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The geodynamics of crustal spreading in the transition zone from the Asian continent to the Pacific Ocean
OLR (1986)33 (12)
D. SubmarineGeologyand Geophysics
of Linosa where volcanic activity is related to structures paralleling the Lampedusa trend. In the central Mediterranean area, NW-SE trending structures are characterized by normal faulting and are found from SE Sicily to central Tunisia. A second NNW-SSE trending fault pattern reveals evidence of sinistral motion commencing in Upper Miocene and continuing to Recent time. The movements associated with the two fault trends are consistent with a northwestward maximal horizontal compressive stress. Ist. Sci. della Terra, Univ. di Catania, Corso Italia 55, 95129 Catania, Italy. 86:6944 Ishida, Mizuho, 1986. The configuration of the Philippine Sea and Pacific plates as estimated from the high-resolution microearthquake hypocenters in the Kanto-Tokai District, Japan.
Rept natn. Res. Cent. Disaster Prevent., Tokyo, 36:1-19. (In Japanese, English abstract.) Microearthquake distributions are used to delineate the Philippine Sea and Pacific plates. The upper surfaces (beneath the Eurasian Plate) of the subducting slabs are 10 to 20 km shallower than previously estimated, based on an estimate of slab surface ca. 10 km above the inclined seismic zone. The Pacific Plate slab configuration offered no surprises; the Philippine Sea Plate showed some differences from previously published results. Natl. Res. Center for Disaster Prevention, Japan. (slr) 86:6945 Page, R.A. et al., 1986. Accretion and subduction tectonics in the Chugach Mountains and Copper River Basin, Alaska: initial results of the TransAlaska Crustal Transect. Geology, geol. Soc. Am., 14(6):501-505. USGS, 345 Middlefield Rd., Menlo Park, CA 94025, USA. 86:6946 Reuther, C.D., 1984. Tectonics of the Maltese Islands. CENTRO, 1(1):1-20. Geol. Inst., Univ. Karlsruhe, Kaiserstrasse, 12,6500 Karlsruhe FRG. 86:6947 Searle, R.C. and J. Francheteau, 1986. Morphology and tectonics of the Galapagos Triple Junction [of the Pacific, Cocos, and Nazca plates]. Mar. geophys. Res., 8(2):95-129. All three plate boundaries change character as the triple junction is approached: the fast-spreading EPR develops the morphology of a medium-spreading rise, and the medium-spreading Cocos-Nazca Rise takes on the appearance of a slow-spreading ridge. The EPR axis was continuous throughout the
10t7
survey area, where it runs along the 102°05"W meridian. The Cocos-Nazca axis, however, fails to meet it, leaving a 20-km-wide band of apparently normal EPR crust between its tip and the EPR axis, implying considerable intra-plate deformation within the Cocos and Nazca plates. True sea-floor spreading on the Cocos-Nazca axis apparently does not begin until 60 km east of the EPR axis. We present a model involving intermittent rifting, rift propagation, and sea-floor spreading, to explain these observations. Includes 4-color outfold: Topography of the Galapagos Triple Junction. Inst. of Oceanogr. Sci., Brook Rd., Wormley, Godalming, Surrey GU8 5UB, UK. 86:6948 Srimal, Neptune, 1986. India-Asia collision: implications from the geology of the eastern Karakoram [NW India]. Geology, geol. Soc. Am., 14(6):523-527. Dept. of Geol. Sci., Univ. of Rochester, NY 14627, USA. 86:6949 Utkin, V.P., 1985. The geodynamics of crustal spreading in the transition zone from the Asian continent to the Pacific Ocean. Geotectonics (a translation of Geotektonika), 19(1):51-63. The tectonomagmatic processes of the transition zone are regarded as a reflection of lateral displacements of the articulated Asian and Pacific Ocean blocks of tectonosphere. Crustal spreading of the transition zone is a result of wrench activation of deep-seated faults; spreading along the northeastern system of wrench faults led during Late Cretaceous time to large-scale release of deep-seated energy and material with the development of the East Asian volcanic belt. During Cenozoic time, wrench activation was responsible for the development of the continental basins and marginal seas. Far Eastern Geol. Inst., Acad. of Sci., USSR. 86:6950 Zolotarev, V.G., 1986. Geodynamic characteristics of the Mricano-Sicilian sill. Okeanologiia, 26(2): 261-266. (In Russian, English abstract.)
D250. Plate and global tectonics 86:6951 Bath, Markus, 1985. Global tectonic relations--a project for the future. Rept seism. Inst., Uppsala, 4-85:32pp. During the 48-year period 1927-74, earthquake activities in Greece and the Kurile Islands are
D. SubmarineGeologyand Geophysics
of Linosa where volcanic activity is related to structures paralleling the Lampedusa trend. In the central Mediterranean area, NW-SE trending structures are characterized by normal faulting and are found from SE Sicily to central Tunisia. A second NNW-SSE trending fault pattern reveals evidence of sinistral motion commencing in Upper Miocene and continuing to Recent time. The movements associated with the two fault trends are consistent with a northwestward maximal horizontal compressive stress. Ist. Sci. della Terra, Univ. di Catania, Corso Italia 55, 95129 Catania, Italy. 86:6944 Ishida, Mizuho, 1986. The configuration of the Philippine Sea and Pacific plates as estimated from the high-resolution microearthquake hypocenters in the Kanto-Tokai District, Japan.
Rept natn. Res. Cent. Disaster Prevent., Tokyo, 36:1-19. (In Japanese, English abstract.) Microearthquake distributions are used to delineate the Philippine Sea and Pacific plates. The upper surfaces (beneath the Eurasian Plate) of the subducting slabs are 10 to 20 km shallower than previously estimated, based on an estimate of slab surface ca. 10 km above the inclined seismic zone. The Pacific Plate slab configuration offered no surprises; the Philippine Sea Plate showed some differences from previously published results. Natl. Res. Center for Disaster Prevention, Japan. (slr) 86:6945 Page, R.A. et al., 1986. Accretion and subduction tectonics in the Chugach Mountains and Copper River Basin, Alaska: initial results of the TransAlaska Crustal Transect. Geology, geol. Soc. Am., 14(6):501-505. USGS, 345 Middlefield Rd., Menlo Park, CA 94025, USA. 86:6946 Reuther, C.D., 1984. Tectonics of the Maltese Islands. CENTRO, 1(1):1-20. Geol. Inst., Univ. Karlsruhe, Kaiserstrasse, 12,6500 Karlsruhe FRG. 86:6947 Searle, R.C. and J. Francheteau, 1986. Morphology and tectonics of the Galapagos Triple Junction [of the Pacific, Cocos, and Nazca plates]. Mar. geophys. Res., 8(2):95-129. All three plate boundaries change character as the triple junction is approached: the fast-spreading EPR develops the morphology of a medium-spreading rise, and the medium-spreading Cocos-Nazca Rise takes on the appearance of a slow-spreading ridge. The EPR axis was continuous throughout the
10t7
survey area, where it runs along the 102°05"W meridian. The Cocos-Nazca axis, however, fails to meet it, leaving a 20-km-wide band of apparently normal EPR crust between its tip and the EPR axis, implying considerable intra-plate deformation within the Cocos and Nazca plates. True sea-floor spreading on the Cocos-Nazca axis apparently does not begin until 60 km east of the EPR axis. We present a model involving intermittent rifting, rift propagation, and sea-floor spreading, to explain these observations. Includes 4-color outfold: Topography of the Galapagos Triple Junction. Inst. of Oceanogr. Sci., Brook Rd., Wormley, Godalming, Surrey GU8 5UB, UK. 86:6948 Srimal, Neptune, 1986. India-Asia collision: implications from the geology of the eastern Karakoram [NW India]. Geology, geol. Soc. Am., 14(6):523-527. Dept. of Geol. Sci., Univ. of Rochester, NY 14627, USA. 86:6949 Utkin, V.P., 1985. The geodynamics of crustal spreading in the transition zone from the Asian continent to the Pacific Ocean. Geotectonics (a translation of Geotektonika), 19(1):51-63. The tectonomagmatic processes of the transition zone are regarded as a reflection of lateral displacements of the articulated Asian and Pacific Ocean blocks of tectonosphere. Crustal spreading of the transition zone is a result of wrench activation of deep-seated faults; spreading along the northeastern system of wrench faults led during Late Cretaceous time to large-scale release of deep-seated energy and material with the development of the East Asian volcanic belt. During Cenozoic time, wrench activation was responsible for the development of the continental basins and marginal seas. Far Eastern Geol. Inst., Acad. of Sci., USSR. 86:6950 Zolotarev, V.G., 1986. Geodynamic characteristics of the Mricano-Sicilian sill. Okeanologiia, 26(2): 261-266. (In Russian, English abstract.)
D250. Plate and global tectonics 86:6951 Bath, Markus, 1985. Global tectonic relations--a project for the future. Rept seism. Inst., Uppsala, 4-85:32pp. During the 48-year period 1927-74, earthquake activities in Greece and the Kurile Islands are