DOCSLIB.ORG

Integrated Acoustic and Coring Investigation of Glacigenic Deposits in Spitsbergen Fjords

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Integrated Acoustic and Coring Investigation of Glacigenic Deposits in Spitsbergen Fjords Integrated acoustic and coring investigation of glacigenic deposits in Spitsbergen fjords Liv Plassen, Tore O. Vorren & Matthias Forwick In many areas of Svalbard, the Neoglacial terminal deposits represent the Holocene glacial maximum. The glaciers began the retreat from their Neoglacial maximum positions around 1900 AD. Based on high reso- lution acoustic data and sediment cores, sedimentation patterns in four tidewater glacier-infl uenced inlets of the fjord Isfjorden (Tempel fjorden, Billefjorden, Yoldiabukta and Borebukta), Spitsbergen, were inves- tigated. A model for sedimentation of tidewater glaciers in these High Arctic environments is proposed. Glacigenic deposits occur in proximal and distal basins. The proximal basins comprise morainal ridges and hummocky moraines, bounded by terminal moraines marking the maxi- mum Neoglacial ice extent. The distal basins are characterized by debris lobes and draping stratifi ed glacimarine sediments beyond, and to some extent beneath and above, the lobes. The debris lobe in Tempelfjorden is composed of massive clayey silt with scattered clasts. Distal glacimarine sediments comprise stratifi ed clayey silt with low ice-rafted debris (IRD) content. The average sedimentation rate for the glacimarine sediments in Tempelfjorden is 17 mm/yr for the last ca. 130 years. It is suggested that the stratifi ed sediments in Tempelfjorden are glacimarine varves. The high sedimentation rate and low IRD content are explained by input from rivers, in addition to sedimentation from suspension of glacial meltwater. The debris lobes in Borebukta are composed of massive clayey silt with high clast content. Distal glacimarine sediments in Yoldiabukta comprise clayey silt with high IRD content. The average sedimentation rate for these sediments is 0.6 mm/yr for the last 2300 years. L. Plassen, Norwegian Geological Survey, Polar Environmental Centre, NO-9296 Tromsø, Norway, liv. [email protected]; T. O. Vorren & M. Forwick, Dept. of Geology, University of Tromsø, NO-9037 Tromsø, Norway. This paper concerns the sedimentary processes many of them surge (Liestøl 1969; Jiskoot et al. and products associated with four tidewater gla- 2000). Environmental factors controlling surges cier-dominated inlets of the fjord Isfjorden, Spits- are not fully understood, and advances related to bergen: Tempelfjorden, Billefjorden, Yoldiabuk- surges are not necessarily climatically induced ta and Borebukta (Fig. 1). The study is based on (e.g. Hamilton & Dowdeswell 1996). high resolution acoustic data and sediment cores. The inner parts of Isfjorden were deglaciat- About 60 % of the Svalbard archipelago is cov- ed around 10 14C Kya (thousands of radiocarbon ered by glaciers, many of which terminate in years ago) (Svendsen et al. 1996). During the early fjords as tidewater glaciers. Most of the present and mid-Holocene, the inner parts of Is fjorden Svalbard glaciers are referred to as polythermal were probably not infl uenced by tidewater gla- (Hagen et al. 1993; Hambrey et al. 1999), and ciers (Svendsen & Mangerud 1997). The Neogla- Plassen et al.: Polar Research 23(1), 89–110 89 Fig. 1. (a, b) Location maps. (c) Map of the Isfjorden area. Boxes refer to study areas. cial major readvance of the glaciers commenced water and sediment to the Spitsbergen fjord sys- during the late Holocene, about 4 14C Kya (Svend- tems (Dowdes well 1989). Stratifi ed, draping sed- sen & Mangerud 1997), culminating in maximum iments, 10 - 20 m thick, are present in the main glacier extents at different times (Werner 1993; fjord basins (Elverhøi et al. 1995). Glacimarine Svendsen & Mangerud 1997; Huddart & Ham- environments are commonly characterized by brey 1996). Expedition charts (De Geer 1910) stratifi ed sediments (as discussed by Ó Cofaigh & and moraines mapped from aerial photographs Dowdeswell 2001). These include varves, which show marked glacier retreat in Isfjorden during refl ect seasonal changes in deposition (e.g. Elver- the 20th century. In the Isfjorden area, prominent høi et al. 1980; Cowan et al. 1997; Stevens 1990; distal sediment wedges of > 40 m thickness mark Gilbert 2003) and, for example, tidal rhythmites the terminal moraines deposited during the max- refl ecting more rapid variations (e.g. Mackiewicz imum glacier extent of the Neoglacial (Elverhøi et al. 1984; Powell & Molnia 1989; Cowan et al. et al. 1995). These authors have mapped a sedi- 1999; Gilbert et al. 2002). ment volume of 22.5 km3 that has accumulated Models for the evolution of marine ice-contact in Is fjorden since the deglaciation, i.e. during the fans and deltas have been proposed by several last 13 14C Ky (thousands of radiocarbon years). authors (e.g. Boulton 1986; Powell 1990; Lønne Subglacial meltwater streams, as well as 1995; Lyså & Vorren 1997). However, little atten- calved icebergs provide the main sources of tion has been paid to the landforms and sediment 90 Investigation of glacigenic deposits in Spitsbergen fjords assemblages that result from the rapid advance of data, acquired in 1998. The total profi ling dis- tidewater glaciers, either due to a surge, or simply tance of the acoustic data was 190 km. The acous- as a result of the non-climatic ice-marginal fl uc- tic system consisted of: (a) 10 kW hull-mounted tuations common to tidewater glaciers (Warren Geoacoustic/Ferranti O.R.E. 3.5 kHz penetration 1992). echo sounder (bandpass fi lter setting 3 - 5 kHz); The seismic character can be interpreted in (b) 300 J O.R.E. Model 5813A boomer (band- terms of the processes infl uencing deposition in pass fi lter setting 500-1500 Hz); (c) 800 J Bennex the fjord complex and the known history of tide- multi-electrode sparker (bandpass fi lter setting water glacier fl uctuations (Sexton et al. 1992). The 150 - 700 Hz); (d) 100 kHz O.R.E. side-scan sonar. aim of our study is to evaluate the sedimentary A single channel Fjord Instruments streamer was systems of the four tidewater glacier-infl uenced used as the receiver for (b) and (c). inlets Tempelfjorden, Billefjorden, Yoldiabukta The seismic interpretation is based on later- and Borebukta (Fig. 1), and to propose a model ally persistent high amplitude refl ections that for glacigenic sedimentation of surging and non- defi ne boundaries between acoustic units. Acous- surging tidewater glaciers in a High Arctic envi- tic attributes, bedding style and geometry give ronment. Furthermore, we briefl y discuss the information about sediment properties, deposi- chronology of Holocene glacier advances. tional processes and environments (e.g. Syvit- All these inlets are tributaries to Isfjorden, ski & Praeg 1989), and the intensity of the grey which is the largest fjord in western Spits bergen tone between refl ections determines the degree (Fig. 1). It has a length of 100 km and a maximum of acoustic transparency on the 3.5 kHz records depth of 425 m. The catchment area is 7309 km2, (King 1967). of which 40 % is covered by glaciers (Hagen et When the sediment thickness in metres is men- al. 1993). Tidewater glaciers occur in the north- tioned, it is calculated from an assumed acoustic ern and eastern branches of Isfjorden (Fig. 1). The velocity of 1700 m/s. This was chosen as an aver- glacier termini are grounded (Dowdeswell et al. age from measured values of about 1600 m/s for 1984). surge-distal sediments, and about 1800 m/s for surge moraines (Solheim 1991). Autocad 13 soft- ware, with the surface modelling system Quick- Material and methods Surf 5.2, was used to estimate sediment volumes and areas. This study was based on high resolution acoustic Four gravity cores were recovered in 1997 and data (seismic and side-scan sonar) and sediment 1998 (Table 1). The gravity corer had a weight of cores collected from the University of Tromsø’s 1600 kg and an inner diameter of 11 cm. Labora- research vessel the Jan Mayen, using a Global tory analysis included Multi-sensor core-logging, Positioning System for navigation. Bathymetric interpretation of X-radiographs, visual descrip- data collected by the Norwegian Hydrograph- tion (using Munsell Soil Color Chart), determi- ic Offi ce, as well as topographic maps and aerial nation of water content, shear strength and car- photographs from the Norwegian Polar Institute bonate content, as well as grain size analysis were used. (wet-sieving and Sedigraph). Bivalves from core The acoustic data included 3.5 kHz and spark- JM98-812 were sampled for accelerator mass er profi les, acquired in 1997, and 3.5 kHz and spectrometry (AMS) radiocarbon age determina- boomer profi les, in addition to side-scan sonar tion. The samples were prepared at the Radiolog- ical Dating Laboratory in Trondheim, Norway, and the measurements were carried out at the T. Table 1. Locations, sampling depths and core lengths of the Svedborg Laboratory in Uppsala, Sweden. Radi- sediment cores. ocarbon ages were corrected for a reservoir effect equal to 440 years (Mangerud & Gulliksen 1975). Core iden- Latitude Longitude Water depth Core length tifi cation (N) (E) (m) (cm) The dates were calibrated using the 1998 marine calibration dataset with ∆R = 491 ± 24 (Stuiver et JM97-937 78°25.01' 17°09.40' 66 318 al. 1986; Stuiver et al. 1998). JM97-938 78°24.80' 17°07.05' 76 415 JM98-812 78°28.43' 14°40.65' 78 197 JM98-816 78°20.52' 14°30.09' 71 200 Plassen et al.: Polar Research 23(1), 89–110 91 Results horizontal couplets of reddish brown and dark to very dark greyish brown clayey silt with scattered Tempelfjorden clasts. The thickness of the individual couplets varies from ca. 2 mm to 50 mm. The boundaries The tidewater glacier Tunabreen (north) and the between the couplets are predominantly grada- land-based glacier Von Postbreen (south) merge tional. Black mottles (< 5 mm diameter) are scat- at the head of Tempelfjorden (Figs. 1, 2a). A surge tered throughout the whole unit.
Load more

Recommended publications
  • Introduction to Geological Process in Illinois Glacial
    INTRODUCTION TO GEOLOGICAL PROCESS IN ILLINOIS GLACIAL PROCESSES AND LANDSCAPES GLACIERS A glacier is a flowing mass of ice. This simple definition covers many possibilities. Glaciers are large, but they can range in size from continent covering (like that occupying Antarctica) to barely covering the head of a mountain valley (like those found in the Grand Tetons and Glacier National Park). No glaciers are found in Illinois; however, they had a profound effect shaping our landscape. More on glaciers: http://www.physicalgeography.net/fundamentals/10ad.html Formation and Movement of Glacial Ice When placed under the appropriate conditions of pressure and temperature, ice will flow. In a glacier, this occurs when the ice is at least 20-50 meters (60 to 150 feet) thick. The buildup results from the accumulation of snow over the course of many years and requires that at least some of each winter’s snowfall does not melt over the following summer. The portion of the glacier where there is a net accumulation of ice and snow from year to year is called the zone of accumulation. The normal rate of glacial movement is a few feet per day, although some glaciers can surge at tens of feet per day. The ice moves by flowing and basal slip. Flow occurs through “plastic deformation” in which the solid ice deforms without melting or breaking. Plastic deformation is much like the slow flow of Silly Putty and can only occur when the ice is under pressure from above. The accumulation of meltwater underneath the glacier can act as a lubricant which allows the ice to slide on its base.
    [Show full text]
  • Landtype Associations (Ltas) of the Northern Highland Scale: 1:650,000 Wisconsin Transverse Mercator NAD83(91) Map NH3 - Ams
    Landtype Associations (LTAs) of the Northern Highland Scale: 1:650,000 Wisconsin Transverse Mercator NAD83(91) Map NH3 - ams 212Xb03 212Xb03 212Xb04 212Xb05 212Xb06 212Xb01 212Xb02 212Xb02 212Xb01 212Xb03 212Xb05 212Xb03 212Xb02 212Xb 212Xb07 212Xb07 212Xb01 212Xb03 212Xb05 212Xb07 212Xb08 212Xb03 212Xb07 212Xb07 212Xb01 212Xb01 212Xb07 Landtype Associations 212Xb01 212Xb01 212Xb02 212Xb03 212Xb04 212Xb05 This map is based on the National Hierarchical Framework of Ecological Units 212Xb06 (NHFEU) (Cleland et al. 1997). 212Xb07 The ecological landscapes used in this handbook are based substantially on 212Xb08 Subsections of the NHFEU. Ecological landscapes use the same boundaries as NHFEU Sections or Subsections. However, some NHFEU Subsections were combined to reduce the number of geographical units in the state to a manageable Ecological Landscape number. LTA descriptions can be found on the back page of this map. County Boundaries 0 2.75 5.5 11 16.5 22 Miles Sections Kilometers Subsections 0 4 8 16 24 32 Ecological Landscapes of Wisconsin Handbook - 1805.1 WDNR, 2011 Landtype Association Descriptions for the Northern Highland Ecological Landscape 212Xb01 Northern Highland Outwash The characteristic landform pattern is undulating pitted and unpitted Plains outwash plain with swamps, bogs, and lakes common. Soils are predominantly well drained sandy loam over outwash. Common habitat types include forested lowland, ATM, TMC, PArVAa and AVVb. 212Xb02 Vilas-Oneida Sandy Hills The characteristic landform pattern is rolling collapsed outwash plain with bogs common. Soils are predominantly excessively drained loamy sand over outwash or acid loamy sand debris flow. Common habitat types include PArVAa, ArQV, forested lowland, AVVb and TMC. 212Xb03 Vilas-Oneida Outwash Plains The characteristic landform pattern is nearly level pitted and unpitted outwash plain with bogs and lakes common.
    [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]
  • A Glacier Runs Through It: Effects of Late Wisconsinan Glaciation on Stream Drainage Near the Terminal Moraine Boundary in North Central Pennsylvania
    University of Pennsylvania ScholarlyCommons Master of Environmental Studies Capstone Department of Earth and Environmental Projects Science May 2008 A Glacier Runs Through It: Effects of Late Wisconsinan Glaciation on Stream Drainage Near the Terminal Moraine Boundary in North Central Pennsylvania Krista Heinlen University of Pennsylvania, [email protected] Follow this and additional works at: https://repository.upenn.edu/mes_capstones Heinlen, Krista, "A Glacier Runs Through It: Effects of Late Wisconsinan Glaciation on Stream Drainage Near the Terminal Moraine Boundary in North Central Pennsylvania" (2008). Master of Environmental Studies Capstone Projects. 21. https://repository.upenn.edu/mes_capstones/21 Presented to the Faculties of the University of Pennsylvania in Partial Fulfillment of the Requirements for the Degree of Master of Environmental Studies 2007. This paper is posted at ScholarlyCommons. https://repository.upenn.edu/mes_capstones/21 For more information, please contact [email protected]. A Glacier Runs Through It: Effects of Late Wisconsinan Glaciation on Stream Drainage Near the Terminal Moraine Boundary in North Central Pennsylvania Abstract Stream morphology in north central Pennsylvania has been influenced yb the passage of multiple glaciers during the Quaternary period, and most recently by the Late Wisconsinan ice sheet which began to recede just 10,000 years ago. While glaciers can take a heavy erosive toll on the landscape, the Late Wisconsinan and previous glaciers stopped when they reached Pennsylvania, and as such were not as thick and did not cover the ground as long as in regions to the north. This paper examines current morphology in an area along the north central part of the state that contains both glaciated and non-glaciated regions.
    [Show full text]
  • A Glacial-Process Model: the Role of Spatial and Temporal Variations in Glacier Thermal Regime
    A glacial-process model: The role of spatial and temporal variations in glacier thermal regime H. D. MOOERS Department of Geology and Geophysics, 108 Pillsbury Hall and Limnological Research Center, 220 Pillsbury Hall University of Minnesota, Minneapolis, Minnesota 55455 ABSTRACT ucts of glaciation also provide important infor- there are several distinct thermal environments, mation on the physical nature and dynamics of each of which has a dominant set of erosional or Glacial landform assemblages associated the ice. Moran (1971), Clayton and Moran depositional processes. The position and charac- with the retreat of the Rainy and Superior (1974, 1977), and Moran and others (1980) teristics of these zones also vary with time during lobes of the Laurentide Ice Sheet in Minne- used field relationships to reconstruct the glacio- glacial advance and retreat. sota provide a record of spatial and temporal logical conditions necessary for the formation of The glacial sediments and landforms in Min- variations in glaciological processes. The large-scale glaciotectonic features, and they pro- nesota associated with the late Wisconsin St. two lobes advanced contemporaneously to vided a major advance in the understanding of Croix Phase provide a detailed record of the their maximum at the St. Croix moraine. The ice-marginal glacial processes. Mathews (1974) maximum and recessional events of the Superior portion of the moraine formed by the Rainy reconstructed longitudinal profiles of the Lau- and Rainy lobes. During recession, each major lobe is characterized by large frontal outwash rentide Ice Sheet and changed the way subse- lobe broke up into multiple, smaller sublobes, plains, broad ice-stagnation topography, gla- quent researchers have viewed ice lobes along its dynamically independent from one another.
    [Show full text]
  • Glacial Terminology
    NRE 430 / EEB 489 D.R. Zak 2003 Lab 1 Glacial Terminology The last glacial advance in Michigan is known as the Wisconsin advance. The late Wisconsin period occurred between 25,000 and 10,000 years ago. Virtually all of Michigan's present surface landforms were shaped during this time. A. Glacial Materials Glacial Drift: material transported and deposited by glacial action. Note that most glacial features are recessional, i.e., they are formed by retreating ice. Materials deposited during glacial advance are usually overridden and destroyed or buried before the glacier has reached its maximum. Till: unstratified drift (e.g., material not organized into distinct layers), ice-transported, highly variable, may consist of any range of particles from clay to boulders. Ice-deposited material is indicated by random assemblage of particle sizes, such as clay, sand and cobbles mixed together. Ice-worked material is indicated by sharp-edged or irregular shaped pebbles and cobbles, formed by the coarse grinding action of the ice. Outwash: stratified drift (e.g., material organized into distinct horizontal layers or bands), water-transported, consists mainly of sand (fine to coarse) and gravel rounded in shape. Meltwater streams flowing away from glacier as it recedes carries particles that are sorted by size on deposition dependent upon the water flow velocity – larger particles are deposited in faster moving water. Water-deposited material is indicated by stratified layers of different sized sand particles and smooth rounded pebbles, consistent in size within each band. Water-worked material is indicated by smooth, rounded particles, formed by the fine grinding action of particles moved by water.
    [Show full text]
  • Geologic Site of the Month: Maine's Glacial Moraines: Living on the Edge
    Maine's Glacial Moraines: Living on the Edge Maine Geological Survey Maine Geologic Facts and Localities January, 2000 Maine's Glacial Moraines: Living on the Edge Text by Woodrow Thompson Maine Geological Survey, Department of Agriculture, Conservation & Forestry 1 Maine's Glacial Moraines: Living on the Edge Maine Geological Survey Introduction Toward the end of the "Ice Age," a glacier of vast proportions covered Maine. This was the Laurentide Ice Sheet, which advanced southward out of Canada about 25,000 years ago and remained here for nearly 15,000 years. The slowly flowing ice was thick enough to cover Maine's highest mountains. It swept away much of the evidence of earlier glaciations, eroding both the bedrock and previously existing sediment cover. Many glacial features that we see today were actually left behind during the final northward retreat of the ice sheet, when the pulverized rock debris was released from the melting ice. Even as the ice margin withdrew, internal flow within the glacier continued to transport its sediment load southward toward the edge of the ice sheet. Through a variety of processes, this dirty material was either released directly from the ice, forming a stony deposit called "till," or washed out of the glacier in meltwater streams. The water-laid sediments were deposited as layered accumulations in river valleys, lake basins, and Maine's coastal lowland. They include the majority of our sand and gravel deposits, and the finer silts and clays commonly found near the coast. Maine Geological Survey, Department of Agriculture, Conservation & Forestry 2 Maine's Glacial Moraines: Living on the Edge Maine Geological Survey Introduction The clearest markers of glacial retreat are ridges of sediment called "end moraines," which will be referred to here as simply "moraines" (Figure 1).
    [Show full text]
  • Kettle Moraine State Forest T Glenbeulah Northern Unit Glen Rd
    to Elkhart Lake CCC C C P Kettle Moraine State Forest T Glenbeulah Northern Unit Glen Rd. Camp Evelyn Rd. Sugarbush Rd. Designated Trails and Public Use Areas Old Wade House State Historic Site 23 A . d R S e g d i P . R Rd to Center Rd. nk Pla Fond du Lac Greenbush 23 23 to Plymouth G . r T D Spring Valley Rd. e n i a r A o M . e l d t t R e Mullet Creek K Greenbush Outdoor e g State Group Camp id R Wildlife Area Hill Top Rd. Z Greenbush Greenbush T Trail Area Kettle U ZZ Summit Rd. 5 Graham T Corners Mullet Lk. A to Plymouth Forest Dr. 67 S Watercress Rd. G Dog Training Area (field) U Armstrong 67 Woodside Rd. U V Parnell 4 Trail B Johnson Area Log Cabin Rd. Cabin Log Hill Parnell Tower Glacier Rd. Glacier Clems Rd. Kettle View Rd. Rd. Lane Cedar SHEBOYGAN CO. SHEBOYGAN FOND DU LAC CO. LAC DU FOND Conner Rd. Shamrock Garriety Hill Hill N Scenic Dr. A Chinatown Lakeview Rd. Nichols Creek State Wildlife Mc Mullen Hill Areas Long V Deer Rd. V is ta Lk. Rd. Division Ash Rd. D r . 67 Long Lake Spruce Recreation Parnell Lk. Area Rd. Slatts Rd. Hughview V S . r D Butler P d Butler Lk. R a n d. d. rne to a l l t R Lk. l R d r d. o po A Cascade o ir A Dr. Scenic W Mud Lk. Butler Lake Trail Area Pine Rd.
    [Show full text]
  • Glaciers of the Canadian Rockies
    Glaciers of North America— GLACIERS OF CANADA GLACIERS OF THE CANADIAN ROCKIES By C. SIMON L. OMMANNEY SATELLITE IMAGE ATLAS OF GLACIERS OF THE WORLD Edited by RICHARD S. WILLIAMS, Jr., and JANE G. FERRIGNO U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1386–J–1 The Rocky Mountains of Canada include four distinct ranges from the U.S. border to northern British Columbia: Border, Continental, Hart, and Muskwa Ranges. They cover about 170,000 km2, are about 150 km wide, and have an estimated glacierized area of 38,613 km2. Mount Robson, at 3,954 m, is the highest peak. Glaciers range in size from ice fields, with major outlet glaciers, to glacierets. Small mountain-type glaciers in cirques, niches, and ice aprons are scattered throughout the ranges. Ice-cored moraines and rock glaciers are also common CONTENTS Page Abstract ---------------------------------------------------------------------------- J199 Introduction----------------------------------------------------------------------- 199 FIGURE 1. Mountain ranges of the southern Rocky Mountains------------ 201 2. Mountain ranges of the northern Rocky Mountains ------------ 202 3. Oblique aerial photograph of Mount Assiniboine, Banff National Park, Rocky Mountains----------------------------- 203 4. Sketch map showing glaciers of the Canadian Rocky Mountains -------------------------------------------- 204 5. Photograph of the Victoria Glacier, Rocky Mountains, Alberta, in August 1973 -------------------------------------- 209 TABLE 1. Named glaciers of the Rocky Mountains cited in the chapter
    [Show full text]
  • Submarine Glacial Landforms in Southeast Greenland Fjords Reveal Contrasting Outlet-Glacier Behaviour Since the Last Glacial Maximum C
    EGU2020: Sharing Geoscience Online Submarine glacial landforms in Southeast Greenland fjords reveal contrasting outlet-glacier behaviour since the Last Glacial Maximum C. L. Batchelor 1,2 J. A. Dowdeswell2, E. Rignot3,4, R. Millan3 1 2 3 4 Email: [email protected] 1. We use bathymetric data to investigate the deglacial history of SE Greenland • The SE Greenland margin (Fig. 1), (a) (b) (c) which includes the Julianehåb Ice Cap (JIC), is suggested to have been sensitive to past climatic changes (Bjørk et al., 2012). • Mountainous terrain and a lack of ice-free areas have hitherto largely prevented analysis of the deglacial and Holocene behaviour of SE Greenland’s marine-terminating outlet glaciers. • We use bathymetric data, from NASA’s Oceans Melting Greenland (OMG) mission and from gravity inversion derived from Operation Fig. 1. (a) Map of SE Greenland and major ocean currents. (b) and (c) Maps of the SE Greenland margin Icebridge gravity data (Millan et al., and the Julianehåb Ice Cap (JIC), respectively, showing OMG bathymetric data and the distribution of 2018), to map the distribution of submarine moraines. Background is IBCAO bathymetry (Jakobsson et al., 2012). Yellow circles are submarine moraines (Fig. 1). published 10Be and 14C deglacial ages (Bennike and Björck, 2002; Weidick et al., 2004; Roberts et al., 2008; Larsen et al., 2011; Dyke et al., 2014; Winsor et al., 2014). Adapted from Batchelor et al. (2019). 2. Inner-fjord moraines exist in many SE Greenland fjords (a) b • Major moraine ridges exist in an inner‐fjord (landward third of the fjord length) setting for 26 (~65%) of the surveyed fjords of SE Greenland, including beyond the JIC (Fig.
    [Show full text]
  • 10Be Exposure Age Chronology of the Last Glaciation of the Roháčská Valley in MARK the Western Tatra Mountains, Central Europe
    Geomorphology 293 (2017) 130–142 Contents lists available at ScienceDirect Geomorphology journal homepage: www.elsevier.com/locate/geomorph 10Be exposure age chronology of the last glaciation of the Roháčská Valley in MARK the Western Tatra Mountains, central Europe ⁎ Zbyněk Engela, , Pavel Mentlíkb, Régis Braucherc, Marek Křížeka, Markéta Pluháčkováb, Aster Teamc a Charles University, Faculty of Science, Department of Physical Geography and Geoecology, Albertov 6, 12843 Praha, Czech Republic b University of West Bohemia, Center of Biology, Geoscience and Environmental Education, Klatovská 51, 30619 Plzeň, Czech Republic c Aix Marseille Université, CNRS, IRD, Collége de France, 13545 Aix-en-Provence cedex 4, France ARTICLE INFO ABSTRACT Keywords: 10Be exposure ages from moraines and bedrock sites in the Roháčská Valley provide chronology of the last Quaternary glaciation in the largest valley of the Western Tatra Mts., the Western Carpathians. The minimum apparent Cosmogenic nuclides exposure age of 19.4 ± 2.1 ka obtained for the oldest sampled boulder and the mean age of 18.0 ± 0.8 ka Glaciation chronology calculated for the terminal moraine indicate that the oldest preserved moraine was probably deposited at the Western Tatra Mts. time of the global Last Glacial Maximum (LGM). The age of this moraine coincides with the termination of the Carpathians maximum glacier expansion in other central European ranges, including the adjacent High Tatra Mts. and the Alps. The equilibrium line altitude (ELA) of the LGM glacier in the Roháčská Valley, estimated at 1400–1410 m a.s.l., was 50–80 m lower than in the eastern part of the range, indicating a positive ELA gradient from west to east among the north-facing glaciers in the Tatra Mts.
    [Show full text]
  • Erosion and Glaciers
    Erosion and Glaciers In this lesson you will: 1.4.1 Define the terms outwash plain, terminal moraine, erratic, drumlin, and esker. (k) Continental Glaciers vs. Alpine glaciers Continental glaciers cover parts of continental land masses like Greenland; Alpine glaciers are found high in mountain valleys, above the snow-line. Ice Age Over the last million years, there were at least four major ice ages. Geographers have found evidence to support this theory by drilling into existing ice sheets in Greenland and Antarctica. The last ice age ended about 10 000 years ago. Differences: Alpine/Continental Glaciers Location; Alpine glaciers are only found on mountain tops Continental glaciers are only found at the earth's poles regardless of elevation. Size; Alpine glaciers are smaller compared to Continental glaciers. Similarities: Alpine/Continental Glaciers Both move and cause erosion Both change the landscape Both developed in constantly cold temperatures below freezing. Figure 2.13 on page 34 of your text shows a continental glacier and the the land forms it creates through weathering and deposition. Features of Continental Glaciation Features of Continental Glaciation Outwash plain Terminal Moraine Erratics Drumlins Eskers Outwash plain: like a river Delta; meltwater flowing from a glacier deposits silt like river deltas; silt is deposited in layers; small particles are carried further away; larger particles drop closer to the glacier. Terminal Moraine & Erratics: : Terminal Moraine: heap or ridge of bulldozed gravel that marks the end of the forward motion of a glacier; as a glacier retreats it deposits debris/gravel. Erratics: large boulders that were transported long distances and dropped; they now sit in a region and look very much out- of-place.
    [Show full text]