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The Coompana Province is one of the most poorly understood pieces of crystalline basement geology in the Australian continent. It lies entirely concealed beneath a variable thickness of Neoproterozoic to Cenozoic sedimentary rocks, and is situated between the Gawler Craton to the east, the Musgrave Province to the north, and the Madura and Albany-Fraser Provinces to the west. A recently-acquired reflection seismic transect (13GA-EG1) provides an east-west cross-section through the southern part of the Coompana Province, and yields new insights into the thickness, seismic character and gross structural geometry within the Coompana Province. To assist geological interpretation of the 13GA-EG1 seismic line, new SHRIMP U-Pb zircon ages have been acquired from samples from the limited drill-holes that intersect the Coompana Province. New results from several granitic and gneissic rocks from the Coompana Province yield magmatic and/or high-grade metamorphic ages in the interval 1100 1200 Ma. Magmatic or high-grade metamorphic ages in this interval have not been identified in the Gawler Craton, in which the last major magmatic and metamorphic event took place at ~1590 1570 Ma. The Gawler Craton was largely unaffected by ~1100 1200 Ma events, as evidenced by the preservation of pre-1400 Ma 40Ar/39Ar cooling ages. In contrast, magmatic and metamorphic ages of 1100 1200 Ma are characteristic of the Musgrave Province (Pitjantjatjara Supersuite) and Madura Province (Moodini Supersuite). The new results from the Coompana Province have also yielded magmatic or inherited zircon ages at ~1500 Ma and ~1640 Ma. Once again, these ages are not characteristic of the Gawler Craton and no pre-1700 Ma inherited zircon has been identified in Coompana Province magmatic rocks, as might be expected if the province was underlain by older, Gawler Craton-like crust. The emerging picture from this study and recent work from the Madura Province and the Forrest Zone of the western Coompana Province is that the Coompana Province has a geological history that is quite distinct from, and generally younger than, the Gawler Craton to its east, but that is very similar to the Musgrave and Madura Provinces to the north and west. The contact between the Coompana Province and the Gawler Craton is interpreted in the 13GA-EG1 seismic line as a prominent west-dipping crustal-scale structure, termed the Jindarnga Shear Zone. The nature and timing of this boundary remain relatively poorly constrained, but the seismic and geochronological evidence suggests that it represents the western edge of the Gawler Craton, marking the western limit of an older, more isotopically evolved and multiply re-worked craton to the east, from a younger, more isotopically primitive crust that separates the South Australian Craton from the West Australian Craton.
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Recovering a groundwater basin degraded by salinity caused by an overdraft is difficult and involves significant conflict with the community. This paper discusses how a successful reduction in the overdraft of the Angas-Bremer Basin, South Australia, is being achieved through an innovative management program developed with extensive community involvement. The Angas-Bremer Basin is 50 km southeast of Adelaide adjacent to Lake Alexandrina. It developed rapidly as a irrigation area in the early post-war period before the introduction of groundwater management legislation. Groundwater salinity increases became evident during the 1960s and 1970s. Development was finally stopped in 1979, when formal management controls were introduced. By this stage, irrigation areas on the basin margins had ceased production due to encroaching high groundwater salinities. Groundwater salinities continued to rise, and in 1987 positive action was finally taken to recover the situation. The management strategy developed in 1987 involved the establishment of a new partnership between the water agency and the community water resources management committee. In this new partnership, the committee and the community accepted the responsibility for dealing with the problem, and the water agency adopted a supporting and facilitating role in the management process. An innovative five year management plan incorporating substantial restructuring with accompanying incentives was developed through this process and was endorsed by the community after considerable debate. This plan has fulfilled its aims and has now been updated by the community building on the success achieved over the past five years. The development of the Angas-Bremer management strategy illustrates the effectiveness of community involvement in implementing the major adjustments required to recover seriously degraded water resources .
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The Blue Lake is a high value groundwater resource in a high risk environment. The lake has several beneficial uses. It is a water supply for the City of Mount Gambier. It is the premier tourist attraction for the City, because of its picturesque setting within a volcanic crater and its habit of changing colour from a steel grey-green in winter to an intense blue in summer. The lake also supports a considerable diversity of aquatic life, although individual numbers of any species are not abundant. The City of Mount Gambier is located on the northern flank of the volcanic complex . The complex occurs within an unconfined karstic limestone aquifer, and the lake is a window into the groundwater. Historical waste disposal practices have caused a number of point-source pollution plumes within the unconfined aquifer. Sewage and septic tank effluent routinely reached the aquifer before a sewerage system was installed in the mid 1960s. The effluent has polluted the groundwater beneath the city with nitrate. Regional hydraulic gradients show that the city is located immediately upgradient of the lake. Nitrogen levels in the lake have climbed to around 3.6 mg/L. There appears to be a relationship between extraction rate from the lake and nitrogen levels in the lake. Other pollutants are not evident in the lake. The Engineering and Water Supply Department are developing a Management Plan for the Blue Lake and the surrounding groundwaters. This Plan is being developed with the assistance of a small group from the community and with a broader community consultation program, with several benefits. These include community education about the issues and community ownership of the solutions.
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Digital Elevation data record the terrain height variations from the processed point- or line-located data recorded during a geophysical survey. This GSSA Marree Elevation Grid Geodetic is elevation data for the Marree-Warrina Airborne Magnetic & Radiometric Survey, SA, 2012. This survey was acquired under the project No. 1255 for the geological survey of SA. The grid has a cell size of 0.00083 degrees (approximately 87m). This grid contains the ground elevation relative to the geoid for the Marree-Warrina Airborne Magnetic & Radiometric Survey, SA, 2012. It represents the vertical distance from a location on the Earth's surface to the geoid. The data are given in units of meters. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose.
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The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium (K), uranium (U) and thorium (Th). The data collected are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. The terrestrial dose rate grid is derived as a linear combination of the filtered K, U and Th grids. A low pass filter is applied to this grid to generate the filtered terrestrial dose rate grid. This GSSA Marree Dose Grid Geodetic has a cell size of 0.00083 degrees (approximately 87m) and shows the terrestrial dose rate of the Marree-Warrina Airborne Magnetic & Radiometric Survey, SA, 2012. The data used to produce this grid was acquired in 2012 by the SA Government, and consisted of 132484 line-kilometres of data at 400m line spacing and 80m terrain clearance.
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The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium (K), uranium (U) and thorium (Th). The data collected are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. This radiometric thorium grid has a cell size of 0.00083 degrees (approximately 87m) and shows thorium element concentration of the Marree-Warrina Airborne Magnetic & Radiometric Survey, SA, 2012 in units of parts per million (or ppm). The data used to produce this grid was acquired in 2012 by the SA Government, and consisted of 132484 line-kilometres of data at 400m line spacing and 80m terrain clearance.
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Total magnetic intensity (TMI) data measures variations in the intensity of the Earth's magnetic field caused by the contrasting content of rock-forming minerals in the Earth crust. Magnetic anomalies can be either positive (field stronger than normal) or negative (field weaker) depending on the susceptibility of the rock. The data are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. This GSSA Marree TMI Grid Geodetic has a cell size of 0.00083 degrees (approximately 87m). The units are in nanoTesla (or nT). The data used to produce this grid was acquired in 2012 by the SA Government, and consisted of 132484 line-kilometres of data at 400m line spacing and 80m terrain clearance.
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The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium (K), uranium (U) and thorium (Th). The data collected are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. This radiometric uranium grid has a cell size of 0.00083 degrees (approximately 87m) and shows uranium element concentration of the Marree-Warrina Airborne Magnetic & Radiometric Survey, SA, 2012 in units of parts per million (or ppm). The data used to produce this grid was acquired in 2012 by the SA Government, and consisted of 132484 line-kilometres of data at 400m line spacing and 80m terrain clearance.
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The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium (K), uranium (U) and thorium (Th). The data collected are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. This radiometric uranium grid has a cell size of 0.00083 degrees (approximately 87m) and shows uranium element concentration of the Marree-Warrina Airborne Magnetic & Radiometric Survey, SA, 2012 in units of parts per million (or ppm). The data used to produce this grid was acquired in 2012 by the SA Government, and consisted of 132484 line-kilometres of data at 400m line spacing and 80m terrain clearance.
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The Digital Elevation Model represents ground surface topography between points of known elevation. The elevation data was calculated using the altimeters and Global Positioning System (GPS) sensor used for the benefit of airborne magnetic and radiometric data on the same survey. The elevation is the height relative to the Australian Height Datum GDA94 (AUSGEOID09). The processed elevation data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. These line dataset from the Marree-Warrina Airborne Magnetic & Radiometric Survey, SA, 2012 survey were acquired in 2012 by the SA Government, and consisted of 132484 line-kilometres of data at 400m line spacing and 80m terrain clearance.