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Geology and Geophysics research enquires into earth materials and earth structures, into earth processes and earth history, and thus is central to the human concerns of earth resources and earth environments. The Discipline has an outstanding record of achievement in a broad range of research fields as evident by consistently high levels of international publications and conference presentations and extensive funding from government agencies. The Discipline enjoys business links with groups such as the minerals and petroleum industries, Primary Industry Resources of South Australian (PIRSA), CSIRO and the SA Museum.
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Item Metadata only A guide to the petrology and field relationships of the Encounter Bay granites, South Australia(1969) Milnes, A.R.; Australian & New Zealand Association for the Advancement of Science (1969 : Adelaide)Item Metadata only Discovery of Late Precambrian tillites (Sturt Group) and younger metasediments (Marino Group) on Dudley Peninsula, Kangaroo Island(Australian & New Zealand Association for the Advancement of Science, 1971) Daily, B.; Milnes, A.Introduction: We have recently investigated the geology of the coastline of Dudley Peninsula, which forms the eastern extremity of Kangaroo Island. The aim of the survey was to test a newly devised stratigraphic scheme (Daily and Milnes, 1971), erected to describe the lower part of the type section of the metasedimentary rocks constituting the Kanmantoo Group of Lower Cambrian age. These metasedimentary rocks occur along the southern coastline of Fleurieu Peninsula (Sprigg and Campana, 1953), which is separated from Dudley Peninsula by a stretch of water some twelve kilometres wide and known as Backstairs Passage.Item Metadata only Stratigraphic notes on the Lower Cambrian fossiliferous sediments between Campbell Creek and Tunkalilla Beach in the type section of the Kanmantoo Group, Fleurieu Peninsula, South Australia(1971) Daily, B.; Milnes, A.Hyolithids and other Lower Cambrian fossils occur within marbles in low-stage metamorphic rocks (Forktree Limestone and Heatherdale Shale) forming the core of a north-east plunging regional anticline, overturned to the south-east. A great thickness of partially bioturbated Kanmantoo Group metasediments, dominantly clastics, but including sulphide-rich calc-phyllites of the Talisker Calc-siltstone, conformably overlie the Heatherdale Shale. The rapidly deposited elastics, including numerous thin conglomerates, are interpreted as products of the Kangarooian Movements known to have affected the region now occupied by Investigator Strait and Gulf St. Vincent. The newly proposed stratigraphic subdivision for that part of the Group discussed should lead to a more reliable picture of the occurrence and the relationships of these rocks to other sequences within the Mt. Lofty Ranges and Kangaroo Island.Item Metadata only Rubidium-strontium geochronology of the Encounter Bay granites and adjacent metamorphic rocks, South Australia(Geological Society of Australia, 1971) Dasch, E.J.; Nesbitt, R.W.; Milnes, A.R.Rubidium-strontium and strontium isotope data for eight whole-rock samples of granite varieties from the Encounter Bay area, South Australia, yield an isochron age of 487 ± 37 m.y. Two specimens of albitised granite, formed as a result of late stage metasomatic alteration of original megacrystic granite, conform to this isochron. These data support a genetic relation between granites and late-stage metasomatic alteration as suspected from field, petrographical and geochemical studies. Eight samples from contiguous Kanmantoo Group metasedimentary rocks have an isochron age of 487 ± 60 m.y. Thus this metamorphic event is coincident with emplacement of the Encounter Bay Granite. The initial Sr87/Sr86 ratio for the Encounter Bay Granite (0.719) is significantly higher than initial ratios for the Palmer (0.709) and Anabama (0.705) granites from the same region and can be attributed to either remobilisation or incorporation of strontium from older crustal material in the intrusion. The apparent initial Sr87/Sr86 ratio for the Kanmantoo Group metasedimentary rocks (0.722) can not be distinguished from that for the Encounter Bay Granite within the analytical uncertainties. Compatability of ages and high initial Sr87/Sr86 ratios suggest that the granites formed by remobilisation of associated crustal rock.Item Metadata only A Late Palaeozoic glaciated granite surface at Port Elliot, South Australia(Royal Society of South Australia, 1972) Milnes, A.; Bourman, R.A glaciated granite pavement, discovered at Port Elliot, South Australia, shows features that indicate an east to west movement of Late Palaeozoic ice, and thus significantly extends the known area of approximate east to west ice movement on Fleurieu Peninsula. The granite pavement and the profusion of granite erratics, together with the probable existence of an originally extensive pluton of Encounter Bay Granites, suggest the possible dissection of the pluton during the glaciation to form the present outcrop distribution.Item Metadata only Revision of the stratigraphic nomenclature of the Cambrian Kanmantoo Group, South Australia(Informa UK Limited, 1972) Daily, B.; Milnes, A.R.A new subdivision for the Cambrian Kanmantoo Group into a basal Carrickalinga Head Formation and overlying Inman Hill, Brown Hill and Wattaberri Subgroups is proposed for the type section. Investigations have shown that the stratigraphic subdivision formerly erected and utilized in the Nairne area is inappropriate when applied to the type section of the Kanmantoo Group. The Nairne Pyrite Member is correlated with part of the Talisker Calc-siltstone and does not occur in the type section of the Kanrnantoo Group in the position as shown on recently published maps. We identify rocks in that position as belonging to the lower parts of the Brown Hill Sub-group which, in the Nairne-Callington region, are 3,000-4,000m above the true Nairne Pyrite Member.Item Metadata only Significance of basal Cambrian metasediments of andalusite grade, Dudley Peninsula, Kangaroo Island, South Australia(ANZAAS, 1972) Daily, B.; Milnes, A.Item Metadata only Composition and genesis of silcretes and silcrete skins from the Beda Valley, southern Arcoona plateau, South Australia(Geological Society of Australia, 1972) Hutton, J.; Milnes, A.R.; Twidale, C.; Rosser, H.Detailed petrographic and chemical studies of silcretes collected from Beda Valley near the southern extremity of Lake Torrens, South Australia, have shown that there are at least two distinct types. One type, often found attached to quartzite, has very angular grains of quartz in a matrix very high in titanium. Electron probe studies clearly show that the areas between the quartz grains are mostly titania containing very little silica. These skins, besides containing 2-10% Ti, contain 0.05 to 0.25% Zr with a very high correlation between the ratio of the amount of these elements in the skin to that in the quartzite and it is suggested they have been produced by the loss of silica. The other type of silcrete has subrounded grains of quartz in a matrix of chalcedonic silica. It is also low in titanium (<1%) and low in zirconium (<.04%). It is suggested this type, which in this area is massive with columnar structure, is formed by the addition of silica.Item Metadata only Phosphorian lavendulan from the Dome Rock Mine, South Australia(Royal Society of South Australia, 1973) Kleeman, A.; Milnes, A.A new variety of the rare mineral lavendulan (= freirinite) has been found in Precambrian rocks in South Australia. It is notable for containing a significant amount of phosphorous replacing arsenic. Its formula, based on microprobe analysis, is (Na1.07 Ca1.01 Cu4.80) (As3.10 P0.84)016 Cl1.55.4H20. Powder diffraction data are also recorded.Item Metadata only Stratigraphy, structure and metamorphism of the Kanmantoo Group (Cambrian) in its type section east of Tunkalilla Beach, South Australia(Royal Society of South Australia, 1973) Daily, B.; Milnes, A.An apparently conformable sequence of metaclastics forming the upper part of the type Kanmantoo Group (Cambrian) has been mapped along 50km of coastline between Tunkalilla Beach and Middleton Beach. Sporadically occurring black carbonaceous and sulphide-rich phyllites are confined to and characterise the Brown Hill Sub-group. Associated immature "flysch-like" metasediments were deposited very rapidly in an actively subsiding basin by currents flowing mainly from the NW. Numerous pebble beds, similar to those in the underlying Inman Hill Sub-group, reflect the continuity of the Kangarooian Movements. The cross-bedded Middleton Sandstone at the top of the overlying Wattaberri Sub-group was deposited by currents directed mainly towards the east. Kanmantoo Group rocks younger than the Middleton Sandstone are unknown in the Mt. Lofty Ranges. Because the formation is intruded by the Encounter Bay Granites, a thick cover must have been present at the time of intrusion and metamorphism. Worm casts were the only fossils located in the study area and are suggestive of a marine environment of deposition. The sequence mapped forms the eastern limb of a regional anticline overturned towards the NW. Two phases of folding are recognised. F1 folds plunge shallowly towards the SSW or NE. Eastwards from the core of the highly appressed and asymmetrical regional anti cline, F1 folds in metasandstones become progressively more open, symmetrical and upright. Mesoscale F2 folds with E to SE plunges are confined to the eastern part of the type section. A weak crenulation of S1 is observable near Coolawang Creek, and becomes progressively stronger towards the east. The Encounter Bay Granites were intruded and had crystallised prior to the main phase of F1 deformation because thin granite sheets, concordant with bedding, developed the S1 and S2 schistosities during the folding episodes. Stability fields for the observed metamorphic mineral assemblages show that the metamorphism of the Kanmantoo Group was effected at moderate temperatures (below 540°C) and low pressures (below 3 kb). This is indicated also by the well preserved sedimentary structures found throughout this sequence of andalusite-staurolite grade rocks. Cordierite, restricted to the proximity of the granite, records the highest grade of metamorphism within the type section. Petrographic evidence suggests that cordierite crystallised during the pre to early syn-F1 phase, a conclusion in harmony with the suggested pre-tectonic emplacement of the Encounter Bay Granites. Petrographic evidence indicates that most of the andalusite formed during the late syn-F1 phase of metamorphic crystallisation. In the post-F1 and pre-F2 static phase of metamorphic crystallisation, some andalusite, garnet, hornblende, scapolite and chlorite grew across the S1 schistosity. The S2 crenulation cleavage, where developed, deformed porphyrohlasts of this age. Albitisation postdates the S2 schistosity. A peculiar "striped" layering, post-S1 and pre-S2 in age, occurs within the Petrel Cove Formation west of Rosetta Head and resulted from alteration adjacent to tensional fractures. Two distinct groups of basic dykes, post-S1 and pre-S2 in age, cut Kanmantoo Group metasediments.Item Metadata only Large-scale horizontal displacement within Australo-Antarctica in the Ordovician(Nature Publishing Group, 1973) Daily, B.; Jago, J.B.; Milnes, A.R.Item Metadata only Pre‐ to syn‐tectonic emplacement of early Palaeozoic granites in southeastern South Australia(Geological Society of Australia, 1977) Milnes, A.R.; Compston, W.; Daily, B.Stratigraphic and structural observations indicate that the Encounter Bay Granites concordantly intruded the youngest formations of the Kanmantoo Group in the Mount Lofty Ranges metamorphic belt prior to the culmination of the first phase of folding and associated schistosity development recorded during the early Palaeozoic Delamerian Orogeny. Metamorphic textures in the metasediments of the Kanmantoo Group suggest that cordierite crystallized locally near the granites prior to and during the F1 folding, whereas andalusite crystallized on a regional scale during the F1 folding and in the post-F1 and pre-F2 static phase. Rb-Sr isotope data for total-rock, feldspar, and muscovite samples of the metasediment-contaminated border facies and the uncontaminated inner facies of the Encounter Bay Granites indicate that the granites were emplaced between 515±8 m.y. and 506±6 m.y. ago in the Late Cambrian epoch. Rb-Sr and K-Ar data for biotite from the granites record variable radiogenic Sr loss until about 469 m.y. ago and comparatively uniform radiogenic Ar loss until 460-475 m.y. ago. Rb-Sr data for Kanmantoo Group metasediments and a metamorphic pegmatite indicate crystallization ages between 459-463 m.y. ago. Thus the regional andalusite-grade temperatures and pressures, which appear responsible for the leakage of radiogenic Sr and Ar from biotite in the granites and the redistribution of Rb and Sr in the metasediments, seem to have persisted for some 50 m.y. after emplacement of the granites until the Early Ordovician epoch. There is evidence for further leakage of Sr and Ar from biotite in deformed granites from the margins of the intrusion more than 50 m.y. afterwards in the Late Silurian or Early Devonian, possibly during the F2 folding. Geological observations and radiometric data for other granitic rocks in south-eastern South Australia, including the Palmer Granite, are consistent with this structural and metamorphic history of the Encounter Bay region.Item Metadata only Calcretes in Australia(CSIRO, 1983) Milnes, A.; Hutton, J.; Handreck, K.Item Metadata only Studies in calcareous aeolian landscapes of southern Australia.(China Ocean Press, 1987) Milnes, A.; Kimber, R.; Phillips, S.; Liu, T.-S.; Wei, L.Item Metadata only An excursion guide to arid zone soils and landscapes north of Port Augusta, South Australia(Australian Society of Soil Science Inc., 1992) Wright, M.; Milnes, A.; Raven, M.; Merry, R.; National Soils Conference (19 Apr 1992 - 23 Apr 1992 : Adelaide, South Australia)Item Metadata only Field guide for Post-Conference 5 day Tour F.5 24-28 July 1993: Andamooka & Coober Pedy Opalfields(Association Internationale pour L'Etude des Argiles, Commission VII of the International Society of Soil Science, Australian Clay Minerals Society, 1993) Milnes, A.; Wright, M.; 10th International Clay Conference (18 Jul 1993 - 28 Jul 1993 : Adelaide, Australia)Item Metadata only Character and interpretation of the regolith exposed at Point Drummond, west coast of Eyre Peninsula, South Australia(W.C. Rigby, 1995) Molina Ballesteros, E.; Campbell, E.; Bourne, J.; Twidale, C.Item Metadata only Review of Palaeoclimates and their modelling(Elsevier, 1995) Frakes, L.Item Metadata only Crayfish Group hydrocarbons-Implications for palaeoenvironment of Early Cretaceous rift fill in the western Otway Basin(Australian Petroleum Exploration Association, 1995) Padley, D.; McKirdy, D.; Skinner, J.; Summons, R.; Morgan, R.Item Metadata only Burial history of the eastern Officer Basin, South Australia(Australian Petroleum Exploration Association, 1995) Moussavi-Harami, R.; Gravestock, D. I.