A phytoplankton bloom dominated by the pennate diatom Nitzschia
curta (Van Heurck) Hasle was observed during January-February 1983 at
a receding ice-edge in the Western Ross Sea, Antarctica. The core of
the bloom was found between 100-150 Km from the ice-edge. Nitzschia
curta cell densities up to 22 x 10⁶...
Major (Fe, Mn, Al) and minor (Cr, Mo, Pb, Zn, Cd) element
analyses of metalliferous sediments in cores from the East Pacific
Rise and Bauer Deep indicate that the Bauer Deep sediments are
similar in chemistry and origin to metalliferous sediments of the
East Pacific Rises.
Fe, Pb, and Zn...
Quartz is an ubiquitous component of marine sediments. Textural
characteristics of this component reflect the dynamics of its transport
and at the same time are indicative of its source.
Quartz may be extracted from marine sediments by means of a
sodium pyrosulfate fusion and hydrofluosilicic acid dissolution without
significantly modifying...
The abundance and distribution of biogenic, terrigenous and
volcanic particles in the Panama Basin are markedly dependent on
bottom topography and dissolution of calcite in the deeper parts of the
basin. Of the coarse fraction (>62μ), foraminiferal tests and acidic
volcanic glass shards are concentrated on the Cocos and Carnegie...
Illite, chlorite, montmorillonite and kaolinite, as well as
natural marine sediments and mixtures of the standards were subjected
to density separation by centrifugation in a linear heavy-liquid
gradient.
The density layers yielded by centrifugation were recovered
and analyzed by X-ray diffraction. Separates were not monomineralic
but rather were polymineralic usually...
Here we investigate the relationships between modern foraminiferal assemblages from Atlantic and Pacific surface sediment samples and multiple environmental properties including water column and preservation variables using Canonical Correspondence Analysis (CCA). CCA finds two fauna] dimensions that are highly correlated to the environmental variables included in the analysis, and then...
Ninety-five oriented samples were obtained from nine Recent
Cascade lava flows in Oregon. Directions and intensities of remanent
magnetization were measured on a spinner magnetometer which measures
directions of magnetization to within 1.2° s.d. Angle measurements
were plotted graphically using an equal area projection. Mean
directions and statistics were calculated...
Cores taken from the ridge areas of the Gorda-Juan de Fuca
plate have a sedimentation rate that is appropriate for the study of
late Quaternary stratigraphy. An analysis of the clay and silt
mineralogy of the cores using X-ray diffraction methods and by
noting changes in the foraminiferan-radiolarian abundances in...
A new technique for determining the amount of opal in deep-sea
sediments of any age is described. Using a normative calculation, a
portion of the analytical silica concentration of sediments is subtracted
as non-biogenic in proportion to the concentration of aluminum in the
sample. The ratio of SiO₂:Al₂O₃ used to...
Recent organic-rich deposits on the Peru continental margin
occur along the upper slope (100-450 m) between about ll°S and 16°S
and along the lower continental slope (>2000 m). The upper slope
deposits reflect high biological production in response to coastal
upwelling, but preservation of organic matter is enhanced by the...
Holocene hemipelagic deposition of terrigenous silts and clays
dominates sedimentation on most of the Oregon and Washington continental
slope. The sources of these sediments, the mechanisms causing sediment
dispersal, and the relative contributions of the various continental
sources to the marine deposits have been investigated using quantitative
mineral and geochemical...
The local and remote sources of variability of the South Atlantic Ocean are investigated using a set of numerical experiments and satellite data. A global, eddy-permitting, numerical simulation is analyzed to investigate the dynamical links between the Antarctic Circumpolar Current (ACC) and the Malvinas Current (MC). The model results indicate...
Transition metal and rare earth element (REE) data are presented
for various sedimentary materials from two Manganese Nodule
Program (MANOP) sites in the eastern tropical Pacific. These data
constrain the sources of elemental supply to the seafloor and the
processes that control ferromanganese nodule genesis. Investigation
of elemental partitioning between...
This thesis investigates the behavior of major inorganic nutrients (P, N, Si), trace metals (Mn, Fe), and alkaline-earth metals (Ba) within Tillamook Bay over seasonal cycles and under a range of river discharge conditions from October 1997 through December 1999. Located in the Pacific Northwest region, Tillamook Bay is an...
Dissolved silicic acid (Si(OH)4) and biogenic silica (BSiO2) concentrations were measured on four different cruises in the Southern Ocean along 1700 W from late October 1997 to mid-March 1998. These data were used to construct a vertically integrated Si budget in the surface layer from 58° to 68° S. Throughout...