A Critical Note on ‘Eco‐Civic Regionalisation’ as the Basis for Local Government Boundaries in Australia

The notion of ‘eco‐civic regionalisation’ has been applied recently to New South Wales by Brunckhorst, Coop and Reeve (2004 Brunckhorst D Coop P Reeve I 2004 An eco‐civic regionalisation for rural New South Wales: final report to the NSW government Institute for Rural Futures and Centre for Bioregional Resource Management, University of New England, Armidale  [Google Scholar]) in order to identify the appropriate administrative boundaries for ‘socio‐civic’ regions and ‘biophysical’ regions. On the basis of this analysis, they recommended inter alia that 49 future non‐metropolitan ‘local government areas’ be established. This proposal was adopted with alacrity by advocates of the NSW government's program of compulsory council amalgamation, including official ‘Facilitators’ appointed by the State government to draft formal consolidation proposals. This paper disputes the applicability of ‘eco‐civic regionalisation’ as the foundation for local government boundaries in Australia.     

THE DISTRIBUTION AND ECOLOGICAL-BIOLOGICAL FEATURES OF CREPIDULA ONYX IN HONG KONG

C. onyx, originally distributed in California, was found in great quantities in Victoria Harbour, Hong Kong in 1982 and was identified according to the study of its morphology and the radula teeth. Lots of the individuals of the species lived in overlapping colony, with the female at the lower, and the male in the upper while the sex-transforming individual at the middle. They attached on the shells of Perna viridis in a high density of 715 ind./m2. Studies have been carried out on its population structure, individual size, age and sex composition and on reproductive biology, such as sex transformation, change of the length of penis and fecundity.     

Structure of gravel beaches and their relationship to tidal range

The height of accretionary gravel beaches, determined by the vertical distance between the large sphere zone at the seaward margin and the large disc zone at the landward margin, is determined mainly by tidal range. As the beach builds seaward, this height translates into thickness and so the complete thickness of gravel beach accumulations is a good indicator, in the geological record, of tidal range. Beaches with a small tidal range have the zone between the large discs and the large spheres compressed and sometimes steepened. These beaches are characterized mainly by cusps and berms, both of which yield steeply dipping, seaward building, cross‐strata. Beaches built by large, persistent waves generally have a steep profile, whereas those with small wave height appear to have a shallow profile. Cusps generally have extremely well‐sorted gravels, often in an openwork fabric and with a landward crown of coarse gravel that may grade seaward into shape‐sorted, gently dipping gravels. Berms, which may extend for hundreds of metres along the coast, comprise, in section, very well‐sorted cross‐stratified gravels that may intermittently build seaward for a distance >15 m. Extensive selection pavements typify beaches with a high tidal range and comprise sheets of gravel which are well‐sorted and dip at comparatively low angles towards the sea. These selection pavements form beds that, in section, can be >50 m in seaward length; they grow from clasts, supplied to them from swash or backwash, and which are selected by the fabric of the existing sheet. In some cases, the selection pavements can be very mature having only a specific clast shape and size remaining. Total preservation of the beach sequence in the geological record is more likely to take place in areas of rapid deposition of sediments, such as the marine fringes to a fan delta.     

Fine particle deposition to initially starved,stationary, planar beds

Reported here are results from new flume experiments examining deposition and entrainment of inert, silt‐sized particles (with spherical diameters in the range from 20 to 60 μm) to and from planar, impermeable and initially starved beds underlying channel flows. Bed surfaces comprised smooth or fixed sand‐size granular roughness and provided hydraulically smooth to transitionally rough boundaries. Results of these experiments were analysed with a simple model that describes the evolution of vertically averaged concentration of suspended sediment and accommodates the simultaneous delivery to and entrainment of grains from the bed. The rate of particle arrival to a bed diminishes linearly, and the rate of particle entrainment increases by the 5/2 power, as the value of the dimensionless Saffman parameter S = u_*³/g’ν approaches a threshold value of order unity, where u is the conventional friction velocity of the turbulent channel flow, g’ is the acceleration due to gravity adjusted for the submerged buoyancy of individual particles and ν is the kinematic viscosity of the transporting fluid. This transport behaviour is consistent with the notion that non‐cohesive, silt‐sized particles can neither reach nor remain on an impermeable bed under flow conditions where mean lift imposed on stationary particles in the viscous sublayer equals or exceeds the submerged weight of individual particles. Within the size range of particles used in these experiments, particle size and the characteristic size of granular roughness, up to that of medium sand, did not affect rates of dimensionless arrival or entrainment to a significant degree. Instead, a new but consistent picture of fine‐particle transport is emerging. Silt‐sized material, at least, is subject to potentially significant interaction with the bed during intermittent suspension transport at intermediate flow speeds greater than the value required for initiation of transport (ca 20 cm sec^?1) but less than the value (ca 50 cm sec^?1) required by the Saffman criterion ensuring transport in fully passive suspension or, equivalently, ‘wash‐load’.     

CHANNELS FROM THE UPPER CARBONIFEROUS COAL MEASURES OF SOUTH WALES

Sandstone-filled channels occur widely in the Upper Carboniferous (Westphalian) rocks of South Wales. Subsurface and outcrop studies of channels and associated structures in three formations within the Westphalian sequence reveal significant regional variations in orientation, transverse profile, geometry and lithology of fill. The pattern of channel-orientation in each formation is consistent with the system of palaeocurrents derived from independent studies of cross-bedding and indicates that in the lowest Westphalian (Basal Coal Measures) derivation was principally from the north and east, with intermittent supply from the south, whereas in the Upper Westphalian material was derived mainly from the south and east but with substantial contributions from the north.
Formation of the channels is ascribed to fluvial erosion and filling. The mutually consistent regional variations in channel-parameters are compared with the conspic- uous changes in lithofacies and interpreted as indicating diRerences in Auviohydraulic locale within the original basin of sedimentation.     

Hummocky cross-stratification and post-vortex ripples: length scales and hydraulic analysis

Duke (1987) argues that the structure reported by Greenwood & Sherman (1986) as hummocky cross-stratification from a shallow lacustrine environment is, instead, bedding formed by simple post-vortex oscillation ripples. His primary concern is with the length scale of the structures identified in box cores. However, using measured flow data, it is shown here that existing models of bedform generation based upon wave orbital velocity, orbital diameter and grain diameter do not support a simple post-vortex ripple interpretation. In particular, the relative steepness of the structure refutes such an origin. The structural characteristics of the lacustrine cores most closely match those associated with classic hummocky cross-stratification and were produced under a combined oscillatory/quasi-steady flow field.     

Crystal fabrics and microbiota in large pisoliths from Laguna Pastos Grandes, Bolivia

Large pisoliths from the Laguna Pastos Grandes playa in the Bolivian Altiplano have a wide diversity of cortical fabrics and variable mineralogical composition. The cortical laminae are composed of radial calcite bundles, spar calcite, micrite, amorphous silica, mixed micrite-amorphous silica, quartz, gypsum and halite. Diatoms are common in the outer parts of some radial calcite laminae and amorphous silica laminae, but cyanobacterial filaments are rare. Although the organization of the cortical laminae is highly variable, some repetitive sequences of different laminae are present. Cavities in and between pisoliths contain micrite, detrital grains, calcite bundles and peloids morphologically similar to those found in marine reefs. The pisoliths grow in shallow ephemeral pools fed by hot springs. Radial bundles of calcite precipitate rapidly by degassing and photosynthetic removal of CO₂ following spring snowmelt. Conditions for micrite precipitation are unclear, but there is evidence to suggest formation in partially stagnant waters, some of elevated salinity. Amorphous silica laminae precipitate mainly by evaporative concentration; quartz may precipitate from warm silica-rich spring waters that remain below amorphous silica saturation. The evaporite minerals form during desiccation of the pools or from spray. The peloids in cavities are probably primary precipitates. Different types of laminae may form simultaneously in different pools because of the highly variable conditions across the playa. Lateral migration of spring locations through time has created a complex carbonate-silica pavement. Large spherical pisoliths form in outflow channels near spring orifices and across discharge aprons where waters are several decimetres deep. With mineral precipitation, channels are filled and become shallow, producing discoid pisoliths and crusts. In shallow waters and on distal aprons only small pisolith gravels form. As spring pools fill with deposits, their locations shift laterally; new pisoliths form elsewhere or precipitation may recommence on older abandoned pisoliths.     

COMPUTER TECHNIQUES FOR THE ZONING AND CORRELATION OF WELL-LOGS*

This paper reviews computer techniques used in the automatic zoning and correlation of well-logs. Prior to correlating, well-logs are to be segmented–or ‘zoned’–so as to delineate sections that have similar properties. Techniques discussed include statistical methods such as variance tests and Student's t-test, linguistic analysis, the use of Walsh functions and spectral analysis. Well-log correlation, which may be between traces from different wells or between traces from the same hole (as in dip logs), is used in basin studies and the determination of structural dip. A variety of methods are reviewed including conventional time and frequency correlation, sequence slotting, pattern recognition and frequency analysis. Future directions for investigation are proposed.