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New data on basalts of the East Indian Ocean Ridge. (Russian original.)
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Oceanographic Abstracts JOHNSON W. S., 1976. Population energetics of the intertidal isopod Cirolana harfordi.
Mar. Biol., 36 (4): 351-357.
Laboratory experiments and field measurements generated a population energy-budget estimate for the isopod O'rolana harfordi (Lockington). Assimilation of food energy averaged 88% on a diet of fish. About 35% of assimilated energy is allocated for growth and reproduction, while the bulk of the remainder is used for maintenance and activity (respiration). The high growth efficiency of C. harfordi is discussed with respect to "ecological efficiency" and energy tlansfer in marine systems. JONES R.W., 1976. A moving nested grid with applications to a tropical cyclone. Annhl Met., (N. F.) 11: 173-176. Mild overspecification of the boundary conditions at the interface between nested grids leads to grid-scale noise on the finer grids when disturbances are advected from fine to coarser grids. This noise has been controlled by smoothing data near the interface. Two improvements are suggested here. It is shown that noise in the vorticity field is reduced by computing the wind advection at outflow points of the fine grid by the upstream method. Vorticity noise is also substantially reduced by smoothing more data points, but smoothing less at each point. The amount of smoothing is now a function of distance from the grid center. These results were obtained with a vortex advected by 5, 10, and 20 m/sec currents. Moving nested grids follow the vortex center. KAME1 MASANORI, 1976. Biology of Hiratsume-gani, Ovalipes punctatus (De Haan), in Sagami Bay. (In Japanese; English abstract.) Japan J. Ecol., 26 (2): 65-69. This crab was observed seasonally in Sagami Bay. The period of the good catch occurs twice a year, April-July and October-January. They mainly inhabit the littoral region at a depth of about 5 m throughout the year, and are scanty in more than 20 m. The group of crabs measuring 30 mm in carapace width in June grows up to 55 mm in December and to 70- 80 mm in April of the following year. The rate of growth tends to slow down in October. It is assumed that the spawning period is twice a year, from September to October, and from lanuary to April. The latter period is especially long with a peak from January to March. The biological minimum size of this c~ab is thought to be about 43 mm in carapace width. KASHINTSEV G. L. and C. B. RUDNIK, 1975. New data on basalts of the East Indian Ocean Ridge. (Russian original.)
lzv. Akad. NaukSSSR Set. Geol., 1975 (6): 5-12. Translation in: Int. Geol. Rev., (1976) 18 (10): 1165-1172. In the eastern flank of the East Indian Ocean Ridge and its eastern foothills (13°S) basic rocks are represented by tholeiitic and alkali basalts and dolerites. The alkaline varieties of the eastern flank of the ridge are similar in chemical composition to traps of Hindustan. Their high degree of oxidation suggests that their effusions were formed in a subcontinental environment. KEENE J.B., D. A. CLAGUE and R. K. NISHIMORI, 1976. Experimental hydrothermal alteration of tholeiitic basalt: resultant mineralogy and textures. J. sedim. Petrology, 46 (3): 647-653. Analcime and montmorillonite were synthesized from naturally occurring Hawaiian tholeiitic glass and artifical seawater at 200°C and 300°C and 1 Kb over a period of 32 days. The Na/K ratio for the closed system was 12. Phillipsite and montmorillonite were synthesized at temperatures of 175°C and 250°C and 1 Kb with Na/K ratios for the closed system between 1 and 5. With Na/K = 0.5, no zeolites were formed. Scanning electron microscope photos show volcanic glass surfaces covered by layers and rosettes of montmorillonite, euhedral and subhedral zeolites, and palagonite-like spherules. The phillipsite crystals grow within the altering glass, whereas the analcime crystals grow on the glass surfaces as euhedral crystals and as interpenetrating crystals in circular groups. The textures observed in the experimental charges are remarkably similar to textures observed in naturally altered submarine basaltic glass and palagonite. Phillipsite, the most common authigenic marine zeolite, formed only if potassium was added to the experimental charge. This could correspond to glass altered in an environment open to a large potassium reservoir such as circulating seawater, In the experimental closed seawater system, analcime was formed. Analcime is found in rapidly deposited volcanic sandstones and breccias probably closed off from seawater circulation. KELLEHER JOHN and WILLIAM McCANN, 1976. Buoyant zones, great earthquakes, and unstable boundaries of subduction. J. geophys. Res., 81 (26): 4885-4896. The distribution of large shallow earthquakes along subduction boundaries does not agree with the distribution pattern that might be predicted from a simple model of plate tectonics. That is, along extensive sections of some island arcs, large shocks occurred infrequently or not at all during recorded history. Most of these zones of long-term quiescence are nearly coterminous with segments of the margin where zones of seamounts, aseismic ridges, or other bathymetric highs of the underthrust slab appear to be interacting with the subduction process. This spatial correlation suggests that at least some of the long-term absences of great shocks may result from a tectonic origin and not from temporary intervals of strain accumulation. The zones where rises interact with active trenches are also characterized in many instances by a near absence of low-angle thrust type mechanisms, by gaps in intermediate depth hypocenters, and by gaps and offsets in the line of active volcanoes. Thus major departures from classic subduction activity may develop where significant bathymetric features interact with a convergent margin. To explain these observations, we favor the hypothesis that aseismic ridges or other uplifted regions may delineate zones of oceanic lithosphere which are relatively buoyant and resist subduction upon collision with an active trench. In place of "typical" oceanic lithosphere therefore there may exist a broad spectrum
Oceanographic Abstracts JOHNSON W. S., 1976. Population energetics of the intertidal isopod Cirolana harfordi.
Mar. Biol., 36 (4): 351-357.
Laboratory experiments and field measurements generated a population energy-budget estimate for the isopod O'rolana harfordi (Lockington). Assimilation of food energy averaged 88% on a diet of fish. About 35% of assimilated energy is allocated for growth and reproduction, while the bulk of the remainder is used for maintenance and activity (respiration). The high growth efficiency of C. harfordi is discussed with respect to "ecological efficiency" and energy tlansfer in marine systems. JONES R.W., 1976. A moving nested grid with applications to a tropical cyclone. Annhl Met., (N. F.) 11: 173-176. Mild overspecification of the boundary conditions at the interface between nested grids leads to grid-scale noise on the finer grids when disturbances are advected from fine to coarser grids. This noise has been controlled by smoothing data near the interface. Two improvements are suggested here. It is shown that noise in the vorticity field is reduced by computing the wind advection at outflow points of the fine grid by the upstream method. Vorticity noise is also substantially reduced by smoothing more data points, but smoothing less at each point. The amount of smoothing is now a function of distance from the grid center. These results were obtained with a vortex advected by 5, 10, and 20 m/sec currents. Moving nested grids follow the vortex center. KAME1 MASANORI, 1976. Biology of Hiratsume-gani, Ovalipes punctatus (De Haan), in Sagami Bay. (In Japanese; English abstract.) Japan J. Ecol., 26 (2): 65-69. This crab was observed seasonally in Sagami Bay. The period of the good catch occurs twice a year, April-July and October-January. They mainly inhabit the littoral region at a depth of about 5 m throughout the year, and are scanty in more than 20 m. The group of crabs measuring 30 mm in carapace width in June grows up to 55 mm in December and to 70- 80 mm in April of the following year. The rate of growth tends to slow down in October. It is assumed that the spawning period is twice a year, from September to October, and from lanuary to April. The latter period is especially long with a peak from January to March. The biological minimum size of this c~ab is thought to be about 43 mm in carapace width. KASHINTSEV G. L. and C. B. RUDNIK, 1975. New data on basalts of the East Indian Ocean Ridge. (Russian original.)
lzv. Akad. NaukSSSR Set. Geol., 1975 (6): 5-12. Translation in: Int. Geol. Rev., (1976) 18 (10): 1165-1172. In the eastern flank of the East Indian Ocean Ridge and its eastern foothills (13°S) basic rocks are represented by tholeiitic and alkali basalts and dolerites. The alkaline varieties of the eastern flank of the ridge are similar in chemical composition to traps of Hindustan. Their high degree of oxidation suggests that their effusions were formed in a subcontinental environment. KEENE J.B., D. A. CLAGUE and R. K. NISHIMORI, 1976. Experimental hydrothermal alteration of tholeiitic basalt: resultant mineralogy and textures. J. sedim. Petrology, 46 (3): 647-653. Analcime and montmorillonite were synthesized from naturally occurring Hawaiian tholeiitic glass and artifical seawater at 200°C and 300°C and 1 Kb over a period of 32 days. The Na/K ratio for the closed system was 12. Phillipsite and montmorillonite were synthesized at temperatures of 175°C and 250°C and 1 Kb with Na/K ratios for the closed system between 1 and 5. With Na/K = 0.5, no zeolites were formed. Scanning electron microscope photos show volcanic glass surfaces covered by layers and rosettes of montmorillonite, euhedral and subhedral zeolites, and palagonite-like spherules. The phillipsite crystals grow within the altering glass, whereas the analcime crystals grow on the glass surfaces as euhedral crystals and as interpenetrating crystals in circular groups. The textures observed in the experimental charges are remarkably similar to textures observed in naturally altered submarine basaltic glass and palagonite. Phillipsite, the most common authigenic marine zeolite, formed only if potassium was added to the experimental charge. This could correspond to glass altered in an environment open to a large potassium reservoir such as circulating seawater, In the experimental closed seawater system, analcime was formed. Analcime is found in rapidly deposited volcanic sandstones and breccias probably closed off from seawater circulation. KELLEHER JOHN and WILLIAM McCANN, 1976. Buoyant zones, great earthquakes, and unstable boundaries of subduction. J. geophys. Res., 81 (26): 4885-4896. The distribution of large shallow earthquakes along subduction boundaries does not agree with the distribution pattern that might be predicted from a simple model of plate tectonics. That is, along extensive sections of some island arcs, large shocks occurred infrequently or not at all during recorded history. Most of these zones of long-term quiescence are nearly coterminous with segments of the margin where zones of seamounts, aseismic ridges, or other bathymetric highs of the underthrust slab appear to be interacting with the subduction process. This spatial correlation suggests that at least some of the long-term absences of great shocks may result from a tectonic origin and not from temporary intervals of strain accumulation. The zones where rises interact with active trenches are also characterized in many instances by a near absence of low-angle thrust type mechanisms, by gaps in intermediate depth hypocenters, and by gaps and offsets in the line of active volcanoes. Thus major departures from classic subduction activity may develop where significant bathymetric features interact with a convergent margin. To explain these observations, we favor the hypothesis that aseismic ridges or other uplifted regions may delineate zones of oceanic lithosphere which are relatively buoyant and resist subduction upon collision with an active trench. In place of "typical" oceanic lithosphere therefore there may exist a broad spectrum