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Cambridge University Press978-1-107-05764-7 - Structural Geology: Second EditionHaakon FossenFrontmatterMore informationHow to use this bookEach chapter starts with a general introduction,which presents a context for the topic withinstructural geology as a whole. These introductionsprovide a roadmap for the chapter and will help17Contractional regimesContractional faults occur in any tectonic regime,but they are most common along destructive plateboundaries and in intracratonic orogenic zones.The e-module for this chapter, Contraction,provides further support on the followingtopics:Contractional structures received much attentionyou to navigate through the book. The box alongsideidentifies which online e-module accompanies thechapter and the topics that it covers.from the last part of the nineteenth century up tothe end of the twentieth century, when the focusshifted somewhat towards extensional structures.The study of contractional faults resulted in the development of balanced cross-sections, and broughtattention to the role of fault overlaps and relaystructures, the relation between displacement andfault length, and the mechanical aspects of faulting. Understanding contractional faults is importantnot only for better understanding of orogenic processes in general, but also for improved petroleumexploration methods, because a number of theworld’s oil resources are located in fold and thrustbelts. The fundamentals of contractional faults andrelated structures are covered in this chapter, with afocus on thrust structures found in orogenic belts.The main text contains highlighted terms and key expressions that you will need to understand and becomefamiliar with. Many of these terms are listed in the Glossary at the back of the book. The Glossary allows youto easily look up terms whenever needed and can also beused to review important topics and key facts. Each chapteralso contains a series of highlighted statements toencourage you to pause and review your understanding ofwhat you have read.Boxes present in-depth information about a particularsubject, helpful examples or relevant background information. Other important points are brought together in thechapter summaries. Review questions should be usedto test your understanding of the chapter before movingon to the next topic. Answers to these questions are givenon the book’s webpage. Further reading sections providereferences to selected papers and books for those interestedin more detail or advanced information. in this web service Cambridge University Presswww.cambridge.org

Cambridge University Press978-1-107-05764-7 - Structural Geology: Second EditionHaakon FossenFrontmatterMore informationHow to use this bookixE-learning modules further reinforce key topicsusing summaries, additional examples and figures,and innovative animations to bring concepts to life.Use of these e-modules is highly recommended afterreading the chapter as part of review and exampreparation. The modules provide supplementaryinformation that complements the main text.Online resourceswww.cambridge.org/fossen2eSpecially prepared resources, unique to this book, areavailable from the book’s webpage. These include: E-learning modules that combine animations, text,illustrations and photographs. These present keyaspects of structural geology in a highly visual andinteractive environment. Answers to the end-of-chapter review questionsfor instructors. Additional student exercises (with solutions forinstructors). All of the figures for each chapter as jpeg andPowerPoint files. An electronic glossary of terms. A gallery of supplementary figures illustratingadditional geologic structures and field examples. Tutorial videos from the field. Links to other web-based structural geologyresources including software. Links to the author’s blog and community Facebook page. in this web service Cambridge University Presswww.cambridge.org

Cambridge University Press978-1-107-05764-7 - Structural Geology: Second EditionHaakon FossenFrontmatterMore information in this web service Cambridge University Presswww.cambridge.org

Cambridge University Press978-1-107-05764-7 - Structural Geology: Second EditionHaakon FossenFrontmatterMore informationPrefaceThis is the second edition of Structural Geology; a textbookthat was first published in 2010. The first edition was verywell received among students, lecturers and industry professionals alike. I received a lot of encouraging commentsand helpful feedback from readers, and this has been amotivating factor for preparing a new and improved version with updated text, illustrations and photographs thatpreserves the overall structure of the previous edition.The purpose of the book is to introduce undergraduatestudents, and others with a general geologic background,to the basic principles, aspects and methods of structuralgeology. It is mainly concerned with the structural geology of the crust, although the processes and structuresdescribed are relevant also for deformation that occursat deeper levels within our planet. Further, remote datafrom Mars and other planets indicate that many aspectsof terrestrial structural geology are relevant also beyondour own planet.The field of structural geology is very broad, and thecontent of this book presents a selection of importantsubjects within this field. Making the selection has notbeen easy, knowing that lecturers tend to prefer theirown favorite aspects of, and approaches to, structural geology, or make selections according to their localdepartmental course curriculum. Existing textbooksin structural geology tend to emphasize the ductile orplastic deformation that occurs in the middle and lower crust. In this book I have tried to treat the frictionalregime in the upper crust more extensively so that it better balances that of the deeper parts of the crust, whichmakes some chapters particularly relevant to courseswhere petroleum geology and brittle deformation ingeneral are emphasized. This philosophy is extendedwith the second edition, particularly by the addition of anew chapter on joints and veins.Obtaining this balance was one of several motivatingfactors for writing this book, and is perhaps related to mymixed petroleum geology and hard-rock structural geol ogy experience. Other motivating factors include the desire to make a book where I could draw or redraw all of theillustrations and be able to present the first full-color bookin structural geology. I also thought that a fundamental in this web service Cambridge University Pressstructural geology text of the twenty-first century shouldcome with specially prepared e-learning resources, sothe package of e-learning material that is presented withthis book should be regarded as part of the present bookconcept.Book structureThe structure of the book is in many ways traditional, going from strain (Chapters 2 and 3) to stress (Chapters 4and 5) and via rheology (Chapter 6) to brittle deformation (Chapters 7–10). Of these, Chapter 2 contains somemater ial that would be too detailed and advanced for somestudents and classes, but selective reading is possible.Then, after a short introduction to the microscale structures and processes that distinguish crystal-plastic frombrittle deformation (Chapter 11), ductile deformationstructures such as folding, boudinage, foliations and shearzones are discussed (Chapters 12–16). Three consecutivechapters then follow that are founded on the three principal tectonic regimes (Chapters 17–19) before salt tectonics and restoration principles are presented (Chapters20 and 21). A final chapter, where links to metamorphicpetrology as well as stratigraphy are drawn, rounds off thebook, and suggests that structural geology and tectonicslargely rely on other disciplines. The chapters do not haveto be read in numerical order, and most chapters can beused individually.Emphasis and examplesThe book seeks to cover a wide ground within the field ofstructural geology, and examples presented in the text arefrom different parts of the world. However, pictures andillustrations from a few geographic areas reappear. Oneof those is the North Sea rift system, which I know frommy years with the Norwegian oil company Statoil and later academic research. Another is the Colorado Plateau,which over the last two decades has become one of myfavorite places to do field work. A third, and much wetterand greener one, is the Scandinavian Caledonides, balanced by the much hotter Araçuai-Ribeira Belt in Brazil.Many of the examples used to illustrate structures typicalof the plastic regime come from these orogenic belts.www.cambridge.org

Cambridge University Press978-1-107-05764-7 - Structural Geology: Second EditionHaakon FossenFrontmatterMore informationAcknowledgmentsDuring the writing of this textbook I have built on experience and knowledge achieved as a student, duringvarious industrial and academic positions, and throughthe writing of this book. In this respect I want to thankfellow students, geologists and professors with whom Ihave interacted during my time at the Universitiesof Bergen, Oslo, Minnesota and Utah, at Utah StateUniversity, in Statoil and at the Geological Survey ofNorway. In particular, my advisers and friends Tim Holst,Peter Hudleston and Christian Teyssier deserve specialthanks for generously sharing their knowledge duringmy time as a student, and also once fellow student BasilTikoff for valuable discussions and exchange of ideas inPillsbury Hall. Among my many co-workers, colleaguesand former students I wish to extend special thanks toRoy Gabrielsen, Jan Inge Faleide, Jonny Hesthammer,Rich Schultz, Roger Soliva, Gregory Ballas, Rob Gawthorpe, Ritske Huismans and Carolina Cavalcante.Special thanks also go to Wallace Bothner, Rob Butler, Nestor Cardozo, Declan DePaor, Jim Evans, James in this web service Cambridge University PressKirkpatrick, Stephen Lippard, Christophe Pascal, AtleRotevatn, Zoe Shipton, Holger Stunitz, Bruce Trudgill,Carolina Cavalcante, Luiz Morales and Fred Vollmerfor critically reading various parts of the text. Valuableassist ance and company in the field that have influencedthis book were provided by Julio Almeida, Renato Almeida, Nicolas Badertscher, Wallace Bothner, Jean M. Crespi, Rui Dias, Marcos Egydia, Jim Evans, Jonny Hesthammer, Fernando O. Marques, Roger Soliva, John Walshand Adolph Yonkee. Thanks also to readers who sentcomments on various parts of the first editions. Finally,other textbooks have been of invaluable worth both during my time as a student of structural geology in generaland during the preparation of this book. In particular Ihave enjoyed and learned a lot from the books by Hobbs,Means and Williams (1976), Twiss and Moores (2007),van der Pluijm and Marshak (2004), and various editionsof George H. Davis and co-authors’ Structural Geologytext, as well as the excellent Microtectonics text by Passchier and Trouw (2005).www.cambridge.org

Cambridge University Press978-1-107-05764-7 - Structural Geology: Second EditionHaakon FossenFrontmatterMore informationSymbolsalong axis of ellipse representing a microcrackA area;empirically determined constant in flow lawsBlayer thicknesscshort axis of ellipse representing a microcrackCcohesion or cohesional strength of a rockCfcohesive strength of a faultdoffsetdclthickness of clay layerD displacement;fractal dimensionDmaxmaximum displacement along a fault trace or on a fault surfaceDdeformation (gradient) matrixe εelongationė ε̇elongation rate (de / dt)ėx , ėyelongation rates in the x and y directions (s 1)e1, e2 , e3 eigenvectors of deformation matrix, identical to the three axes of the strainellipsoidēlogarithmic (natural) elongationēsnatural octahedral unit shearE Young’s modulus; activation energy for migration of vacancies through a crystal(J mol 1 K 1)E*activation energyFforce vector (kg m s 2, N)Fnnormal component of the force vectorFsshear component of the force vectorgacceleration due to gravity (m/s2)hlayer thicknessh0initial layer thicknesshTlayer thickness at onset of folding (buckling)ISA1 3instantaneous stretching axesk parameter describing the shape of the strain ellipsoid(lines in the Flinn diagram)Kbulk modulusKistress intensity factorKcfracture toughnesskx , ky pure shear components, diagonal elements in the pure shear and simpleshear matriceslline length (m)l0line length prior to deformation (m)Lvelocity tensor (matrix)L fault length;wavelength in this web service Cambridge University Presswww.cambridge.org

Cambridge University Press978-1-107-05764-7 - Structural Geology: Second EditionHaakon FossenFrontmatterMore informationxivList of symbolsLddominant wavelengthLTactual length of a folded layer over the distance of one wavelengthnexponent of displacement-length scaling lawpffluid pressurePpressure (Pa)Qactivation energyR ellipticity or aspect ratio of ellipse (long over short axis); gas constant(J kg 1 K 1)Rffinal ellipticity of an object that was non-circular prior to deformationRiinitial ellipticity of an object (prior to deformation)Rs same as R, used in connection with the Rf/ϕ-method to distinguishit from RfRxyX/YRyzY/ZsstretchingṠstretching tensor, symmetric part of Lttime (s)T temperature (K or C);uniaxial tensile strength (bar);local displacement or throw of a fault when calculating SGR and SSFvvelocity vector (m/s)Vvolume (m3)V0volume prior to deformationVpvelocity of P-wavesVsvelocity of S-waveswvorticity vectorwvorticityWvorticity (or spin) tensor, which is the skew-symmetric component of LWkkinematic vorticity numberxvector or point in a coordinate system prior to deformationx'vector or point in a coordinate system after deformationx, y, zcoordinate axes, z being verticalX, Y, Zprincipal strain axes; X Y ZZcrustal depth (m)α thermal expansion factor (K 1);Biot poroelastic parameter;angle between passive marker and shear direction at onset ofnon-coaxial deformation (Chapter 15);angle between flow apophyses (Chapter 2)α' angle between passive marker and shear direction after a non-coaxialdeformationβstretching factor, equal to s volume change factor σchange in stressγshear strainγ̄octoctahedral shear strainγ̇shear strain rateΓnon-diagonal entry in deformation matrix for subsimple shearηviscosity constant (N s m 2)λquadratic elongationλ 1, λ2 , λ 3eigenvalues of deformation matrix λ1, λ2, λ3 length of strain ellipse axes in this web service Cambridge University Presswww.cambridge.org

Cambridge University Press978-1-107-05764-7 - Structural Geology: Second EditionHaakon FossenFrontmatterMore informationList of symbolsxvμ shear modulus;viscosityμfcoefficient of sliding frictionμLviscosity of buckling competent layerμMviscosity of matrix to buckling competent layerν Poisson’s ratio;Lode’s parameterθ angle between the normal to a fracture and σ1;angle between ISA1 and the shear planeθ'angle between X and the shear planeρdensity (g/cm3)σstress ( F/ A) (bar: 1 bar 1.0197 kg/cm2 105 Pa 106 dyne/cm2)σstress vector (traction vector)σ1 σ2 σ3 principal stressesσ̄effective stressσaaxial stressσ devdeviatoric stressσ diffdifferential stress (σ1 σ 3)σHmax horizontal stressσhmin horizontal stressσ h* average horizontal stress in thinned part of the lithosphere(constant-horizontal-stress model)σmmean stress (σ1 σ 2 σ 3)/3σnnormal stressσrremote stressσsshear stressσttectonic stressσtipstress at tip of fracture or point of max curvature along pore marginσtottotal stress (σ m σ dev)σvvertical stressσgnnormal stress at grain–grain or grain–wall contact areas in porous mediumσnwaverage normal stress exerted on wall by grains in porous mediumϕ internal friction (rock mechanics);angle between X and a reference line at onset of deformation (Rf/ϕ-method)ϕ'angle between X and a reference line after a deformation (Rf/ϕ-method)Φporosityψangular shearωangular velocity vector in this web service Cambridge University Presswww.cambridge.org

Cambridge University Press978-1-107-05764-7 - Structural Geology: Second EditionHaakon FossenFrontmatterMore information in this web service Cambridge University Presswww.cambridge.org

Structural geology and structural analysis 1 1.1 Approaching structural geology 2 1.2 Structural geology and tectonics 2 1.3 Structural data sets 4 1.4 Field data 5 1.5 Remote sensing and geodesy 8 1.6 DEM, GIS and Google Earth 10 1.7 Seismic data 10 1.8 Experimental data 14 1.9 Numerical modeling 15 1.10 Other data sources 15