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Conversion of GISP2-Based Sediment Core Age Models to the GICC05 Extended Chronology
Quaternary Geochronology 20 (2014) 1e7 Contents lists available at ScienceDirect Quaternary Geochronology journal homepage: www.elsevier.com/locate/quageo Short communication Conversion of GISP2-based sediment core age models to the GICC05 extended chronology Stephen P. Obrochta a, *, Yusuke Yokoyama a, Jan Morén b, Thomas J. Crowley c a University of Tokyo Atmosphere and Ocean Research Institute, 227-8564, Japan b Neural Computation Unit, Okinawa Institute of Science and Technology, 904-0495, Japan c Braeheads Institute, Maryfield, Braeheads, East Linton, East Lothian, Scotland EH40 3DH, UK article info abstract Article history: Marine and lacustrine sediment-based paleoclimate records are often not comparable within the early to Received 14 March 2013 middle portion of the last glacial cycle. This is due in part to significant revisions over the past 15 years to Received in revised form the Greenland ice core chronologies commonly used to assign ages outside of the range of radiocarbon 29 August 2013 dating. Therefore, creation of a compatible chronology is required prior to analysis of the spatial and Accepted 1 September 2013 temporal nature of climate variability at multiple locations. Here we present an automated mathematical Available online 19 September 2013 function that updates GISP2-based chronologies to the newer, NGRIP GICC05 age scale between 8.24 and 103.74 ka b2k. The script uses, to the extent currently available, climate-independent volcanic syn- Keywords: Chronology chronization of these two ice cores, supplemented by oxygen isotope alignment. The modular design of Ice core the script allows substitution for a more comprehensive volcanic matching, once it becomes available. Sediment core Usage of this function highlights on the GICC05 chronology, for the first time for the entire last glaciation, GICC05 the proposed global climate relationships during the series of large and rapid millennial stadial- interstadial events. -
Office of Polar Programs
DEVELOPMENT AND IMPLEMENTATION OF SURFACE TRAVERSE CAPABILITIES IN ANTARCTICA COMPREHENSIVE ENVIRONMENTAL EVALUATION DRAFT (15 January 2004) FINAL (30 August 2004) National Science Foundation 4201 Wilson Boulevard Arlington, Virginia 22230 DEVELOPMENT AND IMPLEMENTATION OF SURFACE TRAVERSE CAPABILITIES IN ANTARCTICA FINAL COMPREHENSIVE ENVIRONMENTAL EVALUATION TABLE OF CONTENTS 1.0 INTRODUCTION....................................................................................................................1-1 1.1 Purpose.......................................................................................................................................1-1 1.2 Comprehensive Environmental Evaluation (CEE) Process .......................................................1-1 1.3 Document Organization .............................................................................................................1-2 2.0 BACKGROUND OF SURFACE TRAVERSES IN ANTARCTICA..................................2-1 2.1 Introduction ................................................................................................................................2-1 2.2 Re-supply Traverses...................................................................................................................2-1 2.3 Scientific Traverses and Surface-Based Surveys .......................................................................2-5 3.0 ALTERNATIVES ....................................................................................................................3-1 -
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. -
A Globally Complete Inventory of Glaciers
Journal of Glaciology, Vol. 60, No. 221, 2014 doi: 10.3189/2014JoG13J176 537 The Randolph Glacier Inventory: a globally complete inventory of glaciers W. Tad PFEFFER,1 Anthony A. ARENDT,2 Andrew BLISS,2 Tobias BOLCH,3,4 J. Graham COGLEY,5 Alex S. GARDNER,6 Jon-Ove HAGEN,7 Regine HOCK,2,8 Georg KASER,9 Christian KIENHOLZ,2 Evan S. MILES,10 Geir MOHOLDT,11 Nico MOÈ LG,3 Frank PAUL,3 Valentina RADICÂ ,12 Philipp RASTNER,3 Bruce H. RAUP,13 Justin RICH,2 Martin J. SHARP,14 THE RANDOLPH CONSORTIUM15 1Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO, USA 2Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK, USA 3Department of Geography, University of ZuÈrich, ZuÈrich, Switzerland 4Institute for Cartography, Technische UniversitaÈt Dresden, Dresden, Germany 5Department of Geography, Trent University, Peterborough, Ontario, Canada E-mail: [email protected] 6Graduate School of Geography, Clark University, Worcester, MA, USA 7Department of Geosciences, University of Oslo, Oslo, Norway 8Department of Earth Sciences, Uppsala University, Uppsala, Sweden 9Institute of Meteorology and Geophysics, University of Innsbruck, Innsbruck, Austria 10Scott Polar Research Institute, University of Cambridge, Cambridge, UK 11Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, USA 12Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia, Canada 13National Snow and Ice Data Center, University of Colorado, Boulder, CO, USA 14Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, Canada 15A complete list of Consortium authors is in the Appendix ABSTRACT. The Randolph Glacier Inventory (RGI) is a globally complete collection of digital outlines of glaciers, excluding the ice sheets, developed to meet the needs of the Fifth Assessment of the Intergovernmental Panel on Climate Change for estimates of past and future mass balance. -
Glaciers and Their Significance for the Earth Nature - Vladimir M
HYDROLOGICAL CYCLE – Vol. IV - Glaciers and Their Significance for the Earth Nature - Vladimir M. Kotlyakov GLACIERS AND THEIR SIGNIFICANCE FOR THE EARTH NATURE Vladimir M. Kotlyakov Institute of Geography, Russian Academy of Sciences, Moscow, Russia Keywords: Chionosphere, cryosphere, glacial epochs, glacier, glacier-derived runoff, glacier oscillations, glacio-climatic indices, glaciology, glaciosphere, ice, ice formation zones, snow line, theory of glaciation Contents 1. Introduction 2. Development of glaciology 3. Ice as a natural substance 4. Snow and ice in the Nature system of the Earth 5. Snow line and glaciers 6. Regime of surface processes 7. Regime of internal processes 8. Runoff from glaciers 9. Potentialities for the glacier resource use 10. Interaction between glaciation and climate 11. Glacier oscillations 12. Past glaciation of the Earth Glossary Bibliography Biographical Sketch Summary Past, present and future of glaciation are a major focus of interest for glaciology, i.e. the science of the natural systems, whose properties and dynamics are determined by glacial ice. Glaciology is the science at the interfaces between geography, hydrology, geology, and geophysics. Not only glaciers and ice sheets are its subjects, but also are atmospheric ice, snow cover, ice of water basins and streams, underground ice and aufeises (naleds). Ice is a mono-mineral rock. Ten crystal ice variants and one amorphous variety of the ice are known.UNESCO Only the ice-1 variant has been – reve EOLSSaled in the Nature. A cryosphere is formed in the region of interaction between the atmosphere, hydrosphere and lithosphere, and it is characterized bySAMPLE negative or zero temperature. CHAPTERS Glaciology itself studies the glaciosphere that is a totality of snow-ice formations on the Earth's surface. -
Edges of Ice-Sheet Glaciology
Important Things Ice Sheets Do, but Ice Sheet Models Don’t Dr. Robert Bindschadler Chief Scientist Hydrospheric and Biospheric Sciences Laboratory NASA Goddard Space Flight Center [email protected] I’ll talk about • Why we need models – from a non-modeler • Why we need good models – recent observations have destroyed confidence in present models • Recent ice-sheet surprises • Responsible physical processes “…understanding of (possible future rapid dynamical changes in ice flow) is too limited to assess their likelihood or provide a best estimate or an upper bound for sea level rise.” IPCC Fourth Assessment Report, Summary for Policy Makers (2007) Future Sea Level is likely underestimated A1B IPCC AR4 (2007) Ice Sheets matter Globally Source: CReSIS and NASA Land area lost by 1-meter rise in sea level Impact of 1-meter sea level rise: Source: Anthoff et al., 2006 Maldives 20th Century Greenland Ice Sheet Sea level Change (mm/a) -1 0 +1 accumulation 450 Gt/a melting 225 Gt/a ice flow 225 Gt/a Approximately in “mass balance” 21st Century Greenland Ice Sheet Sea level Change (mm/a) -1 0 +1 accumulation melting ice flow Things could get a little better or a lot worse Increased ice flow will dominate the future rate of change A History Lesson • Less ice in HIGH SEA LEVEL Less warmer ice climates • Ice sheets More shrink faster LOW ice than they TEMPERATURE WARM grow • Sea level change is not COLD THEN NOW smooth Time Decreasing Mass Balance (Source: Luthcke et al., unpub.) Greenland Ice Sheet Mass Balance GREENLAND (Source: IPCC FAR) Antarctic Ice Sheet Mass Balance ANTARCTICA (Source: IPCC FAR) Pace of ice sheet changes have astonished experts is the common agent behind these changes Ice sheets HATE water! Fastest Flow at the Edges Interior: 1000’s meters thick and slow Perimeter: 100’s meters thick and fast Source: Rignot and Thomas Response time and speed of perturbation propagation are tied directly to ice flow speed 1. -
Ilulissat Icefjord
World Heritage Scanned Nomination File Name: 1149.pdf UNESCO Region: EUROPE AND NORTH AMERICA __________________________________________________________________________________________________ SITE NAME: Ilulissat Icefjord DATE OF INSCRIPTION: 7th July 2004 STATE PARTY: DENMARK CRITERIA: N (i) (iii) DECISION OF THE WORLD HERITAGE COMMITTEE: Excerpt from the Report of the 28th Session of the World Heritage Committee Criterion (i): The Ilulissat Icefjord is an outstanding example of a stage in the Earth’s history: the last ice age of the Quaternary Period. The ice-stream is one of the fastest (19m per day) and most active in the world. Its annual calving of over 35 cu. km of ice accounts for 10% of the production of all Greenland calf ice, more than any other glacier outside Antarctica. The glacier has been the object of scientific attention for 250 years and, along with its relative ease of accessibility, has significantly added to the understanding of ice-cap glaciology, climate change and related geomorphic processes. Criterion (iii): The combination of a huge ice sheet and a fast moving glacial ice-stream calving into a fjord covered by icebergs is a phenomenon only seen in Greenland and Antarctica. Ilulissat offers both scientists and visitors easy access for close view of the calving glacier front as it cascades down from the ice sheet and into the ice-choked fjord. The wild and highly scenic combination of rock, ice and sea, along with the dramatic sounds produced by the moving ice, combine to present a memorable natural spectacle. BRIEF DESCRIPTIONS Located on the west coast of Greenland, 250-km north of the Arctic Circle, Greenland’s Ilulissat Icefjord (40,240-ha) is the sea mouth of Sermeq Kujalleq, one of the few glaciers through which the Greenland ice cap reaches the sea. -
Ice Core Science 21
Science Highlights: Ice Core Science 21 Dating ice cores JAKOB SCHWANDER Climate and Environmental Physics, Physics Institute, University of Bern, Switzerland; [email protected] Introduction 200 [ppb An accurate chronology is the ba- NO 100 3 ] sis for a meaningful interpretation - 80 ] of any climate archive, including ice 2 0 O 2 40 [ppb cores. Until now, the oldest ice re- H 0 200 Dust covered from a continuous core is [ppb 100 that from Dome Concordia, Antarc- 2 ] ] tica, with an estimated age of over -1 1.6 0 Sm 1.2 µ 800,000 years (EPICA Community [ Conduct. 0.8 160 [ppb Members, 2004). But the recently SO 80 4 2 recovered cores from near bedrock ] 60 - ] at Kohnen Station (Dronning Maud + 40 0 Na Land, Antarctica) and Dome Fuji [ppb 20 40 [ 0 Ca (Antarctica) compete for the longest ppb 2 20 + climatic record. With the recovery of ] 80 0 + more and more ice cores, the task of ] 4 establishing a good common chro- 40 [ppb NH nology has become increasingly im- 0 portant for linking the fi ndings from 1425 1425 .5 1426 1426 .5 1427 the different records. Moreover, in Depth [m] order to create a comprehensive Fig. 1: Seasonal variations of impurities in early Holocene ice from the North GRIP ice core. picture of past climate dynamics, it Summer layers are indicated by grey lines. is crucial to aim at a common chro- al., 1993, Rasmussen et al., 2006). is assessed with such a model, then nology for all paleo-records. Here Ideally the counting uncertainty is one can construct a chronology of the different methods for dating ice on the order of 1%. -
Scientific Dating of Pleistocene Sites: Guidelines for Best Practice Contents
Consultation Draft Scientific Dating of Pleistocene Sites: Guidelines for Best Practice Contents Foreword............................................................................................................................. 3 PART 1 - OVERVIEW .............................................................................................................. 3 1. Introduction .............................................................................................................. 3 The Quaternary stratigraphical framework ........................................................................ 4 Palaeogeography ........................................................................................................... 6 Fitting the archaeological record into this dynamic landscape .............................................. 6 Shorter-timescale division of the Late Pleistocene .............................................................. 7 2. Scientific Dating methods for the Pleistocene ................................................................. 8 Radiometric methods ..................................................................................................... 8 Trapped Charge Methods................................................................................................ 9 Other scientific dating methods ......................................................................................10 Relative dating methods ................................................................................................10 -
Glacier Movement
ISSN 2047-0371 Glacier Movement C. Scott Watson1 and Duncan Quincey1 1 School of Geography and water@leeds, University of Leeds ([email protected]) ABSTRACT: Quantification of glacier movement can supplement measurements of surface elevation change to allow an integrated assessment of glacier mass balance. Glacier velocity is also closely linked to the surface morphology of both clean-ice and debris-covered glaciers. Velocity applications include distinguishing active from inactive ice on debris-covered glaciers, identifying glacier surge events, or inferring basal conditions using seasonal observations. Surface displacements can be surveyed manually in the field using trigonometric principles and a total station or theodolite for example, or dGPS measurements, which allow horizontal and vertical movement to be quantified for accessible areas. Semi-automated remote sensing techniques such as feature tracking (using optical or radar imagery) and interferometric synthetic aperture radar (InSAR) (using radar imagery), can provide spatially distributed and multi-temporal velocity fields of horizontal glacier surface displacement. Remote-sensing techniques are more practical and can provide a greater distribution of measurements over larger spatial scales. Time-lapse imagery can also be exploited to track surface displacements, providing fine temporal and spatial resolution, although the latter is dependent upon the range between camera and glacier surface. This chapter outlines the costs, benefits, and methodological considerations -
Glacial Geomorphology☆ John Menzies, Brock University, St
Glacial Geomorphology☆ John Menzies, Brock University, St. Catharines, ON, Canada © 2018 Elsevier Inc. All rights reserved. This is an update of H. French and J. Harbor, 8.1 The Development and History of Glacial and Periglacial Geomorphology, In Treatise on Geomorphology, edited by John F. Shroder, Academic Press, San Diego, 2013. Introduction 1 Glacial Landscapes 3 Advances and Paradigm Shifts 3 Glacial Erosion—Processes 7 Glacial Transport—Processes 10 Glacial Deposition—Processes 10 “Linkages” Within Glacial Geomorphology 10 Future Prospects 11 References 11 Further Reading 16 Introduction The scientific study of glacial processes and landforms formed in front of, beneath and along the margins of valley glaciers, ice sheets and other ice masses on the Earth’s surface, both on land and in ocean basins, constitutes glacial geomorphology. The processes include understanding how ice masses move, erode, transport and deposit sediment. The landforms, developed and shaped by glaciation, supply topographic, morphologic and sedimentologic knowledge regarding these glacial processes. Likewise, glacial geomorphology studies all aspects of the mapped and interpreted effects of glaciation both modern and past on the Earth’s landscapes. The influence of glaciations is only too visible in those landscapes of the world only recently glaciated in the recent past and during the Quaternary. The impact on people living and working in those once glaciated environments is enormous in terms, for example, of groundwater resources, building materials and agriculture. The cities of Glasgow and Boston, their distinctive street patterns and numerable small hills (drumlins) attest to the effect of Quaternary glaciations on urban development and planning. It is problematic to precisely determine when the concept of glaciation first developed. -
A New Mass Spectrometric Tool for Modelling Protein Diagenesis
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Institutional Research Information System University of Turin 114 Abstracts / Quaternary International 279-280 (2012) 9–120 budgets, preferably spanning an entire glacial cycle, remain the most by chiral amino acid analysis. However, this knowledge has not yet been accurate for extrapolating glacial erosion rates to the entire Pleistocene able to produce a model which is fully able to explain the patterns of and for assessing their impact on crustal uplift. In the Carlit massif, where breakdown at low (burial) temperatures. By performing high temperature topographic conditions have allowed the majority of Würmian sediments experiments on a range of biominerals (e.g. corals and marine gastropods) to remain trapped within the catchment, clastic volumes preserved and and comparing the racemisation patterns with those obtained in fossil widespread 10Be nuclide inheritance on ice-scoured bedrock steps in the samples of known age, some of our studies have highlighted a range of path of major iceways reveal that mean catchment-scale glacial denuda- discrepancies in the datasets which we attribute to the interplay of tion depths were low (5 m in w100 ka), non-uniform across the landscape, a network of diagenesis reactions which are not yet fully understood. In and unsteady through time. Extrapolating to the Pleistocene, the trans- particular, an accurate knowledge of the temperature sensitivity of the two formation of Cenozoic landscapes by glaciers has thus been limited, many main observable diagenetic reactions (hydrolysis and racemisation) is still cirques and valleys being pre-glacial landforms merely modified by glacial elusive.