Will Mechanics Allow a Rapid Ice Age Following the Flood?
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LESSON PLAN #2: Creating the Driftless: a Study in Glacial Movement
LESSON PLAN #2: Creating the Driftless: A Study in Glacial Movement Overview: Glaciers are moving mountains of ice. They move like slow rivers and actually flow. Gravity and the sheer weight of the ice mass are the causes of glacial motion. Ice is softer than rock so is easily deformed by the pressure of its own weight. Movement at the underside of a glacier is slower than movement along the top. Glaciers retreat and advance, depending on snow accumulation, evaporation, or ice melt. Glaciers transport materials as they move. They also sculpt and carve the land beneath them. A glacier’s weight combined with gradual movement, reshapes the land over hundreds to thousands of years. The ice erodes the land surface and carries broken rock and soil debris far from their original places, resulting in some interesting glacial landforms. Due to the nature of land formations, some areas in northwest Illinois along with southwest Wisconsin, southeast Minnesota, and northeast Iowa were missed by the four glaciers that at different times covered the rest of these states. This area not covered by glaciers and the resulting glacial drift is called “The Driftless Area.” This Driftless Area is rich with historic and geological information free from glacial impact. Duration: 30 minutes Subject Areas: Earth Science, Physical Science, Geography Standards Addressed: 4-PS3-1 4-PS3-4 5-ESS3-1 MS-ESS3-1 MS-ESS2-5 MS-ESS2-3 MS-ESS1-C MS-PS2-4 Objectives: Gain an understanding of how glaciers move Understand the types of landforms created from glacial movement and glacial scraping Define what is meant by The Driftless Area Teacher Background: Glaciers are made up of fallen snow that, over many years, compresses into large, thickened ice masses. -
Gradient Approach to INSAR Modelling of Glacial Dynamics and Morphology
Gradient approach to INSAR modelling of glacial dynamics and morphology A. I. Sharov Institute of Digital Image Processing, Joanneum Research, Wastiangasse 6, A - 8010 Graz, Austria E-mail: [email protected] Keywords: differential interferometry, phase gradient, change detection, glacier velocity, geodetic survey ABSTRACT: This paper describes the development and testing of an original gradient approach (GINSAR) to the reconstruction of glacial morphology and ice motion estimation from the interferometric phase gradient that does not involve the procedure of interferometric phase unwrapping, thus excluding areal error propagation and improving the modelling accuracy. The global and stringent GINSAR algorithm is applicable to unsupervised glacier change detection, ice motion estimation and glacier mass balance measurement at regional scale. Experimental studies and field surveys proved its efficacy and robustness. Some algorithmic singularities and limitations are discussed. 1 INTRODUCTION detect and to measure quite small glacier motions and ice deformations in the centimetre range from There is a close interrelation between glacier motion spaceborne SAR interferograms with a nominal and glacial topography. Irregularities in the glacier ground resolution of several tens of meters. Accurate width, thickness, slope or direction alter the reconstruction of the configuration and external character of ice flow. On the other hand, glacial structure of the glacier surface from INSAR data is topography is dynamically supported by the moving also possible. Differential interferometry (DINSAR) ice (Fatland & Lingle 1998). Both, glacier dynamic based on differencing between two different SAR quantities and topographic variables are essential interferograms of the same glacier allows the parameters for studying the glacier mass balance and impacts of glacial topography and surface monitoring actual and potential glacier changes. -
Glacial Processes and Landforms
Glacial Processes and Landforms I. INTRODUCTION A. Definitions 1. Glacier- a thick mass of flowing/moving ice a. glaciers originate on land from the compaction and recrystallization of snow, thus are generated in areas favored by a climate in which seasonal snow accumulation is greater than seasonal melting (1) polar regions (2) high altitude/mountainous regions 2. Snowfield- a region that displays a net annual accumulation of snow a. snowline- imaginary line defining the limits of snow accumulation in a snowfield. (1) above which continuous, positive snow cover 3. Water balance- in general the hydrologic cycle involves water evaporated from sea, carried to land, precipitation, water carried back to sea via rivers and underground a. water becomes locked up or frozen in glaciers, thus temporarily removed from the hydrologic cycle (1) thus in times of great accumulation of glacial ice, sea level would tend to be lower than in times of no glacial ice. II. FORMATION OF GLACIAL ICE A. Process: Formation of glacial ice: snow crystallizes from atmospheric moisture, accumulates on surface of earth. As snow is accumulated, snow crystals become compacted > in density, with air forced out of pack. 1. Snow accumulates seasonally: delicate frozen crystal structure a. Low density: ~0.1 gm/cu. cm b. Transformation: snow compaction, pressure solution of flakes, percolation of meltwater c. Freezing and recrystallization > density 2. Firn- compacted snow with D = 0.5D water a. With further compaction, D >, firn ---------ice. b. Crystal fabrics oriented and aligned under weight of compaction 3. Ice: compacted firn with density approaching 1 gm/cu. cm a. -
Glaciers and Glaciation
M18_TARB6927_09_SE_C18.QXD 1/16/07 4:41 PM Page 482 M18_TARB6927_09_SE_C18.QXD 1/16/07 4:41 PM Page 483 Glaciers and Glaciation CHAPTER 18 A small boat nears the seaward margin of an Antarctic glacier. (Photo by Sergio Pitamitz/ CORBIS) 483 M18_TARB6927_09_SE_C18.QXD 1/16/07 4:41 PM Page 484 limate has a strong influence on the nature and intensity of Earth’s external processes. This fact is dramatically illustrated in this chapter because the C existence and extent of glaciers is largely controlled by Earth’s changing climate. Like the running water and groundwater that were the focus of the preceding two chap- ters, glaciers represent a significant erosional process. These moving masses of ice are re- sponsible for creating many unique landforms and are part of an important link in the rock cycle in which the products of weathering are transported and deposited as sediment. Today glaciers cover nearly 10 percent of Earth’s land surface; however, in the recent ge- ologic past, ice sheets were three times more extensive, covering vast areas with ice thou- sands of meters thick. Many regions still bear the mark of these glaciers (Figure 18.1). The basic character of such diverse places as the Alps, Cape Cod, and Yosemite Valley was fashioned by now vanished masses of glacial ice. Moreover, Long Island, the Great Lakes, and the fiords of Norway and Alaska all owe their existence to glaciers. Glaciers, of course, are not just a phenomenon of the geologic past. As you will see, they are still sculpting and depositing debris in many regions today. -
Short-Lived Ice Speed-Up and Plume Water Flow Captured by a VTOL UAV
Remote Sensing of Environment 217 (2018) 389–399 Contents lists available at ScienceDirect Remote Sensing of Environment journal homepage: www.elsevier.com/locate/rse Short-lived ice speed-up and plume water flow captured by a VTOL UAV give insights into subglacial hydrological system of Bowdoin Glacier T Guillaume Jouveta,*, Yvo Weidmanna, Marin Kneiba, Martin Deterta, Julien Seguinota,c, Daiki Sakakibarab, Shin Sugiyamab a ETHZ, VAW, Zurich, Switzerland b Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan c Arctic Research Center, Hokkaido University, Sapporo, Japan ARTICLE INFO ABSTRACT Keywords: The subglacial hydrology of tidewater glaciers is a key but poorly understood component of the complex ice- Unmanned Aerial Vehicle ocean system, which affects sea level rise. As it is extremely difficult to access the interior of a glacier, our Structure-from-Motion photogrammetry knowledge relies mostly on the observation of input variables such as air temperature, and output variables such Feature-tracking as the ice flow velocities reflecting the englacial water pressure, and the dynamics of plumes reflecting the Particle Image Velocimetry discharge of meltwater into the ocean. In this study we use a cost-effective Vertical Take-Off and Landing (VTOL) Calving glaciers Unmanned Aerial Vehicle (UAV) to monitor the daily movements of Bowdoin Glacier, north-west Greenland, and Meltwater plume Ice flow the dynamics of its main plume. Using Structure-from-Motion photogrammetry and feature-tracking techniques, we obtained 22 high-resolution ortho-images and 19 velocity fields at the calving front for 12 days in July 2016. Our results show a two-day-long speed-up event (up to 170%) – caused by an increase in buoyant subglacial forces – with a strong spatial variability revealing that enhanced acceleration is an indication of shallow bedrock. -
The Formation of Eskers
Proceedings of the Iowa Academy of Science Volume 21 Annual Issue Article 31 1914 The Formation of Eskers Arthur C. Trowbridge State University of Iowa Let us know how access to this document benefits ouy Copyright ©1914 Iowa Academy of Science, Inc. Follow this and additional works at: https://scholarworks.uni.edu/pias Recommended Citation Trowbridge, Arthur C. (1914) "The Formation of Eskers," Proceedings of the Iowa Academy of Science, 21(1), 211-218. Available at: https://scholarworks.uni.edu/pias/vol21/iss1/31 This Research is brought to you for free and open access by the Iowa Academy of Science at UNI ScholarWorks. It has been accepted for inclusion in Proceedings of the Iowa Academy of Science by an authorized editor of UNI ScholarWorks. For more information, please contact [email protected]. Trowbridge: The Formation of Eskers THE FORMATION OF ESKERS. 211 -· THE FORMATION OF ESKERS. .ARTHUR C. TROWBRIDGE. Ever since work has been in progress in glaciated regions, long, nar -row, winding, steep-sided, conspicuous ridges of gravel and sand have been recognized by geologists. They are best developed and were first recognized as distinct phases of drift in Sweden, where they are called Osar. The term Osar has the priority over other terms, but in this country, probably for phonic reasons, the Irish term Esker has come into use. With apologies to Sweden, Esker will be used in the present paper. Other terms which have been applied to these ridges in various parts of the world are serpent-kames, serpentine kames, horsebacks, whalebacks, hogbacks, ridges, windrows, turnpikes, back furrows, ridge • furrows, morriners, and Indian roads . -
Circumpolar Mapping of Antarctic Coastal Polynyas and Landfast Sea Ice: Relationship and Variability
Title Circumpolar Mapping of Antarctic Coastal Polynyas and Landfast Sea Ice: Relationship and Variability Author(s) Nihashi, Sohey; Ohshima, Kay I. Journal of climate, 28(9), 3650-3670 Citation https://doi.org/10.1175/JCLI-D-14-00369.1 Issue Date 2015-05-29 Doc URL http://hdl.handle.net/2115/59557 © Copyright [29 January 2015] American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act September 2010 Page 2 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Act (17 USC Rights §108, as revised by P.L. 94-553) does not require the AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a web site or in a searchable database, or other uses of this material, except as exempted by the above statement, requires written permission or a license from the AMS. Additional details are provided in the AMS Copyright Policy, available on the AMS Web site located at (http://www.ametsoc.org/) or from the AMS at 617-227-2425 or [email protected]. Type article File Information jcli-d-14-00369.1(1).pdf Instructions for use Hokkaido University Collection of Scholarly and Academic Papers : HUSCAP 3650 JOURNAL OF CLIMATE VOLUME 28 Circumpolar Mapping of Antarctic Coastal Polynyas and Landfast Sea Ice: Relationship and Variability SOHEY NIHASHI Department of Mechanical Engineering, National Institute of Technology, Tomakomai College, Tomakomai, Hokkaido, Japan KAY I. -
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. -
Glacial Erosion Assessment
Glacial Erosion Assessment March 2011 Prepared by: B. Hallet NWMO DGR-TR-2011-18 Glacial Erosion Assessment March 2011 Prepared by: B. Hallet NWMO DGR-TR-2011-18 Glacial Erosion Assessment - ii - March 2011 THIS PAGE HAS BEEN LEFT BLANK INTENTIONALLY Glacial Erosion Assessment - iii - March 2011 Document History Title: Glacial Erosion Assessment Report Number: NWMO DGR-TR-2011-18 Revision: R000 Date: March 2011 AECOM Canada Ltd. Prepared by: B. Hallet (University of Washington) Reviewed by: W.R. Peltier (University of Toronto), R. Frizzell Approved by: R.E.J. Leech Nuclear Waste Management Organization Reviewed by: M. Jensen Accepted by: M. Jensen Glacial Erosion Assessment - iv - March 2011 THIS PAGE HAS BEEN LEFT BLANK INTENTIONALLY Glacial Erosion Assessment - v - March 2011 EXECUTIVE SUMMARY This report examines the phenomenon of glacial erosion as it is a consideration in the safety and performance of Ontario Power Generation’s proposed Deep Geological Repository for low and intermediate level radioactive waste beneath the Bruce nuclear site located in the Municipality of Kincardine, Ontario. The report reviews currently available knowledge, insights and data that provide a basis for assessing the maximum amount of glacial erosion likely to occur during the next glacial cycle at the Bruce nuclear site. As in the Long-Term Climate Change Study of Peltier (2011), the prudent assumption will be made that the region will be subjected to major glacial cycles, recurring every ~100,000 years, much as they have over the last ~900,000 years. Accordingly, the geologic data and reconstructions of the Laurentide ice-sheet (LIS) during the last major glaciation are used to assess the amount of erosion expected over the next glacial cycle. -
The Use of Simple Physical Models in Seismology and Glaciology
The Use of Simple Physical Models in Seismology and Glaciology A dissertation presented by Victor Chen Tsai to The Department of Earth and Planetary Sciences in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the subject of Earth and Planetary Sciences Harvard University Cambridge, Massachusetts May 2009 c 2009 - Victor Chen Tsai All rights reserved. Dissertation Advisor: Author: Professor James R. Rice Victor Chen Tsai The Use of Simple Physical Models in Seismology and Glaciology Abstract In this thesis, I present results that span a number of largely independent topics within the broader disciplines of seismology and glaciology. The problems addressed in each section are quite different, but the approach taken throughout is to use simplified models to attempt to understand more complex physical systems. In these models, use of solid and fluid mechanics are important elements, though in some cases the mechanics are greatly simplified so that progress can be more easily made. The five primary results of this thesis can be summarized as follows: (1) Glacial earthquakes, which were known as enigmatic M 5 seismic sources prior to the work presented S ∼ here, are now characterized and understood as being due to coupling of gravitational energy from large calving icebergs into the solid Earth. (2) Rapid drainage events from meltwater lakes on Greenland can be understood in terms of models of turbulent hydraulic fracture at the base of the Greenland Ice Sheet. (3) The form of ‘lake star’ melt patterns on lake ice can be quantitatively modeled as arising from flow of warm water through slushy ice. -
Davis Valley and Forlidas Pond, Dufek Massif
Measure 2 (2005) Annex D Management Plan for Antarctic Specially Protected Area No. 119 DAVIS VALLEY AND FORLIDAS POND, DUFEK MASSIF 1. Description of Values to be Protected Forlidas Pond (82°27'28"S, 51°16'48"W) and several ponds along the northern ice margin of the Davis Valley (82°27'30"S, 51°05'W), in the Dufek Massif, Pensacola Mountains, were originally designated as a Specially Protected Area through Recommendation XVI-9 (1991, SPA No. 23) after a proposal by the United States of America. The Area was designated on the grounds that it “contains some of the most southerly freshwater ponds known in Antarctica containing plant life” which “should be protected as examples of unique near-pristine freshwater ecosystems and their catchments”. The original Area comprised two sections approximately 500 metres apart with a combined total area of around 6 km2. It included Forlidas Pond and the meltwater ponds along the ice margin at the northern limit of the Davis Valley. The site has been rarely visited and until recently there has been little information available on the ecosystems within the Area. This Management Plan reaffirms the original reason for designation of the Area, recognizing the ponds and their associated plant life as pristine examples of a southerly freshwater habitat. However, following a field visit made in December 2003 (Hodgson and Convey, 2004) the values identified for special protection and the boundaries for the Area have been expanded as described below. The Davis Valley and the adjacent ice-free valleys is one of the most southerly ‘dry valley’ systems in Antarctica and, as of May 2005, is the most southerly protected area in Antarctica. -
(ASPA) No. 119 DAVIS VALLEY and FORLIDAS POND
Measure 6 (2010) Annex Management Plan for Antarctic Specially Protected Area (ASPA) No. 119 DAVIS VALLEY AND FORLIDAS POND, DUFEK MASSIF, PENSACOLA MOUNTAINS (51° 05' W, 82° 29' S) Introduction Davis Valley and Forlidas Pond Antarctic Specially Protected Area (ASPA) is situated within the Dufek Massif, Pensacola Mountains at 51°4'53"W, 82°29'21"S. Approximate area: 57.3 km2. The primary reason for the designation of the Area is that it contains some of the most southerly freshwater ponds with plant life known to exist in Antarctica, which represent unique examples of near-pristine freshwater ecosystems and their catchments. The geomorphology of the Area represents a unique scientific resource for the reconstruction of previous glacial and climatic events. As a consequence of its extreme remoteness and inaccessibility, the Area has experienced very little human activity and with the total number of visitors estimated to be less than 50 people. As a result, the Area has outstanding potential as a scientific reference site. Furthermore, the Area possesses outstanding wilderness and aesthetic values. The Area is one of the most southerly ‘dry valley’ systems in Antarctica and, as of March 2010, is the most southerly Antarctic Specially Protected Area (ASPA) in Antarctica. The Area was originally proposed by the United States of America and adopted through Recommendation through Recommendation XVI-9 (1991, SPA No. 23) and included Forlidas Pond (82°27'28"S, 51°16'48"W) and several ponds along the northern ice margin of the Davis Valley. The boundaries of the Area were extended to include the entire ice-free region centered on the Davis Valley through Measure 2 (2005).