DOCSLIB.ORG

50Th US Rock Mechanics / Geomechanics Symposium 2016

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
50Th US Rock Mechanics / Geomechanics Symposium 2016 50th US Rock Mechanics / Geomechanics Symposium 2016 Houston, Texas, USA 26 - 29 June 2016 Volume 1 of 4 ISBN: 978-1-5108-2802-5 Printed from e-media with permission by: Curran Associates, Inc. 57 Morehouse Lane Red Hook, NY 12571 Some format issues inherent in the e-media version may also appear in this print version. Copyright© (2016) by the American Rock Mechanics Association All rights reserved. Printed by Curran Associates, Inc. (2016) For permission requests, please contact the American Rock Mechanics Association at the address below. American Rock Mechanics Association Peter Smeallie, Executive Director 600 Woodland Terrace Alexandria, Virginia 22302-3319 Phone: (703) 683-1808 Fax: (703) 997-6112 [email protected] Additional copies of this publication are available from: Curran Associates, Inc. 57 Morehouse Lane Red Hook, NY 12571 USA Phone: 845-758-0400 Fax: 845-758-2633 Email: [email protected] Web: www.proceedings.com TABLE OF CONTENTS VOLUME 1 TECHNICAL SESSION 1: GEOMECHANICS IN GEOTHERMAL PROCESSES 1 3D Analysis of Thermo-poroelastic Processes on Fracture Network Deformation and Induced Micro-Seismicity Potential in EGS .................................................................................................................................................................................................1 Safari, Reza; Ghassemi, Ahmad Experimental and Numerical Investigation of Hydro-Thermally Induced Shear Stimulation .................................................................8 Bauer, Stephen; Huang, Kai; Ghassemi, Ahmad; Barrow, Perry; Chen, Q. Laboratory Study on Cyclic Hydraulic Fracturing of Pocheon Granite in Korea ...................................................................................18 Zhuang, Li; Kim, Kwang Yeom; Jung, Sung Gyu; Diaz, Melvin; Zang, Arno; Stephansson, Ove; Zimmerman, Günter; Yoon, Jeoung Seok; Park, Sehyeok; Min, Ki-Bok Modeling Induced Microseismicity in an Enhanced Geothermal System..................................................................................................24 Sherman, Christopher; Templeton, Dennise; Morris, Joseph; Matzel, Eric Permeability Potential Modeling of Geothermal Prospects Combining Regional Crustal Strain Rates with Geomechanical Simulation of Fault Slip and Volcanic Center Deformation: A Case Study for Washington State Geothermal Play Fairways. .............................................................................................................................................................................31 Swyer, Michael; Cladouhos, Trenton; Davatzes, Nicholas; Forson, Corina; Czajkowski, Jessica; Schmalzle, Gina Thermal Effects During Hydraulic Fracturing in Low-Permeability Brittle Rocks ................................................................................45 Salimzadeh, Saeed; Paluszny, Adriana; Zimmerman, Robert TECHNICAL SESSION 2: GEOMECHANICS IN GEOTHERMAL PROCESSES 2 3D Thermo-poromechanical Analysis of Reservoir Stimulation Using Damage Mechanics with Application to the Fenton Hill HDR Experiment .........................................................................................................................................................................51 Gao, Qian; Ghassemi, Ahmad Application of Hydraulic and Thermal Stimulation Techniques at Raft River, Idaho: A DOE Enhanced Geothermal System Demonstration Project..................................................................................................................................................62 Bradford, Jacob; Moore, Joseph; McLennan, John; Podgorney, Robert; Plummer, Mitchell; Majer, Ernie; Tiwari, Shashank Numerical Modeling of Newberry EGS Stimulation....................................................................................................................................67 Cheng, Qinglu; Ghassemi, Ahmad Parametric Study of Energetic Simulation for Geothermal Applications .................................................................................................76 Morris, Joseph; Vorobiev, Oleg; Herbold, Eric; White, Bradley; Homel, Michael Primary Constraints on the Design of and Enhanced Geothermal System Reservoir .............................................................................81 Mattson, Earl; Plummer, Mitchell; Podgorney, Robert; Ghassemi, Ahmad; Huang, Hai; Xia, Yidong Revisiting Fenton Hill Phase I Reservoir Creation and Stimulation Mechanisms Through the GTO Code Comparison Study............................................................................................................................................................................................93 Fu, Pengcheng; McClure, Mark; Shiozawa, Sogo; White, Mark TECHNICAL SESSION 3: ROCK EXCAVATION, BREAKING, DYNAMIC LOADING Developing the Ground Index (GI) for Rock Collapse Assessment in Tunneling...................................................................................102 Wang, Hao; Jiao, Yu-Yong; Adoko, Amoussou Coffi; Seitshiro, Itumeleng T. Experimental Study of Impact of Creep on Coal Permeability ................................................................................................................112 Bai, Tianhang; Noraei Danesh, Nima; Chen, Zhongwei; Aminossadati, Saiied M.; Kizil, Mehmet; Pan, Zhejun; Connell, Luke D. Influence of Hydrostatic Confining Pressure on the Dynamic Tensile Failure of Rock Material.........................................................118 Wu, Bangbiao; Xia, Kaiwen; Guo, Y. Rock Failure Process in Indirect Tension using SPH Method ..................................................................................................................125 Deb, Debasis; Pramanik, Ranjan; Douillet-Grellier, Thomas; Das, Sudip; Pan, Kai; Jones, Bruce David; Williams, John R. Rock Mass Modeling Approach for Simulating Wave Propagation, Rock Fracture, and Rock Ejection ...........................................132 Raffaldi, Michael; Loken, Mark XFEM Simulation of Blast-induced Crack Propagation in Rocks ...........................................................................................................144 Romanel, Celso; Roehl, Deane; López Bendezú, Marko Antonio TECHNICAL SESSION 4: CIVIL POSTERS Development of Biogrouting Using Plant-derived Urease and Calcium Phosphate Compound...........................................................152 Takatsu, Momoko; Kawasaki, Satoru; Nadeeka, R. A. N. Geomechanics of Heave Due to the Use of Pyritic Mudstone, Ireland .....................................................................................................157 Shrimer, Fred Investigation on a Slope Movement in a Complex Rock Formation: Modeling of the Deformation Mode and Remedial Measures. .......................................................................................................................................................................................167 Lembo-Fazio, Albino; Graziani, Alessandro; Assefa, Siraj Mulugeta Performance Analysis of Multiple Rock Caverns for Thermal Energy Storage.....................................................................................177 Park, Dohyun; Park, Eui-Seob Slaking of Mudstone and its Mechanical Consequences in 1D Compression Condition........................................................................183 Putra, Andius Dasa; Kikumoto, Mamoru Study on Stability and Treatment Project for Yangnangou Tunnel Portal Slope of Shiyan to Baihe Road in Hubei Province ...........................................................................................................................................................................................................191 Luo, Hongming; Chen, Shanxiong Use of Geological Strength Index to Characterize the Miami Formation for Shallow Foundation Design.........................................200 Truzman, Miguel TECHNICAL SESSION 5: INTERDISCIPLINARY POSTERS Acoustic Emission Characterization of Frozen Sandstone in Uniaxial Compression Test ....................................................................207 Liu, Bo; Zhang, Gong; Liu, Lulu; Xu, Wei Bakken Formtion Shales Nano Scale Analysis Understand Mechanical Parameters.............................................................................214 Liu, Kouqi; Ostadhassan, Mehdi; Bubach, Bailey; Jabbari, Hadi Breakage Mechanics Modeling of the Brittle-ductile Transition in Granular Materials.......................................................................222 Wang, Pei; Arson, Chloe Cohesion and Fracturing in a Transparent Jointed Rock Analogue........................................................................................................228 Gomez Rodriguez, Diana; Dusseault, Maurice; Gracie, Robert Connection of Elastic and Thermal Properties of Bentheimer Sandstone Using Effective Medium Theory (Rock Physics) ............................................................................................................................................................................................................237 Yalaev, Tagir; Bayuk, Irina; Abashkin, Vladimir; Tarelko, Nikolay Constrution of a Geological Information CIM Management System and Application to Construction Sites.....................................244 Utsuki, Shinji; Nakaya, Masashi A Coupled Nonlocal Damage Model for Hydraulic Fracture Propagation .............................................................................................250 Huang, K.; Ghassemi, A. Coupled Reservoir Simulation of Geomechanics and Fluid
Load more

Recommended publications
  • Copyright Notice
    COPYRIGHT NOTICE The following document is subject to copyright agreements. The attached copy is provided for your personal use on the understanding that you will not distribute it and that you will not include it in other published documents. Dr Evert Hoek Evert Hoek Consulting Engineer Inc. 3034 Edgemont Boulevard P.O. Box 75516 North Vancouver, B.C. Canada V7R 4X1 Email: [email protected] Support Decision Criteria for Tunnels in Fault Zones Andreas Goricki, Nikos Rachaniotis, Evert Hoek, Paul Marinos, Stefanos Tsotsos and Wulf Schubert Proceedings of the 55th Geomechanics Colloquium, Salsberg Published in Felsbau, 24/5, 2006. Goricki et al. (2006) 22 Support decision criteria for tunnels in fault zones Support Decision Criteria for Tunnels in Fault Zones Abstract A procedure for the application of designed support measures for tunnelling in fault zones with squeezing potential is presented in this paper. Criteria for the support decision based on quantitative parameters are defined. These criteria provide an objective basis for the assignment of the designed support categories to the actual ground conditions. Besides the explanation of the criteria and the implementation into the general geomechanical design process an example from the Egnatia Odos project in Greece is given. The Metsovo tunnel is located in a geomechanical difficult area including fault zones and a major thrust zone with high overburden. Focusing on squeezing sections of this tunnel project the application of the support decision criteria is shown. Introduction Tunnelling in fault zones in general is associated with frequently changing ground and ground water conditions together with large and occasionally long lasting displacements.
    [Show full text]
  • Raplee Ridge Monocline and Thrust Fault Imaged Using Inverse Boundary Element Modeling and ALSM Data
    Journal of Structural Geology 32 (2010) 45–58 Contents lists available at ScienceDirect Journal of Structural Geology journal homepage: www.elsevier.com/locate/jsg Structural geometry of Raplee Ridge monocline and thrust fault imaged using inverse Boundary Element Modeling and ALSM data G.E. Hilley*, I. Mynatt, D.D. Pollard Department of Geological and Environmental Sciences, Stanford University, Stanford, CA 94305-2115, USA article info abstract Article history: We model the Raplee Ridge monocline in southwest Utah, where Airborne Laser Swath Mapping (ALSM) Received 16 September 2008 topographic data define the geometry of exposed marker layers within this fold. The spatial extent of five Received in revised form surfaces were mapped using the ALSM data, elevations were extracted from the topography, and points 30 April 2009 on these surfaces were used to infer the underlying fault geometry and remote strain conditions. First, Accepted 29 June 2009 we compare elevations extracted from the ALSM data to the publicly available National Elevation Dataset Available online 8 July 2009 10-m DEM (Digital Elevation Model; NED-10) and 30-m DEM (NED-30). While the spatial resolution of the NED datasets was too coarse to locate the surfaces accurately, the elevations extracted at points Keywords: w Monocline spaced 50 m apart from each mapped surface yield similar values to the ALSM data. Next, we used Boundary element model a Boundary Element Model (BEM) to infer the geometry of the underlying fault and the remote strain Airborne laser swath mapping tensor that is most consistent with the deformation recorded by strata exposed within the fold.
    [Show full text]
  • Dips Tutorial.Pdf
    Dips Plotting, Analysis and Presentation of Structural Data Using Spherical Projection Techniques User’s Guide 1989 - 2002 Rocscience Inc. Table of Contents i Table of Contents Introduction 1 About this Manual ....................................................................................... 1 Quick Tour of Dips 3 EXAMPLE.DIP File....................................................................................... 3 Pole Plot....................................................................................................... 5 Convention .............................................................................................. 6 Legend..................................................................................................... 6 Scatter Plot .................................................................................................. 7 Contour Plot ................................................................................................ 8 Weighted Contour Plot............................................................................. 9 Contour Options ...................................................................................... 9 Stereonet Options.................................................................................. 10 Rosette Plot ............................................................................................... 11 Rosette Applications.............................................................................. 12 Weighted Rosette Plot..........................................................................
    [Show full text]
  • Fracture Cleavage'' in the Duluth Complex, Northeastern Minnesota
    Downloaded from gsabulletin.gsapubs.org on August 9, 2013 Geological Society of America Bulletin ''Fracture cleavage'' in the Duluth Complex, northeastern Minnesota M. E. FOSTER and P. J. HUDLESTON Geological Society of America Bulletin 1986;97, no. 1;85-96 doi: 10.1130/0016-7606(1986)97<85:FCITDC>2.0.CO;2 Email alerting services click www.gsapubs.org/cgi/alerts to receive free e-mail alerts when new articles cite this article Subscribe click www.gsapubs.org/subscriptions/ to subscribe to Geological Society of America Bulletin Permission request click http://www.geosociety.org/pubs/copyrt.htm#gsa to contact GSA Copyright not claimed on content prepared wholly by U.S. government employees within scope of their employment. Individual scientists are hereby granted permission, without fees or further requests to GSA, to use a single figure, a single table, and/or a brief paragraph of text in subsequent works and to make unlimited copies of items in GSA's journals for noncommercial use in classrooms to further education and science. This file may not be posted to any Web site, but authors may post the abstracts only of their articles on their own or their organization's Web site providing the posting includes a reference to the article's full citation. GSA provides this and other forums for the presentation of diverse opinions and positions by scientists worldwide, regardless of their race, citizenship, gender, religion, or political viewpoint. Opinions presented in this publication do not reflect official positions of the Society. Notes Geological Society of America Downloaded from gsabulletin.gsapubs.org on August 9, 2013 "Fracture cleavage" in the Duluth Complex, northeastern Minnesota M.
    [Show full text]
  • Brittle Deformation in Phyllosilicate-Rich Mylonites: Implication for Failure Modes, Mechanical Anisotropy, and Fault Weakness
    UNIVERSITY OF MILANO-BICOCCA Department of Earth and Environmental Sciences PhD Course in Earth Sciences (XXVII cycle) Academic Year 2014 Brittle deformation in phyllosilicate-rich mylonites: implication for failure modes, mechanical anisotropy, and fault weakness Francesca Bolognesi Supervisor: Dott. Andrea Bistacchi Co-supervisor: Dott. Sergio Vinciguerra 0 Brittle deformation in phyllosilicate-rich mylonites: implication for failure modes, mechanical anisotropy, and fault weakness Francesca Bolognesi Supervisor: Dott. Andrea Bistacchi Co-supervisor: Dott. Sergio Vinciguerra 1 2 1 Table of contents 1. Introduction .......................................................................................................................................... 5 2. Weakening mechanisms and mechanical anisotropy evolution in phyllosilicate-rich cataclasites developed after mylonites in a low-angle normal fault (Simplon Line, Western Alps) ................................ 6 1.1 Abstract ......................................................................................................................................... 7 1.2 Introduction .................................................................................................................................. 8 1.3 Structure and tectonic evolution of the SFZ ............................................................................... 10 1.4 Structural analysis ....................................................................................................................... 14
    [Show full text]
  • APRIL 1982 VOLUME 2 Co NTE NTS Rock Mechanics and Structural
    OFFICE OF THE STATE GEOLOGIST VERMONT GEOLOGY APRIL 1982 VOLUME 2 Co NTE NTS Rock mechanics and structural geologic considerations in siting crushed stone quarries Brian K. Fowler 1 Evolution and structural significance of master shear zones within the parautochthonous flysch of Eastern New York William Bosworth 6 Road salt effects on ground water in the Williston and St. George area, Vermont Craig Heindel 14 The Taconic orogeny of Rodgers, seen from Vermont a decade later Brewster Baldwin 20 EDITOR Jeanne C. Detenbeck EDITORIAL COMMITTEE Charles A. Ratt Frederick D. Larsen VERMONT GEOLOGICAL SOCIETY, INC. Vermont Geological Society Box 304 Montpelier, Vermont 05602 FORWARD The Vermont Geological Society was founded in 1974 for the purpose of "1) advancing the science and profession of geology and its related branches by encouraging education, research and service through the holding of meetings, maintaining communications, and providing a common union of its members; 2) contributing to the public education of the geology of Vermont and promoting the proper use and protection of its natural resources; and 3) advancing the professional conduct of those engaged in the collection, interpretation and use of geologic data". To these ends in its 8 year history, the society has promoted a variety of activities. Four yearly meetings have become established: an all- day fall field trip, presentation of professional papers in the winter and student research papers in the spring, and a fall teacher's workshop and field trip. The Society publishes a quarterly newsletter, The Green Mountain Geologist, containing announcements of these meetings and also short articles. This second issue of Vermont Geology contains papers from two symposia, "The Taconic orogeny- new thoughts on an old problem" and 'Applied geology in Vermont", presented at our fourth annual winter meeting in February 1981 at University of Vermont.
    [Show full text]
  • Assessing the Physical and Hydraulic Properties Of
    THE INFLUENCE OF FRACTURE CHARACTERISTICS ON GROUNDWATER FLOW SYSTEMS IN FRACTURED IGNEOUS AND METAMORPHIC ROCKS OF NORTH CAROLINA (USA) By Justin E. Nixon May, 2013 Director of Thesis: Dr. Alex K. Manda Major Department: Geological Sciences The yield of water wells drilled in crystalline rock aquifers is determined by the occurrence and interaction of open, saturated fractures which decrease with increased depth, outside of the influence of large-scale features such as fault zones. These trends suggest that in the shallow subsurface, (i) fluid flow is controlled by specific fracture types, and (ii) there is a bounding depth below which groundwater flow is significantly reduced. These hypotheses are tested in this paper. The analysis of fracture properties identified in boreholes offers an approach to investigate the depth evolution of groundwater systems in crystalline rocks. Optical televiewer, caliper and heat pulse flow meter logs are utilized to investigate the attributes, distributions, orientations, and the contribution to flow of 570 fractures that intersect 26 bedrock wells drilled in crystalline rocks of North Carolina. Results indicate that the dominant fracture types are foliation parallel fractures (FPFs) (42%), other fractures (32%) and sheet joints (26%). The boreholes are drilled into five lithologic terranes and intersect seven major lithologic and rock fabric types, consisting of: (1) felsic gneiss, (2) andesitic to basaltic flows, (3) diorite, (4) mafic gneiss, (5) gneiss and amphibolite, (6) gneiss and mylonite and (7) schist. The dominant fracture type in the upper 40 m is sheet joints. Rocks with sub-horizontal planar fabric prefer to develop FPFs instead of sheet joints.
    [Show full text]
  • Geomechanical Modeling of Stress and Fracture Distribution During Contractional Fault-Related Folding
    Journal of Geoscience and Environment Protection, 2017, 5, 61-93 http://www.scirp.org/journal/gep ISSN Online: 2327-4344 ISSN Print: 2327-4336 Geomechanical Modeling of Stress and Fracture Distribution during Contractional Fault-Related Folding Jianwei Feng1,2*, Kaikai Gu1,2 1School of Geosciences, China University of Petroleum, Qingdao, China 2Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China How to cite this paper: Feng, J.W. and Gu, Abstract K.K. (2017) Geomechanical Modeling of Stress and Fracture Distribution during Understanding and predicting the distribution of fractures in the deep tight Contractional Fault-Related Folding. Jour- sandstone reservoir are important for both gas exploration and exploitation nal of Geoscience and Environment Pro- activities in Kuqa Depression. We analyzed the characteristics of regional tection, 5, 61-93. structural evolution and paleotectonic stress setting based on acoustic emis- https://doi.org/10.4236/gep.2017.511006 sion tests and structural feature analysis. Several suites of geomechanical Received: September 25, 2017 models and experiments were developed to analyze how the geological factors Accepted: November 5, 2017 influenced and controlled the development and distribution of fractures dur- Published: November 8, 2017 ing folding. The multilayer model used elasto-plastic finite element method to capture the stress variations and slip along bedding surfaces, and allowed large Copyright © 2017 by authors and Scientific Research Publishing Inc. deformation. The simulated results demonstrate that this novel Quasi-Binary This work is licensed under the Creative Method coupling composite failure criterion and geomechanical model can Commons Attribution International effectively quantitatively predict the developed area of fracture parameters in License (CC BY 4.0).
    [Show full text]
  • Extrusion of Subducted Crust Explains The
    Extrusion of subducted crust explains the emplacement of far- travelled ophiolites Kristóf Porkoláb, Thibault Duretz, Philippe Yamato, Antoine Auzemery, Ernst Willingshofer Supplementary Note 1: Explanation for the datasets collected from natural ophiolite belts (Fig. 1) Datasets of 1) peak pressure-temperature (P-T) conditions, 2) duration of continental subduction- exhumation cycle, and 3) width of ophiolite sheets were collected from ophiolite belts worldwide in order to show key characteristics and provide a robust base for comparison with our numerical simulations. Peak P-T conditions of the lower plate units in obduction systems were collected from 8 ophiolite belts, from multiple structural levels, when possible (Supplementary Table 1). The dataset shows the dominance of HP-LT metamorphism that is typical for subduction zones. Two outliers of high temperature-medium pressure (HT-MP) peak conditions have been reported from Cuba 1 and Eastern Anatolia 2. These exceptions might be explained by oblique subduction below the oceanic upper plates and/or active rifting in the upper plate still ongoing during the initial stages of continental subduction 3,4. The duration of continental subduction-exhumation cycle was assessed at each natural example based on a broad literature review focusing on 1) the timing of continental subduction initiation (following the subduction of the oceanic lower plate), that is in most cases constrained by the age of the youngest passive margin sediments accreted to the front of (or overridden by) the oceanic upper plate; 2) geochronological data that constrains the timing of prograde, peak, and retrograde metamorphism and/or cooling of the continental lower plate; 3) timing indications for the surface exposure of the previously subducted continental units (timing of erosion and/or deposition of unconformably overlying sediments).
    [Show full text]
  • Deformation Mechanisms in a High-Temperature Quartz-Feldspar Mylonite: Evidence for Superplastic Flow in the Lower Continental Crust
    Tectonophysics, 140 (1987) 297-305 297 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands Deformation mechanisms in a high-temperature quartz-feldspar mylonite: evidence for superplastic flow in the lower continental crust J.H. BEHRMANN ’ and D. MAINPRICE 2 ’ Institut fti Geowissenschaften und Lithosphiirenforschung, Universitiit Giessen, Senckenbergstr. 3, D-6300 Giessen (West Germany) 2 Luboratoire de Tectonophysique, Universite des Sciences et Techniques du Lmguedoc, Place Eug&te Bqtaillon, F-34060 Montpellier cedex (France) (Received March 24,1986; revised version accepted January 13,1987) Abstract Behnnann, J.H. and Mainprice, D., 1987. Deformation mechanisms in a high-temperature quartz-feldspar mylonite: evidence for superplastic flow in the lower continental crust. Tectonophysics, 140: 297-305. Microstructures and crystallographic preferred orientations in a fme-grained banded quartz-feldspar mylonite were studied by optical microscopy, SEM, and TEM. Mylonite formation occurred in retrograde amphibohte facies metamorphism. Interpretation of the microstructures in terms of deformation mechanisms provides evidence for millimetre scale partitioning of crystal plasticity and superplasticity. Strain incompatibilities during grain sliding in the superplastic quartz-feldspar bands are mainly accommodated by boundary diffusion of potassic feldspar, the rate of which probably controls the rate of superplastic deformation. There is evidence for equal flow stress levels in the superplastic and crystal-plastic domains. In this case mechanism partitioning results in strain-rate partitioning. Fast deformation in the superplastic bands therefore dominates flow, and deformation is probably best modelled by a superplastic law. If this deformational behaviour is typical, shearing in mylonite zones of the lower continental crust may proceed at exceptionally high rates for a given differential stress, or at low differential stresses in case of fixed strain rates.
    [Show full text]
  • USBR Engineering Geology Field Manual Volume 1 Chapter 5
    Chapter 5 TERMINOLOGY AND DESCRIPTIONS FOR DISCONTINUITIES General Structural breaks or discontinuities generally control the mechanical behavior of rock masses. In most rock masses the discontinuities form planes of weakness or surfaces of separation, including foliation and bedding joints, joints, fractures, and zones of crushing or shearing. These discontinuities usually control the strength, deformation, and permeability of rock masses. Most engineering problems relate to discontinuities rather than to rock type or intact rock strength. Discontinuities must be carefully and adequately described. This chapter describes terminology, indexes, qualitative and quantitative descriptive criteria, and format for describing discontinuities. Many of the criteria contained in this chapter are similar to criteria used in other established sources which are accepted as international standards (for example, International Journal of Rock Mechanics, 1978 [1]). Discontinuity Terminology The use of quantitative and qualitative descriptors requires that what is being described be clearly identified. Nomenclature associated with structural breaks in geologic materials is frequently misunderstood. For example, bedding, bedding planes, bedding plane partings, bedding separations, and bedding joints may have been used to identify similar or distinctly different geological features. The terminology for discontinuities which is presented in this chapter should be used uniformly for all geology programs. Additional definitions for various types of discontinuities are presented in the Glossary of Geology [2]; these may be used to further describe structural breaks. The following basic defi- nitions should not be modified unless clearly justified, and defined. FIELD MANUAL Discontinuity.—A collective term used for all structural breaks in geologic materials which usually have zero to low tensile strength.
    [Show full text]
  • Rollback Orogeny Model for the Evolution of the Swiss Alps
    Tectonics RESEARCH ARTICLE Rollback Orogeny Model for the Evolution 10.1002/2017TC004762 of the Swiss Alps Key Points: Edi Kissling1 and Fritz Schlunegger2 • Central Alpine orogeny driven by mantle llithosphere rollback 1Institute of Geophysics, ETH Zürich, Zürich, Switzerland, 2Institute of Geological Sciences, University of Bern, Bern, subduction • No hard collision between two Switzerland continents required to build up the Alps • Deep crustal root compensating loads Abstract The construction of the European Alps and the Himalayas has been related to the convergence of relatively low topography and and subsequent collision of two continental plates. Nearly all models of orogeny build on this concept, and all mantle slab of them relate the stacking of nappes and the buildup of topography to compressional forces at work in response to the collision between two continental plates. For the central European Alps, however, these models fail to explain the first-order observations of a mountain belt, which particularly includes the striking Correspondence to: isostatic imbalance between the low surface topography and the thick crust beneath the Alps. Here we E. Kissling, review and synthesize data on the geologic architecture of the central Alps, the chronology and pattern of [email protected] crustal deformation, and information about the deep crustal structure derived from seismic tomography. Furthermore, we discuss the intrinsic and explicit assumptions in the kinematic models of Alpine evolution in Citation: the context of plate tectonic considerations. We combine these views with progress in understanding that Kissling, E., & Schlunegger, F. (2018). Rollback orogeny model for the has been gained through subduction and collision, isostatic mass and force balancing and with information evolution of the Swiss Alps.
    [Show full text]