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The geochemistry of modern sediments from the Gulf of Paria. 1. The relationship between the mineralogy and the distribution of major elements
Oceanographic Abstracts
395
in cracks by ground water. Thus, the origin of differential corrosion in these structures is not always the same, and slight disparities in petrological constitution can sometimes result in large differences in morphological behaviour. The differences in morphological evolution between parts of the same platform standing at different heights come perhaps from contrasts in corrosion by crystallizing salt. Since observations in temperate and cold areas are not yet numerous, other investigations would be necessary to determine the influence of temperature on coastal corrosion forms in volcanic rocks. The Subantarctic Islands, Jan Mayen, and Aleutian Islands, might be interesting research fields in this respect. GUILLARD R. R. L. and J. H. RYTHER,1962. Studies of marine planktonic diatoms. I. Cyclotel/a nana Hustedt, and Detonula confervacea (Cleve) Gran. Canad. J. Microbiol., 8 (2): 229-240. Bacteria-free clones of the Small centric diatom Cyclotella nana Hustedt were isolated, three from estuarine localities, one from Continental Shelf waters, and one from the Sargasso Sea. Detonula confervacea was isolated from Narrangansett Bay. Morphology of all crones was studied with the light and electron microscopes. Morphological differences between clones of C. nana do not at present warrant separating any as distinct species. Clones of C. nana require only vitamin Blz; D. confervacea has no vitamin requirement. Growth of the estuarine clones of C. nana was unaffected by salinity down to 0"5~ and increased with temperature to 25°C. The Shelf clone grew more rapidly at salinities above 8 ~ and at temperatures between 10~ and 20~C. The Sargasso Sea clone did not survive below 15°C or 17.5~, while D. confer~acea did not survive at temperatures above 15° or at salinities below 8 ~ . The physiological differences between clones correspond roughly to the conditions obtaining in nature where each was collected. HASLE G. R., 1961 (1962). The morphology of Thalassiosira fluviatilis from the polluted inner Oslofjord. Nytt Mag. Botanikk, 9: 151-154. The centric diatom Thalassiosira fluviatilis Hustedt has been recorded from a marine environment, presumably for the first time. The valve structure of the diatom has been studied in the light and the electron microscopes. The details of the structure vary with the size of the valve and with the degree of silicification. HIDAKA K., 1961. Equatorial upwelling and sinking in a zonal ocean with lateral mixing. Geophys. Notes, Tokyo Univ., 14 (2) (22): reprint originally published in: Geophys. ,1., Astr. Soc. 4: 359-371. The two-dimensional dynamical equations were solved and an expression for the vertical motion was derived by assuming a balance between the pressure gradient, Coriolis and frictional forces. The frictional forces consist of terms of both vertical and lateral mixing. Isovels of the upwelling and sinking in a meridional section were obtained, assuming the magnitude of the coefficients of the horizontal and vertical viscosities to be 10 s and 10z c.g.s, respectively. The resulting vertical motion of water seems to be more intense than expected. But the result is quite flexible and reasonable values of vertical motion may be obtained by a proper choice of both the horizontal and vertical viscosity coefficients. HIRST D. M., 1962. The geochemistry of modern sediments from the Gulf of Paria. 1. The relationship between the mineralogy and the distribution of major elements..Geochim, et Cosmochim. Acta, 26: 309-334. The distribution of the major elements in some recent sediments from the Gulf of Paria has been determined. In interpreting the variation in the major element contents across the basin of deposition, consideration is given to such factors as rate of deposition, physico-chemical environment, salinity and facies. The majority of the major elements are already present within the lattices of various clay minerals when they enter the basin of deposition, and the variations in their contents in the different sediments reflect variation in the clay mineralogy is thought to be due to variation in weathering conditions in the source area of the sediments. HOLMBOE J., 1962. On the behavior of symmetric waves in stratified shear layers. Geofys. Publik., Geophysica Norvegica, 24: 67-114. The physical mechanism of hydrodynamical instability is examined in cases where an upper warm layer of air is moving relative to a lower cold layer. The two layers are separated by a shear layer where the wind has a continuous variation with height. Three models with different distribution of temperature in the shear layer are considered, namely: (i) The entire temperature change is located at the centre of the shear layer, in Chapter I. (ii) The shear layer has a constant potential temperature equai to the arithmetic mean of the outer temperatures, in Chapter II. (iii) The wind shear and temperature stratification have continuous (hyperbolic tangent) variations in the shear layer, in Chapter HI. The results represent generalisations of earlier results by HELMFIOLITZ,RAYLEIGH,TAYLORand GOLDSTEIN: The model ( i ) h a s overstability, i.e. oscillations with growing amplitudes, in a spectral band which shifts toward shorter waves with increasing static stability. The kinematic structure and overstable growth mechanism of these waves are discussed in Section 9. This system has no neutral waves
395
in cracks by ground water. Thus, the origin of differential corrosion in these structures is not always the same, and slight disparities in petrological constitution can sometimes result in large differences in morphological behaviour. The differences in morphological evolution between parts of the same platform standing at different heights come perhaps from contrasts in corrosion by crystallizing salt. Since observations in temperate and cold areas are not yet numerous, other investigations would be necessary to determine the influence of temperature on coastal corrosion forms in volcanic rocks. The Subantarctic Islands, Jan Mayen, and Aleutian Islands, might be interesting research fields in this respect. GUILLARD R. R. L. and J. H. RYTHER,1962. Studies of marine planktonic diatoms. I. Cyclotel/a nana Hustedt, and Detonula confervacea (Cleve) Gran. Canad. J. Microbiol., 8 (2): 229-240. Bacteria-free clones of the Small centric diatom Cyclotella nana Hustedt were isolated, three from estuarine localities, one from Continental Shelf waters, and one from the Sargasso Sea. Detonula confervacea was isolated from Narrangansett Bay. Morphology of all crones was studied with the light and electron microscopes. Morphological differences between clones of C. nana do not at present warrant separating any as distinct species. Clones of C. nana require only vitamin Blz; D. confervacea has no vitamin requirement. Growth of the estuarine clones of C. nana was unaffected by salinity down to 0"5~ and increased with temperature to 25°C. The Shelf clone grew more rapidly at salinities above 8 ~ and at temperatures between 10~ and 20~C. The Sargasso Sea clone did not survive below 15°C or 17.5~, while D. confer~acea did not survive at temperatures above 15° or at salinities below 8 ~ . The physiological differences between clones correspond roughly to the conditions obtaining in nature where each was collected. HASLE G. R., 1961 (1962). The morphology of Thalassiosira fluviatilis from the polluted inner Oslofjord. Nytt Mag. Botanikk, 9: 151-154. The centric diatom Thalassiosira fluviatilis Hustedt has been recorded from a marine environment, presumably for the first time. The valve structure of the diatom has been studied in the light and the electron microscopes. The details of the structure vary with the size of the valve and with the degree of silicification. HIDAKA K., 1961. Equatorial upwelling and sinking in a zonal ocean with lateral mixing. Geophys. Notes, Tokyo Univ., 14 (2) (22): reprint originally published in: Geophys. ,1., Astr. Soc. 4: 359-371. The two-dimensional dynamical equations were solved and an expression for the vertical motion was derived by assuming a balance between the pressure gradient, Coriolis and frictional forces. The frictional forces consist of terms of both vertical and lateral mixing. Isovels of the upwelling and sinking in a meridional section were obtained, assuming the magnitude of the coefficients of the horizontal and vertical viscosities to be 10 s and 10z c.g.s, respectively. The resulting vertical motion of water seems to be more intense than expected. But the result is quite flexible and reasonable values of vertical motion may be obtained by a proper choice of both the horizontal and vertical viscosity coefficients. HIRST D. M., 1962. The geochemistry of modern sediments from the Gulf of Paria. 1. The relationship between the mineralogy and the distribution of major elements..Geochim, et Cosmochim. Acta, 26: 309-334. The distribution of the major elements in some recent sediments from the Gulf of Paria has been determined. In interpreting the variation in the major element contents across the basin of deposition, consideration is given to such factors as rate of deposition, physico-chemical environment, salinity and facies. The majority of the major elements are already present within the lattices of various clay minerals when they enter the basin of deposition, and the variations in their contents in the different sediments reflect variation in the clay mineralogy is thought to be due to variation in weathering conditions in the source area of the sediments. HOLMBOE J., 1962. On the behavior of symmetric waves in stratified shear layers. Geofys. Publik., Geophysica Norvegica, 24: 67-114. The physical mechanism of hydrodynamical instability is examined in cases where an upper warm layer of air is moving relative to a lower cold layer. The two layers are separated by a shear layer where the wind has a continuous variation with height. Three models with different distribution of temperature in the shear layer are considered, namely: (i) The entire temperature change is located at the centre of the shear layer, in Chapter I. (ii) The shear layer has a constant potential temperature equai to the arithmetic mean of the outer temperatures, in Chapter II. (iii) The wind shear and temperature stratification have continuous (hyperbolic tangent) variations in the shear layer, in Chapter HI. The results represent generalisations of earlier results by HELMFIOLITZ,RAYLEIGH,TAYLORand GOLDSTEIN: The model ( i ) h a s overstability, i.e. oscillations with growing amplitudes, in a spectral band which shifts toward shorter waves with increasing static stability. The kinematic structure and overstable growth mechanism of these waves are discussed in Section 9. This system has no neutral waves