Attrition Abrasion
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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. -
Topic 4A: Coastal Change and Conflict
Topic 4A: Coastal Change and Conflict Headlands and bays: Bays form due Erosional landform: to rapid erosion of soft rock. Once Caves, arches, stacks and stumps: A cave is formed when a formed bays are sheltered by joint/fault in a rock is eroded and deepens. This can then headlands. Headlands are left develop into an arch when two caves form back to back sticking out where the hard rock has from either side of a headland and meet in the middle. resisted erosion. Once formed When an arch collapses, it creates a stack. When a stack however the headlands are more collapses it creates a stump. vulnerable to erosion. These are generally found along discordant coastlines. Depositional landforms: Beaches—can be straight or curved. Curved beaches are formed by waves refracting or bending as they enter a bay. They can be sandy or pebbly (shingle). Shingle beaches are found where cliffs are being eroded. Ridges in a beach parallel to the sea are called berms and the one highest up the beach shows where the highest tide reaches. Exam questions: Spits– narrow projections of sand or shingle 1. Explain how a wave- Erosional landform: that are attached to the land at one end. cut platform is formed Wave-cut platform: A wave-cut notch They extend across a bay or estuary or (4) is created when erosion occurs at the where the coastline changes direction. They 2. Briefly describe how base of a cliff. As undercutting occurs are formed by longshore drift powered by a spits are formed (2) the notch gets bigger. -
The Path of a Pebble- Coastal Processes Activities
The path of a pebble Teachers notes Indulge your natural sense of exploration on the beach by collecting pebbles and recording sound effects. This activity uses the intuitive games that pupils and adults alike will want to play when exploring the beach for the first (or twentieth) time while helping to embed learning about abrasion, attrition, and other processes of coastal change. Location: Barton on Sea or any shingle or pebble beach Timing: 30-45 minutes Age: Key stage 2 Curriculum links: Maths- 3D shapes, volume, estimation, Geography- coastal processes and change Science- rock types and properties, forces. English- poetry, onomatopoeia. (* check tides, weather conditions and safety of access near actively eroding cliffs prior to visit, take throw rope and appropriate emergency numbers, clearly demarcate and explain which areas pupils can explore safely) Learning Outcomes: Estimate the volume of different beach materials and the energy need to move and lift them Discover that shingle is made from mixed materials (rock types, shells, man-made etc.) which have varying degrees of hardness. Understand that harder rocks erode softer rocks creating shingle and pebbles of varying sizes (attrition) Resources needed: Blank postcard sized plain card Coloured pencils Aerial photo of your coastal site from e.g. google earth in two different time periods. The path of a pebble- Teachers notes Part 1- Does the coast stay the same? From a high point, admire the view and point out landmarks (the Solent, Isle of Wight, Bournemouth). Ask pupils to imagine this landscape 10, 100 and 10,000 years ago and suggest reasons it may have changed. -
Geologic and Physiographic Controls on Bed-Material Yield, Transport, and Channel Morphology for Alluvial and Bedrock Rivers, Western Oregon
Geologic and physiographic controls on bed-material yield, transport, and channel morphology for alluvial and bedrock rivers, western Oregon Jim E. O’Connor1,†, Joseph F. Mangano1,2, Scott W. Anderson1,3, J. Rose Wallick1, Krista L. Jones1, and Mackenzie K. Keith1 1U.S. Geological Survey, Oregon Water Science Center, 2130 SW 5th Avenue, Portland, Oregon 97201, USA 2Department of Geosciences, Colorado State University, Fort Collins, Colorado 80523, USA 3Department of Geography, University of Colorado–Boulder, Boulder, Colorado 80309, USA ABSTRACT geometry and sediment supply. At the scale (Stanford and Ward, 1993; Yarnell et al., 2006). of western Oregon, the physiographic and Most fundamentally, the distinction relates to the The rivers of western Oregon have di- lithologic controls on the balance between balance between bed-material supply and river verse forms and characteristics, with channel bed-material supply and transport capacity transport capacity (Gilbert, 1877, 1914; Howard, substrates ranging from continuous alluvial exert far-reaching infl uence on the distribu- 1980; Whipple, 2004). Rivers in which the long- gravel to bare bedrock. Analysis of several tion of alluvial and nonalluvial channels and term channel transport capacity exceeds bed- measurable morphologic attributes of 24 val- their consequently distinctive morphologies material supply (termed supply- or detachment- ley reaches on 17 rivers provides a basis for and behaviors—differences germane for un- limited rivers) will typically fl ow over bedrock comparing nonalluvial and alluvial channels. derstanding river response to tectonics and beds for part or much of their courses. Where Key differences are that alluvial reaches have environmental perturbations, as well as for supply meets or exceeds transport capacity greater bar area, greater migration rates, and implementing effective restoration and moni- (transport-limited rivers), channel beds are typi- show systematic correlation among variables toring strategies. -
Breaking Down Chipping and Fragmentation in Sediment Transport: the Control of Material Strength Sophie Bodek1 and Douglas J
https://doi.org/10.5194/esurf-2021-17 Preprint. Discussion started: 9 March 2021 c Author(s) 2021. CC BY 4.0 License. Breaking down chipping and fragmentation in sediment transport: the control of material strength Sophie Bodek1 and Douglas J. Jerolmack2,3 1Department of Earth Sciences, University of Delaware, Newark, Delaware, USA 2Department of Earth and Environmental Science, University of Pennsylvania, Philadelphia, Pennsylvania, USA 3Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, Pennsylvania, USA Correspondence: [email protected] Abstract. As rocks are transported, they primarily undergo two breakdown mechanisms: chipping and fragmentation. Chipping occurs at relatively low collision energies typical of bed-load transport, and involves shallow cracking; this process rounds river pebbles in a universal manner. Fragmentation involves catastrophic breakup by fracture growth in the bulk — a response that occurs at high collision energies such as rock falls — and produces angular shards. Despite its geophysical significance, the 5 transition from chipping to fragmentation is not well studied. Indeed, most models implicitly assume that impact erosion of pebbles and bedrock is governed by fragmentation rather than chipping. Here we experimentally delineate the boundary between chipping and fragmentation by examining the mass and shape evolution of concrete particles in a rotating drum. Attrition rate should be a function of both impact energy and material strength; here we keep the former constant, while systematically varying the latter. For sufficiently strong particles, chipping occurred and was characterized by the following: 10 daughter products were significantly smaller than the parent; attrition rate was independent of material strength; and particles experienced monotonic rounding toward a spherical shape. -
Coastal Processes and Landforms
Coastal Processes and Landforms These icons indicate that teacher’s notes or useful web addresses are available in the Notes Page. This icon indicates that the slide contains activities created in Flash. These activities are not editable. For more detailed instructions, see the Getting Started presentation. 1 of 43 © Boardworks Ltd 2005 How do waves operate? What are sub-aerial processes and why are they important? What processes of erosion operate at the coast? What landforms are created by erosion? What processes of transport operate at the coast? What landforms are created by deposition? Learning objectives 2 of 43 © Boardworks Ltd 2005 Why do waves break? Waves are the result of the wind blowing over the sea. As they approach land they break. The bottom of the wave touches the sand and slows down due to increased friction. The top of the wave becomes higher and steeper until it topples over. 3 of 43 © Boardworks Ltd 2005 Swash and backwash Backwash Swash Note: Backwash is always at right angles to the beach 4 of 43 © Boardworks Ltd 2005 Why are waves generally larger in the south west? Wave energy depends on the fetch, the strength of the wind and the length of time over which the wind has blown. fetch = the distance over which the wind has blown Look at an atlas or a wall map to find out the largest fetch around the British Isles. 5 of 43 © Boardworks Ltd 2005 Types of waves 6 of 43 © Boardworks Ltd 2005 What do you know about waves? 7 of 43 © Boardworks Ltd 2005 How do waves operate? What are sub-aerial processes and why are they important? What processes of erosion operate at the coast? What landforms are created by erosion? What processes of transport operate at the coast? What landforms are created by deposition? Learning objectives 8 of 43 © Boardworks Ltd 2005 What are sub-aerial processes? The coast is the narrow zone between the land and the sea. -
Alphabetical Glossary of Geomorphology
International Association of Geomorphologists Association Internationale des Géomorphologues ALPHABETICAL GLOSSARY OF GEOMORPHOLOGY Version 1.0 Prepared for the IAG by Andrew Goudie, July 2014 Suggestions for corrections and additions should be sent to [email protected] Abime A vertical shaft in karstic (limestone) areas Ablation The wasting and removal of material from a rock surface by weathering and erosion, or more specifically from a glacier surface by melting, erosion or calving Ablation till Glacial debris deposited when a glacier melts away Abrasion The mechanical wearing down, scraping, or grinding away of a rock surface by friction, ensuing from collision between particles during their transport in wind, ice, running water, waves or gravity. It is sometimes termed corrosion Abrasion notch An elongated cliff-base hollow (typically 1-2 m high and up to 3m recessed) cut out by abrasion, usually where breaking waves are armed with rock fragments Abrasion platform A smooth, seaward-sloping surface formed by abrasion, extending across a rocky shore and often continuing below low tide level as a broad, very gently sloping surface (plain of marine erosion) formed by long-continued abrasion Abrasion ramp A smooth, seaward-sloping segment formed by abrasion on a rocky shore, usually a few meters wide, close to the cliff base Abyss Either a deep part of the ocean or a ravine or deep gorge Abyssal hill A small hill that rises from the floor of an abyssal plain. They are the most abundant geomorphic structures on the planet Earth, covering more than 30% of the ocean floors Abyssal plain An underwater plain on the deep ocean floor, usually found at depths between 3000 and 6000 m. -
Sediment Budgets As an Organizing Framework in Fluvial Geomorphology
CHAPTER 16 Sediment budgets as an organizing framework in fluvial geomorphology Leslie M. Reid1 and Thomas Dunne2 1USDA Forest Service Pacific Southwest Research Station, Arcata, CA, USA 2University of California, Santa Barbara, CA, USA 16.1 Introduction have been used and describes an approach for designing and constructing useful budgets. Fluvial geomorphology concerns the transport of weathered rock debris and its accumulation and organization into land The sediment budget defined formsthatevolvecontinuously. Whereastheoretical fluvial Asedimentbudgetdescribestheinput,transport,storage and geomorphology focuses on the mechanics of fluvial processes export of sediment in a geomorphic system. For example, and the principles governing the evolution of landforms, Fig. 16.1 encapsulates the operation of the sediment budget of a applied fluvial geomorphology is devoted to understanding small forested mountain catchment. This budget was based ini and designing strategies for coexisting with changing fluvial tially on qualitative field observations and mapping of sediment systems. Whenever a fluvial feature changes form, there is a sources and storage elements and the conceptual diagram was local imbalance in the movement of sediment to and from the then used to guide quantitative estimates of the various transfer site. An understanding of how a river system collects, transports ratesandstoragetimes of thesediment. and deposits sediment is therefore central to addressing both Sediment budgets can be designed to quantify the magnitude applied and theoretical questions regarding how changes in of a process or response rate, its location and its timing or to catchment conditions affect channels, how long the effects explore the influences contributing to a morphological change. will last and what the sequence of responses will be. -
Attrition Experiments for the Beneficiation of Unconsolidated Sand Sources of Potential Hydraulic Fracture Sand, Northeastern British Columbia
AttRITION EXPERIMENTS FOR THE BENEFICIATION OF UNCONSOLIDATED SAND SOURCES OF POTENTIAL HYDRAULIC FRACTURE SAND, NORTHEASTERN BRITISH COLUMBIA Adrian S. Hickin1 and David H. Huntley2 ABSTRACT Sand for use as a hydraulic fracture proppant is critical in the development of shale gas. The cost of transporting proppants from distant suppliers has prompted the evaluation of local sand sources to meet or subsidize demand in northeastern British Columbia. Several sand deposits have been identified as potential proppant sources; however, in their natural state, these sand deposits do not meet industry standards. Several experiments are presented in this paper that focus on washing, sizing and attrition to improve the quality of a promising aeolian sand deposit. These beneficiation methods were selected because they are the least expensive processing steps for improving silica sand proppants. Results suggest attrition will reduce the content of deleterious sand grains; however, success was limited and attrition alone is insufficient to elevate the SiO2 content to industry standards. Other physical, physiochemical or chemical treatments will be required. The most substantial improvement in the silica content was achieved early in the experiments (i.e., in the first 5 minutes), after which results were negligible. A short period of attrition is a beneficial processing step, but prolonged attrition will be of little advantage. Prolonged attrition may, in fact, be detrimental to the quality of the proppant because grain breakage may result in an abundance of undesirable angular grains. Aggressive milling tended to produce the greatest increase in SiO2 and greatest decrease in Al2O3 and Fe2O3. Hickin, A.S. and Huntley, D.H. -
Erosion and Landforms
New Unit: Managing Coasts We are moving onto a new unit called ‘Managing Coasts’. This topic will cover processes and features of the UK coastline. L1: Features of different types of wave. L2 & L3: Different erosion processes and associated features. L4 & 5: Different depositional processes and associated features. L6: Coastal defences L7: UK Case study Starter – what do you remember about waves? Tick the correct box in the table below. Cons = constructive wave Des = destructive wave Feature Cons Des Generally high waves Strong backwash Generally long low waves Break 6 to 9 times per minute Can cause erosion on cliff faces Frequently break between 11 and 15 times per minute Weak backwash Can form beaches Consider what might cause this to happen? Coastal Erosion Learning Objectives: - to know the different coastal erosion processes - to know the different types of landforms created by coastal erosion. What is Coastal Erosion? Task: Fill in the missing vowels (a,e,i,o,u) Coastal Erosion _s th_ w_ _r_ng _w_y _f m_t_r_ _l by s_ _ w_t_r. Th_r_ _r_ 4 pr_c_ss_s _f _r_s_ _n. Th_s_ _r_ * Hydr_ _l_c _ct_ _n * _br_s_ _n * _ttr_t_ _n * S_l_t_ _n. What is Coastal Erosion? Answers Coastal Erosion is the wearing away of material by sea water. There are 4 processes of erosion. These are * Hydraulic action * Abrasion (sometimes called corrasion) * Attrition * Solution (sometimes called corrosion) The processes of erosion. Task: Look at the information on the following 4 slides to match each of the images below with the correct process. Abrasion Attrition Solution Hydraulic action The waves FORCE water into cracks in the rocks. -
TM 3-34.61(TM 5-545/8 July 1971) GEOLOGY February 2013
TM 3-34.61(TM 5-545/8 July 1971) GEOLOGY February 2013 Publication of TM 3-34.61, 12 February 2013 supersedes TM 5-545, Geology, 8 July 1971. This special conversion to the TM publishing medium/nomenclature has been accomplished to comply with TRADOC doctrine restructuring requirements. The title and content of TM 3-34.61 is identical to that of the superseded TM 5-545. This special conversion does not integrate any changes in Army doctrine since 8 July 1971 and does not alter the publication’s original references; therefore, some sources cited in this TM may no longer be current. For the status of official Department of the Army (DA) publications, consult DA Pam 25- 30, Consolidated Index of Army Publications and Blank Forms, at http://armypubs.army.mil/2530.html. DA Pam 25-30 is updated as new and revised publications, as well as changes to publications are published. For the content/availability of specific subject matter, contact the appropriate proponent. DISTRIBUTION RESTRICTION: Approved for public release; distribution is unlimited. HEADQUARTERS, DEPARTMENT OF THE ARMY This publication is available at Army Knowledge Online https://armypubs.us.army.mil/doctrine/index.html. TM 3-34.61 Technical Manual Headquarters No. 3-34.61 Department of the Army Washington, D.C., 12 February 2013 GEOLOGY Contents Page Chapter 1 INTRODUCTION ................................................................................................ 1-1 Purpose and Scope ........................................................................................... -
Teacher's Guide to Geology at Meadowcroft Rockshelter
Teacher’s Guide to Geology at Meadowcroft Rockshelter A Component of First Peoples: Archaeology at Meadowcroft Rockshelter Page 0 of 19 First Peoples: Archaeology at Meadowcroft Rockshelter Teacher’s Guide to Geology Contents Why Geology in First Peoples? ..................................................................................................................... 2 Teaching Geology at Meadowcroft Rockshelter .......................................................................................... 3 Intersection of Geology Theme with Disciplines ...................................................................................... 3 Geology GigaPan Inquiry .......................................................................................................................... 4 Major Terms and Concepts ...................................................................................................................... 5 Geology of the Meadowcroft Rockshelter and the Cross Creek Drainage ................................................... 6 Geography, Geologic Origins, and Physiography ..................................................................................... 6 Formation of Meadowcroft Stratigraphy ............................................................................................... 10 Tables ......................................................................................................................................................... 14 Ancient Geological Activity at Meadowcroft Rockshelter .....................................................................