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Grain size distribution of different minerals in a sediment as a function of their specific density
226
D. SubmarineGeologyand Geophysics
appropriate equations are developed. Finally, the generation of longitudinal tipples is discussed as an example of the complexity of depositional processes. Dept. of Mech. and Environ. Engrg., Univ. of Calif., Santa Barbara, CA 93106, USA. (hbf)
OLR(1986)33 (3)
processes. Results include a zone of ~40% clay between 4000 and 4800 m and a zone of ~20% sand between 4800 and 4900 m. The silt/clay ratio increases with depth from 4000 to 5100 m. MIT/ WHOI Joint Progr. in Oceanogr., Cambridge, MA 02139, USA. (hbf)
86:1562
Richardson, M.J. and W.D. Gardner, 1985. Analysis of suspended--parflde-size distributions over the Nova Scotian continental rise. Mar. Geol., 66(14): 189-203. High particle concentrations (>400 #g L -~) in the intense benthic nepheloid layers are nearly always associated with a coarse ( ~ 8 pm) particle mode; these particles must be renewed on a time scale of weeks in order to be maintained in suspension. Layers composed of hydrographically distinct filaments of bottom water mainly contain fine particles (~2-3 pan) obtained upstream. Where the filament has extremely high particle concentrations ( > 1 mg L-I), the fine particle mode is masked by a locally resuspended coarse mode indicating that the filament must occasionaUy be accelerated by some external energy to the point that the critical shear stress for erosion is exceeded. City Univ. of New York, Lehman COIL, Bronx, NY 10468, USA. 86:1563 Schuiling, R.D., R.J. de Meijer, H.J. Riezebos and M.J. Scholten, 1985. Grain size distribution of different minerals in a sed]Tment aL~ a f ~ o n of their specific density. Geoiogie Mijnb., 64(2): 199203. Inst. of Earth Sci., Dept. of Geochem., State Univ. of Utrecht, The Netherlands.
DI30. Sediments (rocks, formations, type,
86:1566
May, J.A. and D.R. Eyles, 1985. Well log and seismic character of Tertiary Teromlm carbonate, South China Sea, Indonesia. Am. Ass. Petrol. Geol. Bull, 69(9): 1339-1358. Scientific Software-Intercomp, Inc., 1801 California, Denver, CO 80202, USA. 86:1567
McCave, I.N., 1985. Sedimentology and stratigraphy of box cores from the HEBBLE site on the Nova
Scotlan contimental rise. Mar. Geol, 66(1-4):5989. Within the top 1.5 m of sediment sampled by box cores at the HEBBLE site are four stratigraphic units: a pre-Holocene dark gray gravelly mud, probably transported by debris flow, is overlain by soft gray mud and a brown sandy mud containing Holocene Foraminifera and terrigenous material of turbidite origin; the surface unit, termed the HEBBLE mud, is highly mobile and subject to rapid erosion and deposition. Sand in this top layer averages 6% and varies in abundance with deposition rate and thickness, probably due to local winnowing. The size of the main silt mode varies inversely with clay percent, perhaps due to fractionation during deposition; a second silt mode is apparently suppressed under currents of 10-18 cm s-~. Silt size appears to be regulated by turbidite input and is probably a poor indicator of current speed. Dept. of Earth Sci., Univ. of Cambridge, Downing St., Cambridge CB2 3EQ, UK. (hbf)
composition, etc.) 86:1564 Domack, E.W. and D.E. Lawson, 1985. Pebble fabric in an ice-rafted dlamicton. J. Geol., 93(5):577591. Dept. of Geol., Hamilton Cotlege, Clinton, NY 13323, USA. 86:1565
Driscoll, M.L., B.E. Tucholke and I.N. McCave, 1985. Seafioor zonatlon in sediment texture on the Nova Scotlan lower continental rise. Mar. Geol, 66(1-4):25-41. Grain-size analyses of surface samples reveal a slope-parallel zonation of textural patterns which can be correlated with the speeds and position of the Gulf Stream; there is little evidence of downslope
86:1568 Mougenot, Denis, Raymond Capdevila, Christian Palain, P.-A. Dupeuble and Alaln Mauffret, 1985. New data on ante-rift sediments and on basement of the Galicia continental margin. C. r. Acad. Sci., Paris, (S6r. II)301(5):323-328. (In French, English abstract.) Lab. de Geodynam. sous-marine du CEROV, BP No. 48, 06230 Villefranche-sur-Mer, France. 86:1569
Sonnenfield, Peter (comment) and L.A. Hardie (reply), 1985. Comment Ionl 'Evag~tes: marine or ram-marine.~ Am. J. Sci~ 285(7):661-672. Univ. of Windsor, ON N9B 3P4, Canada.
D. SubmarineGeologyand Geophysics
appropriate equations are developed. Finally, the generation of longitudinal tipples is discussed as an example of the complexity of depositional processes. Dept. of Mech. and Environ. Engrg., Univ. of Calif., Santa Barbara, CA 93106, USA. (hbf)
OLR(1986)33 (3)
processes. Results include a zone of ~40% clay between 4000 and 4800 m and a zone of ~20% sand between 4800 and 4900 m. The silt/clay ratio increases with depth from 4000 to 5100 m. MIT/ WHOI Joint Progr. in Oceanogr., Cambridge, MA 02139, USA. (hbf)
86:1562
Richardson, M.J. and W.D. Gardner, 1985. Analysis of suspended--parflde-size distributions over the Nova Scotian continental rise. Mar. Geol., 66(14): 189-203. High particle concentrations (>400 #g L -~) in the intense benthic nepheloid layers are nearly always associated with a coarse ( ~ 8 pm) particle mode; these particles must be renewed on a time scale of weeks in order to be maintained in suspension. Layers composed of hydrographically distinct filaments of bottom water mainly contain fine particles (~2-3 pan) obtained upstream. Where the filament has extremely high particle concentrations ( > 1 mg L-I), the fine particle mode is masked by a locally resuspended coarse mode indicating that the filament must occasionaUy be accelerated by some external energy to the point that the critical shear stress for erosion is exceeded. City Univ. of New York, Lehman COIL, Bronx, NY 10468, USA. 86:1563 Schuiling, R.D., R.J. de Meijer, H.J. Riezebos and M.J. Scholten, 1985. Grain size distribution of different minerals in a sed]Tment aL~ a f ~ o n of their specific density. Geoiogie Mijnb., 64(2): 199203. Inst. of Earth Sci., Dept. of Geochem., State Univ. of Utrecht, The Netherlands.
DI30. Sediments (rocks, formations, type,
86:1566
May, J.A. and D.R. Eyles, 1985. Well log and seismic character of Tertiary Teromlm carbonate, South China Sea, Indonesia. Am. Ass. Petrol. Geol. Bull, 69(9): 1339-1358. Scientific Software-Intercomp, Inc., 1801 California, Denver, CO 80202, USA. 86:1567
McCave, I.N., 1985. Sedimentology and stratigraphy of box cores from the HEBBLE site on the Nova
Scotlan contimental rise. Mar. Geol, 66(1-4):5989. Within the top 1.5 m of sediment sampled by box cores at the HEBBLE site are four stratigraphic units: a pre-Holocene dark gray gravelly mud, probably transported by debris flow, is overlain by soft gray mud and a brown sandy mud containing Holocene Foraminifera and terrigenous material of turbidite origin; the surface unit, termed the HEBBLE mud, is highly mobile and subject to rapid erosion and deposition. Sand in this top layer averages 6% and varies in abundance with deposition rate and thickness, probably due to local winnowing. The size of the main silt mode varies inversely with clay percent, perhaps due to fractionation during deposition; a second silt mode is apparently suppressed under currents of 10-18 cm s-~. Silt size appears to be regulated by turbidite input and is probably a poor indicator of current speed. Dept. of Earth Sci., Univ. of Cambridge, Downing St., Cambridge CB2 3EQ, UK. (hbf)
composition, etc.) 86:1564 Domack, E.W. and D.E. Lawson, 1985. Pebble fabric in an ice-rafted dlamicton. J. Geol., 93(5):577591. Dept. of Geol., Hamilton Cotlege, Clinton, NY 13323, USA. 86:1565
Driscoll, M.L., B.E. Tucholke and I.N. McCave, 1985. Seafioor zonatlon in sediment texture on the Nova Scotlan lower continental rise. Mar. Geol, 66(1-4):25-41. Grain-size analyses of surface samples reveal a slope-parallel zonation of textural patterns which can be correlated with the speeds and position of the Gulf Stream; there is little evidence of downslope
86:1568 Mougenot, Denis, Raymond Capdevila, Christian Palain, P.-A. Dupeuble and Alaln Mauffret, 1985. New data on ante-rift sediments and on basement of the Galicia continental margin. C. r. Acad. Sci., Paris, (S6r. II)301(5):323-328. (In French, English abstract.) Lab. de Geodynam. sous-marine du CEROV, BP No. 48, 06230 Villefranche-sur-Mer, France. 86:1569
Sonnenfield, Peter (comment) and L.A. Hardie (reply), 1985. Comment Ionl 'Evag~tes: marine or ram-marine.~ Am. J. Sci~ 285(7):661-672. Univ. of Windsor, ON N9B 3P4, Canada.