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The Caucasina eocaenica kamchatica zone and the Eocene-Oligocene boundary in the northwestern Pacific
Oceanographic Abstracts
213
profile of the last-formed chamber and by apertural shape. It is referred to G. crassula, sensu lato. The similarity in gross shell form between G. conomiozea and G. crassula, sensu lato, may reflect convergent trends toward truncatuline shape (elongation of chambers in axial direction). Rejection of Blow's identifications eliminates low latitude records of G. conomiozea. The species appears to be limited to upper Miocene-basal Pliocene strata in the middle latitudes of both hemispheres. SCOTT K. J. and R. A. CROKER, 1976. Macroinfauna of northern New England marine sand. III. The ecology of Psarnmonyx nobilis (Stimpson), 1853 (Crustacea: Amphipoda). Can. J. Zool., 54: 1519-1529. The boreal lysianassid Psammonyx nobilis is associated with very well sorted, fine sand of low intertidal and shallow subtidal habitats. It is a winter to early spring breeder, with recruitment from June to August in New England. Females produce up to 50 eggs and have one brood per breeding period. Generation time is 2 years. Larger adults occur only during colder months at more exposed intertidal habitats, while all life stages occur at sheltered intertidal habitats throughout the year. Females are larger than males and are more abundant at the landward periphery of intertidal populations. Subtidal populations show smaller adults and juveniles present most of the year. The species is a scavenger-omnivore exhibiting an aggregated pattern of distribution. Swimming activity is highest in the dark during falling tides. Respiration increases significantly at salinities < 20 °/o0. The length of pereopod 7 was the sole sexually dimorphic character observed. The heretofore enigmatic, elongate gnathopod 2 is not used in precopula, but for removing organic debris from the thoracic cavity. SEHRA P. S., 1976. Structure of the atmosphere over south polar and equatorial regions. J. met. Soc. Japan, (2) 54 (2): 105-117. Average vertical profiles of zonal and meridional components of winds, and of temperatures as obtained from M-100 meteorological rocket soundings conducted at Molodezhnaya, Antarctica in January - February 1972 (southern summer) are compared with those of the corresponding ascents from Thumba. south India. The actual results are also compared with the Groves atmospheric model and the corresponding departures of the actuals from the model are worked out. It is found that in the southern summer the polar tropopause and stratopause were about 27°C and 13°C warmer than the corresponding equatorial tropopause and stratopause, while the mesopause was about 25°C colder. At both the stations the zonal winds in the stratosphere were predominantly easterly in January with speeds less than 50 ms-~, and westerly in February with speeds less than 35 ms -~, while the meridional winds were variable. Zonal wind departures of the actuals from the Groves model were found to be in a range of about -+ 35 ms -~ , while the temperature departures were mostly negative by about 25°C. SEROVA M. Ya., 1976. The Caucasina eocaenica kamchatica zone and the Eocene-Oligocene boundary in the northwestern Pacific. Progress in micropaleontology, 314-328. Micropaleontology Press, N. Y. The present work is devoted to a biostratigraphic study of the Eocene-Oligocene deposits of the eastern Kamchatka Peninsula, in particular of their foraminifera. The Caucasina eocaenica kamchatica zone was recognized in the typical Paleogene section of the llpinsky Peninsula of eastern Kamchatka and dated as Late Eocene. The foraminiferal assemblage of this zone is similar to those of the Refugian Stage of California, the Poronai Formation of Hokkaido, Japan, and the Late Eocene deposits of the Beloglinsky Horizon of the southern USSR. The Eocene-Oligocene boundary is placed at the top of the C. eocaenica kamchatica zone. SHAFFER N. R. and GUNTER FAURE, 1976. Regional variation of 87Sr/S6Sr ratios and mineral compositions of sediment from the Ross Sea, Antarctica. Bull. geoL Soc. Am., 87 (10): 1491-1500. The STSr/S6Sr ratios and concentrations of rubidium and strontium of < 100 mesh noncarbonate fractions of sediment taken from the tops of piston cores vary systematically throughout the Ross Sea. The respective ranges of variation are: 87Sr/S6$r: 0.710 to 0.726; Sr = 91 to 238 ppm, Rb = 56 to 158 ppm. These data are interpreted in terms of two-component mixing of weathering products of old static rocks (high a7Sr/a6Sr ratio, low Sr concentration) and of young volcanic rock of basaltic composition (low aTSr/a6Sr ratio, high Sr concentration). The relevant mixing equation was derived from the data by fitting a straight line to data points in coordinates of STSr/a6Sr and l/Sr. The strontium concentrations of the two components were calculated from the mixing equation for assumed values of the a7Sr/a6Sr ratios. For the basaltic component (87Sr/86Sr = 0.704 -+ 0.001): Sr = 567 -+ 143 ppn for the sialic component (87Sr/a6Sr = 0.729 -+ 0.001): Sr = 82 -+ 3 ppm. The static component consists primarily of" clay minerals, but the basaltic component is represented by less-weathered detrital particles. The concentration of volcanic detritus ranges from nearly zero just north of the Ross Ice Shelf to values in excess of 30 percent in the vicinity of Ross Island and off the coast of northern Victoria Land. Quartz and feldspar correlate positively and are both concentrated in sediment collected along the edge of the continental shelf and along the coast of Victoria Land. lllite and kaolinite/chlorite are most abundant in the immediate vicinity of the Ross Ice Shelf. The mineral compositions of the sediment may have been modified by strong bottom currents which apparently limit contemporary deposition of sediment to sheltered depressions. A plot of rubidium versus strontium concentrations of the noncarbonate sediment shows a wide range of scatter along the Rb-axis which is attributed to uptake of rubidium from sea water but may also indicate inhomogeneity of the rubidium concentrations of the static component. The aTSr/a6Sr and 87Rb/'~'Sr ratios are positively correlated, but this relationship is the result of mixing and does not reflect the age of the provenance nor lhc time of deposition of the sediment.
213
profile of the last-formed chamber and by apertural shape. It is referred to G. crassula, sensu lato. The similarity in gross shell form between G. conomiozea and G. crassula, sensu lato, may reflect convergent trends toward truncatuline shape (elongation of chambers in axial direction). Rejection of Blow's identifications eliminates low latitude records of G. conomiozea. The species appears to be limited to upper Miocene-basal Pliocene strata in the middle latitudes of both hemispheres. SCOTT K. J. and R. A. CROKER, 1976. Macroinfauna of northern New England marine sand. III. The ecology of Psarnmonyx nobilis (Stimpson), 1853 (Crustacea: Amphipoda). Can. J. Zool., 54: 1519-1529. The boreal lysianassid Psammonyx nobilis is associated with very well sorted, fine sand of low intertidal and shallow subtidal habitats. It is a winter to early spring breeder, with recruitment from June to August in New England. Females produce up to 50 eggs and have one brood per breeding period. Generation time is 2 years. Larger adults occur only during colder months at more exposed intertidal habitats, while all life stages occur at sheltered intertidal habitats throughout the year. Females are larger than males and are more abundant at the landward periphery of intertidal populations. Subtidal populations show smaller adults and juveniles present most of the year. The species is a scavenger-omnivore exhibiting an aggregated pattern of distribution. Swimming activity is highest in the dark during falling tides. Respiration increases significantly at salinities < 20 °/o0. The length of pereopod 7 was the sole sexually dimorphic character observed. The heretofore enigmatic, elongate gnathopod 2 is not used in precopula, but for removing organic debris from the thoracic cavity. SEHRA P. S., 1976. Structure of the atmosphere over south polar and equatorial regions. J. met. Soc. Japan, (2) 54 (2): 105-117. Average vertical profiles of zonal and meridional components of winds, and of temperatures as obtained from M-100 meteorological rocket soundings conducted at Molodezhnaya, Antarctica in January - February 1972 (southern summer) are compared with those of the corresponding ascents from Thumba. south India. The actual results are also compared with the Groves atmospheric model and the corresponding departures of the actuals from the model are worked out. It is found that in the southern summer the polar tropopause and stratopause were about 27°C and 13°C warmer than the corresponding equatorial tropopause and stratopause, while the mesopause was about 25°C colder. At both the stations the zonal winds in the stratosphere were predominantly easterly in January with speeds less than 50 ms-~, and westerly in February with speeds less than 35 ms -~, while the meridional winds were variable. Zonal wind departures of the actuals from the Groves model were found to be in a range of about -+ 35 ms -~ , while the temperature departures were mostly negative by about 25°C. SEROVA M. Ya., 1976. The Caucasina eocaenica kamchatica zone and the Eocene-Oligocene boundary in the northwestern Pacific. Progress in micropaleontology, 314-328. Micropaleontology Press, N. Y. The present work is devoted to a biostratigraphic study of the Eocene-Oligocene deposits of the eastern Kamchatka Peninsula, in particular of their foraminifera. The Caucasina eocaenica kamchatica zone was recognized in the typical Paleogene section of the llpinsky Peninsula of eastern Kamchatka and dated as Late Eocene. The foraminiferal assemblage of this zone is similar to those of the Refugian Stage of California, the Poronai Formation of Hokkaido, Japan, and the Late Eocene deposits of the Beloglinsky Horizon of the southern USSR. The Eocene-Oligocene boundary is placed at the top of the C. eocaenica kamchatica zone. SHAFFER N. R. and GUNTER FAURE, 1976. Regional variation of 87Sr/S6Sr ratios and mineral compositions of sediment from the Ross Sea, Antarctica. Bull. geoL Soc. Am., 87 (10): 1491-1500. The STSr/S6Sr ratios and concentrations of rubidium and strontium of < 100 mesh noncarbonate fractions of sediment taken from the tops of piston cores vary systematically throughout the Ross Sea. The respective ranges of variation are: 87Sr/S6$r: 0.710 to 0.726; Sr = 91 to 238 ppm, Rb = 56 to 158 ppm. These data are interpreted in terms of two-component mixing of weathering products of old static rocks (high a7Sr/a6Sr ratio, low Sr concentration) and of young volcanic rock of basaltic composition (low aTSr/a6Sr ratio, high Sr concentration). The relevant mixing equation was derived from the data by fitting a straight line to data points in coordinates of STSr/a6Sr and l/Sr. The strontium concentrations of the two components were calculated from the mixing equation for assumed values of the a7Sr/a6Sr ratios. For the basaltic component (87Sr/86Sr = 0.704 -+ 0.001): Sr = 567 -+ 143 ppn for the sialic component (87Sr/a6Sr = 0.729 -+ 0.001): Sr = 82 -+ 3 ppm. The static component consists primarily of" clay minerals, but the basaltic component is represented by less-weathered detrital particles. The concentration of volcanic detritus ranges from nearly zero just north of the Ross Ice Shelf to values in excess of 30 percent in the vicinity of Ross Island and off the coast of northern Victoria Land. Quartz and feldspar correlate positively and are both concentrated in sediment collected along the edge of the continental shelf and along the coast of Victoria Land. lllite and kaolinite/chlorite are most abundant in the immediate vicinity of the Ross Ice Shelf. The mineral compositions of the sediment may have been modified by strong bottom currents which apparently limit contemporary deposition of sediment to sheltered depressions. A plot of rubidium versus strontium concentrations of the noncarbonate sediment shows a wide range of scatter along the Rb-axis which is attributed to uptake of rubidium from sea water but may also indicate inhomogeneity of the rubidium concentrations of the static component. The aTSr/a6Sr and 87Rb/'~'Sr ratios are positively correlated, but this relationship is the result of mixing and does not reflect the age of the provenance nor lhc time of deposition of the sediment.