) imagery; in Report of Activities 2012, Manitoba Innovation, Energy and Mines, Manitoba Geological Survey, p. 189–193. Summary in Manitoba at the most detailed The aim of this project is to provide an up-to-date scales available, along with a digital compilation of historic and new ice-flow and database index of metadata, has geomorphic data to better assist drift prospecting, land-use been completed (Figure GS-18-1). Tables GS-18-1 and and research projects in Manitoba. Current objectives of -2 provide a list of the included line and point features. the project are to compile data, complete quality control, Line features are digitized to scale, whereas points update with high-resolution remote-sensing imagery represent features occurring at a site but are not to scale. (SPOT1) and digitized aerial photographs, and augment Because this is a compilation, not all original data—such with newly acquired field data. as site numbers, striae characteristics (type, position, abundance) and fossil radiocarbon lab numbers—are Introduction preserved. Instead, the compiled database will serve as a Up-to-date, queryable surficial geological data are guide and the reader will be referred to the original maps essential for the successful interpretation of ice flow and publications for more information.
    [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]
  • Palaeo-Ice Stream Pathways and Retreat Style in the Easternmost Amundsen Sea Embayment, West Antarctica, Revealed by Combined Multibeam Bathymetric and Seismic Data
    ÔØ ÅÒÙ×Ö ÔØ Palaeo-ice stream pathways and retreat style in the easternmost Amundsen Sea Embayment, West Antarctica, revealed by combined multibeam bathymetric and seismic data J.P. Klages, G. Kuhn, A.G.C. Graham, C.-D. Hillenbrand, J.A. Smith, F.O. Nitsche, R.D. Larter, K. Gohl PII: S0169-555X(15)30004-0 DOI: doi: 10.1016/j.geomorph.2015.05.020 Reference: GEOMOR 5226 To appear in: Geomorphology Received date: 20 January 2015 Revised date: 19 May 2015 Accepted date: 21 May 2015 Please cite this article as: Klages, J.P., Kuhn, G., Graham, A.G.C., Hillenbrand, C.- D., Smith, J.A., Nitsche, F.O., Larter, R.D., Gohl, K., Palaeo-ice stream pathways and retreat style in the easternmost Amundsen Sea Embayment, West Antarctica, re- vealed by combined multibeam bathymetric and seismic data, Geomorphology (2015), doi: 10.1016/j.geomorph.2015.05.020 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. ACCEPTED MANUSCRIPT Palaeo-ice stream pathways and retreat style in the easternmost Amundsen Sea Embayment, West Antarctica, revealed by combined multibeam bathymetric and seismic data J.P. Klages a,*, G. Kuhn a, A.G.C.
    [Show full text]
  • Rogen Moraine: an Example of Glacial Reshaping of Pre-Existing Landforms
    ARTICLE IN PRESS Quaternary Science Reviews 25 (2006) 362–389 Rogen moraine: an example of glacial reshaping of pre-existing landforms Per Mo¨llerà GeoBiosphere Science Centre/Quaternary Sciences, Lund University, So¨lvegatan 12, SE-22362 Lund, Sweden Received 23 May 2004; accepted 19 January 2005 Abstract Rogen moraine is widely distributed in the core areas of the former Scandinavian and Laurentide ice sheets. It is generally agreed upon that these gently arched, ice-flow transverse ridges can be used in reconstructions of paleo-ice-flow patterns and that they indicate a melted-bed or poly-thermal basal ice regime. However, the processes of ridge generation have been contentious. This study proposes a two-stage formation of Rogen moraine, based on detailed sedimentological and structural investigations in excavated trenches in a Rogen moraine landscape in the province of Dalarna, central Sweden. Field data suggest that Rogen moraine ridges are the reshaped remains of pre-existing transverse moraine ridges, originally deposited from ice-cored moraines in an ice-marginal zone. Due to back- and down-wasting of ice-cores, inter-ridge troughs were filled with debris flow and fluvial deposits, which after landscape inversion were transformed to areas of transverse and hummocky moraines. It is proposed that this primary landscape formation occurred during an Early Weichselian deglaciation. This relict landscape was later preserved beneath cold-based Mid- to Late-Weichselian ice sheet(s), which turned wet-based during the Preboreal deglaciation phase and re-moulded the precursor landforms into Rogen moraine. r 2005 Elsevier Ltd. All rights reserved. 1. Introduction transition to drumlins (Lundqvist, 1969, 1989), some- times with streamlined moraine hummocks in between Rogen moraine forms one of the most conspicuous the end-member landforms.
    [Show full text]
  • Geology Colloquium Glacial Deposits
    Geology Colloquium Thursday, April 12th, Dr. Mark Abbot, Univ. of Pitt The Holocene Environmental History of the Central Andes from Lakes and Glaciers 4:00 pm in Room 310 White Hall. Refreshments will be available at 3:45 PM. Everybody is welcome! Glacial Deposits • Lodgement Till • Ablation Till • Flow Till Form a Committee and see what you get… Till Genesis: Till Work Group 1977-82 Report (Dreimanis) Till Subglacial Till Supraglacial Till Sub- Melt- aqueous & Out & Subaerial Sublim Mass- ation Movement Till Till (Flow Till) Melt-Out Till Melt-Out Lodgement Till Deformation Till Mass-Movement Till Mass-Movement Key: Subaquatic Till Melt-Out Ortho- Till Allo-Till 1 Till - a Type of Glacial Sediment Basal till from the last major glaciation ~ 18,000 years ago; Loch Torridon, Scotland. M. J. Hambrey photo. http://www.swisseduc.ch/glaciers/glossary/till-en.html Glacier-Till Contact, Iceland Photo by Tom Lowell 2 Striated Boulder, Hargraves Glacier, B.C. Photo by Tom Lowell Striated Boulder, Solheimajokull, Iceland. Photo by Tom Lowell Largest Erratic in Maine MAINE DEPARTMENT OF CONSERVATION PHOTO http://www.state.m e.us/doc/nrimc/pu bedinf/photogal/su rfical/surfphot.htm 3 DEPOSITIONAL LANDFORMS COMPOSED OF TILL: • Moraines = Ice-Marginal Positions Image from Judson L. Ahern http://dynamic.ou.edu/notes/glaciers/moraines.jpg Alpine Moraines Moraine = Landform on Margins of Glacier Lateral Moraine Medial Moraine End Moraine Medial Moraines 4 Photo by Tom Lowell Moraine System, Sierra Nevada, California Massive Lateral & End Moraines New Zealand Photo by Tom Lowell 5 End Moraines Terminal Moraine Recessional Moraines Athabaska Glacier, Alberta Moraine from “Continental” Glaciers: Iceland Photo by Tom Lowell http://www.state .me.us/doc/nrim 700c/pubedinf/facts m ht/bedrock/meg eol.htm Basin Ponds Moraine <60 m Mt.
    [Show full text]
  • Alphabetical Glossary of Geomorphology
    International Association of Geomorphologists Association Internationale des Géomorphologues ALPHABETICAL GLOSSARY OF GEOMORPHOLOGY Version 1.0 Prepared for the IAG by Andrew Goudie, July 2014 Suggestions for corrections and additions should be sent to [email protected] Abime A vertical shaft in karstic (limestone) areas Ablation The wasting and removal of material from a rock surface by weathering and erosion, or more specifically from a glacier surface by melting, erosion or calving Ablation till Glacial debris deposited when a glacier melts away Abrasion The mechanical wearing down, scraping, or grinding away of a rock surface by friction, ensuing from collision between particles during their transport in wind, ice, running water, waves or gravity. It is sometimes termed corrosion Abrasion notch An elongated cliff-base hollow (typically 1-2 m high and up to 3m recessed) cut out by abrasion, usually where breaking waves are armed with rock fragments Abrasion platform A smooth, seaward-sloping surface formed by abrasion, extending across a rocky shore and often continuing below low tide level as a broad, very gently sloping surface (plain of marine erosion) formed by long-continued abrasion Abrasion ramp A smooth, seaward-sloping segment formed by abrasion on a rocky shore, usually a few meters wide, close to the cliff base Abyss Either a deep part of the ocean or a ravine or deep gorge Abyssal hill A small hill that rises from the floor of an abyssal plain. They are the most abundant geomorphic structures on the planet Earth, covering more than 30% of the ocean floors Abyssal plain An underwater plain on the deep ocean floor, usually found at depths between 3000 and 6000 m.
    [Show full text]
  • The Morphology and Sedimentological Analyses of Rogen Moraines, Central Avalon Peninsula, Newfoundland
    Current Research (2005) Newfoundland and Labrador Department of Natural Resources Geological Survey, Report 05-1, pages 1-14 THE MORPHOLOGY AND SEDIMENTOLOGICAL ANALYSES OF ROGEN MORAINES, CENTRAL AVALON PENINSULA, NEWFOUNDLAND A. Marich, M. Batterson1 and T. Bell Department of Geography, Memorial University of Newfoundland ABSTRACT This study examines the morphology and sedimentology of Rogen moraines that occupy an area of approximately 160 km2 in the central Avalon Peninsula, Newfoundland. Moraine morphology is described using a digital-elevation model created for about 40 km2 of the study area. A preliminary review of this model indicates that there are at least three landform types pres- ent within the study area. These are, Rogen moraine, hummocky terrain, and large-scale streamlined bedforms. A distinct northeast–southwest trend to the landscape morphology is likely a result of the underlying bedrock structure. Moraine sedi- mentology including clast fabrics, lithology, angularity and sedimentary structures are described using the available expo- sures. It appears likely that the central Avalon Rogen moraines were formed by northeastward-flowing, warm-based ice. The local sediment provenance and sedimentary structures suggest that the moraines were formed subglacially. Clast-fabric data suggest that the sediment was re-deposited by sediment gravity flows. Further analysis and study of the digital elevation model, field data and air photos will be required before formative processes for the central Avalon Rogen moraine can be pro- posed. INTRODUCTION charges (Shaw, 1983, 2002). Although the various mecha- nisms for the formation of Rogen moraines are discussed Rogen moraines are subglacial landforms composed of later, the depositional history of the moraine has important discontinuous, subparallel to parallel ridges oriented trans- implications for i) ice-flow history of the study area and gla- verse to the glacial flow (Lundqvist, 1969).
    [Show full text]
  • Glacial Deposition Landforms What You Need to Know C
    Glaciated Landscapes Glacial deposition landforms What you need to know c. Transport and deposition i. Processes of glacial and fluvioglacial transport including supraglacial, englacial and sub glacial transfers and their resultant sediment characteristics (size, shape and sorting) ii. Landforms and landscapes of glacial deposition including types of till (ablation, lodgement and deformation) and types of moraine (terminal, recessional, lateral, medial and push) and drumlins iii. Processes of fluvioglacial transport and deposition lead to ice-contact features both for and beyond the UK including eskers, kames, kame terraces iv. proglacial features including sandurs, varves, kettle holes and kettle lakes Glacial Transport How might sediment come to be on top of the glacier (supraglacial)? Glaciers ‘pick up’ (or entrain) sediment subglacially…how? How can subglacial and supraglacial sediment become incorporated into the body of the glacier (englacial)? What happens to sediment as it transported by a glacier? How is this different depending on where the sediment is in the glacier? Glacial Transport Moraine – general term for material transported or deposited by glaciers Lateral moraines – sediment accumulations along the sides of the glacier Where two valley glaciers meet, the two inside lateral moraines join to become a medial moraine. Large valley glaciers can have many medial moraines: Aletsch glacier, Switzerland Glacial Transport Basal moraine – sediment transported subglacially at the ice bed: Leverett Glacier, Western Greenland Glacial Deposition …happens in two main ways: 1. Lodgement Subglacial sediment becomes stuck or lodged in the ice bed when… • friction between debris and rock bed > between debris and ice (caused when more pressure exerted as ice thickens, or where water pressure in sediment decreases making it ‘stickier’) • the glacier slows down Can occur during glacier advance or retreat 2.
    [Show full text]
  • British Geological Survey Annual Report 2008–09
    Navigation Annual2008–09 Report HOW TO NAVIGATE THIS DOCUMENT Bookmarks The main items in the table of contents are bookmarked allowing you to move directly to any article from any other part of the document. The Annual Report is contents page driven. Where there is a double-page article, click on the banner headline to go to the second page. In addition, the Annual Report contains links from each page number back to the contents page. British Geological Survey Annual Report 2008–09 Some research reported here may not yet have been peer-reviewed or published. Cover: The atrium of the new William Smith Building at Keyworth. BGS © NERC (Photographer: Paul Witney, P710841). Unless otherwise stated, © NERC 2009. All rights reserved. Copyright in materials derived from the British Geological Survey’s work is owned by the Natural Environment Research Council (NERC) and/or the authority that commissioned the work. You many not copy or adapt this publication without first obtaining NERC permission. Contact the BGS Intellectual Property Rights Manager, British Geological Survey, Keyworth. You may quote extracts of a reasonable length without prior permission, provided a full acknowledgement is given of the source of the extract. Figures within this report may use Ordnance Survey topography material with the permission of Ordnance Survey on behalf of The Controller of Her Majesty’s Stationery Office. © Crown Copyright. Unauthorised reproduction infringes Crown Copyright and may lead to prosecution or civil proceedings. Licence Number: 100017897/2009. Bibliographical reference BRITISH GEOLOGICAL SURVEY, 2009. Annual Report of the British Geological Survey 2008–2009. (Nottingham: British Geological Survey).
    [Show full text]