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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The timing and source of gold-bearing fluids in the Laverton Greenstone Belt, Yilgarn Craton, with emphasis on the Wallaby gold deposit

Salier, Brock Peter January 2004 (has links)
[Truncated abstract] The Laverton Greenstone Belt (LGB), located in the northeastern part of the Eastern Goldfields Province (EGP) of the Yilgarn Craton, Western Australia, has a total contained gold endowment of over 690t. An important feature of the gold deposits in the LGB is their close spatial association with granitoids, with many gold deposits located adjacent to, or hosted by, granitoids. Recently-proposed genetic models for Archaean orogenic gold deposits have emphasised the role of granitoids in the formation of ore-deposits, but differ significantly in the nature of that role. Some models suggest that the granitoids are a source of ore-fluids and solutes, whereas others suggest that granitoids exert an important structural control on gold mineralisation. Such competing genetic models for gold mineralisation variably propose either a proximal-magmatic or distal-metamorphic, or less commonly distal-magmatic, source for goldbearing fluids, or mixing of fluids from multiple sources. Isotope geochemistry and geochronological studies are used to constrain the source and timing of auriferous fluids at nine gold deposits in the LGB in an attempt to differentiate between conflicting genetic models. To overcome the lack of detailed deposit-scale geological constraints inherent to any regional study, hypotheses generated from regional datasets are tested in a detailed case-study of the Wallaby gold deposit. The Pb-isotope compositions of ore-related sulphides from deposits in the LGB plot along the line representing crustal-Pb in the Norseman-Wiluna Belt of the EGP, with individual deposits clustering with other nearby deposits based on their geographic location. This trend is similar to that recorded in the Kalgoorlie-Norseman region in the southern EGP, and is consistent with a basement Pb reservoir for gold-bearing fluids. As such, data are consistent with a similar fluid source for all gold deposits. The Nd and Sr isotopic composition of goldrelated scheelite in the LGB clusters very tightly. The inferred ore-fluid composition has a slightly positive εNd, similar to ore fluids at other gold deposits in the EGP for which a proximal magmatic source is highly improbable. As such, Sr and Nd data are consistent with a similar fluid source for the gold deposits analysed in the LGB, but cannot unequivocally define that source. The median S, C and O isotopic compositions of ore minerals from all nine different gold deposits studied in the LGB fall in a very narrow range
2

Assessing the growth performance of European olive (Olea europea L.) on Mount Weld pastoral station

Price, Gary Norman January 2006 (has links)
This thesis describes the growth of European olive (Olea europaea L.) at three different trial sites located near Laverton, in the north-eastern Goldfields region of Western Australia. The local region comprises part ofthe rangelands area of Australia and has a semi-arid climate. The initial reason for planting olives was indirectly related to the rapid decrease in the local population and the economic downturn that resulted within that community during the late 1990's. This prompted an investigation into other possibilities for economic diversity for remote communities such as Laverton, which are located in the rangelands area of Australia. In Australia, much of the southern and eastern areas of the country have similar climate to traditional olive growing areas in Europe. [n the rangelands however, the environment is different to most other areas in the world where olive trees are grown and there is a notable absence of a commercial olive industry. Whilst locally, individual trees were also observed to be growing well and fruiting abundantly, it is not known whether it is possible to grow olive trees successfully on a commercial scale. Two preliminary trials were established in an ad-hoc manner, to examine whether olive trees could be grown successfully in the rangelands environment. Eighty-eight trees of 5 different cultivars were planted on a shallow, clay soil profile at the first trial site. Ninety-eight trees of 11 different cultivar were planted on a deep sand soil profile at the second site. Higher mortality rate occurred at the first site, with most tree deaths being recorded in the first two years. Peak growth of branch tips occurred during the spring-summer seasons at both sites. Differences in trial design and timing of planting prevented statistical comparison of growth performance between sites however. / A third olive trial, consisting of 3 olive groves was established according to randomised design. In the north and middle groves, 54 trees of 3 different cultivar were planted on a deep alluvial soil profile. In the south grove, 53 trees of 3 different cultivar were planted on a shallow clay soil profile. High mortality rates were recorded at all 3 groves during the first year, as a result of high salinity levels in irrigation water during the establishment period. Overall, most tree mortality was recorded at the south grove. Significantly higher growth performance occurred within the deeper alluvial soil profile at the north and middle groves, compared to the shallow clay soil profile in the south grove. Negligible olive fruit production occurred at the first site. At the second site, small quantities of olive fruit were produced during some seasons only. No olive fruit production occurred at any grove at the randomized site. Successful fruit formation appears directly related to tree health, as a function of water supply. Ripening of olive fruit occurred earlier than at other more temperate olive growing areas of Australia. Similar major and trace element deficiencies occurred at all sites, interpreted to be a function of universal alkaline ground-water conditions. / This study failed to confirm conclusively, whether European olive could be grown successfully in the semi-arid climate, typical of much of the rangelands area of Australia. As a result of the study however, successful growth in this environment is confirmed to be highly dependent on three factors. Firstly, availability of reliable irrigation waters of sufficient quality. Secondly, choice of suitable soil types. Thirdly, selection of suitable cultivars. Quality of olive oil produced from fruit appears to be influenced by local climatic factors The study also highlighted the issues of land tenure, current management attitudes and level of support within the local community as having a direct and significant impact on the trial.

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