The Migration of Cave Arthropods Across The Nullarbor Plain, Southern Australia, 1972, Richards, Aola, M.

The Nullarbor Plain is a low plateau of Tertiary limestone covering an area of 194,175 km2 in southern Australia. It has a semi-arid climate and supports a stunted vegetation. Ninety-five species of arthropods have been recorded from 47 Nullarbor caves, and many of these species are widely distributed across the Plain. Two possible explanations for their distribution are discussed. Subterranean migration may occur through the widespread zone of small interconnecting cavities in the Nullarbor Limestone, but this has not yet been confirmed. While cave arthropods are confined to the cool, moist cave environment during the day, they have been observed at night in cave entrances, in dolines and on the surface of the Plain. Cave "breathing", similarity in cave and epigean climate at night, strong winds, occasional heavy rain and numerous animal burrows all contribute towards favourable conditions for surface migration.

On the Subterranean Syncarids of Tasmania, 1977, Lake P. S. , Coleman D. J.

The current knowledge on the occurrence of syncarid crustaceans in underground habitats in Tasmania is reviewed. The "mountain shrimp" Anaspides tasmaniae has been recorded on at least five occasions from caves. Syncarid shrimps in the genera Allenaspides, Koonunga and Nicraspides have been collected from crayfish burrows. The term Pholeteros is coined to define the community of organisms dwelling in crayfish burrows. Syncarids in the genera Koonunga and Atopobathynella have been collected in the bed of streams (Hyporheos). The collection of the new species of syncarid from an underground spring at Devonport is reported.

Dissolution tubules: A new karst structure from the English chalk, 2000, Lamontblack J. , Mortimore R. ,

The Chalk of England is not renowned for producing karst landforms. This paper introduces a previously undescribed karst phenomenon, termed here dissolution tubules, from the Chalk of Sussex. The internal structure of these features was investigated by developing a novel method of resin impregnation and acid digestion. This revealed tubules to be a truly dendritic landform. Their relationships with chalk macrotextures were investigated using the Bushinski oil technique (BROMLEY 1981) and revealed an association with trace fossil burrows. Detailed electron microscopic examination of chalk adjacent to the karst surface, employing the textural analysis methods of MORTIMORE & FIELDING (1990), revealed dissolutional textural modification of the chalk to a depth of approximately 15 mm beneath the dissolution surface and a possible spatial association of dissolution tubules with microfractures. Dissolution tubules in the field were found overlying major discontinuities such as subhorizontal sheet flints, marl seams, hardgrounds, major fractures and caves. Evidence gathered suggests mixing corrosion (BOGLI 1964) as the process responsible for their formation

Discrimination of effective from ineffective porosity in heterogeneous Cretaceous carbonates, Al Ghubar field, Oman , 2003, Smith L. B. , Eberli G. P. , Masaferro J. L. , Aldhahab S.

The Natih E heavy-oil reservoir (21j API) atAl Ghubar field, Oman has produced less than 5% of the calculated oil in place. Porosity logs used to calculate reserves show high porosity throughout the reservoir, but further analysis of the only continuous core taken from the field indicates that much of the porosity is ineffective. There are four heavily oil-stained, high-permeability skeletalpelletal grainstone units with interparticle porosity in the core that probably contributed most of the production. The four permeable grainstone units occur at the top of small-scale accommodation cycles that have wackestone and packstone bases. These grainstones make up about 20% of the total thickness of the porous Natih E reservoir. The other 80% is composed of packstone and wackestone with ineffective microporosity, interparticle porosity in burrows, and isolated moldic and intraskeletal porosity. The small-scale reservoirbearing cycles can be correlated across the field using the separation between the medium and deep induction curves as a guide. Resistivity logs are the most reliable tool to distinguish effective from ineffective porosity. Most high-permeability grainstone units have deep induction values more than 100 ohmmand separation of more than 10 ohm m between the medium and deep induction curves. The ineffective intervals with microporosity, burrow porosity, and moldic porosity have lower resistivity and little separation between the medium and deep induction curves 

Influence of depositional setting and sedimentary fabric on mechanical layer evolution in carbonate aquifers, 2006, Graham Wall Brita R. ,

Carbonate aquifers in fold-thrust belt settings often have low-matrix porosity and permeability, and thus groundwater flow pathways depend on high porosity and permeability fracture and fault zones. Methods from sedimentology and structural geology are combined to understand the evolution of fracture controlled flow pathways and determine their spatial distribution. Through this process bed-parallel pressure-solution surfaces (PS1) are identified as a fracture type which influences fragmentation in peritidal and basinal carbonate, and upon shearing provides a major flow pathway in fold-thrust belt carbonate aquifers. Through stratigraphic analysis and fracture mapping, depositional setting is determined to play a critical role in PS1 localization and spacing where peritidal strata have closer spaced and less laterally continuous PS1 than basinal strata. In the peritidal platform facies, units with planar lamination have bed-parallel pressure-solution seams along mudstone laminae. In contrast, burrowed units of peritidal strata have solution seams with irregular and anastamosing geometries. Laminated units with closely spaced bed-parallel solution seams are more fragmented than bioturbated units with anastamosing solution seams. In the deeper-water depositional environment, pelagic settling and turbidity currents are the dominant sedimentation processes, resulting in laterally continuous deposits relative to the peritidal platform environment. To quantify the fracture patterns in the basinal environment, mechanical layer thickness values were measured from regions of low to high bed dip. The results define a trend in which mechanical layer thickness decreases as layer dip increases. A conceptual model is presented that emphasizes the link between sedimentary and structural fabric for the peritidal and basinal environments, where solution seams localize in mud-rich intervals, and the resulting pressure-solution surface geometry is influenced by sedimentary geometry (i.e., stacked fining upward cycles, burrows, planar laminations). In both facies types, laterally continuous PS1 can behave as mechanical layer boundaries. As layer-parallel slip increases to accommodate shear strain in the fold-thrust belt, more PS1 behave as mechanical layer boundaries