Using Knowledge of Glacial Processes in Mineral Exploration
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University Microfilms, Inc., Ann Arbor, Michigan GEOLOGY of the SCOTT GLACIER and WISCONSIN RANGE AREAS, CENTRAL TRANSANTARCTIC MOUNTAINS, ANTARCTICA
This dissertation has been /»OOAOO m icrofilm ed exactly as received MINSHEW, Jr., Velon Haywood, 1939- GEOLOGY OF THE SCOTT GLACIER AND WISCONSIN RANGE AREAS, CENTRAL TRANSANTARCTIC MOUNTAINS, ANTARCTICA. The Ohio State University, Ph.D., 1967 Geology University Microfilms, Inc., Ann Arbor, Michigan GEOLOGY OF THE SCOTT GLACIER AND WISCONSIN RANGE AREAS, CENTRAL TRANSANTARCTIC MOUNTAINS, ANTARCTICA DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University by Velon Haywood Minshew, Jr. B.S., M.S, The Ohio State University 1967 Approved by -Adviser Department of Geology ACKNOWLEDGMENTS This report covers two field seasons in the central Trans- antarctic Mountains, During this time, the Mt, Weaver field party consisted of: George Doumani, leader and paleontologist; Larry Lackey, field assistant; Courtney Skinner, field assistant. The Wisconsin Range party was composed of: Gunter Faure, leader and geochronologist; John Mercer, glacial geologist; John Murtaugh, igneous petrclogist; James Teller, field assistant; Courtney Skinner, field assistant; Harry Gair, visiting strati- grapher. The author served as a stratigrapher with both expedi tions . Various members of the staff of the Department of Geology, The Ohio State University, as well as some specialists from the outside were consulted in the laboratory studies for the pre paration of this report. Dr. George E. Moore supervised the petrographic work and critically reviewed the manuscript. Dr. J. M. Schopf examined the coal and plant fossils, and provided information concerning their age and environmental significance. Drs. Richard P. Goldthwait and Colin B. B. Bull spent time with the author discussing the late Paleozoic glacial deposits, and reviewed portions of the manuscript. -
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. -
Erosional and Depositional Study Guide
Erosional and Depositional Study Guide Erosional 32. (2pts) Name the two ways glaciers erode the bed. 33. (6pts) Explain abrasion. Use the equation for abrasion to frame your answer. 34. (3pts) Contrast the hardness of ice compared to the hardness of bedrock. What is doing the abrading and why? 35. (3pts) Contrast the normal stress (weight of the ice) on the rock tool in the ice compared to the contact pressure. Are they the same, different? Why? 36. (3pts) The tools in the ice abrade along with the bedrock so the tools must be replenished for the glacier to erode over its entire base. What is the source of the tools? Explain. 37. (3pts) What is the role of subglacial hydrology in abrasion? Explain. 38. (3pts) Although we did not explicitly discuss this in class, consider abrasion and bulk erosion in a deforming subglacial till. Explain what might be happening. 39. (2 pts) Name the two ways plucking occurs. 40. (5pts) Explain how plucking occurs at a step in the bedrock. 41. (3pts) What is a roche mountonee and how does it form? 42. (3pts) Name 3 erosional landscapes created by glaciers. Do not include roche mountonee and U-shaped valley. 43. (6pts) How does a U-shaped valley form? Be specific. Depositional 44. (3pts) How does a glacier transport rock debris? 45. (3pts) Where do you find lateral moraines on a glacier and what glacial processes determine their location? Draw a plan view diagram of a glacier, identify its relevant parts and the locations of lateral moraines. 46. (3pts) In class we discussed how the vertical extent of moraines is not correlated with glacier size. -
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. -
Crag-And-Tail Features on the Amundsen Sea Continental Shelf, West Antarctica
Downloaded from http://mem.lyellcollection.org/ by guest on November 30, 2016 Crag-and-tail features on the Amundsen Sea continental shelf, West Antarctica F. O. NITSCHE1*, R. D. LARTER2, K. GOHL3, A. G. C. GRAHAM4 & G. KUHN3 1Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA 2British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK 3Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Alten Hafen 26, D-27568 Bremerhaven, Germany 4College of Life and Environmental Sciences, University of Exeter, Rennes Drive, Exeter EX4 4RJ, UK *Corresponding author (e-mail: [email protected]) On parts of glaciated continental margins, especially the inner leads to its characteristic tapering and allows formation of the sec- shelves around Antarctica, grounded ice has removed pre-existing ondary features. Multiple, elongated ridges in the tail could be sedimentary cover, leaving subglacial bedforms on eroded sub- related to the unevenness of the top of the ‘crags’. Secondary, strates (Anderson et al. 2001; Wellner et al. 2001). While the smaller crag-and-tail features might reflect variations in the under- dominant subglacial bedforms often follow a distinct, relatively lying substrate or ice-flow dynamics. uniform pattern that can be related to overall trends in palaeo- While the length-to-width ratio of crag-and-tail features in this ice flow and substrate geology (Wellner et al. 2006), others are case is much lower than for drumlins or elongate lineations, the more randomly distributed and may reflect local substrate varia- boundary between feature classes is indistinct. -
Part 629 – Glossary of Landform and Geologic Terms
Title 430 – National Soil Survey Handbook Part 629 – Glossary of Landform and Geologic Terms Subpart A – General Information 629.0 Definition and Purpose This glossary provides the NCSS soil survey program, soil scientists, and natural resource specialists with landform, geologic, and related terms and their definitions to— (1) Improve soil landscape description with a standard, single source landform and geologic glossary. (2) Enhance geomorphic content and clarity of soil map unit descriptions by use of accurate, defined terms. (3) Establish consistent geomorphic term usage in soil science and the National Cooperative Soil Survey (NCSS). (4) Provide standard geomorphic definitions for databases and soil survey technical publications. (5) Train soil scientists and related professionals in soils as landscape and geomorphic entities. 629.1 Responsibilities This glossary serves as the official NCSS reference for landform, geologic, and related terms. The staff of the National Soil Survey Center, located in Lincoln, NE, is responsible for maintaining and updating this glossary. Soil Science Division staff and NCSS participants are encouraged to propose additions and changes to the glossary for use in pedon descriptions, soil map unit descriptions, and soil survey publications. The Glossary of Geology (GG, 2005) serves as a major source for many glossary terms. The American Geologic Institute (AGI) granted the USDA Natural Resources Conservation Service (formerly the Soil Conservation Service) permission (in letters dated September 11, 1985, and September 22, 1993) to use existing definitions. Sources of, and modifications to, original definitions are explained immediately below. 629.2 Definitions A. Reference Codes Sources from which definitions were taken, whole or in part, are identified by a code (e.g., GG) following each definition. -
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. -
Glaciers and Glaciation in Glacier National Park
Glaciers and Glaciation in Glacier National Park ICE CAVE IN THE NOW NON-EXISTENT BOULDER GLACIER PHOTO 1932) Special Bulletin No. 2 GLACIER NATURAL HISTORY ASSOCIATION Price ^fc Cents GLACIERS AND GLACIATION In GLACIER NATIONAL PARK By James L. Dyson MT. OBERLIN CIRQUE AND BIRD WOMAN FALLS SPECIAL BULLETIN NO. 2 GLACIER NATURAL HISTORY ASSOCIATION. INC. In cooperation with NATIONAL PARK SERVICE DEPARTMENT OF INTERIOR PRINTED IN U. S. A. BY GLACIER NATURAL HISTORY ASSOCIATION 1948 Revised 1952 THE O'NEIL PRINTERS- KAUSPELL *rs»JLLAU' GLACIERS AND GLACIATION IN GLACIER NATIONAL PARK By James L. Dyson Head, Department of Geology and Geography Lafayette College Member, Research Committee on Glaciers American Geophysical Union* The glaciers of Glacier National Park are only a few of many thousands which occur in mountain ranges scattered throughout the world. Glaciers occur in all latitudes and on every continent except Australia. They are present along the Equator on high volcanic peaks of Africa and in the rugged Andes of South America. Even in New Guinea, which manj- veterans of World War II know as a steaming, tropical jungle island, a few small glaciers occur on the highest mountains. Almost everyone who has made a trip to a high mountain range has heard the term, "snowline,"' and many persons have used the word with out knowing its real meaning. The true snowline, or "regional snowline"' as the geologists call it, is the level above which more snow falls in winter than can be melted or evaporated during the summer. On mountains which rise above the snowline glaciers usually occur. -
Planet Earth Glaciers & Ice Ages Earth Portrait of a Planet Fifth Edition
CE/SC 10110-20110: Planet Earth Glaciers & Ice Ages Earth Portrait of a Planet Fifth Edition Chapter 22 Ice ages recognized by the observation of large boulders of non- local country rock being present in certain areas - erratics.! Glacier: masses of ice formed on land and moving because of their weight.! Glaciers have covered up to one third of the Earths surface in the recent geologic past, with most of the recent ice ending ~10,000 years ago. Proterozoic = snowball earth - complete ice cover.! Ice forms from snow that forms in layers The snow (sedimentary rock). ! recrystallizes into ice - metamorphic rock.! 2 Ice Formation! Snowflakes fall and accumulate.! As ice compacts, flakes undergo pressure solution.! Continual compaction produces packed granular snow - firn.! Pressure solution of firn produces glacial ice with trapped air that produces the blue color.! Older ice is coarser grained.! 3 Types of Glaciers! Mountain Glaciers (Alpine Glaciers)! Exist in or adjacent to mountain ranges.! Include valley glaciers, mountain ice caps (cover the mountains), piedmont glaciers.! 4 Types of Glaciers! Mountain Glaciers (Alpine Glaciers)! Types of Glaciers! Piedmont Glaciers! Piedmont)glaciers)spread)out)at)the)base)of)a)mountain)valley.)) ! Types of Glaciers! Continental Glaciers! Vast ice sheets covering continents - Greenland, Antarctica.! Flow out from the thickest point.! Front edge may form several tongue- shaped lobes due to differential speed.! 7 Types of Glaciers! Temperate Glaciers: temperature is at or near to the melting point of ice for a substantial portion of the year.! Polar Glaciers: temperature is below freezing year round.! Glaciers can form at any latitude as long as altitude permits.! Conditions for glacier formation:! 1) Local climate - cold enough for snow to remain year round;! 2) Snowfall is sufficient for accumulation;! 3) Surface is gentle so snow does not slide away (glaciers do not exist on slopes >30˚ - avalanches).! 8 Glacial Movement! Gravity driven.! Wet-Bottomed Glaciers: meltwater at the base reduces friction. -
Glacial Geology of Adams Inlet, Southeastern Alaska
Institute of Polar Studies Report No. 25 Glacial Geology of Adams Inlet, Southeastern Alaska l/h':'~~~~2l:gtf"'" SN" I" '" '" 7, r.• "'. ~ i~' _~~ ... 1!!JW'IIA8 ~ ' ... ':~ ~l·::,.:~·,~I"~,.!};·'o":?"~~"''''''''''''~ r .! np:~} 3TATE Uf-4lVERSnY by t) '{;fS~MACf< ROAD \:.~i~bYMaUi. OHlOGltltM Garry D. McKenzie " Institute of Polar Studies November 1970 GOLDTHWAIT POLAR LIBRARY The Ohio State University BYRD POLAR RESEARCH CENTER Research Foundation THE OHIO STATE UNIVERSITY Columbus, Ohio 43212 1090 CARMACK ROAD COLUMBUS, OHIO 43210 USA INSTITUTE OF POLAR STUDIES Report No. 25 GLACIAL GEOLOGY OF ADAMS INLET, SOUTHEASTERN ALASKA by Garry D. McKenzie Institute of Polar Studies November 1970 The Ohio State University Research Foundation Columbus, Ohio 43212 ABSTRACT Adams Inlet is in the rolling and rugged Chilkat-Baranof Mountains in the eastern part of Glacier Bay National Monument, Alaska. Rapid deglaciation of the area in the first half of the twentieth century has exposed thick sections of post-Hypsithermal deposits and some of the oldest unconsolidated deposits in Glacier Bay. About 30 percent of the area is underlain by uncon solidated material; 14 percent of the area is still covered with ice. The formations present in Adams Inlet are, from the oldest to the youngest: Granite Canyon till, Forest Creek glaciomarine sediments, Van Horn Formation (lower gravel member), Adams lacustrine-till complex, Berg gravel and sand, Glacier Bay drift, and Seal River gravel. No evidence of an early post-Wisconsin ice advance, indicated by the Muir Formation in nearby Muir Inlet, is present in Adams Inlet. Following deposition of the late Wisconsin Granite Canyon till, the Forest Creek glaciomarine sediments were laid down in water 2 to 20 m deep; they now occur as much as 30 m above present sea level. -
Glacial Erosion: Plucking and Abrasion As a Function of Bedrock Properties
CORE Metadata, citation and similar papers at core.ac.uk Provided by NERC Open Research Archive Krabbendam & Glasser: Glacial erosion: Abrasion vs Plucking. MS for Geomorphology Glacial erosion and bedrock properties in NW Scotland: abrasion and plucking, hardness and joint spacing Maarten Krabbendam a,* and Neil F. Glasser b a British Geological Survey, Murchison House, West Mains road, Edinburgh, Scotland, UK b Institute of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, Wales, UK * Corresponding author. Tel: ++44 131 650256 ; E-mail: [email protected] ABSTRACT Subglacial erosion beneath glaciers occurs predominantly by abrasion and plucking, producing distinct erosional forms. The controls on the relative importance of abrasion vs. plucking are poorly understood. On the one hand, glacial conditions that favour or suppress cavity formation (ice velocity, ice thickness, and water pressure) are thought to favour plucking or abrasion, respectively. Conversely, bedrock properties are also known to control landforms, but this has rarely been analysed quantitatively. In this study we compare landforms and bedrock properties of sandstone and quartzite at the bed of a palaeo-ice stream near Ullapool in NW Scotland. The boundary between the rock types is at right angles to the westward palaeo-ice flow, and palaeoglacial conditions on both rock types were similar. We report quantitative parameters for bedrock properties (Schmidt hammer hardness and joint spacing) and use morphometric parameters to analyse the landforms. Torridon sandstone is soft but thick-bedded and with a wide joint spacing. Erosional bedforms include roche moutonnées with smoothed tops and concave stoss sides, whalebacks, and elongate p-forms, indicating a high proportion of abrasion over plucking. -
Glaciers and Glacial Erosional Landforms
GLACIERS AND GLACIAL EROSIONAL LANDFORMS Dr. NANDINI CHATTERJEE Associate Professor Department of Geography Taki Govt College Taki, North 24 Parganas, West Bengal Part I Geography Honours Paper I Group B -Geomorphology Topic 5- Development of Landforms GLACIER AND ICE CAPS Glacier is an extended mass of ice formed from snow falling and accumulating over the years and moving very slowly, either descending from high mountains, as in valley glaciers, or moving outward from centers of accumulation, as in continental glaciers. • Ice Cap - less than 50,000 km2. • Ice Sheet - cover major portion of a continent. • Ice thicker than topography. • Ice flows in direction of slope of the glacier. • Greenland and Antarctica - 3000 to 4000 m thick (10 - 13 thousand feet or 1.5 to 2 miles!) FORMATION AND MOVEMENT OF GLACIERS • Glaciers begin to form when snow remains Once the glacier becomes heavy enough, it in the same area year-round, where starts to move. There are two types of enough snow accumulates to transform glacial movement, and most glacial into ice. Each year, new layers of snow bury movement is a mixture of both: and compress the previous layers. This Internal deformation, or strain, in glacier compression forces the snow to re- ice is a response to shear stresses arising crystallize, forming grains similar in size and from the weight of the ice (ice thickness) shape to grains of sugar. Gradually the and the degree of slope of the glacier grains grow larger and the air pockets surface. This is the slow creep of ice due to between the grains get smaller, causing the slippage within and between the ice snow to slowly compact and increase in crystals.