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Experiments on fault reactivation in strike-slip mode
332A
916007 Experiments on oblique rifting in brittle-ductile systems Tron, V; Brun, J P Tectonophysics V188, N1/2, March 1991, P71-84 In extensional environments, the geometry and kinematics of fault patterns often indicate that extension is not perpendicular to the boundaries of the deforming domain (oblique rifling). This problem has been studied for brittle-ductile systems using small scale model tests on analogues fabricated from sand and silicone putty. Uniaxial stretching was applied oblique to the external boundaries and resultant fault patterns analysed on both free surface and serial cross sections. Characteristic features of the oblique rifting are en-echelon fault patterns, mean fault trends not perpendicular to the stretching vector, and mean initial fault dips higher than for dip slip normal faults.
916011 Geophysical and geological investigations of the geothermal resources in Fujian province Tan Tjong Kie; Xiong Shao Bai; Ou Yang Ting Proe 6th International Congress International Association of Engineering Geology, Amsterdam, 6-10 August 1990 V2. P1053-1060. Publ Rotterdam, A A Balkema, 1990 Study of tectonic faulting, a survey of geothermic manifestations, and deep seismic profiling have been used to assess potential for geothermal energy exploitation in Fujian Province, China. Results show an anomalous upper mantle at depth 29km, fissured massive inclusions, and radioactive granitic rock masses. Deep faults create favourablc conduits for upward movement of molten rocks. Water circulation is promoted in fissured fault zones. Further engineering geological studies can be planned on the basis of these works.
Environmental effects, weathering and soil formation 916008 Experiments on fault reactivation in strike-slip mode Richard, P; Krantz, R W Tectonophysics 11188, N1/2, March 1991, Pl17-131 Reactivation of normal or reverse faults in a cover over a 54 deg reverse,45 deg normal, or 90 deg basement fault, reactivated in the strike slip mode, has been studied in the laboratory. Analogues of sand and silicone putty were used to represent models of various theologies, purely brittle or brittle-ductile. Little reactivation was evident in surface views, but faults were seen to reactivate at depth in cross sections. Large scale structural implications are considered.
916009 Slip system domains, 3. New insights in fault kinematics from plane-strain sandbox experiments Gapais, D; Fiquet, G; Cobbold, P g Tectonophysics V188, N1/2, March 1991, P143-157 Plane strain deformation of sandpacks under different imposed bulk kinematic conditions from coaxial stretching to strike slip simple shearing is described. Arrays of conjugate faults were seen after about 10% uniform strain, which accommodate most of the deformation. Initial fault orientations reflect stress directions. Domains with one dominant fault set and separated by incoherent boundaries are developed. Fault patterns similar to those of the brittle crust are reproduced.
916010 Stress distribution and orientation of Riedei shears Dresen, G Tectonophysies 1,'188, N3/4, March 1991, P239-247 Finite element modelling with the A D I N A code was used to investigate the influence of stress field and material parameters on the development of Riedel shears. Simple shear deformation of an almost isotropic material required a stress distribution inconsistent with the nature of fracture sets seen in the field. Rotation of principal stresses due to changes in loading state did, however, allow fractures to form in different orientations. That material properties influence the final position of a fault or fracture was demonstrated by systematic variation of stress boundary conditions, cohesion, and friction angle.
See also: 916056, 916207 916012 Statistical analysis of factors influencing cliff erosion along a section of the West Wales coast, U.K. Jones, D G; Williams, A T Earth Surf Process Land V16, N2, March 1991, P95-111 Cliff erosion of the Cardigan Bay area has been examined. The coast is dominated by cliffs of alternate layers of greywacke and mudstone, about 30m high, with smaller expanses of glacial deposits. Mean recession rates of up to 0.25m/yr were recorded for the glacial embayments. Theoretical predictions using wave refraction theory with the program W A V E N R G and visual examination confirm the existence of high and low beaches. Morphogenic environment, cliff and beach factors, and protective features and their influence on erosion have been analysed. The volume of beach-face material is the most important factor for short term cliff erosion.
916013 Chemical weathering mechanisms and their effects on engineering properties of soft sandstone and conglomerate cemented by zeolite in a mountainous area Chigira, M; Sone, K Engng Geol V30, N2. April 1991, P195-219 Weathering by groundwater flow of marine sandstone and conglomerate of the Toyonikawa formation in Japan has been studied. Near the surface, acidity due to dissolved atmospheric carbon dioxide causes dissolution of the zeolite, weakening the rock. At the oxidation front, the base of the oxidised zone, dissolved oxygen reacts with pyrite in the rock, producing sulphuric acid and iron oxide/hydroxide, the latter of which precipitates on zeolite surfaces and strengthens the rock by cementation. Beneath the oxidation front, the rock is again weakened as the percolating sulphuric acid solution dissolves zeolites. Differences between this weathering mechanism and that for clay rich rocks are discussed.
916014 Marble weathering in an industrial environment, Eastern Australia Dragovich, D Environ Geol Water Sci II17, N2, March-April 1991, P127132 Data presented on surface reduction of marble tombstones show mean weathering rate has increased over the period 1885-1955, particularly since the establishment of sulphur
© 1991 Pergamon Press pic. Reproduction not permitted
916007 Experiments on oblique rifting in brittle-ductile systems Tron, V; Brun, J P Tectonophysics V188, N1/2, March 1991, P71-84 In extensional environments, the geometry and kinematics of fault patterns often indicate that extension is not perpendicular to the boundaries of the deforming domain (oblique rifling). This problem has been studied for brittle-ductile systems using small scale model tests on analogues fabricated from sand and silicone putty. Uniaxial stretching was applied oblique to the external boundaries and resultant fault patterns analysed on both free surface and serial cross sections. Characteristic features of the oblique rifting are en-echelon fault patterns, mean fault trends not perpendicular to the stretching vector, and mean initial fault dips higher than for dip slip normal faults.
916011 Geophysical and geological investigations of the geothermal resources in Fujian province Tan Tjong Kie; Xiong Shao Bai; Ou Yang Ting Proe 6th International Congress International Association of Engineering Geology, Amsterdam, 6-10 August 1990 V2. P1053-1060. Publ Rotterdam, A A Balkema, 1990 Study of tectonic faulting, a survey of geothermic manifestations, and deep seismic profiling have been used to assess potential for geothermal energy exploitation in Fujian Province, China. Results show an anomalous upper mantle at depth 29km, fissured massive inclusions, and radioactive granitic rock masses. Deep faults create favourablc conduits for upward movement of molten rocks. Water circulation is promoted in fissured fault zones. Further engineering geological studies can be planned on the basis of these works.
Environmental effects, weathering and soil formation 916008 Experiments on fault reactivation in strike-slip mode Richard, P; Krantz, R W Tectonophysics 11188, N1/2, March 1991, Pl17-131 Reactivation of normal or reverse faults in a cover over a 54 deg reverse,45 deg normal, or 90 deg basement fault, reactivated in the strike slip mode, has been studied in the laboratory. Analogues of sand and silicone putty were used to represent models of various theologies, purely brittle or brittle-ductile. Little reactivation was evident in surface views, but faults were seen to reactivate at depth in cross sections. Large scale structural implications are considered.
916009 Slip system domains, 3. New insights in fault kinematics from plane-strain sandbox experiments Gapais, D; Fiquet, G; Cobbold, P g Tectonophysics V188, N1/2, March 1991, P143-157 Plane strain deformation of sandpacks under different imposed bulk kinematic conditions from coaxial stretching to strike slip simple shearing is described. Arrays of conjugate faults were seen after about 10% uniform strain, which accommodate most of the deformation. Initial fault orientations reflect stress directions. Domains with one dominant fault set and separated by incoherent boundaries are developed. Fault patterns similar to those of the brittle crust are reproduced.
916010 Stress distribution and orientation of Riedei shears Dresen, G Tectonophysies 1,'188, N3/4, March 1991, P239-247 Finite element modelling with the A D I N A code was used to investigate the influence of stress field and material parameters on the development of Riedel shears. Simple shear deformation of an almost isotropic material required a stress distribution inconsistent with the nature of fracture sets seen in the field. Rotation of principal stresses due to changes in loading state did, however, allow fractures to form in different orientations. That material properties influence the final position of a fault or fracture was demonstrated by systematic variation of stress boundary conditions, cohesion, and friction angle.
See also: 916056, 916207 916012 Statistical analysis of factors influencing cliff erosion along a section of the West Wales coast, U.K. Jones, D G; Williams, A T Earth Surf Process Land V16, N2, March 1991, P95-111 Cliff erosion of the Cardigan Bay area has been examined. The coast is dominated by cliffs of alternate layers of greywacke and mudstone, about 30m high, with smaller expanses of glacial deposits. Mean recession rates of up to 0.25m/yr were recorded for the glacial embayments. Theoretical predictions using wave refraction theory with the program W A V E N R G and visual examination confirm the existence of high and low beaches. Morphogenic environment, cliff and beach factors, and protective features and their influence on erosion have been analysed. The volume of beach-face material is the most important factor for short term cliff erosion.
916013 Chemical weathering mechanisms and their effects on engineering properties of soft sandstone and conglomerate cemented by zeolite in a mountainous area Chigira, M; Sone, K Engng Geol V30, N2. April 1991, P195-219 Weathering by groundwater flow of marine sandstone and conglomerate of the Toyonikawa formation in Japan has been studied. Near the surface, acidity due to dissolved atmospheric carbon dioxide causes dissolution of the zeolite, weakening the rock. At the oxidation front, the base of the oxidised zone, dissolved oxygen reacts with pyrite in the rock, producing sulphuric acid and iron oxide/hydroxide, the latter of which precipitates on zeolite surfaces and strengthens the rock by cementation. Beneath the oxidation front, the rock is again weakened as the percolating sulphuric acid solution dissolves zeolites. Differences between this weathering mechanism and that for clay rich rocks are discussed.
916014 Marble weathering in an industrial environment, Eastern Australia Dragovich, D Environ Geol Water Sci II17, N2, March-April 1991, P127132 Data presented on surface reduction of marble tombstones show mean weathering rate has increased over the period 1885-1955, particularly since the establishment of sulphur
© 1991 Pergamon Press pic. Reproduction not permitted