OLR (1986) 33 (3) D. Submarine Geology and Geophysics 225

of clay mineral diagenesis and itself varies system- atically with burial depth and temperature. Dept. of Geol., Beaumont Bldg., Univ. of Sheffield, Brookhill, Sheffield $3 7HF, UK.

86:1556 DeMaster, D.J., B.A. McKee, C.A. Nittrouer, D.C.

Brewster and P.E. Biscaye, 1985. Rates of sediment reworking at the HEBBLE site [Nova Scotian continental rise] based on measurements of Th-234, Cs--137 and Pb-210. Mar. Geol., 66(1-4): 133-148.

Th-234 data from HEBBLE cores indicate that particles at the sediment-water interface are mixed to depths of 1-5 cm on a 100-day time scale. Cs-137 and Pb-210 data indicate that on time scales of 30-100 yrs surface sediments are reworked to depths ranging 1 to 12 cm. In some HEBBLE sediments there is good agreement between the Th-234 and the Pb-210 mixing coefficients; in others, however, Th-234 data indicate that the Pb-210 profile has not reached steady state. Implications for modelling are noted. Dept. of Mar., Earth and Atmos. Sci., North Carolina State Univ., Raleigh, NC 27695-8208, USA.

86:1557 Hagan, P.S. and D.S. Cohen, 1985. Stratified layer

formation in particle suspensions. Physica, The Hague, 17D(1):54-62.

Initially homogeneous suspensions of colloidal par- ticles often develop 'staircase' layers of nearly constant concentration, separated by sharp bound- aries, with the concentration of each successive layer increasing with depth. Siano has demonstrated experimentally that diffusion against the concen- tration gradient occurs. Thus, these patterns appear to be the result of spinodal decomposition. These patterns cannot be explained by the classical spinodal decomposition theory of Cahn and Hilliard, but they can be explained if the linear gradient- energy term of Tiller, Pound, and Hirth is added to the free energy. The physical origin of this extra term may be the Rayleigh-Taylor instability. Exxon Corp. Sci. Lab., Rte. 22 East, Aunandale, NJ 08801, USA.

86:1558 Hanes, D.M. and A.J. Bowen, 1985. A grunuiar-fluid

model for steady intense bed-load transport. J. geophys. Res., 90(C5):9149-9158.

Flow is modeled as two fluid regions with contin- uous stress, velocity, and granular concentration; a simple kinematic model is developed to predict the grain transport in the saltation zone and to provide the upper boundary conditions for the granular-fluid region. Velocity in the latter is approximately

proportional to the applied shear stress raised to the 3/2 power under the assumption of a linearly varying volume concentration. The grain flux and energy dissipation are proportional to the applied shear stress raised to the 5/2 power. Compared with observations and previous models, the present formulation predicts significantly greater transport at extremely high stresses. RSMAS, Univ. of Miami, FL 33149, USA.

86:1559 McCave, I.N., 1985. Properties of suspended sedi.

ment over the HEBBLE area on the Nova S¢otlan Rise. Mar. Geol., 66(1-4):169-188.

Twenty samples from 20, 40, 250 and 1000 m above bottom were analysed by Coulter Counter giving a size range of 1.59-256/an. Aggregates were common in most samples, particularly with associated mucus. Blobs and strings of mucus were common with and without particles. Apparent density of particles (a) increases with overall concentration, but Co) de- creases with increasing concentration when only larger particles are included. This probably reflects (a) aggregation during ageing of a suspension and (b) presence of more mucus in larger coarse-mode populations. Dept. of Earth Sci., Univ. of Cam- bridge, Downing St., Cambridge CB2 3EQ, UK.

86:1560 McCave, I.N. and C.D. Hollister, 1985. Sedimen-

tatiun under deep-sea current systems: pre- HEBBLE ideas. Mar. Geol., 66(1-4):13-24.

Studies of the interaction of deep ocean current systems with the seabed are briefly traced from their beginnings in the mid-1950s. Subsequent lines of study in physical oceanography, suspended sediment measurement, echo-character mapping, microphy- siography, sedimentology and developments of instrumentation are noted up to 1978 when the High Energy Benthic Boundary Layer Experiment started. Dept. of Earth Sci., Univ. of Cambridge, Downing St., Cambridge CB2 3EQ, UK.

86:1561 McLean, S.R., 1985. Theoretical m o ~ l l i n ~ of deep

ocean sediment tr~sport. Mar. Geol., 660- 4):243-265.

The physics of the general processes involved in the resuspension, transport, and deposition of sediments is examined using a 'quasi-one-dimensional' mod- elling approach which is then applied to three- dimensional site specific models. The interrela- tionships of boundary shear stress, the Ekman layer, sediment entrainment, stratification, turbulence, cohesion, material size, etc. are explored and

226 D. Submarine Geology and Geophysics OLR (1986) 33 (3)

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)

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(1- 4): 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 fil- aments 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 fila- ment 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): 199- 203. Inst. of Earth Sci., Dept. of Geochem., State Univ. of Utrecht, The Netherlands.

DI30. Sediments (rocks, formations, type, composition, etc.)

86:1564 Domack, E.W. and D.E. Lawson, 1985. Pebble fabric

in an ice-rafted dlamicton. J. Geol., 93(5):577- 591. 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

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)

86:1566 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-Inter- comp, 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):59- 89.

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 depo- sition rate and thickness, probably due to local winnowing. The size of the main silt mode varies inversely with clay percent, perhaps due to frac- tionation 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)

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.