Late to postvariscan extensional tectonics in south cornwall. Your chance to have a onetoone lesson with bestselling language expert paul noble, try a free audio sample of his brand new mandarin chinese course. Box 1047, blindern, n0316 oslo, norway received 24 october 1995. The section reproduced convincingly demon strates that parts of a given hanging wall may remain unrotated while other parts may rotate in opposite direc tions. Since middle pliocene, the axial part of this foldthrust belt underwent an extensional tectonics. Extensional tectonics in the vicinity of a transform fault in.
Recent extensional tectonics on the moon revealed by the lunar reconnaissance orbiter camera. Extensional tectonics is concerned with the structures formed by, and the tectonic processes associated with, the stretching of a planetary bodys crust or lithosphere deformation styles. The fact that lowangle normal faults exist in both extensional and compressional tectonic settings, and can actively slip at low angles extensional tectonics workshop course summary extensional structures provide some of the worlds largest known oil reservoirs and remain one of the major frontier plays of the immediate future, both onshore and, particularly, in deep water offshore. Extensional tectonics free online course materials. The model predicts significant extensional deformation in regions with surface heat flow 65 mwm 2 subjected to a tensile tectonic force of 3.
Faults which postdate variscan contractional deformation are ubiquitous in south cornwall. Study of the structures formed by, and the processes associated with, the stretching of a planetary bodys crust. Pdf extensional tectonics in the basin and range, the aegean. Dec 22, 2019 extensional tectonics is concerned with the structures formed by, and the tectonic processes associated with, the stretching of a planetary bodys crust or lithosphere. Granite magmatism and extensional tectonics in southern. Public domain topics comparison, computer programs, free flow, mach number, separated flow, subsonic flow, three dimensional flow, convergentdivergent nozzles, experiment design, predictions, pressure gradients, propulsion system configurations. The basin is bounded to the north by the lunedalewigglesworthbutterknowle en echelon suite of normal faults. Extensional tectonism may form during as well as after the contractional history of a collisional orogeny. Extensional tectonics of the outer hebrides fault zone, south. Pdf extensional tectonics in the himalayan orogen, zanskar. Extensional tectonics is associated with the stretching and thinning of the crust or the lithosphere. The aegean region western anatolia, aegean sea and greece is one of the areas of the earth under the effect of extensional tectonics and includes the typical features of core complexes in this type of region.
The first type comprises low angle dip extensional faults which exhibit listric. The title extensional tectonics of centralnorthern mexico reflects a fraction of studies on mexican country, which are summed up in a research sponsored by the ministry of education and the national council for science and technology and identified with number 167638. Wikipedia definition extensional tectonics is concerned with the structures formed by, and the tectonic processes associated with, the stretching of a planetary bodys crust or lithosphere. Hancock and others published continental extensional tectonics find, read and cite all the research you need on researchgate.
Kinematic studies combined with various age constraints in the southern scandinavian caledonides have revealed an extensional history which started by hinterland. The structural and sedimentological evolution of a 100 km. The eastern margin of the gulf of suez displays spectacular interrelationships between riftborder fault systems and sedimentation patterns. Normal faults form in divergent plate boundaries, areas of gravitational collapse and extension above salt domes. Pdf on jun 1, 2010, ibrahim cemen and others published extensional tectonics in the basin and range, the aegean, and western anatolia. Abstract this paper discusses the geological and geophysical interpretation of rift structures in the region extending from the rio grande rise, in the southeastern brazilian margin, towards the cabo frio high, which separates the campos and santos basins. Dec 08, 2011 this file contains additional information such as exif metadata which may have been added by the digital camera, scanner, or software program used to create or digitize it. The sverdrup basin originated due to an episode of extensional tectonics that affected much of the caledonianellesmerian orogenic belt in early. Extensional crustal tectonics and crustmantle coupling, a. An animated tectonic reconstruction of southwestern north america since 36 ma nadine mcquarrie brian p. Faulting and faultrelated processes key issues in earth sciences on free shipping on qualified orders. Longer aftershocks duration in extensional tectonic. A curve with a negative gradient results, and the intercept of the curve with the ordinate defines the null point.
Extensional tectonic regimes are primarily associated with divergent plate boundaries, but can also commonly be found in plate interiors in the form of localized rift zones and extensional basins. The trollaskagi peninsula is located just south of the junction between the kolbeinsey ridge and the tjornes fracture zone and offers a rare opportunity for studying the three. A characteristic pattern of normal faults that we have studied in several regions illustrates successive geometries relating to increasing amounts. Lecture notes section contains class notes for the topic covered in the lectures. Extensional tectonics and salt structures, maribshabwa. Extensional tectonics wikipedia republished wiki 2. Sometime after the first and before the start of the second episode of. Extensional tectonics in the himalayan orogen, zanskar, nw india. Extensional tectonics and stratigraphy of the north atlantic margins authors a.
Rifting, seafloor spreading, and extensional tectonics. Tectonics presents original research articles that describe and explain the evolution, structure, and deformation of earths lithosphere including across the range of geologic time. Compressional and extensional tectonics in lowmedium. Upper miocenelower pliocene extension in mt parnon was. The types of structure and the geometries formed depend on the amount of stretching involved.
Geological society, london, special publications geometry. Geological society, london, special publications geometry and. Lecture notes structural geology earth, atmospheric, and. Any synorogenic extensional deformation must have occurred prior to the onset of this extensional history, which is dated to circa 405 ma. Extensional tectonic regimes are therefore primarily associated with divergent i. Regional tectonics are extensional and there is little structural evidence for earlier crustal thickening. The tectonics of the fault zone on south uist are dominated by structures associated with several episodes of pervasive topdowntothese to ene brittle extensional deformation, which are progressively overprinted by protophyllonitic and phyllonitic fabrics associated with topdowntothee to ene extension. Rifting the process by which continental lithosphere undergoes extensional deformation stretching by the formation and activity of normal faults. We have analysed potential field data gravity and magnetic from the argentine to the brazilian oceanic basins and extending over the. Extensional tectonic environment a region of the earths crust or lithosphere that is spreading apart due to tectonic forces acting on the surrounding areas. We attempt, by means of quantitative theoretical analysis guided by real geological examples, to establish some ground rules for interpreting extensional phenomena. The central and southern appalachians have a long history of interrelated extensional and compressional tectonics. Extensional tectonics and collapse structures in the suez. Compressional metamorphic core complexes, lowangle normal.
Extensional tectonics fall 2005 1 the jargon of extensional tectonics for the following terms, draw a simple illustrative diagram consisting of either a map and crosssection or a block diagram. The earth is composed of layers of different composition and physical properties, principally the solid central core, the fluid peripheral core, the viscous mantle, and the solid. Tension fractures and extensional tectonics nature. Three broad geometrickinematic types can be defined. On the moon, extensional tectonic features have only been observed close to the influence of the mare basaltfilled basins and floorfractured craters. Sedimentary models for extensional tiltblockhalfgraben basins. Proprietary seismicreflection profiles show a system of downtotheeast precambrian extensional faults. Backarc basins are regions of extension behind subduction zones and are often locations where volcanoes form. It is proposed that each episode was controlled by a reactivation of a fracture system in the precambrian basement. Previously unrecognised extensional tectonics exposed in.
Several episodes of granite magmatism are recorded, culminating in the late. Drilling through an extensional normal fault encounters a stratigraphic gap. Longer aftershocks duration in extensional tectonic settings. Extensional tectonics, a slab window and the arrival of.
If you need to print pages from this book, we recommend downloading it as a pdf. Extensional tectonics in the caledonides of southern norway, an overview torgeir b. The course covers the field level all the way up to basinscale architecture, and the role of salt and strikeslip tectonics in the development of extensional basins. Download and read free online basin and range extensional tectonics near the latitude of las vegas, nevada memoir geological society of america by brian p. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses. Basin and range extensional tectonics at the latitude of las vegas, nevada brian wernicke.
Extensional definition and meaning collins english. The shape of this curve is a result of extensional tectonics, and gradient changes record vari. Ashton embry, benoit beauchamp, in the sedimentary basins of the united states and canada second edition, 2019. Basins that form within an extensional tectonic setting are characterized by the development of depressions, bounded by normal faults, within. Tectonics, in situ stress stress, faults and rock failure.
Extensional tectonics an overview sciencedirect topics. Predictive permeability model of extensional faults in crystalline. Extensional tectonics and sedimentation, eastern gulf of. There are still many important questions of extensional tectonics. Extensional tectonics wikimili, the free encyclopedia. Kt magmatism and basin tectonism in western rajasthan. Burchfiel department of earth and planetary sciences, massachussetts institute of technology, cambridge, ma 029, u. Sharma government postgraduate college, sirohi rajasthan 307001 india email. This type of tectonics is found at divergent plate boundaries, in continental rifts, during and after a period of continental collision caused by the lateral spreading of the thickened crust formed, at releasing bends in strikeslip faults, in backarc basins, and on the continental end of. In terms of plate tectonics, extension systems are associated with.
Structural geology, tectonics and geodynamics form a coherent and interdependent. Divergent extensional tectonic regimes springerlink. This first episode of extension left the cms with the normal ocotillo canyon fault and a related graben containing nonmarine syn extensional sediments lower part of the split mountain group. Compressional and extensional tectonics in lowmedium pressure granulites from the larsemann hills, east antarctica volume 2 issue 2 c. Extensional tectonics is concerned with the structures formed by, and the tectonic processes associated with, the stretching of a planetary bodys crust or lithosphere. Front matter continental tectonics the national academies.
The lithosphere lithosphere is comprised of the upper mantle and the crust, the outer shell of the earth. Modes of extensional tectonics brian wernicke and b. Extensional tectonics and collapse structures in the suez rift egypt. This type of tectonics is found at divergent plate boundaries, in continental rifts, during and after a period of continental collision caused by the lateral spreading of the thickened crust formed. Geological and geophysical interpretation of the rio. Sedimentary models for extensional service email alerting new articles cite this article click here to receive free email alerts when request permission part of this article click here to seek permission to reuse all or subscribe collection london, special publications or the lyell click here to subscribe to geological society, notes. The identification of early cretaceous, riftoblique extension that predated the main rifting event in the barmer basin. It underlines the role of extensional tectonics during sedimentation.
Extensional tectonics in the caledonides hardangerfjord shear zone figure 2. Lecture notes structural geology earth, atmospheric. Another widespread setting for extensional tectonics are upper plates above subduction zones subjected to. Subsidence the sinking of the surface of the lithosphere. Extensional tectonics and stratigraphy of the north. The majority of the chapter is devoted to a discussion of stretching processes that affect the whole lithosphere and are driven by the relative motion of lithospheric plates. Rifts are regions in which extensional tectonics i. The menderes massif in western anatolia was exhumed initially as an asymmetric core complex in the early miocene due to extension beginning in the oligocene and then the central. Andersen institutt for geologi, universitetet i oslo, p.
An animated tectonic reconstruction of southwestern north. Rifting, seafloor spreading, and extensional tectonics geokniga. Extensional tectonics is concerned with the structures formed by, and the tectonic processes. Apr 01, 2000 read extensional tectonics in the caledonides. Extensional tectonics in the caledonides of southern. As the surface of the earth is stress free, the component of simple shear must be transmitted from below and implies a displacement of the crust relative to the mantle. Recently released industry seismic data image a 6 km thick dinantian succession in the stainmore basin, and are used to interpret deposition in response to extensional subsidence. Arundian synrift sequence more than 4 km thick includes footwallderived. Abstract we investigate the feedbacks between surface processes and tectonics in an extensional setting by coupling a 2. Wernicke division of geological and planetary sciences, ms 10023, california institute of technology, pasadena, ca 91125 abstract we present tectonic reconstructions and an. Pdf on oct 11, 2015, jesus galindozaldivar and others published extensional tectonics, graben development paper find, read and cite all the research you need on researchgate. Kt magmatism and basin tectonism in western rajasthan, india, results from extensional tectonics and not from reunion plume activity kamal k.
Although hundreds of papers have been devoted to the geometric and kinematic analysis of compressional tectonic regimes, surprisingly little has been written about the details of largescale strain in extended areas. Received 1 september 1981, accepted in revised form 10 march 1982. Pdf extensional tectonics, graben development paper. Recent extensional tectonics on the moon revealed by the. Article pdf available in geological society london special publications 741.
Pdf continental extensional tectonics researchgate. Aulacogen an unsuccessful rift that cuts across a continental margin at a high angle to the margin. Analysis of structural traps in extensional settings. Typically, aulacogens transect the grain of an orogen that borders the margin. Strikeslip faulting is a common mode of deformation in both continental and oceanic crust and. Aulacogens may represent failed arms of threearmed rifts, or they may simply be older rifts formed long before the development of the continental margin, during an earlier episode of rifting at a different. Peloponnesus in the southwestern part of the aegean is formed by a heterogeneous pile of alpine thrust sheets that was reworked by normal faulting from upper miocene to recent times. Basin and range extensional tectonics at the latitude of.
Pdf extensional tectonics in mt parnon peloponnesus. The relationship of extensional and compressional tectonics. The remaining por tions of the orogenic wedge are dominated by rocks of the jotun nappe, which is a major fragment of mostly crystal line proterozoic crust that appears to have been thrust for more than 300 km e. Modes of extensional faulting controlled by surface processes. At the junction between an oceanic transform fault and the adjacent ridge segments, there is normally a curved fabric. A systematic comparison of experimental setups for. Extensional tectonics is concerned with the structures formed, and the tectonic processes associated with, the stretching of the crust or lithosphere. Rotational normal fault a normal fault whose hanging wall block rotates around a horizontal axis during slip. View extensional tectonics research papers on academia.