Estimation of Continuity of a Fault Based on Composite Planar Fabric

2018 ◽  
pp. 25-32
Author(s):  
Yasuhiko Wakizaka ◽  
Atsushi Kajiyama ◽  
Hiroyuki Watatani ◽  
Mutsuo Kozuma
Keyword(s):  
Planar Fabric

The Northern Suture, Pakistan: margin of a Cretaceous island arc

1986 ◽  
Vol 123 (4) ◽  
pp. 405-423 ◽  
Author(s):  
Carol J. Pudsey
Keyword(s):  
Sedimentary Rocks ◽  
Island Arc ◽  
Two Phase ◽  
The North ◽  
Tethys Ocean ◽  
Radiometric Ages ◽  
Back Arc ◽  
Northwest Himalayas ◽  
Planar Fabric ◽  
Early Late

AbstractThe Northern Suture is a fault separating the Cretaceous Kohistan island arc terrain (northwest Himalayas) from Palaeozoic sediments of the Asian Plate to the north. The Kohistan arc includes volcanic and sedimentary rocks (andesitic lavas, tuffs, volcaniclastics, slates and limestones), metamorphosed to greenschist facies and intruded by the two-phase Kohistan Batholith. Asian continental margin sediments are mainly of shelf type, are variably metamorphosed and intruded by the Karakoram Batholith. The Northern Suture is a zone of melange from 150 m to 4 km wide, and contains blocks of volcanic greenstone, limestone, red shale, conglomerate, quartzite and serpentinite in a slate matrix. It has a strong planar fabric; but in many places bedding is preserved in blocks and matrix, and depositional rather than tectonic contacts are seen between the two. The melange is inferred to be an olistostrome largely derived from the Kohistan arc, formed in a small back-arc basin between Kohistan and Asia. Limestone blocks in the melange are dated as Aptian–Albian; post-tectonic intrusions yield radiometric ages from 111 to 62 Ma. The Northern Suture therefore probably formed in the early Late Cretaceous during closure of the back-arc basin. The Tethys ocean lay south of Kohistan, where the Main Mantle Thrust represents the westward continuation of the Indus–Tsangpo Suture.

Structural evolution of migmatites in granulite facies terrane: Precambrian crystalline complex of Angul, Orissa, India

1982 ◽  
Vol 73 (2) ◽  
pp. 109-118 ◽  
Author(s):  
N. M. Halden ◽  
D. R. Bowes ◽  
B. Dash
Keyword(s):  
Structural Evolution ◽  
Granulite Facies ◽  
Brittle Deformation ◽  
Crystalline Complex ◽  
Polyphase Deformation ◽  
Kink Bands ◽  
The Third ◽  
Heterogeneous Nature ◽  
Igneous Activity ◽  
Planar Fabric

ABSTRACTBasic granulites, a variety of gneisses including sillimanite-garnet gneiss (khondalite), charnockite and intruded quartzofeldspathic material make up a migmatite complex showing evidence of polyphase deformation, polymetamorphism and successive neosome emplacement. The heterogeneity of the migmatites is dominantly the result of folding and boudinage rather than igneous activity.Tight to isoclinal folds of the second recognised deformational phase affect lithological layering, granulite facies fabric elements of the first deformational phase and early neosome; they played a major role in the development of the macroscopically heterogeneous nature of the complex and they are also a key structure for correlation. Upright folds of the third deformational phase control the major disposition of lithological units and, together with their axial planar fabric, controlled the uprise of quartzofeldspathic neosome and of volatiles and heat which caused localised ‘charnockitisation’ of sillimanite-bearing gneisses. The effects of semibrittle and brittle deformation, including kink bands, fractures and shears, express late deformational phases during which there was neosome emplacement, some at 854 ± 6 m.y. ago (Rb–Sr muscovite age).

scholarly journals Controls on dolomitization in extensional basins: An example from the Derbyshire Platform, U.K.

2020 ◽  
Vol 90 (9) ◽  
pp. 1156-1174 ◽  
Author(s):  
Catherine Breislin ◽  
Stephen Crowley ◽  
Vanessa J. Banks ◽  
Jim D. Marshall ◽  
Ian L. Millar ◽  
...  
Keyword(s):  
Geothermal Gradient ◽  
Volcanic Complex ◽  
Carbonate Platforms ◽  
Rift Basins ◽  
Southern Margin ◽  
North Wales ◽  
Platform Drowning ◽  
Platform Margin ◽  
Platform Carbonates ◽  
Planar Fabric

ABSTRACT Fault-controlled dolomitization has been documented in Lower Carboniferous (Viséan) platform carbonates at various localities in the Pennine Basin and North Wales. The largest of these dolomite bodies (approx. 60 km2) occurs on the Derbyshire Platform, on the southern margin of the Pennine Basin. This study tests the hypothesis that dolomitization occurred at this locality during deposition, platform drowning, and the earliest stages of burial, coincident with the transition from a late syn-rift to post-rift regime. It also assesses the importance of syn-rift volcanism on dolomitization. Planar, fabric-retentive dolomite with single-phase (i.e., low temperature) fluid inclusions occurs along NW–SE and E–W oriented faults, and in platform margin facies and in proximity to the Masson Hill Volcanic Complex. Oxygen isotope data are consistent with dolomitization from seawater, but slightly depleted δ13C values reflect mixing with magmatic fluids. Volcanic activity is likely to have produced a thermal drive for fluid circulation on the platform margin, and post-depositional alteration of basalts by CO2-rich fluids could have led to alteration of olivine and release of magnesium to convecting seawater. Consequently, the large volume of dolostone on the southern margin of the Derbyshire Platform is attributed to the increased geothermal gradient and a localized increase in the Mg/Ca ratio of dolomitizing fluids at this locality, compared to elsewhere in the Pennine Basin. The results suggest that syn-rift carbonate platforms in volcanically active areas of rift basins have a greater potential for dolomitization from seawater than non-volcanic platforms in the same basin.

The Ainslie Detachment: a regional flat-lying extensional fault in the Carboniferous evaporitic Maritimes Basin of Nova Scotia, Canada

1996 ◽  
Vol 33 (2) ◽  
pp. 169-181 ◽  
Author(s):  
Gregory Lynch ◽  
Peter S. Giles
Keyword(s):  
Nova Scotia ◽  
Hanging Wall ◽  
Cape Breton Island ◽  
Fine Grained ◽  
Cape Breton ◽  
Westerly Direction ◽  
Maritimes Basin ◽  
Highly Strained ◽  
Planar Fabric ◽  
Stratigraphic Succession

The Ainslie Detachment occurs near the base of the Carboniferous Windsor Group, forming a regional flat-lying extensional fault distributed across 10 000 km2. New mapping has delineated the structure through southwestern Cape Breton Island and into central Nova Scotia. Shearing is concentrated at the top of the basal Macumber limestone along its contact with overlying evaporites and younger allochthonous units. The highly contrasting rheologies of the formations created an anisotropic zone of weakness which acted as an upper crustal stress guide, stratigraphically controlling the trajectory of the detachment through the basin. The detachment is characterized by an approximately 3–10 m thick calc-mylonite zone, with an intense planar fabric featuring alternating very fine grained shear planes and coarser annealed layers. Coarser layers are boudinaged into pinch and swell structures, locally producing segmented augen. Highly strained intraclasts, ooids, and peloids, recrystallized carbonate boudins, and carbonate vein segments are included in the calc-mylonite as semirigid inclusions and rotated porphyroclasts. Thick zones of fault breccia straddle portions of the detachment and overprint the mylonite, demonstrating an evolution to brittle conditions during progressive shear. Listric faults in the hanging wall of the detachment feature a ramp and flat geometry, with an upper detachment occurring along the upper contact of the Windsor Group with the overlying Namurian Mabou Group. Locally up to 2 km of the stratigraphic succession has been removed, with faults cutting downsection in a westerly direction producing rollover in the hanging wall.

Quartz c-axis fabrics in constrictionally strained orthogneisses: implications for the evolution of the Orlica-Śnieżnik Dome, the Sudetes, Poland

2013 ◽  
Vol 63 (4) ◽  
pp. 697-722
Author(s):  
Andrzej Żelaźniewicz ◽  
Olga Kromuszczyńska ◽  
Natalia Biegała
Keyword(s):  
High Temperature ◽  
Large Scale ◽  
Joint Control ◽  
Texture Formation ◽  
Strain Partitioning ◽  
Multistage Process ◽  
Tectonic Structure ◽  
Mixed Features ◽  
Planar Fabric ◽  
Western Limb

ABSTRACT Żelaźniewicz, A., Kromuszczyńska, O. and Biegała, N. 2013. Quartz c-axis fabrics in constrictionally strained orthogneisses: implications for the evolution of the Orlica-Śnieżnik Dome, the Sudetes, Poland. Acta Geologica Polonica, 63(4), 697-722, Warszawa. The Orlica-Śnieżnik Dome (OSD), NE Bohemian Massif, contains in its core several gneiss variants with protoliths dated at ~500 Ma. In the western limb of the OSD, rodding augen gneisses (Spalona gneiss unit) are mainly L>S tectonites with a prominent stretching lineation. The few quartz LPO studies have produced somewhat discrepant results. Reexamination of these rocks revealed that texture formation was a protracted, multistage process that involved strain partitioning with changing strain rate and kinematics in a general shear regime at temperatures of the amphibolite facies (450-600°C). Quartz c-axis microfabrics show complex yet reproducible patterns that developed under the joint control of strain geometry and temperature; thus the LPOs are mixed features represented by pseudogirdle patterns. Domainal differences in quartz microfabrics (ribbons, tails, quartzo-feldspathic aggregate) are common in the Spalona orthogneisses but uncommon in the sheared migmatitic gneisses. In the latter rocks, the constrictional strain was imposed on the originally planar fabric defined by high-temperature migmatitic layering. The constrictional fabric of the Spalona gneisses may have developed in the hinge zones of kilometer-scale folds, where the elongation occurred parallel to the fold axes. Other occurrences of rodding gneisses throughout the Orlica-Śnieżnik Dome are thought to occupy similar structural positions, which would point to the significance of large-scale folds in the tectonic structure of the dome.

Folding and pressure solution in a laminated calcite-quartz vein from the Silurian slates of the Llangollen region of N Wales

1978 ◽  
Vol 115 (1) ◽  
pp. 47-54 ◽  
Author(s):  
R. Nicholson
Keyword(s):  
Late Stage ◽  
Quartz Vein ◽  
Length Ratio ◽  
Pressure Solution ◽  
Arc Length ◽  
Planar Fabric

SummaryFolds of a 12 mm thick calcite-rich vein, embedded in slate and with a primary planar fabric of parallel, thin and plate-like calcite crystals, or laminae, have a vein thickness/arc length ratio near 1. Folds were first entirely dependent for development on intra-laminar strain and inter-laminar sliding. As limb dips increased, however, pressure solution began to thin laminae in limb regions only. As adjacent inter-laminar surfaces met at fold inflexion points, where laminae were first cut through, loss on fabric-cutting surfaces began to replace inter-laminar pressure solution. The resulting stylolites grew across the vein in fold limbs, at the limit eliminating them. In contrast, in folded equigranular calcite rocks stylolites are widely developed in both limbs and hinges, and eventual fold collapse through late stage concentration of pressure solution takes place in fold hinges and not limbs.

Design and Analysis of SMA Woven Fabric

2018 ◽  
Author(s):  
Amanda Skalitzky ◽  
Austin Gurley ◽  
David Beale ◽  
Kyle Kubik
Keyword(s):  
Uniaxial Tension ◽  
Active Material ◽  
Woven Fabric ◽  
Stress And Strain ◽  
Self Healing ◽  
Thermomechanical Loading ◽  
Cross Sectional ◽  
Aerospace Applications ◽  
Wearable Medical ◽  
Planar Fabric

Shape Memory Alloys (SMAs) are often used for robotic, biomedical, and aerospace applications because of their unique ability to undergo large amounts of stress and strain during thermomechanical loading compared to traditional metals. While SMAs such as NiTi have been used in wire, plate, and tubular forms, NiTi as a woven dry fabric has yet to be analyzed for use as protective materials and actuators. Applications of SMA fabric as a “passive” material include shields, seatbelts, watchbands and window screens. Applications as an “active” material include robotic actuators, wearable medical and therapy devices, and self-healing shields and screens. This paper applies a macro-mechanical model from composites analysis to NiTi plain woven fabric to determine the effective elastic constants. The fabric model is based on actual weave geometry, including the presence of open gaps and wire cross-sectional area, and with the same diameter and alloy in the warp and weft. A woven NiTi ribbon has been manufactured (Figure 1) using a narrow weaving machine and has been tested in uniaxial tension. Planar fabric constants were measured at a range of temperatures. The analytically and experimentally derived constants for various weave patterns and cover factor combinations are presented and compared. It was determined that in uniaxial tension the fabric behaves like a collection of unidirectional wires, but has 78% of the rigidity, on average, across all test temperatures. This result is predicted by the fabric model with a 16% error, demonstrating that the proposed analytical model offers a useful tool for design and simulation of SMA fabrics.

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