Thesis (M.L.S.)--Eastern Michigan University, 2000. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 39-40).

The Kluane Ranges are underlain by a sequence of stratified rocks ranging in age from Permian to Triassic, cut by .Cretaceous and Tertiary intrusions. Flow and pyroclastic rocks of Lower Permian Station Creek Formation were probably part of a volcanic arc environment. Argillaceous and tuffaceous rocks of the Transition Zone of Station Creek Formation and overlying sedimentary rocks of Lower Permian Hasen Creek Formation were deposited in a subaqueous environment, possibly a back-arc basin. Upper Triassic basalts of the Nikolai Greenstone are largely subaerial and were probably a product of rift volcanism. Lower Triassic Kluane gabbro-ultramafic complexes are sill- or sheet-like bodies, divisible into a Lower Group (within the Transition Zone) that consist of peridotite and dunite with associated nickel-copper sulphide deposits, and an Upper Group (within Hasen Creek rocks) that consist of gabbro and peridotite but with no known associated nickel-copper deposits. The ultramafic rocks are piagioclase-bearing and chemically are pyroxenitic and peridotitic komatiites. Bulk chemical composition of the Quill Creek complex is similar to that of pyrolite and calculations show the complex could have formed from an upper mantle diapir, affected by 40 percent partial melting and composed of residual olivine crystals and ultramafic liquid. Prominent copper lode deposits in the Kluane Ranges include: (1) vein and disseminated types in Station Creek volcanic rocks; (2) nickel-copper associated with Kluane complexes; and (3) vein-type in the Nikolai Greenstone. A narrow, positive range of sulphur isotopic compositions for vein sulphides in Station Creek Formation contrast sharply with a large range for those in the Nikolai Greenstone. The former deposits resulted from only local mobilization of sulphur (and metals) during metamorphism in a closed system, whereas mineralization in the Nikolai Greenstone involved considerable variation in chemical parameters of ore fluids in an open system with more than one source of sulphur. Anomalously negative sulphur isotopic values for nickel-copper sulphide bodies resulted from contamination of magmatic sulphur by 30 to 60 percent sulphur from wall rocks. Much of this contamination occurred prior to or during segregation of an immiscible sulphide liquid as at Quill Creek, with further contamination during injection of still liquid sulphide bodies into footwall rocks in the case of Canalask deposit. Substantial contaminant.sulphur may have been crucial in achieving sulphur saturation of magmas of Lower Group Kluane complexes and subsequent formation of associated nickel-copper sulphide deposits. Isotopic data for both magmatic sulphides and sulphur-bearing country rock support a strong case for a general sulphur contamination model for nickel-copper deposits related to mafic and ultramafic intrusions on a worldwide scale. Pyrite in wallrock is considered to be the most likely general source of sulphur contributed to ultramafic magmas and several different stages of sulphur contamination are possible throughout consolidation of the magmas and its associated sulphides. Sulphur transfer to the magma can occur by bulk country rock assimilation or by fluid ingress where the fluid derives sulphur from the contact zone by incongruent melting of pyrite or by complete dissociation of pyrite. Important features of this model, having economic implications, are: (1) emplacement of the ultramafic complex as a magma; (2) presence of sulphur-bearing country rocks; and (3) presence of a sulphur-depletion halo adjacent to the ultramafite. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

No description available.

Utilizing geochemical and geospatial data to explore the spatial variability of metals within streambed sediment of a local waterway may help to identify anthropogenic input of copper, lead, and zinc in urbanized streams. Utoy Creek is an urbanized stream located just southwest of downtown Atlanta. Baseline trace metal values and a reference site were used to determine if copper, lead, and zinc concentrations were higher or lower than baseline or reference site values. The Atlanta Metro Region (AMR) had over 2,100 miles of impaired streams listed on the 2008 303(d) list. This type of study can be used as a proxy to help determine how "impaired" local urbanized streams really are and to identify areas of interest for future studies. For this study, 42 sites were selected for streambed sediment collection, chemical analysis was preformed, and GIS and statistical analysis were preformed. This study shows that several areas in Utoy Creek show elevated metal concentrations of copper, lead, and zinc.

There was a major discharge into Restronguet Creek, south-west Cornwall in January 1992 of metalled acidic mine water drainage from the recently closed Wheal Jane tin mine. Shortly after this discharge a post-impact study using the responses of Recent benthic foraminifera as indicators of metal pollution was carried out on this Creek which had not been investigated previously. Because of a lack of pre-discharge foraminiferal data from Restronguet Creek, other estuaries, which previously drained metal mining regions, have been sampled in order to determine the background levels in foraminiferal populations. These estuaries, Fowey (Cornwall), Avon and Erme (south-west Devon) have not been investigated previously. The research programme included reconnaissance sampling of the estuaries Looe, Yealm, Kingsbridge, Axe and Carrick Roads (south-west England), primarilly to determine the geographical distribution of the agglutinated species. In all, 651 samples were taken for micropalaeontological and laser analysis from which an estimated 260,000 tests have been picked and some 70 species identified. A further 395 samples were taken for metal, carbon, nitrogen, sediment grain size and mineralogical analysis. The results of this research show changes over time with the colonisation of barren stations, increased abundance of living individuals, reduced proportions of deformed tests, less severe acid dissolution of the test walls and a seasonal species distribution which is similar to that of the Fowey Estuary. Low diversity is unchanged and the agglutinating foraminifera, which form distinct assembage zones in the control estuaries, remain absent from Restronguet Creek. The data provided by the short cores from Restronguet Creek suggest that the 1992 discharge does not account for the absence of these species. During the period of investigation the sediment-bound metals in terms of the concentrations have, in general, increased but the river water quality entering the Creek has improved in terms of metals and acidity. This suggests that the foraminifera are more directly influenced by metals in solution and that tangible benefits have been gained from the water quality improvement programme inaugurated by the Environment Agency.

No description available.

[Abstract]: The Julia Creek dunnart (Sminthopsis douglasi) is an endangered carnivorous marsupial. A recovery plan for the species has been initiated by Queensland Parks and Wildlife Service, which includes captive breeding.An important factor in breeding S. douglasi is the identification of oestrus. The current method to identify oestrus consists of examining urine samplesfor presence of cornified cells. To collect urine, the animals have to be removed from their cages and restrained. This method is stressful for theanimals, as well as time consuming. The aim of this study was to identify specific behaviour of S. douglasi associated with oestrus, which could be readily observed without the need for handling the animal. This wouldprovide a non-invasive way of identifying oestrus, which would facilitate breeding the species in captivity and planning conservation programs.Behaviour of S. douglasi was observed throughout the night by video recording. The most striking result was the increase in activity of the female when she was in oestrus compared to non-oestrus. The most informativebehaviour to observe was entry by the female into the nest box and the frequency with which she entered the area closest to the wall of the enclosure. A discriminant function analysis generated an equation with anover-all predictive power (OPP, the probability of making an accurate identification of reproductive state) of 89%. This result was obtained by watching two random five-minute periods of activity. The equation was tested and verified with new individuals and attained a similar level of OPP. However, the equation was less accurate when the observed female’s social context was changed from being housed adjacent to a male, to being accompanied by another female or housed singularly. Consistent with thesensitivity of activity levels as an indicator, the distance run in an exercise wheel was also a good predictor of oestrous state. Females ran a significantly longer distance in their exercise wheel when in oestruscompared to non-oestrus (p<0.001).

Dams have altered flow distributions in rivers everywhere, causing a host of changes in channel morphology and sediment dynamics. Although major changes in flow regime have occurred along Yegua Creek, Texas, since the closure of Somerville Dam in 1967, the issue of sediment transport has not been studied in detail. The extent to which sediment is moving through the system remains unclear. This study addresses the extent to which sediment is moving through and downstream of the dam. Analysis of sediment samples collected at 23 sites in the Yegua Creek channel system showed that coarse sand to silt-sized materials dominate the creek upstream of the dam, whereas finer silt and clay sediments characterize the downstream portions. Calculation of the trapping efficiency of the dam indicates that approximately 99.8% of materials from the upper watershed are trapped behind Somerville Dam. Investigations of sediment mobility further suggest that present flows are capable of mobilizing sediments downstream of the dam. Although a de-coupling between the upper and lower portions of the Yegua Creek watershed has likely occurred due to the high rate of sediment trapping, new sediment sources that include tributaries and alluvial storage likely play a larger role in providing materials for sediment transport downstream. Despite a reuction in peak flows, the channel morphology of Yegua Creek has apparently adjusted over the four decades since construction of Somerville Dam to achieve a new equilibrium characterized by sediment movement. These results are corroborated by analysis of aerial photographs. These findings augment our understanding of the many facets of the response of fluvial systems to the disturbance posed by dam construction. Because Yegua Creek is a major tributary to the Brazos River draining to the Texas coast, increased understanding of sediment dynamics within Yegua Creek provides critical insights into the efficacy of sediment delivery in a regional context, and ultimately to the Texas coastline. The findings of this study also provide useful information for managing stream ecosystems affected by impoundments.

The coastal wetlands at Aransas National Wildlife Refuge near Austwell, Texas, support the last migrating population of whooping cranes during the winter months (October through April). With a population currently at 216 individuals, these are the rarest cranes in the world. The wetlands in which they winter are a part of the San Antonio Bay system, a bay that receives constant fresh water flow from the Guadalupe River. Currently there is a plan for using water diverted from the Guadalupe River just before it enters San Antonio Bay as a water supply for the greater San Antonio metropolitan area located 200 km to the northwest. The Guadalupe River delivers nutrients and sediment into the estuary along with fresh water. Because of the importance of sediment within a tidal wetland ecosystem, it is imperative to understand the sediment budget and underlying forces that drive it if one is to ultimately grasp how this ecosystem functions. To document natural and anthropogenic factors exerting control over sediment movement in this system, three sites on tidal creeks near the boundary between marsh and bay were chosen. The Gulf Intracoastal Waterwayparallels the marsh edge. Over six, non-consecutive weeks water level and velocity were automatically monitored in the tidal creeks. Automated water samplers extracted water samples that were analyzed for suspended sediment. In addition, bedload traps were deployed in one creek to monitor sediment movement along the channel bottom. Inflow exceeded outflow during the study. As a result there was a net influx of suspended sediments into the marsh. Bedload material also moves with current direction, and it appears to move in response to barge induced outflow currents. Barges passing on the Gulf Intracoastal Waterway exert influence on water level, flow direction, and velocity within tidal creeks. Natural factors such as winds, tides, and freshwater input from upland runoff or river discharge also impact suspended and bedload sediments.

Thesis (M.L.A) -- University of Texas at Arlington, 2008.