Showing papers in "Journal of Structural Geology in 1989"

TL;DR: The detachment terranes are relatively young features, formed late in the geological evolution of these bodies, and are only the last in a succession of low-angle normal faults that sliced through the upper crust at the upward terminations of major, shallow-dipping, ductile shear zones in the Cordilleran orogen as mentioned in this paper.

TL;DR: In this paper, a review of previous work suggests that no single criterion can consistently distinguish foliations in granitoids formed by flow during ascent, diapiric emplacement and expansion, or regional deformation post-dating emplacements.

TL;DR: In this article, it was shown that the thickness of the seismogenic upper crust of the continental crust is an important determinant of the length of large normal faults and the size of blocks that can rotate coherently about a horizontal axis.

TL;DR: In this paper, structural geologists have been preoccupied with the complexity of the finite deformation within fault zones and with the stress states prevailing at the initiation of faults in intact crust.

TL;DR: In this article, the orientation of principal stress axes and the ratio Φ of the differences between principal stress magnitudes were determined by using rupture and friction laws, where the depth of overburden brought an additional constraint.

TL;DR: In this article, a triaxial apparatus was used to shear 4.0 mm-thick layers of quartz sand between rough steel surfaces using simulated fault gouge and porosity changes were measured throughout shear and microstructural observations were carried out on the deformed layers.

TL;DR: In this article, a review identifies four areas where future studies need to concentrate: the identification of fracture mechanisms, the detailed assessment of the characteristics and effects of cyclic deformation events or flow instabilities on deformation mechanism paths.

TL;DR: In this paper, the authors measured the frictional properties of a layer of simulated Westerly granite fault gouge sandwiched between sliding blocks of Westerly granite, and observed that the gouges which were initially non-fractal evolved to a fractal distribution with dimension 2.6.

TL;DR: In this article, the physical basis of the development of fabrics in plastic and viscous flow is discussed and typical fabrics formed by these processes in the main rock-forming silicates of the lower crust (feldspar, quartz, pyroxene and amphibole).

TL;DR: In this article, the geometric features of a large (50 × 40 km) granitic batholith and its surrounding greenstone belt envelope are described, and it appears that the batholith was built up by a succession of magmatic pulses each of which led to a stretching of the previously consolidated igneous material.

TL;DR: The decollement zone comprises the plate boundary and is marked by profound structural disharmony, by changes in stress orientation and by a discontinuity in plate velocity at convergent margins.

TL;DR: In this paper, the authors examined the theoretical ranges and distributions of rates of change of displacement on fault surfaces using a limited number of displacement gradient measurements, based on a knowledge of the effective shear modulus of the rocks containing a fault.

TL;DR: In this article, a detailed field study of turbiditic sequences from South Georgia (South Atlantic), North Devon (England) and Cardigan Bay (Wales) showed that flexural slip occurs on discrete movement horizons between rock packets in which the beds have welded contacts.

TL;DR: In this paper, it is argued that transient, dilatancy-driven fluid pressure gradients, and consequent fluid migration within the fluid-containing grain-boundary and microcrack network, can play an important role in contributing to mass transfer between dissolution sites and dilatant microfracture sites.

TL;DR: In this paper, the authors examined the development of fine-grained, glassy slickensides which are now exposed along the surface trace of a large, seismically active normal fault zone in Dixie Valley, Nevada, U.S.A. Geologic and mineralogic constraints indicate the slickenside surfaces formed at depths of less than 2 km and temperatures less than 270°C.

TL;DR: In this article, the authors studied the mechanism responsible for these observations by performing frictional sliding experiments on sawcut granite samples filled with a layer of several different fault gouge types.

TL;DR: The geometry of beds in the volume surrounding a single blind planar fault depends on: (i) the axial ratio of the fault surface ellipse, (ii) the ratio between the maximum displacement and the maximum dimension of the surface, and (iii) the displacement distribution on the surface from the point of maximum displacement to zero displacement at the tip-line loop (fault surface displacement profile) and (iv) the rate at which the displacement decreases to zero along a normal to the sink curve as discussed by the authors.

TL;DR: In this article, the hinge line angle and the ratio of the length of the cone axis to that of the long axis of the cross-section of the structure at the position where the hinge angle was measured were used in the classification of highly non-cylindrical folds.

TL;DR: In this paper, the authors have produced more than 100 mushroom-shaped diapirs in eight centrifuged models under acceleration of 1200 g and the modelling results allow natural examples to be recognized.

TL;DR: In this article, the run products of a series of triaxial friction experiments on an illite-rich gouge have been examined petrographically to study the relationship between textural development and sliding mode.

TL;DR: In this paper, mesoscopic faults and joints affecting Neogene and Pleistocene deposits in the Iberian Chain and the Ebro Basin, involving statistical study of fracture directions and palaeostress analysis from striated fault planes, together with analysis of macrostructures, suggest a complex late Cenozoic stress field in which both primary and secondary stress systems are superposed.

TL;DR: The Marlborough fault system is a zone of dextral transpression in continental crust, and marks the southern end of the Hikurangi subduction system between the obliquely convergent Australian and Pacific plates.

TL;DR: In this article, the average grain size is maintained constant in steady-state recrystallization flow, and the complete microstructural evolution can be recorded photographically, along with the complete kinematic history.

TL;DR: A lineament analysis of the ENE-WSW Verran and Hitra-Snasa Faults of the long-lived More-Trondelag Fault Zone (MTFZ) has revealed the presence of a complex array of anastomosing faults and fractures as mentioned in this paper.

TL;DR: In this paper, the authors present a synthesis of experimental data on mechanical behavior and deformation textures of simulated halite shear zones with special regard to the internal structures of S -C mylonites and their mechanical implications.

TL;DR: In this paper, the kinematics of the development of paired hook-shaped asymmetric folds and the relationship of the folds to the fractures or veins can be understood by considering the nature of glacial flow and utilizing simple clay experiments.

TL;DR: In this paper, the structural relationships between the Cordilleran suspect terranes and cratonic North America, and within the suspect terrranes themselves, are reviewed for eastern Alaska, western Canada and United States and northern Mexico.

TL;DR: Pseudotachylite has been recently discovered at numerous localities in the Nason terrane of the North Cascade Mountains, Washington as mentioned in this paper, and these veins are typically found in narrow foliation-parallel zones.

TL;DR: Closed extensional microfractures are useful indicators of paleostress directions in shallowly buried quartz-cemented quartz-arenites of the Lower Cretaceous Travis Peak Formation.

TL;DR: The Erzincan Basin was initially formed as a result of a 4 km wide releasing stepover and a 15° divergence angle between segments 1 and 2 of the North Anatolian Fault Zone (NAFZ) along which the westward tectonic escape of the Anatolians Block has been taking place as discussed by the authors.