Water supply for the town of Alice Springs is obtained from the Roe Creek Borefield, 15 km to the south-southwest. This borefield currently consists of 20 production bores which pump water from four discrete aquifers in three formations in the Amadeus Basin: Mereenie Sandstone, Pacoota Sandstone (2), and Shannon Formation. Annual extraction is of the order of 10 x 106 m3, of which more than 80 per cent comes from the Mereenie Sandstone. Peak daily extraction rates are 55 000 m3. Regional investigations show that the Mereenie Sandstone will continue to be the major source of Alice Springs water supply. Models have been developed to determine the economically sustainable yield from the Roe Creek Borefield. These models indicate that borefield abstraction is primarily from local aquifer storage, and, as such, drawdown is linearly related to total withdrawal from the aquifers.

The Coolibah Formation outcropping around the Toko Syncline, southeastern Georgina Basin, was sampled for conodonts during a multidisciplinary study of Georgina Basin geology by the Australian Geological Survey organisation. Twenty-two species of conodonts belonging to 17 genera recovered from acid insoluble residues are described. Alcoorina and Tokoconus are new genera; Alcoorina nadala, Bergstroemognathus kirki and Tokoconus wheelamanensis are previously undescribed species. Four species remain in open nomenclature awaiting more material. The conodont faunas are grouped into three broad biostratigraphic associations, although few sections record all three. Faunas low in the Coolibah Formation are dominated by Drepanoistodus costatus (Abaimova) and Scolopodus multicostatus Barnes and Tuke, with Diaphorodus tortus (McTavish), Scandodus sp. nov. A and hyaline conical elements. The succeeding conodont association records first appearances of Ansella fengxiangensis (An and others). Aurilobodus? leptosomatus An. Paroistodus originalis (Sergeeva). Protoprioniodus nyinti Cooper. and Triangulodus larapintinensis (Crespin). Specimens of younger species are found in the uppermost Coolibah Formation. Examination of these associations within different sections indicates that both upper and lower contacts of the Coolibah Formation are probably diachronous. Recovered conodonts are closest in affinity to those of North China, and North and South Korea. They range in age from middle to late Arenig.

Nettletons concept of density profiling can be utilised to give useful estimates of the bulk density of topographic features. These estimates can be used to infer the composition of such topography, or to assist in the interpretation of local gravity anomalies. Two methods that facilitate multiple density profiling over elongate topography are presented. One is a simulation reduction method utilising the two-dimensional line integral formula of Talwani, Worzel and Landisman (1959). It enables data from any detailed gravity traverse crossing an elongate topographic feature at right angles to be automatically reduced by computer to a set of multiple density Bouguer profiles. From these profiles, the bulk density of the topographic feature can be estimated by visual correlation. The other is a graphical method of converting a set of multiple density Bouguer profiles directly to point density estimates, without the need for visual correlation. Both methods are theoretically exact for the ideal case. A visual correlation determination of 2.85 ± 0.05 g cm^-3 is demonstrated for a traverse crossing the 300 m high Harts Range, Northern Territory, and three point determinations of 2.97,2.97, and 2.99 g c^-3, for a traverse crossing the 100 m high Fraser Range, Western Australia.

Nolans Bore is a REE-U-P deposit (47 Mt grading 2.6% REO, 186 ppm U3O8 and 11% P2O5) hosted by apatite veins and breccias within the ~1805 Ma Boothby Orthogneiss of the Aileron Province, Northern Territory. Allanite SHRIMP U-Pb analyses indicate a vein crystallisation age of 1525±40 Ma, but mineral system processes necessary to the development of the deposit commenced before 1800 Ma and continue today. Processes leading to the formation of Nolans Bore began with north-dipping subduction along the south margin of the Aileron Province at 1820-1750 Ma, producing a metasomatised, volatile-rich lithospheric mantle wedge. About 200 Ma later, towards the end of the Chewings Orogeny, this reservoir became a source of alkaline low-degree partial melts which passed into the mid- and upper-crust. Among these alkaline products was a phosphate-rich magmatic-hydrothermal fluid which deposited the Nolans Bore apatite veins by local fluid-rock interaction and/or fluid mixing at ~400 degrees C. The deposit then became a radiogenic heat source, owing to its size and high concentration of Th, raising the local ambient temperature to ~300 degrees C, above the closure temperature of some mineral isotopic systems. For example, vein apatite U-Pb ages are in the range ~1240 to ~960 Ma, significantly younger than initial emplacement. The system finally cooled below 300 degrees C (the 40Ar-39Ar closure temperature of biotite) at ~370 Ma, possibly in response to unroofing during the Alice Springs Orogeny. Subsequent to surface exposure, weathering of fluorapatite produced acidic fluids and intense, near-surface kaolinitised zones that form high-grade, supergene-enriched cheralite-rich ores. This groundwater-mediated process continues today. The local heat production of Th- and/or U-rich deposits is an important feature that may be partly responsible for the arrays of post-emplacement isotopic ages which characterise such mineral systems. Other physical and chemical processes continue to be generated by the high abundances of reactive and heat-producing elements at Nolans Bore, with significant effects on the economic, isotopic and geochemical characteristics of the deposit and its host, an observation that may apply to other such deposits.

Rb-Sr data reveal a long and complex Proterozoic history for the Arunta Inlier of central Australia. The first event was a widespread, dominantly granulite-facies episode, known as the Strangways Event, at 1790 ± 35 Ma. Five relatively precise ages from metamorphic and granitic rocks give an estimate between 1650 and 1700 Ma for widespread deformation and metamorphism during the Aileron Event. Two granites in the northern Arunta Inlier were probably emplaced at about 1500 m.y. Deformation and low-grade metamorphism during the Anmatjira Event are dated by generally imprecise isochrons at about 1400 Ma. Four isochrons, documenting both primary events and resetting, are in accord with an age of 900-1050 Ma for the Ormiston Event. The Rb-Sr data do not define the time of initial crust formation in the Arunta Inlier.

The format of most existing metallogenic maps is not adequate for scales of 1:500 000 or less. The major problem is the colourful out-of-scale locality symbols, which mask the map detail in the most important areas, the immediate vicinity of the ore occurrences. The design of the symbols is also a problem, most being influenced considerably by genetic interpretations that are subjective and change with time; they are incapable of expressing transitionality, correlation of metallogenetic and lithogenetic events, and they cannot accommodate incomplete information. A substantially different philosophy of metallogenic mapping has been tested using the Pine Creek Geosyncline as an example. Ideally, the product would be a set of three matching maps. Map 1 would be a base map, a modified geological map that consistently shows the age of units by colour and the lithology of units by pattern, regardless of genesis and the level of emplacement. Mineralised occurrences would be identified in the simplest way possible, so as not to obscure the background information. Map 2 would be a gitological map, or map of mineral deposits, providing information on the geological properties of occurrences. The symbols suggested are based on simplified geological cross-sections, and are colour and pattern coordinated with the base map, to give the reader an immediate impression about the contemporaneity of rock-and ore-forming events and of the hosts to the ore. Within the symbol framework for a given mineralisation style, a wide range of properties of individual occurrences can be shown, and unknown information can be truthfully expressed as a blank component of the symbol. Map 3 would be a commodity map, showing the ore metals, their individual and total accumulations, and the concentration of the major metal.

A moderately well-preserved miospore flora has been obtained from the type section of the Late Devonian Buttons beds in the southwestern Bonaparte Gulf Basin, Western Australia. It is characterised by relatively abundant specimens of Retispora lepidophyta (Kedo) Playford, 1976 and by other trilete miospore species that collectively constitute the R. lepidophyta Assemblage as defined from the lower part of the Fairfield Group of the Canning Basin, Western Australia. On this basis, the Buttons beds are datable as latest Devonian, probably within the interval Fa2d to Tn1a or early Tn1b of Belgian terminology. This palynological age determination is somewhat younger than previous, faunally based age assessments of the Buttons beds, which have suggested, not altogether unequivocally, an earlier Famennian age (i.e., doIIß-doIII, Falc-Fa2b). One new species of trilete cingulate miospores - Lophozono-triletes varionodosus - is instituted herein.

A U-Pb zircon age for acid volcanics in the Bernborough Formation of the Warramunga Group indicates a depositional age of between 1819 m.y. and 1849 m.y. If a previously postulated correlation is correct, Division II rocks of the Arunta Block are also this age. The new data show unequivocally that amphibolite-facies rocks west-southwest of Tennant Creek are basement to the Warramunga Group and not merely its higher-grade equivalents.

Upper crustal seismic investigations of the Tennant Creek Block indicate that the Warramunga Group rocks have P-wave velocities of 5.22-5.55 km/s (average 5.42 km/s) and S-wave velocities of 3.26-3.41 km/s (average 3.34 km/s). The P-wave velocity beneath these surface rocks is 6.06 km/s. A simple layered model for the thickness of the Warramunga Group gives values of about 2.6 km near Nobles Nob mine, thinning to about 1.2 km near Warrego mine. South of the Warramunga Group rocks, granitic rocks have an estimated upper value for the P-wave velocity of 5.69 km/s. Underneath, the P-wave velocity of 6.06 km/s is the same as that further north, under the Warramunga Group rocks, but the depth to this velocity is as much as 0.7 km less. The corresponding S-wave velocity is 3.53-3.59 km/s. An intracrustal S-wave velocity of 3.86 km/s is observed from the Warrego shot. The nature of the change between the surface and basement rocks is likely to be complex, resulting in a velocity transition zone rather than a simple boundary. The estimated depths to basement are, therefore, minimum estimates. Because of the expected increase in the seismic velocity of the rocks when subjected to overburden pressures equivalent to depths of 2-3 km, there is little evidence from the present work that the basement is compositionally or lithologically different from the surface rocks. At recording distances beyond 50 km there is evidence in the record sections that both P and S-wave energy is being returned from deeper intracrustal refractors/reflectors.