Thesis (M.S.)--Auburn University, 2007. / Abstract. Includes bibliographic references (ℓ. 54-62)

Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Geophysics, 2003. / Bibliography: leaves [156-167].

Iron-formations are ferruginous sedimentary rocks which have their source from fumarolic activity associated with submarine volcanism, with deposition of iron as oxides, hydroxides, and hydrous oxide-silicate minerals in shallow and/or deep marine sedimentary systems. The Precambrian ironformations of southern Africa have a wide age range, but are more prominently developed before 1.SGa. These iron formations occur in greenstone belts of the Kaapvaal and Zimbabwean cratons, in the Limpopo mobile belt, in cratonic basins and in the Damara mobile belt. The Archaean-Proterozoic sedimentary basins and greenstone belts host iron ore deposits in iron-formation. Iron formations have a lengthy geological history. Most were subjected to intense, and on occasions repeated, tectonic and metamorphic episodes which also included metasomatic processes at times to produce supergene/hypogene high grade iron ores. Iron-formations may be enriched by diagenetic, and metamorphic processes to produce concentrating-grade ironformations. Uplift, weathering and denudation, have influenced the mineral association and composition of the ores, within which magnetite, haematite and goethite constitute the major ore minerals. The iron resources of the southern Africa region include the Sishen deposits, hosting to about 1200 Mt of high grade direct shipping ore, at >63% Fe. Deposits of Zimbabwe have more than 33 000 Mt of beneficiable iron-formation. The evaluation of an iron ore prospect involves many factors which must be individually assessed in order to arrive at an estimate of the probable profitability of the deposit. Many of these are geological and are inherent in the deposit itself. Other factors are inherent aspects of the environment in which the ore is formed. Although the geological character of the ore does not change, technological advances in the processing techniques may have a great effect on the cost of putting the ore into marketable form. Geochemical, geophysical and remote sensing methods would be used for regional exploration. Chip sampling and drilling are useful for detailed exploration. Purely geological exploration techniques are applicable on a prospect scale in the exploration of iron ore deposits. Regional exploration targeting should choose late Archaean greenstone belts containing oxide facies iron-formation or Early Proterozoic basins located at craton margins as they are both known to host high-grade haematite orebodies formed by supergene/hypogene enrichment. Most types of iron ore deposits in southern Africa are described and classified. An attempt is made to emphasize the major controls on mineralisation, in the hope that these may be applicable to exploration both in the southern African region and within analogous settings around the world.

No description available.

Bibliography: leaves 78-83. "The dissertation brings together discourses relating to sustainability with that of the environment, at least in terms of its meaning and responses to it being culturally constructed. The Central Adelaide Hills provides the locality for achieving this, which a peri-urban environment is subject to the power exerted by urban Adelaide as well as the tension arising out of land use conflict and attitudes to the environment."

The undermining of bridge foundations can lead to either costly repairs or a bridge collapse. These foundations must be designed to counter the effects of scour. Current practice does not allow for accurate estimates of scour in erodible rock. Scour in rock can be related to geotechnical and hydraulic properties. A field study of eleven bridge sites provided samples of the bedrock where the abrasive resistance of the rock was determined and hydraulic properties of the channel were calculated. Laboratory abrasion resistance values from a modified slake durability test and hydraulic variables such as stream power were compared to recent and past stream channel cross-sections. A preliminary model has been proposed wherein the degradation of the stream channel is related to the abrasive resistance of the bedrock and the area under the daily stream power. This method provides an estimate of the degradation of the stream bed due to abrasion by bedload and flood events, not necessarily local or contraction scour. / Graduation date: 1998

Ten species of bats occur in the Oregon Coast Range and are hypothesized to be associated with late-successional forests. The development of characteristics of late-successional forests in young forest stands can be accelerated through silvicultural practices such as thinning I examined the effects of thinning on the use of forests by bats in the Oregon Coast Range. I used automated ultrasonic detectors to record bat calls in 50- to 100-year-old thinned and =thinned stands as well as in old-growth (2200-year-old) stands in 11 sites in the Oregon Coast Range during the summers of 1994 and 1995. I compared bat activity levels among the 3 stand types. In addition, I classified bat calls into 1 of 5 species groups: Eptes/Las, Myev/vo, Myyu/ca, MythCory, and Mysp. I measured selected vegetation and environmental variables in conjunction with bat activity. I also compared bat activity on roads with activity in the stand interior at 1 site. Bat activity was higher in old growth than in young stands, and higher in thinned than in =thinned stands in 1995 and over both seasons combined. I did not detect a difference in bat activity among stand types in 1994, until I removed 1 site from the analysis. The Mysp and MythCory species groups exhibited differences among stand types. Bat activity along roads was higher than activity within stands. Tree density, tree diameter, tree height, shrub cover, and shrub height varied significantly between old-growth and young stands. Tree density, tree diameter, shrub cover, canopy cover, and crown height varied significantly between thinned and unthinned stands. Bat activity, overall or by species group, was significantly related to structural variables, including mean snag diameter, mean distance from the detector to snags, and percent shrub cover. My results suggest that bats are sensitive to stand structure and that silvicultural practices, such as thinning, which promote development of structural characteristics found in old-growth stands, would benefit bat populations. Further study is needed to clarify the habitat preferences of separate bat species and to specify habitat elements required by bat species. / Graduation date: 1997

No studies have evaluated the effects of limited vehicle access on movements, survival and habitat use of Roosevelt elk (Cervus elaphus roosevelti) . We installed twenty gates, restricting motorized vehicle access by the public in seven discrete Road Management Areas (RMAs), comprising 35% of the study area. We radio-tracked 31 cow elk for 13 months in a 38,000 ha area of the Oregon Coast Range. Prior to the installation of the gates, 20 of these elk had been tracked for 14 months, allowing a paired comparison of elk movements and habitat use before and during the limited access period. The percentage of elk home ranges or core areas within the RMAs did not differ between periods, but there was a clear decrease in daily movement of elk during the limited access period. Survival rates increased during the limited access period and declined after the removal of the gates. During the limited access period, there was a significant increase in the use of open, foraging habitats and areas <150 m from roads. We conducted habitat selection analysis on vegetative cover types, distance from roads and distance from water. In general elk use of vegetative cover types was not significantly different from availability (p<0.05). Elk avoided areas <150 m from roads and selected areas >150 m from roads. Elk selected areas <150 m from streams and avoided areas >600 m from streams. Roosevelt elk should benefit from the preferred alternative of the President's forest Plan, which maintains roadless areas near streams. / Graduation date: 1996

Title page, contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / In many areas of south-eastern Australia, the clearance of temperate eucalypt woodlands for agriculture has been so extensive that only scattered remnant trees remain. The loss of habitat and increased spatial isolation of trees in paddocks is predicted to lead to a decline in plant fecundity because of disruptions to plant-pollinator interactions, which has important implications for the long-term persistence and maintenance of these populations. In order to assess the ability of paddock trees to contribute to population regeneration, this study assessed the reproductive viability and patterns of mating of paddock trees of two woodland species, Eucalyptus camaldulensis and E.leucoxylon in the Mt. Lofty Ranges, South Australia. This study revealed that paddock tree populations of E. camaldulensis and E.leucoxylon were reproductively viable and received sufficient visits by pollinators that resulted in high outcrossing rates. The results suggest that seed collected from these paddock trees are both genetically diverse and representative of adult populations. Therefore, such trees could contribute successfully to conservation strategies that sought to regenerate cleared paddocks. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1292793 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2007

Title page, contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / In many areas of south-eastern Australia, the clearance of temperate eucalypt woodlands for agriculture has been so extensive that only scattered remnant trees remain. The loss of habitat and increased spatial isolation of trees in paddocks is predicted to lead to a decline in plant fecundity because of disruptions to plant-pollinator interactions, which has important implications for the long-term persistence and maintenance of these populations. In order to assess the ability of paddock trees to contribute to population regeneration, this study assessed the reproductive viability and patterns of mating of paddock trees of two woodland species, Eucalyptus camaldulensis and E.leucoxylon in the Mt. Lofty Ranges, South Australia. This study revealed that paddock tree populations of E. camaldulensis and E.leucoxylon were reproductively viable and received sufficient visits by pollinators that resulted in high outcrossing rates. The results suggest that seed collected from these paddock trees are both genetically diverse and representative of adult populations. Therefore, such trees could contribute successfully to conservation strategies that sought to regenerate cleared paddocks. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1292793 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2007