The Role of Lithospheric Delamination and Ice-Driven Rockfall

Total Page:16

File Type:pdf, Size:1020Kb

The Role of Lithospheric Delamination and Ice-Driven Rockfall THE ROLE OF LITHOSPHERIC DELAMINATION AND ICE-DRIVEN ROCKFALL EROSION IN THE EVOLUTION OF MOUNTAINOUS LANDSCAPES by TRISTRAM CHARLES HALES A DISSERTATION Presented to the Department of Geological Sciences and the Graduate School of the University of Oregon in partial fulfillment of the requirements for the degree of Doctor of Philosophy December 2006 ii “The Role of Lithospheric Delamination and Ice-Driven Rockfall Erosion in the Evolution of Mountainous Landscapes,” a dissertation prepared by Tristram Charles Hales in partial fulfillment of the requirements for the Doctor of Philosophy degree in the Department of Geological Sciences. This dissertation has been approved and accepted by: ____________________________________________________________ Joshua J. Roering, Chair of the Examining Committee ________________________________________ Date Committee in Charge: Joshua J. Roering, Chair Eugene D. Humpherys Ray J. Weldon II W. Andrew Marcus Accepted by: ____________________________________________________________ Dean of the Graduate School iii © 2006 Tristram Charles Hales iv An Abstract of the Dissertation of Tristram Charles Hales for the degree of Doctor of Philosophy in the Department of Geological Sciences to be taken December 2006 Title: THE ROLE OF LITHOSPHERIC DELAMINATION AND ICE-DRIVEN ROCKFALL EROSION IN THE EVOLUTION OF MOUNTAINOUS LANDSCAPES Approved: _______________________________________________ Joshua J. Roering This dissertation discusses the evolution of mountains, particularly the interaction between uplift, which is controlled by horizontally-directed plate tectonic and vertically- directed isostatic forces, and erosion, which encompasses glacial, periglacial, fluvial and hillslope processes. Eruption of the Columbia River Basalts (CRB) in northeastern Oregon is coincident with rapid uplift of the Wallowa Mountains. I mapped the modern distribution of CRB flows to quantify the amount of post-eruptive uplift in northeastern Oregon, which creates a broad “bull’s eye” pattern centered on a large granitic pluton. Rapid Wallowa Mountain uplift appears to be related to delamination of dense lower crust beneath the Wallowa batholith and is the likely cause of flood basalt volcanism at ~17 Ma B.P. v Rapid rockfall erosion rates in high mountains create extensive talus slopes. Parts of the Southern Alps, New Zealand, are dominated by kilometer-scale scree-mantled slopes which reduce hillslope gradients and decrease drainage densities. Field and aerial photograph-based analysis of scree slopes (i.e. rockfall deposits) reveal a peak in the areal extent and rate of scree slope formation in the eastern Southern Alps. This spatial distribution precludes earthquakes, post-glacial stress release, and rock type as primary rockfall triggering mechanisms. Instead, scree slopes occupy a narrow elevation range across the New Zealand Alps and the mean elevation of scree slopes is consistent with a theory for rockfall initiation by frost cracking and segregation ice growth, a process that breaks rocks through surface interactions at the ice/rock interface. Supported by data from the Southern Alps and other mountainous areas, I propose a simple numerical heat flow model to predict the climatic conditions and rock fracture spacing required for frost cracking. This model suggests that in highly fractured rocks the ultimate elevation of mountain peaks may be governed by the efficacy of frost action. This dissertation includes both my previously published and co-authored material. vi CURRICULUM VITAE NAME OF AUTHOR: Tristram Hales PLACE OF BIRTH: Christchurch, New Zealand DATE OF BIRTH: 21 May 1979 GRADUATE AND UNDERGRADUATE SCHOOLS ATTENDED: University of Oregon University of Canterbury DEGREES AWARDED: Doctor of Philosophy, 2006, University of Oregon Bachelor of Science with Honours (Geological Science), 2000, University of Canterbury AREAS OF SPECIAL INTEREST: Tectonic Geomorphology Landscape Evolution PROFESSIONAL EXPERIENCE: Graduate Teaching Fellow, University of Oregon, 2001-2006 Glacier Guide, Franz Josef Glacier Guides, 1999 vii GRANTS, AWARDS AND HONORS: PRIME Lab Seed Analysis Grant, Cosmogenic Isotope Sampling of Headwall Erosion, Purdue University, 2004 Graduate Student Research Award, Scree Production and Landscape Evolution, Geological Society of America, 2004 Outstanding Student Paper Award, Estimates of Erosion Rates for the Central Southern Alps, New Zealand, American Geophysical Union, 2002 PUBLICATIONS: Hales, T.C., D.L. Abt, E.D. Humphreys, and J.J. Roering, (2005) Convective Instability as an origin for the Columbia River Basalts and Wallowa Mountain uplift in NE Oregon, USA. Nature, 438, 842-845. Hales, T.C., and J.J. Roering (2005). Climate controlled variations in scree production, Southern Alps, New Zealand. Geology, 33, 701-704. Hales, T.C., and J.J. Roering, (2006), Climatic controls on frost cracking and the evolution of bedrock landscapes. Journal of Geophysical Research. In press. viii ACKNOWLEDGMENTS With the acceptance of this dissertation I will become the first person in my family to be awarded a Ph.D. The award is not the achievement of an individual, but instead is a testimonial to the love and support of my whanau, who are dearest to me. It has been my whanau that has taught me to love, appreciate and learn from nature, to work and play hard, and to enjoy life, and it gives me pleasure to dedicate this thesis to them. I would like to say many thanks to Josh Roering, my advisor who has provided me with much financial, academic, and emotional support over the last five years. Not only is he an example of a great scientist, but an example of a balanced human being. He is not only a great advisor and a great example of how to take the most from life. I really appreciate his friendship and collaboration and hope that it continues into the future. I am also grateful for the support of Gene Humphreys, who opened my horizons beyond process geomorphology to thinking about the dynamics of the earth at a large scale. His approach to science, particularly his focus on understanding, using simple physics, the processes that govern the evolution of Earth’s surface have been an inspiration. To the rest of the faculty at the University of Oregon who have provided me with help, support and friendship over the past five years. In particular thanks to Andrew Marcus, Ray Weldon, Becky Dorsey, and Alan Rempel, who have provided great ix scientific support throughout my dissertation. I would also especially like to thank Kathy Cashman and Marli Miller for exemplary teachers. I would also like to recognize the support of the many friends that I have made during my time in Oregon, in particular, Kate Scharer, Todd Lamaskin, Heather Wright, Reed Burgette, Noah Fay, and Darwin Villagomez for making the Geology department such a great place to work. Also many thanks to the people who kept my life balanced by taking me into the outdoors, watching world rally, teaching me about American sports, and eating Sunday brunch, particularly Pete and Sarah Erslev, Heather and Brian Ulrich, Jake Casper, Garner Britt, Jacob Selander, and George (Mac) Jenkins. Finally to the many people that made my day to day life happy in the Roering lab, many thanks to Alison Rust, Mackenzie Johnson, Molly Gerber, Suzanne Walther, Amanda Macleod, Ben Mackey, and Lisa Emerson. Last but by no means least this dissertation would not have happened without the love and support of my wife, field assistant and the best field camp student that I have ever had, Jenny Riker. x For Ralph Edward Thomas Hales and Joie Louisa Lyttle xi TABLE OF CONTENTS Chapter Page I. INTRODUCTION ...............................................................................................1 II. A LITHOSPHERIC INSTABILITY ORIGIN FOR COLUMBIA RIVER FLOOD BASALTS AND WALLOWA MOUNTAINS UPLIFT IN NORTHEAST OREGON ....................................................................................5 III. CLIMATE-CONTROLLED VARIATIONS IN SCREE PRODUCTION, SOUTHERN ALPS, NEW ZEALAND ............................................................17 3.1. Introduction ....................................................................................................17 3.2. Study Area .....................................................................................................19 3.3. Methods ..........................................................................................................21 3.4. Results ............................................................................................................23 3.5. Discussion and Conclusions .........................................................................25 IV. ROCKFALL EROSION AND POSTGLACIAL EVOLUTION OF THE SOUTHERN ALPS, NEW ZEALAND ............................................................33 4.1. Introduction ....................................................................................................33 4.2. Study Area .....................................................................................................38 4.2.1. Western Southern Alps ..........................................................................42 4.2.2. Axial Southern Alps ...............................................................................44 4.2.3. Eastern Southern Alps ............................................................................45 4.2.4. Topographic Characteristics...................................................................50 4.3. Field and Topographic Analysis of the Eastern Southern
Recommended publications
  • Full Article
    NOTORNIS QUARTERLY JOURNAL of the Ornithological Society of New Zealand Volume Sixteen, Number Two, lune, 1969 NOTICE TO CONTRIBUTORS Contributions should be type-written, double- or treble-spaced, with a wide margin, on one side of the paper only. They should be addressed to the Editor, and are accepted o?, condition that sole publication is being offered in the first instance to Notornis." They should be concise, avoid repetition of facts already published, and should take full account of previous literature on the subject matter. The use of an appendix is recommended in certain cases where details and tables are preferably transferred out of the text. Long contributions should be provided with a brief summary at the start. Reprints: Twenty-five off-prints will be supplied free to authors, other than of Short Notes. When additional copies are required, these will be produced as reprints, and the whole number will be charged to the author by the printers. Arrangements for such reprints must be made directly between the author and the printers, Te Rau Press Ltd., P.O. Box 195, Gisborne, prior to publication. Tables: Lengthy and/or intricate tables will usually be reproduced photographically, so that every care should be taken that copy is correct in the first instance. The necessity to produce a second photographic plate could delay publication, and the author may be called upon to meet the additional cost. nlastrutions: Diagrams, etc., should be in Indian ink, preferably on tracing cloth, and the lines and lettering must be sufficiently bold to allow of reduction. Photographs must be suitable in shape to allow of reduction to 7" x 4", or 4" x 3f".
    [Show full text]
  • Ïg8g - 1Gg0 ISSN 0113-2S04
    MAF $outtr lsland *nanga spawning sur\feys, ïg8g - 1gg0 ISSN 0113-2s04 New Zealand tr'reshwater Fisheries Report No. 133 South Island inanga spawning surv€ys, 1988 - 1990 by M.J. Taylor A.R. Buckland* G.R. Kelly * Department of Conservation hivate Bag Hokitika Report to: Department of Conservation Freshwater Fisheries Centre MAF Fisheries Christchurch Servicing freshwater fisheries and aquaculture March L992 NEW ZEALAND F'RESTTWATER F'ISHERIES RBPORTS This report is one of a series issued by the Freshwater Fisheries Centre, MAF Fisheries. The series is issued under the following criteria: (1) Copies are issued free only to organisations which have commissioned the investigation reported on. They will be issued to other organisations on request. A schedule of reports and their costs is available from the librarian. (2) Organisations may apply to the librarian to be put on the mailing list to receive all reports as they are published. An invoice will be sent for each new publication. ., rsBN o-417-O8ffi4-7 Edited by: S.F. Davis The studies documented in this report have been funded by the Department of Conservation. MINISTBY OF AGRICULTUBE AND FISHERIES TE MANAlU AHUWHENUA AHUMOANA MAF Fisheries is the fisheries business group of the New Zealand Ministry of Agriculture and Fisheries. The name MAF Fisheries was formalised on I November 1989 and replaces MAFFish, which was established on 1 April 1987. It combines the functions of the t-ormer Fisheries Research and Fisheries Management Divisions, and the fisheries functions of the former Economics Division. T\e New Zealand Freshwater Fisheries Report series continues the New Zealand Ministry of Agriculture and Fisheries, Fisheries Environmental Report series.
    [Show full text]
  • Rivermouth-Related Shore Erosion at Hokitika and Neils Beach, Westland
    Rivermouth-related shore erosion at Hokitika and Neils Beach, Westland Prepared for West Coast Regional Council February 2016 © All rights reserved. This publication may not be reproduced or copied in any form without the permission of the copyright owner(s). Such permission is only to be given in accordance with the terms of the client’s contract with NIWA. This copyright extends to all forms of copying and any storage of material in any kind of information retrieval system. Whilst NIWA has used all reasonable endeavours to ensure that the information contained in this document is accurate, NIWA does not give any express or implied warranty as to the completeness of the information contained herein, or that it will be suitable for any purpose(s) other than those specifically contemplated during the Project or agreed by NIWA and the Client. Prepared by: D M Hicks For any information regarding this report please contact: Murray Hicks Sediment Processes +64-3-343 7872 [email protected] National Institute of Water & Atmospheric Research Ltd PO Box 8602 Riccarton Christchurch 8011 Phone +64 3 348 8987 NIWA CLIENT REPORT No: CHC2016-002 Report date: February 2016 NIWA Project: ELF16506 Quality Assurance Statement Reviewed by: Richard Measures Formatting checked by: America Holdene Approved for release by: Jo Hoyle Contents Executive summary ............................................................................................................. 5 1 Introduction .............................................................................................................
    [Show full text]
  • +Tuhinga 27-2016 Vi:Layout 1
    27 2016 2016 TUHINGA Records of the Museum of New Zealand Te Papa Tongarewa Tuhinga: Records of the Museum of New Zealand Te Papa Tongarewa The journal of scholarship and mätauranga Number 27, 2016 Tuhinga: Records of the Museum of New Zealand Te Papa Tongarewa is a peer-reviewed publication, published annually by Te Papa Press PO Box 467, Wellington, New Zealand TE PAPA ® is the trademark of the Museum of New Zealand Te Papa Tongarewa Te Papa Press is an imprint of the Museum of New Zealand Te Papa Tongarewa Tuhinga is available online at www.tepapa.govt.nz/tuhinga It supersedes the following publications: Museum of New Zealand Records (1171-6908); National Museum of New Zealand Records (0110-943X); Dominion Museum Records; Dominion Museum Records in Ethnology. Editorial board: Catherine Cradwick (editorial co-ordinator), Claudia Orange, Stephanie Gibson, Patrick Brownsey, Athol McCredie, Sean Mallon, Amber Aranui, Martin Lewis, Hannah Newport-Watson (Acting Manager, Te Papa Press) ISSN 1173-4337 All papers © Museum of New Zealand Te Papa Tongarewa 2016 Published June 2016 For permission to reproduce any part of this issue, please contact the editorial co-ordinator,Tuhinga, PO Box 467, Wellington. Cover design by Tim Hansen Typesetting by Afineline Digital imaging by Jeremy Glyde Tuhinga: Records of the Museum of New Zealand Te Papa Tongarewa Number 27, 2016 Contents A partnership approach to repatriation: building the bridge from both sides 1 Te Herekiekie Herewini and June Jones Mäori fishhooks at the Pitt Rivers Museum: comments and corrections 10 Jeremy Coote Response to ‘Mäori fishhooks at the Pitt Rivers Museum: comments 20 and corrections’ Chris D.
    [Show full text]
  • Review West Coast Regional Coastal
    Review of West Coast Region Coastal Hazard Areas Prepared for West Coast Regional Council June 2012 Authors/Contributors: Richard Measures Helen Rouse For any information regarding this report please contact: Helen Rouse Resource Management Consultant +64-3-343 8037 [email protected] National Institute of Water & Atmospheric Research Ltd 10 Kyle Street Riccarton Christchurch 8011 PO Box 8602, Riccarton Christchurch 8440 New Zealand Phone +64-3-348 8987 Fax +64-3-348 5548 NIWA Client Report No: CHC2012-081 Report date: June 2012 NIWA Project: ELF12226 © All rights reserved. This publication may not be reproduced or copied in any form without the permission of the copyright owner(s). Such permission is only to be given in accordance with the terms of the client’s contract with NIWA. This copyright extends to all forms of copying and any storage of material in any kind of information retrieval system. Whilst NIWA has used all reasonable endeavours to ensure that the information contained in this document is accurate, NIWA does not give any express or implied warranty as to the completeness of the information contained herein, or that it will be suitable for any purpose(s) other than those specifically contemplated during the Project or agreed by NIWA and the Client. Contents Executive summary .............................................................................................................. 5 1 Introduction ................................................................................................................. 6
    [Show full text]
  • Cryogenic Displacement and Accumulation of Biogenic Methane in Frozen Soils
    atmosphere Article Cryogenic Displacement and Accumulation of Biogenic Methane in Frozen Soils Gleb Kraev 1,*, Ernst-Detlef Schulze 2, Alla Yurova 3,4, Alexander Kholodov 5,6, Evgeny Chuvilin 7 and Elizaveta Rivkina 6 1 Centre of Forest Ecology and Productivity, Russian Academy of Sciences, Moscow 117997, Russia 2 Department of Biogeochemical Processes, Max Planck Institute for Biogeochemistry, Jena 07745, Germany; [email protected] 3 Institute of Earth Sciences, Saint Petersburg State University, Saint Petersburg 199034, Russia; [email protected] 4 Nansen Centre, Saint Petersburg 199034, Russia 5 Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK 99775-9320, USA; [email protected] 6 Institute of Physicochemical and Biological Problems in Soil Science, Russian Academy of Sciences, Pushchino 142290, Russia; [email protected] 7 Faculty of Geology, Lomonosov Moscow State University, Moscow 119992, Russia; [email protected] * Correspondence: [email protected]; Tel.: +7-499-743-0026 Received: 28 March 2017; Accepted: 9 June 2017; Published: 15 June 2017 Abstract: Evidences of highly localized methane fluxes are reported from the Arctic shelf, hot spots of methane emissions in thermokarst lakes, and are believed to evolve to features like Yamal crater on land. The origin of large methane outbursts is problematic. Here we show, that the biogenic methane (13C ≤ −71 ) which formed before and during soil freezing is presently held in the permafrost. Field and experimentalh observations show that methane tends to accumulate at the permafrost table or in the coarse-grained lithological pockets surrounded by the sediments less-permeable for gas. Our field observations, radiocarbon dating, laboratory tests and theory all suggest that depending on the soil structure and freezing dynamics, this methane may have been displaced downwards tens of meters during freezing and has accumulated in the lithological pockets.
    [Show full text]
  • Different Causes of the Delamination on the Example of Caucasus and Kyrgyz Tien Shan Collision Zones
    EGU2020-6412 https://doi.org/10.5194/egusphere-egu2020-6412 EGU General Assembly 2020 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. Different causes of the delamination on the example of Caucasus and Kyrgyz Tien Shan collision zones. Irina Medved1,2,3, Ivan Koulakov2,3, and Mikhail Buslov1 1IGM SB RAS, Novosibirsk, Russian Federation ([email protected]) 2IPGG SB RAS, Novosibirsk, Russian Federation 3Novosibirsk State University, Novosibirsk, Russian Federation The causes of delamination of the mantle lithosphere in collision zones is actively debated in the scientific community. The main discussions are focused on the initiation of sinking of the continental lithosphere into the asthenosphere to a depth. Most scientists believe that such kind of immersion is impossible. However, there are several articles showing that this process is nonetheless taking place. For example Kay and Kay, (1993), Faccenda, Minelli, Gerya, (2009), Ueda et. al., (2012) and others propose various mechanisms of delamination, for example: eclogitization of the mafic layer of the lower crust, the effect of convection in the upper mantle, or gradual transition of the oceanic subduction into continental collision. Does the mantle part of the lithosphere sink into the mantle or spread laterally, as described in [for example, Deep Geodynamics, 2001; Bird, 1991; Schmeling and Marquart, 1991]? To answer these questions, we study deep structures beneath the Caucasus and Kyrgyz Tien Shan collision zones. The studies were carried out on the basis of multiscale seismic tomography methods: regional and global. This approach made it possible to study heterogeneities both in the crust and in the upper mantle.
    [Show full text]
  • The Modelling of Freezing Process in Saturated Soil Based on the Thermal-Hydro-Mechanical Multi-Physics Field Coupling Theory
    water Article The Modelling of Freezing Process in Saturated Soil Based on the Thermal-Hydro-Mechanical Multi-Physics Field Coupling Theory Dawei Lei 1,2, Yugui Yang 1,2,* , Chengzheng Cai 1,2, Yong Chen 3 and Songhe Wang 4 1 State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221008, China; [email protected] (D.L.); [email protected] (C.C.) 2 School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou 221116, China 3 State Key Laboratory of Coal Resource and Safe Mining, China University of Mining and Technology, Xuzhou 221116, China; [email protected] 4 Institute of Geotechnical Engineering, Xi’an University of Technology, Xi’an 710048, China; [email protected] * Correspondence: [email protected] Received: 2 September 2020; Accepted: 22 September 2020; Published: 25 September 2020 Abstract: The freezing process of saturated soil is studied under the condition of water replenishment. The process of soil freezing was simulated based on the theory of the energy and mass conservation equations and the equation of mechanical equilibrium. The accuracy of the model was verified by comparison with the experimental results of soil freezing. One-side freezing of a saturated 10-cm-high soil column in an open system with different parameters was simulated, and the effects of the initial void ratio, hydraulic conductivity, and thermal conductivity of soil particles on soil frost heave, freezing depth, and ice lenses distribution during soil freezing were explored. During the freezing process, water migrates from the warm end to the frozen fringe under the actions of the temperature gradient and pore pressure.
    [Show full text]
  • Study on the Mechanical Criterion of Ice Lens Formation Based on Pore Size Distribution
    applied sciences Article Study on the Mechanical Criterion of Ice Lens Formation Based on Pore Size Distribution Yuhang Liu 1,2, Dongqing Li 1 , Lei Chen 1,2 and Feng Ming 1,* 1 State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; [email protected] (Y.L.); [email protected] (D.L.); [email protected] (L.C.) 2 College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China * Correspondence: [email protected] Received: 5 November 2020; Accepted: 9 December 2020; Published: 16 December 2020 Abstract: Ice lens is the key factor which determines the frost heave in engineering construction in cold regions. At present, several theories have been proposed to describe the formation of ice lens. However, most of these theories analyzed the ice lens formation from a macroscopic view and ignored the influence of microscopic pore sizes and structures. Meanwhile, these theories lacked the support of measured data. To solve this problem, the microscopic crystallization stress was converted into the macro mean stress through the principle of statistics with the consideration of pore size distribution. The mean stress was treated as the driving force of the formation of ice lens and induced into the criterion of ice lens formation. The influence of pore structure and unfrozen water content on the mean stress was analyzed. The results indicate that the microcosmic crystallization pressure can be converted into the macro mean stress through the principle of statistics. Larger mean stress means the ice lens will be formed easier in the soil.
    [Show full text]
  • West Coast Regional Council: Natural Hazards Review
    WEST COAST REGIONAL COUNCIL: NATURAL HAZARDS REVIEW CLIENT REFERENCE: 1065.136WCRC CLIENT: WEST COAST REGIONAL COUNCIL AUTHOR: DTEC CONSULTING LTD COPIES SENT TO: WEST COAST REGIONAL COUNCIL BULLER DISTRICT COUNCIL GREY DISTRICT COUNCIL WESTLAND DISTRICT COUNCIL CONTENTS Page No. 1.0 INTRODUCTION 1.1 Background 1 1.2 WCRC Natural Hazards Projects 1 1.3 Project Brief 2 1.4 Project Team 3 1.5 References 4 2.0 FLOODING AND RIVERBED AGGRADATION 2.1 Introduction 5 2.2 Causes of Flooding 6 2.3 Effects of Flooding 10 2.4 Magnitude and Frequency of Flooding 12 2.5 Flood Hazard Research 15 2.6 River Bed Aggradation Research 21 2.7 Gaps in Knowledge and Information 25 2.8 Summary 31 2.9 Flood and Aggradation References 32 3.0 LANDSLIP HAZARDS 3.1 Introduction 37 3.2 Causes of Landslides 38 3.3 Effects of Landslides 41 3.4 Magnitude and Frequency of Events 42 3.5 West Coast Landslide Research 44 3.6 Gaps in Knowledge and Information 53 3.7 Summary 55 3.8 Landslide References 56 4.0 COASTAL HAZARDS 4.1 Introduction 60 4.2 Causes of Coastal Hazards 61 4.3 Effects of Coastal Hazards 64 4.4 Magnitude and Frequency 68 4.5 Coastal Hazard Research 71 4.6 Knowledge and Information Gaps 77 4.7 Summary 82 4.8 Coastal References 83 5.0 EARTHQUAKE HAZARDS 5.1 Introduction 88 5.2 Causes of Earthquakes 89 5.3 Effects of Earthquakes 91 5.4 Earthquake Magnitude, Intensity, and Frequency 95 5.5 Earthquake Research 98 5.6 Knowledge and Information Gaps 102 West Coast Regional Council: i Natural Hazards Review July 2002 Client Reference: 1065.136WCRC 5.7 Summary 104
    [Show full text]
  • Periglacial Processes, Features & Landscape Development 3.1.4.3/4
    Periglacial processes, features & landscape development 3.1.4.3/4 Glacial Systems and landscapes What you need to know Where periglacial landscapes are found and what their key characteristics are The range of processes operating in a periglacial landscape How a range of periglacial landforms develop and what their characteristics are The relationship between process, time, landforms and landscapes in periglacial settings Introduction A periglacial environment used to refer to places which were near to or at the edge of ice sheets and glaciers. However, this has now been changed and refers to areas with permafrost that also experience a seasonal change in temperature, occasionally rising above 0 degrees Celsius. But they are characterised by permanently low temperatures. Location of periglacial areas Due to periglacial environments now referring to places with permafrost as well as edges of glaciers, this can account for one third of the Earth’s surface. Far northern and southern hemisphere regions are classed as containing periglacial areas, particularly in the countries of Canada, USA (Alaska) and Russia. Permafrost is where the soil, rock and moisture content below the surface remains permanently frozen throughout the entire year. It can be subdivided into the following: • Continuous (unbroken stretches of permafrost) • extensive discontinuous (predominantly permafrost with localised melts) • sporadic discontinuous (largely thawed ground with permafrost zones) • isolated (discrete pockets of permafrost) • subsea (permafrost occupying sea bed) Whilst permafrost is not needed in the development of all periglacial landforms, most periglacial regions have permafrost beneath them and it can influence the processes that create the landforms. Many locations within SAMPLEextensive discontinuous and sporadic discontinuous permafrost will thaw in the summer months.
    [Show full text]
  • Overview of the Westland Cultural Heritage Tourism Development Plan 1
    Overview of the Westland Cultural Heritage Tourism Development Plan 1. CULTURAL HERITAGE THEMES DEVELOPMENT • Foundation Māori Settlement Heritage Theme – Pounamu: To be developed by Poutini Ngāi Tahu with Te Ara Pounamu Project • Foundation Pākehā Settlement Heritage Theme – West Coast Rain Forest Wilderness Gold Rush • Hokitika - Gold Rush Port, Emporium and Administrative Capital actually on the goldfields • Ross – New Zealand’s most diverse goldfield in terms of types of gold deposits and mining methods • Cultural Themes – Artisans, Food, Products, Recreation derived from untamed, natural wilderness 2. TOWN ENVIRONMENT ENHANCEMENTS 2.1 Hokitika Revitalisation • Cultural Heritage Precincts, Walkways, Interpretation, Public Art and Tohu Whenua Site • Wayfinders and Directional Signs (English, Te Reo Māori, Chinese) 2.2 Ross Enhancement • Enhancement and Experience Plan Development • Wayfinders and Directional Signs (English, Te Reo Māori, Chinese) 3. COMMERCIAL BUSINESS DEVELOPMENT • Go Wild Hokitika and other businesses at TRENZ 2020 • Chinese Visitor Business Cluster • Mahinapua Natural and Cultural Heritage Iconic Attraction 4. COMMUNITY OWNED BUSINESSES AND ACTIVITIES • Westland Industrial Heritage Park Experience Development • Ross Goldfields Heritage Centre and Area Experience Development 5. MARKETING • April 2020 KUMARA JUNCTION to GREYMOUTH Taramakau 73 River Kapitea Creek Overview of the Westland CulturalCHESTERFIELD Heritage 6 KUMARA AWATUNA Londonderry West Coast Rock Tourism Development Plan Wilderness Trail German Gully
    [Show full text]