Sediments of the Tay Estuary. III. Sedimentological and Faunal Relationships on the Southern Shore at the Entrance to the Tay.

Author(s):  
Christopher D. Green

SynopsisThe southern entrance shores to the Tay estuary form an area of extensive inter-tidal sedimentation. Tidal currents of varying strengths characterise the area and the situation is modified by both wind and wave. The net result is a series of seven sub-environments of sedimentation. The textural characteristics of the sediment and the distribution of major and minor sedimentary structures in each subenvironment is closely linked to stability and changing physical processes. The distribution of organisms, live and dead, provides a good indication of these patterns of sediment and stability.

Author(s):  
A. T. Buller ◽  
J. McManus

SynopsisA lack of modern river-borne sediment and a steady supply of marine materials have led to the hypothesis that the upper Tay estuary is undergoing an erosive phase counterbalanced by a headward moving sheet of largely marine-derived sand presently occupying the upper-middle estuary. This primal division (based on sediment budget criteria) is also reflected in the bathymetry, distribution of sediment types, and sedimentary structures. The situation of two contrasting ‘phase zones’ juxtaposed within a relatively small area is ideal for an empirical and indirect analysis of the response of a wide variety of sediment types to the gross physical processes acting on them. The analysis takes the form of standard grain-size characterisations using conventional sedimentary statistics, supplemented by adaptations of C-M and QDa-Md diagrams transformed for display on distribution maps.


Author(s):  
J. A. Charlton

SynopsisMeasurements of tidal currents in the outer Tay Estuary, and from the hydraulic model of the estuary, are used to present a tidal atlas of the area and to deduce residual tidal circulation. Additional tests on the model show that the volumetric exchange rate with the sea of the outer estuary can be as high as 58 per cent per tide, but may be lowered to about 35 per cent if multiple tide recirculation is considered. Fresh water discharge into the estuary does not materially affect this exchange rate.


1987 ◽  
Vol 2 ◽  
pp. 52-61
Author(s):  
Michael J. Hayes

I observed and measured the orientations of common physical sedimentary structures on the beach and spit, estero, tidal channel, and inner and outer tidal flats of Bahia la Choya. The spit is characterized by wind ripples and the beach typically displays swash marks. Mudcracks typify the high marsh portions of the estero while the meandering estero channel contains ripples and megaripples. The inner and outer tidal flats are dominated by small, ebb-oriented, straight-crested to undulatory current ripples. The current ripples are often superimposed on flood-oriented ridges and runnels of the outer flat. Rill marks, tool marks, and current crescents occur sporadically. Ebb-oriented megaripples, small current ripples, and primary current lineations occur in the tidal channel.Ripple crests trend from N15E - N40E on the southern tidal flats to N10W - N20W on the northern flats. The crests roughly parallel the shoreline and are normal to tidal currents.


1979 ◽  
Vol 44 ◽  
pp. 349-355
Author(s):  
R.W. Milkey

The focus of discussion in Working Group 3 was on the Thermodynamic Properties as determined spectroscopically, including the observational techniques and the theoretical modeling of physical processes responsible for the emission spectrum. Recent advances in observational techniques and theoretical concepts make this discussion particularly timely. It is wise to remember that the determination of thermodynamic parameters is not an end in itself and that these are interesting chiefly for what they can tell us about the energetics and mass transport in prominences.


Author(s):  
Randall W. Smith ◽  
John Dash

The structure of the air-water interface forms a boundary layer that involves biological ,chemical geological and physical processes in its formation. Freshwater and sea surface microlayers form at the air-water interface and include a diverse assemblage of organic matter, detritus, microorganisms, plankton and heavy metals. The sampling of microlayers and the examination of components is presently a significant area of study because of the input of anthropogenic materials and their accumulation at the air-water interface. The neustonic organisms present in this environment may be sensitive to the toxic components of these inputs. Hardy reports that over 20 different methods have been developed for sampling of microlayers, primarily for bulk chemical analysis. We report here the examination of microlayer films for the documentation of structure and composition.Baier and Gucinski reported the use of Langmuir-Blogett films obtained on germanium prisms for infrared spectroscopic analysis (IR-ATR) of components. The sampling of microlayers has been done by collecting fi1ms on glass plates and teflon drums, We found that microlayers could be collected on 11 mm glass cover slips by pulling a Langmuir-Blogett film from a surface microlayer. Comparative collections were made on methylcel1ulose filter pads. The films could be air-dried or preserved in Lugol's Iodine Several slicks or surface films were sampled in September, 1987 in Chesapeake Bay, Maryland and in August, 1988 in Sequim Bay, Washington, For glass coverslips the films were air-dried, mounted on SEM pegs, ringed with colloidal silver, and sputter coated with Au-Pd, The Langmuir-Blogett film technique maintained the structure of the microlayer intact for examination, SEM observation and EDS analysis were then used to determine organisms and relative concentrations of heavy metals, using a Link AN 10000 EDS system with an ISI SS40 SEM unit. Typical heavy microlayer films are shown in Figure 3.


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