Role of faults and folding in controlling gold mineralisation. Pdf overlying fold shape purple contours depends on interaction among subsurface faults red lines. Reflection profiles across the wind river uplift in wyoming, usa, show that folding of basement rocks occurs in the footwall of the main fault at depths between 6 and 10km. In addition, fault related folding can occur in strikeslip situations e. These types of structures form the majority of the large hydrocarbon traps in both orogenic and passivemargin fold and thrust belts worldwide. Insights into contractional faultrelated folding processes. Fault scarps formed during the earthquakes of october 2, 1915, in pleasant valley, nevada, and some tectonic implications. Highdensity regions of fractures are mainly located in the fold limbs during initial folding stage, then gradually migrate from forelimb to backlimb, from limbs to hinge, from deep to shallow along with the fold uplift. Faultbend folds are caused by displacement along a nonplanar fault. Thus, we explore other mapview patterns of fault related folds to establish additional criteria for recognizing and interpreting imbricate thrust systems. The chapters include kinematic and geometric analyses of faultpropagation folding, trishear folding, detachment folding, wedgethrust fold systems, and basementinvolved thrust systems. With this aim, we used a new experimental setup that allows accurate measurements of fault slip kinematics and of the associated deformation field dominguez, et al.
Limbs widen self similarly growth triangle records progressively more slip with time inactive axial surfaces once at. We used a natural example of faultrelated folding from the limon foldandthrust belt in eastern costa rica to test two different algorithms and to compare the resulting. Memoir 94 thrust faultrelated folds form numerous important hydrocarbon traps in subaerial and deepwater fold and thrust belts as well as in inversion fold and thrust belts. This motion is still active today as the alps continue to uplift, fold, fault, and accrete. Larger faults are mostly from action occuring in earths plates. Journal of structural geology faultrelated folding. We analyze the kinematics of fault tip folding at the front of a foldandthrust wedge using a sandbox experiment. Geomechanical modeling of stress and fracture distribution.
Introduction structural geology is the study of factors such as origin, occurrence, classification, type and effects of various secondary structures like folds, faults, joints, rock cleavage and are different from those primary structures such as bedding and vesicular structure, which develop in rocks at the time of their formation. Growth and lateral propagation of faultrelated folds in the. The first section illustrates the application of fault related folding theories to many wellimaged seismic examples by way of stepbystep interpretations and ubiquitous models. Back thrusts accommodate hangingwall strain during the formation of fault related folds. A fault line is the trace of a fault, or the line of intersection between the fault line and the earths surface. Thrust fault related folds form numerous important hydrocarbon traps in subaerial and deepwater fold and thrust belts as well as in inversion fold and thrust belts. This memoir presents 16 papers on new advances in the analysis and understanding of thrustrelated fold systems including detachment folds, thrustfault propagation folds, wedge thrustrelated fold systems, and. Other readers will always be interested in your opinion of the books youve read. Passive margins and rift basins often present intriguing structural complexities that are potential sites for the development of extensional faultrelated folds.
In this group, folds are formed on the top and at the tip of upwarddeveloping thrusts like fault bend folds and thrusttip folds. Pdf active faultrelated folding in the epicentral area of. The folding resembles that of subjacent strata and indicates that the folding may have been taking place for at least the past 2 m. Extensional fault related folds were firstly described by hamblin 1965, who found that the rollover folds had close relationship with nomal faults1. However, its basic requirement of an instantaneous propagation of the entire fault before hangingwall deformation, limits its. A fault is a break in the rocks that make up the earths crust, along which on either side rocks move pass eachother. We derive expected displacements for kinematic models of endmember fault related folding styles, and validate this approach for natural structures imaged in. We present a method of using fault displacementdistance profiles to. Occurrence and development of folding related to normal.
Comparison of faultrelated folding algorithms to restore a. Fault dynamics research group, department of earth sciences, royal holloway university of london. Many folds are directly related to faults, associated with their propagation, displacement and the accommodation of strains between neighboring faults. This memoir presents 16 papers on new advances in the analysis and understanding of thrustrelated fold systems including detachment folds, thrustfault propagation folds, wedge. The occurrence of faultrelated folds in extensional settings has been gaining increased recognition during the past 20 yr. The 16 chapters presented in this memoir cover some of the recent advances made in the descriptions and analysis of thrustrelated fold systems.
The emphasis is on contractional faultrelated folds, including faultbend folds, faultpropagation folds, detachment folds, shear faultbend folds, imbricate thrust systems, and structural wedges. Active folding and blind thrust faulting induced by basin inversion. A dense grid of petroleum industry seismic reflection profiles, coupled with field mapping, exploratory trenching and geomorphic and structural analysis are used to characterize the quaternary growth history of the capriano del colle fault system. Williams, andrea artoni, jaume verges, stuart hardy pages 4441. The analog model consists of sand layers intercalated with lowfriction glass bead layers, deposited in a glasssided experimental device and with a total thickness h 4. In a reverse fault, the block above the fault moves up relative to the block below the fault. Faulting related to the es in pleasant valley, j 7 nevada u.
Pdf overlying fold shape purple contours depends on. The balanced models in figure 8 illustrate that imbricate structures have. Typical thrust belts with coexisted structural styles of fault. St53 seismic interpretation of contractional faultrelated. Extensional folds occur in most extensional basins and regions, the. Patterns of imbricate thrusting harvard university. Geological survey professional paper 1274a, b bibliographies. Abstract weldon beauchamp, and david mcdonald,transatlantic petroleum corp. Kinematics of faultrelated folding derived from a sandbox experiment. In addition, faultrelated folding can occur in strikeslip situations e. Extensional faultrelated folds were firstly described by hamblin 1965, who found that the rollover folds had close relationship with nomal faults1. The faultrelated folds observed in the south pyrenean fold and thrust belt are hybrid structures with elements of detachment folding as well as. The emphasis is on contractional faultrelated folds, including faultbend folds, faultpropagation folds, detachment folds, shear faultbend. They either form selectively in competent units or propagate through the.
Memoir 94 thrust fault related folds form numerous important hydrocarbon traps in subaerial and deepwater fold and thrust belts as well as in inversion fold and thrust belts. An investigation into the role of fault interaction on fold pattern, journal of structural geology, vol. This memoir presents 16 papers on new advances in the analysis and understanding of thrust related fold systems including detachment folds, thrust fault propagation folds, wedge. Coseismic faultrelated fold model, growth structure, and the. Faultrelated folds in the southern pyrenees geoscienceworld. It is also significant in the field of deepwater foldandthrust belts camerlo and benson, 2006, morley et al. Thrust faultrelated folds form numerous important hydrocarbon traps in subaerial and deepwater fold and thrust belts as well as in inversion fold and thrust belts. In the kinematic model of faultrelated passive folds, hinges must be mobile. Faultrelated folding during extension geoscienceworld. With this aim, we used a new experimental setup that allows accurate measurements of fault slip kinematics and of the associated deformation field dominguez et al. The emphasis is on contractional fault related folds, including fault bend folds, fault propagation folds, detachment folds, shear fault bend folds, imbricate thrust systems, and structural wedges. Major orogenic events involved recumbent folding and thrust faulting of crystalline basement rocks. Mcclay and others published thrust faultrelated folding find, read and cite all the research you need on researchgate. Mechanical models are used to infer three dimensional subsurface fault geometry from maps of fault scarps and deformed topography, represented by airborne lidar data.
Faulting related to the 1915 earthquakes in pleasant valley, nevada. Among these factors, the fold uplift and slip displacement along fault have. Limbs widen self similarly growth triangle records progressively more slip with time inactive axial surfaces once at axial surfaces, now translated above thrust. Folds that form in cover rocks in response to steep basement fault offsets have been called forced, drape, faultrelated, or faultpropagation folds. Chapter 2 focuses on faulting processes in the volcanic tableland, bishop, ca. Schematic cross sections showing kinematic link between coseismic fold fault scarps and geometries of underling thrustsin case of a emergent thrustramp, b singlestep fault bend fold suppe, 1983,andcwedgethrustfold medwedeff,1992. Structural geology team, chevron exploration technology company. Kinematics of faultrelated folding derived from a sandbox. This fault motion is caused by compressional forces and results in shortening. Introduction to thrust faultrelated folding aapg datapages. Thrust faultrelated folding mcclay, kenneth r suppe. This memoir presents 16 papers on new advances in the analysis and understanding of thrust related fold systems including detachment folds, thrust fault propagation folds, wedge thrust related fold systems, and basement. Pdf link pdf add to citation manager folding mechanisms in a faultpropagation fold inferred from the analysis of unconformity angles.
In chapter 1, we develop an independent means of determining the faultrelated folding style of a natural structure through observation of the distribution of displacement along the fault. Thus, we explore other mapview patterns of faultrelated folds to establish additional criteria for recognizing and interpreting imbricate thrust systems. Pdf faultrelated fold styles and progressions in foldthrust belts. Schematic cross sections showing kinematic link between coseismic foldfault scarps and geometries of underling thrustsin case of a emergent thrustramp, b singlestep fault bend fold suppe, 1983,andcwedgethrustfold medwedeff,1992. However, its basic requirement of an instantaneous propagation of the entire fault before hangingwall deformation, limits its kinematic effectiveness. Fault related folding near the wind river thrust, wyoming. In this73 paper we use 2 and 3d seismic reflection data from the inner moray firth basin, 74 offshore scotland, to investigate the influence of hostrock lithology, and fault geometry and fault interaction75 on the development of. The first section illustrates the application of faultrelated folding theories to many wellimaged seismic examples by way of stepbystep interpretations and ubiquitous models. Large faults within the earths crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as subduction zones or. The 16 chapters presented in this memoir cover some of the recent advances made in the descriptions and analysis of thrust related fold systems. Fault bend folds are caused by displacement along a nonplanar fault. A compilation of 25 case studies from petroleum basins around the world comprises the second section of the atlas. In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rockmass movement. Seismic interpretation of contractional faultrelated folds.
Pdf faultrelated folds of variable structural styles and assemblages commonly coexist in orogenic belts with competentincompetent. The chapters include kinematic and geometric analyses of fault propagation folding, trishear folding, detachment folding, wedgethrust fold systems, and basementinvolved thrust systems. We derive expected displacements for kinematic models of endmember faultrelated folding styles, and validate this approach for natural structures imaged in. Faultrelated folds are important anticlinal traps for.
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