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In contrast to the detection and resolution of Late Pleistocene interstadials (Marine Isotope Stages; MIS 5c, 5a and 3) in marine and ice core-based oxygen isotope records, accurately defining palaeosea-levels for these events from sea level indicators remains a challenge. Commonly, such investigations have been undertaken in tectonically active, subduction-related settings, on emergent marginal marine-coastal successions above present sea level, given that the higher ice volumes during these Marine Isotope Stages resulted in ice-equivalent sea levels significantly below present, particularly in far-field settings. Delineation of palaeosea-levels for this period, has accordingly involved an assumption about the long-term rate of coastal uplift. Core SV#23 collected from the tectonically highly stable, remote far-field setting of southern Gulf St Vincent, southern Australia, in a present water depth of 40 m obtained a 3.89 m undisturbed sedimentary record of Late Pleistocene to Holocene age. The basal 2.39 m of the sediment record is of Late Pleistocene interstadial age, as it overlies the Last Interglacial Glanville Formation (128–118 ka; MIS 5e) and occurs beneath the Holocene St Kilda Formation. The extent of aspartic acid and glutamic acid racemization in the benthic foraminifer Elphidium macelliforme sampled at 2 cm intervals continuously from the interstadial succession in Core SV#23, confirms the relative age interpreted from lithostratigraphy. A mean amino acid racemization (AAR) age of 75 ± 13 ka indicates a correlation with MIS 5a, and highlights the utility of E. macelliforme as a species for AAR geochronology. As the foraminifers more closely define the timing of sedimentation, the interstadial succession is regarded as beyond the range of radiocarbon dating (>50 kyr), as revealed in a comparison of radiocarbon ages of fossil molluscs with AAR ages for E. macelliforme from the same depth intervals within the interstadial succession. All of the radiocarbon ages for fossil marine molluscs from the interstadial succession represent minimum ages, resulting from contamination by trace levels of modern radiocarbon. The foraminiferal faunal assemblages within the interstadial succession reveal changes of water depth at the time of deposition, pointing to millennial-scale sea level variability. In particular, the ratio of Elphidium crispum to E. macelliforme indicates several oscillations in relative sea level within a bandwidth of 26 to 24 ± 4.6 m below present sea level (BPSL). Notwithstanding the large uncertainty associated with palaeosea-level estimation based on the Elphidium ratio, the inferred relative sea level record is in accord with the sea level records of Barbados and the Red Sea, and points to Sub-Milankovitch interstadial sea level variability as noted in Greenland and Antarctic ice cores. Refereed/Peer-reviewed

Alluvial-channel and overlying eolian deposits exposed in coastal cliffs in the Port Campbell australite (Australian tektite) strewn field, SW Victoria, were studied stratigraphically and dated by optically stimulated luminescence (OSL) for quartz sand grains to illuminate the occurrence of australites in this area. The channel deposits, termed the Dog Trap Bay Sand, yielded OSL ages from 420 ± 40 to 230 ± 15 ka for four sites, and the two eolian units OSL ages of 203 ± 16 and 93 ± 11 ka. The ages support field evidence that, contrary to the conclusions of a previous study by others, the channel deposits are stratigraphically distinct from and much younger than the Pliocene Hanson Plain Sand, which forms a regionally extensive system of marine strandlines to the north and NE of Port Campbell. The OSL ages show some preference for times of negative temperature anomalies marking the last four glacial periods of the Middle and Late Pleistocene as indicated by ice-core data from Antarctica. Eolian and at leas...

The Flinders Ranges and its surroundings in South Australia comprise an impressive rugged terrain that rises abruptly from piedmont plains to the east and west and merges into the plains of the Cenozoic Lake Eyre Basin to the north. Folded and faulted Neoproterozoic-Cambrian clastic and carbonate sedimentary rocks of the Adelaide Geosyncline (Adelaide Rift Complex) form the predominant geology of the ranges and record varied depositional environments and metamorphic overprints and have had a complex landscape history, resulting in a diverse regolith. This ancient, arid terrain represents some of the best analogue landscapes and settings in Australia to observe features and processes fundamental to the evolution of the Earth. The strata of the Flinders Ranges record the evolution of terrestrial surface environments and the biosphere through the Cryogenian, Ediacaran and Cambrian periods, including evidence for Neoproterozoic glaciations, orbital and rotational dynamics and asteroid impact. The diverse assemblages of stromatolites, ancient and modern hydrothermal systems, and alteration assemblages provide field laboratories for astrobiological and hyperspectral research and training. For these reasons the northern Flinders Ranges near Arkaroola have been selected as a site for multi-disciplinary Mars analogue research and space education.

–Ejecta from the large subsurface Tookoonooka impact structure have been foundin the Lower Cretaceous strata of the extensive Eromanga Basin of centralAustralia. Observations from 31 wells spanning 400,000 km 2 of the basin provide compellingevidence for the presence of a marine impact horizon of regional extent. Drill core wasexamined to determine the sedimentary context of the Tookoonooka impact event, thepresence of ejecta, and the nature of the impact horizon. The base of the Wyandra SandstoneMember of the Cadna-owie Formation is an unconformity commonly overlain by very poorlysorted sediment with imbricated pebbles, exotic clasts, and occasional boulders. The basalWyandra Sandstone Member is bimodal: a fine sand mode reflects an ambient sedimentcontribution and a coarse mode is interpreted to be impact-derived. Wells Thargomindah-1and Eromanga-1, within four crater radii of Tookoonooka, contain distinctive clast-supported breccia-conglomerate beds at the base of the Wyandra Sandstone Member. Clastsin these beds include altered accretionary and melt impactoclasts, as well as lithic and mineralgrains corresponding to the Tookoonooka target rock sequence, including basement.Petrographic evidence includes shock metamorphosed quartz and lithic grains with planardeformation features. These breccia-conglomerates are in stark contrast to the underlying,laterally persistent, unimodal Cadna-owie sediments and overlying shales deposited in anepeiric sea. The base of the Wyandra Sandstone Member is therefore interpreted to be theTookoonooka impact horizon. The timing of the impact event is confirmed to be theBarremian-Aptian boundary, at 125 ± 1 Ma. The Wyandra Sandstone Member preservesboth impact ejecta and postimpact marine sediments.INTRODUCTIONTookoonooka and Talundilly are two subsurfaceanomalies in the Eromanga Basin of central Australiathat were recognized by petroleum exploration in the1980s (Fig. 1). Tookoonooka and Talundilly are some300 km apart, buried under almost 1 km of flat-lyingsediments near the center of the basin in southwestQueensland. The impact origin of subsurface structuresis notoriously difficult to investigate due to inaccessibilityand paucity of data. Tookoonooka was confirmed as animpact structure through the identification andmeasurement of shock metamorphic features in quartzgrains (Gorter et al. 1989; Gostin and Therriault 1997)from the structure’s buried central uplift. However,Talundilly has not been adequately drilled to date, andremains a possible impact structure.Tookoonooka is the second-largest known impactstructure in Australia, and possibly the tenth largest inthe world (Earth Impact Database, 2011). It wasestimated to have a final crater diameter of 66 km(Gostin and Therriault 1997), which is a recalculation ofan earlier estimate of 55 km from seismic data (Gorteret al. 1989). Talundilly was estimated to have a 95 kmdiameter from seismic data (Longley 1989). A Talundillycrater diameter cited by Bevan (1996) and Gorter (1998)of 30 km, while it may be more accurate according tomore recent crater-scaling techniques (cf. Turtle et al.1

Sedimentary features characteristic of ice-rafting are present in the Bunyeroo Formation (Wilpena Group) of the Adelaide Geosyncline and in the coeval Dey Dey Mudstone (Ungoolya Group) of the eastern Officer Basin (Figs 66.1 & 66.2), providing evidence of a mid-Ediacaran glacial climate in South Australia. The Acraman asteroid impact, a negative shift in marine δ 13 C, and a major acritarch turnover coincided with this frigid epoch.

Deposits of the late Cryogenian Elatina glaciation constitute the Yerelina Subgroup in the Adelaide Geosyncline region, South Australia. They have a maximum thickness of c . 1500 m, cover 200 000 km 2 , and include the following facies: basal boulder diamictite with penetrative glaciotectonites affecting preglacial beds; widespread massive and stratified diamictites containing faceted and striated clasts, some derived from nearby emergent diapiric islands and others of extrabasinal provenance; laminated siltstone and mudstone with dropstones; tidalites and widespread glaciofluvial, deltaic to marine-shelf sandstones; a regolith of frost-shattered quartzite breccia up to 20 m thick that contains primary sand wedges 3+ m deep and other large-scale periglacial forms; and an aeolian sand sheet covering 25 000 km 2 and containing primary sand wedges near its base. These deposits mark a spectrum of settings ranging from permafrost regolith and periglacial aeolian on the cratonic platform (Stuart Shelf) in the present west, through glaciofluvial, marginal-marine and inner marine-shelf in the central parts of the Adelaide Geosyncline, to outer marine-shelf in sub-basins in the present SE and north. The Elatina glaciation has not been dated directly, and only maximum and minimum age limits of c . 640 and 580 Ma, respectively, are indicated. Palaeomagnetic data for red beds from the Elatina Formation (Fm.) and associated strata indicate deposition of the Yerelina Subgroup within 10° of the palaeoequator. The Yerelina Subgroup is unconformably to disconformably overlain by the dolomitic Nuccaleena Fm., which in most places is the lowest unit of the Wilpena Group and marks Early Ediacaran marine transgression. Supplementary material: Photographs are available at http://www.geolsoc.org.uk/SUP18481.

The record of two Neoproterozoic glaciations in South Australia has been known for about a century. The earlier glaciation, of Sturtian age, is represented by the Yudnamutana Subgroup and is characterized by widespread diamictites with both intrabasinal and extrabasinal clasts, some locally faceted and striated. Associated facies include shallow-water sandstone, bedded and laminated siltstone with lonestones and dropstones, and sedimentary ironstones (mainly ferruginous siltstone and diamictite). Proximal settings adjacent to the Curnamona Province display massive basement-derived conglomerate and gigantic basement megaclasts (up to hundreds of metres across). Sturtian glaciogenic sediments of the Yudnamutana Subgroup unconformably overlie a variety of older rock units, including crystalline basement near basin margins and uppermost Burra Group sediments in the depocentre, and were deposited both in shallow marine shelf environments and in tectonically active rift basins encircling the Curnamona Province, with corresponding increases in total thickness from 100–300 m to more than 5 km. Recent U–Pb zircon SHRIMP dating of a thin volcaniclastic layer indicates that the waning stages of the Sturtian glaciation occurred at c. 660 Ma. Unlike the deposits of the younger Elatina glaciation, the Yudnamutana Subgroup has so far not yielded reliable palaeomagnetic data.

Isolated quartzose pebbles, clusters of quartz granules, orthogonal aggregates of poorly sorted quartzose coarse sand, and ovoid pellets (≤2 mm long) of quartz silt occur in hemipelagic marine mudstone of the mid-Ediacaran Bunyeroo Formation exposed in the Adelaide Geosyncline (Adelaide Rift Complex), and ovoid pellets of quartz silt in cores of the correlative marine Dey Dey Mudstone from deep drillholes in the Officer Basin, South Australia. This detritus is interpreted respectively as dropstones, dumps, and frozen aggregates dispersed by sea ice possibly of seasonal origin, and till pellets transported by glacial ice. The ice-rafted material in the Bunyeroo Formation only has been found 500 km northwest of ...

David Haberlah, Peter Glasby, Martin A. J. Williams, Steven M. Hill, Frances Williams, Edward J. Rhodes, Victor Gostin, Anthony O'Flaherty and Geraldine E. Jacobsen

The late Cryogenian Elatina glaciation in South Australia, of Marinoan age, is named after the Elatina Formation of the glaciogenic Yerelina Subgroup, which covers ∼200,000 km2 in the Adelaide Geosyncline and on the cratonic Stuart Shelf and is up to ∼1500 m thick. The Elatina glaciation is marked by numerous facies that are like those of Phanerozoic glaciations: • Basal diamictite displaying glacitectonites with penetrative deformation of preglacial beds, indicating grounded ice or scouring by icebergs. • Glaciomarine diamictites containing numerous faceted and striated clasts up to several metres across of intrabasinal and extrabasinal origin. • Laminated siltstone and mudstone containing scattered, ice-rafted dropstones in outer marine-shelf environments. • Sandstones deposited in fluvial, deltaic and inner marine-shelf settings. • Tidalites deposited in estuaries and on tidal deltas during interstadial rise of sea level, with cyclic tidal rhythmites recording the annual oscillation of sea level and displaying wave-generated ripple marks, which together indicate long-lived and extensive open seas. • Siltstone containing acicular crystal pseudomorphs implying the formation of evaporite minerals in littoral deposits. • Permafrost regolith of frost-shattered quartzite breccia ≤20 m deep, displaying large-scale periglacial structures including primary sand wedges 3 m deep that indicate a frigid, strongly seasonal climate near sea level. • Periglacial–aeolian sandstone covering 25,000 km2 and containing primary sand wedges near its base. These deposits record a spectrum of settings ranging from permafrost regolith and periglacial sand sheet on the Stuart Shelf in the west, through fluvial, deltaic and inner marine-shelf in the western and central parts of the Adelaide Geosyncline, to outer marine-shelf in the north and southeast. The widespread and persistent rainout of fine-grained sediment and ice-rafted debris indicates that the sea was not frozen over during the Elatina glaciation. No direct age determination is available for the Elatina glaciation, and only maximum and minimum age limits of ∼640 and ∼580 Ma, respectively, can at present be applied. High-quality palaeomagnetic data for red beds from the Elatina Formation, supported by positive fold tests on soft-sediment slump folds that demonstrate the early acquisition of magnetic remanence, indicate deposition within 10° of the palaeoequator. The Yerelina Subgroup in the Adelaide Geosyncline and on the Stuart Shelf is disconformably to unconformably overlain by the Nuccaleena Formation “cap carbonate” that marks the early Ediacaran post-glacial marine transgression. The presence in near-equatorial palaeolatitudes of glaciomarine deposition, grounded ice and permafrost near sea level, a strongly seasonal periglacial climate, and widespread open seas implies a paradoxical palaeoclimate and palaeogeographic setting for the Elatina glaciation. The strong evidence for a non-actualistic late Cryogenian glacial climate in South Australia has been a stimulus to worldwide multidisciplinary research on Cryogenian glaciogenic successions.

The Holocene carbonate sequence of perennial North Stromatolite Lake, located adjacent to the Coorong Lagoon near Salt Creek, South Australia, includes a prominent sapropelic unit (7 – 12% total organic carbon), in places more than 2 m thick, that was sampled for the purpose of radiocarbon dating and documenting its diatom and ostracod biostratigraphy. The recovered ostracods were also subjected to carbon and oxygen isotopic analysis. The bulk organic matter at the base of the sapropel yielded an uncalibrated 14C age of 6080 ± 60 y BP. Diatoms, where preserved, are almost exclusively benthic. Stratigraphic variation of the proportions of key indicator species in diatom assemblages records a marked oscillation between oligosaline and eusaline conditions in the hypolimnion during deposition of the sapropel. Ostracod carbon isotope data indicate that the lake at this time was eutrophic, thereby enriching the dissolved inorganic carbon of the hypolimnion in 13C. However, the observed secular variation in δ13C...

Organic matter preserved in marine mudstones from three late Neoproterozoic depocentres – the Officer and Amadeus Basins and the Adelaide Fold Belt – was examined using standard microscopic and geochemical methods, including gas chromatography-mass spectrometry (GC–MS). Total organic carbon (TOC) contents of these sediments are typically low (

Multidisciplinary research during the past 25 years has established that the Acraman impact structure in the 1.59 Ga Gawler Range Volcanics on the Gawler Craton, and an ejecta horizon found 240 – 540 km from Acraman in the ⩽ 580 Ma Bunyeroo Formation in the Adelaide Fold Belt and Dey Dey Mudstone in the Officer Basin, record a Late Neoproterozoic (Ediacaran) event of major environmental importance. Research since 1995 has verified Acraman as a complex impact structure that has undergone as much as 3 – 5 km of denudation and which originally had a transient cavity up to 40 km in diameter and a final structural rim possibly 85 – 90 km in diameter. The estimated impact energy of 5.2 × 106 Mt (TNT) for Acraman exceeds the threshold of 106 Mt nominally set for global catastrophe, and the impact probably caused a severe perturbation of the Ediacaran environment. The occurrence of the impact at a low palaeolatitude (12.5 + 7.1/ − 6.1°) may have magnified the environmental effects by perturbing the atmosphere in ...

In anticipation of a future crewed mission to Mars, the international non-profit organisation known as the Mars Society is currently establishing four mockup bases at which planetary surface operations simulations, equipment testing and personnel training exercises will be conducted over the next decade. These should provide valuable design data for, and raise public awareness about, plans to explore the red planet. One of these bases, which are organised around a habitat of the kind that is likely to serve as shelter for surface-dwelling astronauts, is to be sited in central Australia under the name MARS-OZ. To find a suitable location, the Mars Society Australia has conducted a ground-truth survey of 15 potential sites as practical scientific analogues of the Martian surface, recording these in a specialised database. Each site was assessed on a set of geomorphic, science/engineering, logistic and visual analogue criteria. Six circular exploration zones 200 km in diameter were identified as clusters of the most significant, observed, comparative planetological features. These zones were then ranked to recommend a series of 'landing sites', at which future field seasons of exploratory science may be conducted.

New occurrences of the Acraman impact ejecta layer were recently discovered in two drillholes, Giles 1 and Murnaroo 1, in the eastern Officer Basin, South Australia, using acritarch biostratigraphy and lithostratigraphy to predict the position. Fractured crystals were also observed in palynological preparations from drillhole SCYW 1a on the Stuart Shelf. These discoveries improve stratigraphic control of Late Neoproterozoic successions, especially in the eastern Officer Basin and will allow a test of the hypothesis that the Acraman impact event caused a global catastrophe.

The Mars Society is an international private organisation advocating the exploration and settlement of Mars. Part of its mission involves selecting areas for Martian analogue research, to test hardware, technology, strategies and human factors relevant to sending people to Mars. Mars Society Australia has selected an area in the Arkaroola region in the Flinders Ranges as the site for the first Australian analogue facility. The facility will be an invaluable public education and outreach tool for Australian science, focusing on astrobiology, and its role in future human Mars missions; demonstrating Australian contributions to astrobiology related science and work on terrestrial analogues to Martian environments.

Within the Neoproterozoic sequence of the Adelaide Fold-Thrust Belt, South Australia, two of the most severe ice ages in Earth history (Sturtian and Marinoan) are recorded in the glacigenic rocks which mark the base and top of the 4.5 km-thick Umberatana Group, the focus of the present chemostratigraphic study. Rock units from three drillholes and ten measured outcrop sections, located in the southern and central Flinders Ranges and on the Stuart Shelf, were sampled for isotopic analysis of their co-existing calcite (δ13Ccal), dolomite (δ13Cdol) and kerogen (δ13Corg). Strontium and sulphur isotopic analyses were also run on selected samples. The sample sites are in tectonic domains where regional metamorphism has been insufficient to significantly alter the isotopic composition of the kerogen. The resulting data, when integrated with the lithostratigraphy of the Umberatana Group, yield one of the most complete records of secular variation in the C-isotope signature of the late Cryogenian ocean between ∼750 and 680 Ma. Its composite δ13Ccarb curve begins with a sharp positive excursion (−3 to +1.5‰ in the dolomitic Tindelpina Shale which caps Sturtian glacial diamictites (Wilyerpa Formation). Then follows a steady climb through the shoaling upward Tapley Hill Formation reaching +4‰ in the Brighton Limestone and culminating in a plateau of 13C enrichment within the platformal carbonates of the Etina Formation (+8 to +10‰). The upper part of the temporal trend shows a decline to +6 to +7‰ in the stromatolite reef facies of the Enorama Shale; and a dramatic drop to −8 to −9.5‰, followed by a recovery to –3‰, in the youngest carbonate unit (Trezona Formation) beneath the Marinoan glacigenic Elatina Formation. The latter is capped by a thin dolostone, the Nuccaleena Formation, which records a consistent up-section decrease in δ13C (−1 to −3‰). Superimposed on this overall pattern of C-isotopic variation are second and third-order fluctuations attributable to eustatic sea-level change. Pyritic sulphur in the lower Tapley Hill Formation (δ34S=+9 to +40‰) is distinctly heavier than that in the underlying Wilyerpa Formation (+4 to +20‰). Minimum 87Sr/86Sr values obtained from the Brighton Limestone (0.7071) and Etina Formation (0.7076) are consistent with their late Cryogenian age. This Sturtian to Marinoan interglacial succession is more complete than equivalent sequences elsewhere, and thus provides a useful reference for global chemostratigraphic correlation. Notable features of its C-isotope curve are the strong post-Wilyerpa positive excursion, also seen in key sections from Svalbard and western Mongolia; the ‘Etina plateau’ of 13C enrichment which is remarkably similar to maxima in the terminal Proterozoic C-isotope records of western Mongolia, north-western Canada and Brazil; and the spectacular depletion of 13C in the lower Trezona relative to similar carbonate facies in the underlying Etina Formation and Enorama Shale. A preglacial offset in δ13Ccarb values of such proportions (∼14‰) is almost unprecedented, except perhaps for that recently documented in the upper Ombaatjie Formation beneath tillites of the Ghaub Formation, Otavi Group, Namibia. It represents a key piece of evidence in the case presented by the proponents of a Neoproterozoic ‘snowball’ Earth.

In South Australia, canyons 200–250 km long are incised to depths of c . 1.5 km in late Neoproterozoic (after c . 590 Ma) marine deposits of the Adelaide fold belt and canyons 90 km long and 700 m deep occur in correlative marine strata of the Officer Basin 1000 km to the NW. In the Adelaide fold belt, the isotopic signature of limestone veneering canyon walls, canyon sinuosity and sedimentary structures in canyon fill suggest that the canyons were cut subaerially and filled by shallow-water marine deposits during coastal onlap. Eustacy cannot account for the kilometre-scale change in sea level required for subaerial canyon erosion and chemostratigraphy and the lack of evaporites at that stratigraphic level in southern Australia argue against a Messinian-style drawdown. In each region, uplift and crustal extension preceding or coeval with canyon incision are indicated by a regional unconformity, turbidite or mass-flow deposition, and extensional faults. These features and canyon incision may be explained by regional uplift above a rising mantle plume over a distance of >1000 km in southern Australia. Flood basalt volcanism in the Officer Basin tentatively dated at 563±40 Ma may have followed this uplift. Mantle plume uplift is expressed in the sedimentary record by emergent trends in facies, regional thinning, regional unconformities, turbidites, gravity slides, normal faults and incised canyons and palaeovalleys.

The Acraman impact ejecta from Bunyeroo Gorge in the central Flinders Ranges consist of clast- bearing and sandy sublayers set in a shale host rock. A calculated transient crater diameter for the Acraman impact of at least 34 km was obtained fiom average thicknesses and estimated distances of the ejecta fiom the impact in the Gawler Ranges. The ejecta contain numerous grains of quartz and zircon that display impact-produced features, including one or more sets of decorated planar deformation features. There is also much unshocked material incorporated in the ejecta layer. The coarse-grained ejecta layer embedded within fine-grained sediments allowed easy passage for diagenetic fluids that produced a porous honeycomb structure in the clays and enhanced the content of elements such as Cu, Pb, Zn, and U. The clay fraction of the ejecta layers consists of vermiculite and kaolinite, probably formed ffom alteration and weathering of glassy components. It appears that quartz and zircon grains are the only remnants unaltered by diagenetic processes.

The Sydney Basin of New South Wales, Australia is a foreland basin containing a thick (up to 10 km) Permo-Triassic succession. The southern margin of the basin exposes strata deposited during Late Palaeozoic glaciation of south-eastern Gondwana. The Early Permian Wasp Head, Pebbley Beach, Snapper Point Formations and Wandrawandian Siltstone were deposited between 277 and 258 Ma on a polar, glacially influenced continental margin adjacent to ice sheets located over East Antarctica and eastern Australia. Sedimentary facies, together with related ichnofacies and fauna, can be grouped into six facies associations that record marine sub-environments ranging from high energy, storm-dominated inner shelf to turbidite-dominated upper slope settings. Cold marine conditions, with near-freezing bottom water temperatures, are recorded by glendonites. Ice-rafted debris, most likely deposited by icebergs, occurs in almost all facies associations. An allostratigraphic approach, emphasizing the recognition of bounding discontinuities (i.e. erosion surfaces and marine flooding surfaces), is used to subdivide the Early Permian stratigraphy into facies successions. Three types of succession can be identified and record changes in the relative influence of allocyclic controls such as basin tectonics, sediment supply and glacio-eustatic sea level variation. Together, sedimentological and allostratigraphic data allow reconstruction of the depositional history of the south-western margin of the Sydney Basin. Initial marine sedimentation, characterized by sediment gravity flows and storm-deposited sandstones of the lower Wasp Head Formation, occurred adjacent to a faulted basin margin. Overlying successions within the upper Wasp Head, Pebbley Beach and Snapper Point Formations, record aggradation in inner to outer shelf settings along a storm- and glacially influenced continental margin. Tectonic subsidence and basin flooding is recorded by deeper water turbidites of the Wandrawandian Siltstone.

This paper describes multiple layers of ice-rafted debris and an ice-scour structure in Early Permian marine strata within the Shoalhaven Group of the Sydney Basin, New South Wales, Australia. Strata were deposited on a high-latitude, glacially influenced continental margin during the final stages of Late Palaeozoic glaciation between 277 and 260 Ma. Poorly sorted ice-rafted debris, forming layers up to 1.25 m thick, is common within inner to outer shelf and continental slope facies of the Shoalhaven Group. More than 120 layers can be identified. These are argued to record the enhanced delivery of debris by icebergs drifting north from marine-based Antarctic ice margins. Deformation structures in associated sediments are interpreted as iceberg scours and ice keel turbates. Associated glendonites record early diagenesis of organic-rich sediment and bottom water temperatures close to freezing. A speculative hypothesis relates layers of ice-rafted debris within the Shoalhaven Group to multiple episodes of accelerated calving at the margins of a marine-based Early Permian ice sheet in East Antarctica. These events may be analogous to late Pleistocene Heinrich events, when huge armadas of icebergs were released from the marine-based Laurentide Ice Sheet and triggered abrupt changes in ocean circulation and climate. Similar forcing may have characterized the Early Permian ice-ocean system. Regardless of the climatic significance of ice-rafted layers, this is the first time such facies have been documented in the pre-Pleistocene literature; to date, few ice scour structures, and no ice keel turbates, have been reported.

It appears that differences in the signature of biogenic components and cements under cathodoluminescence may aid in the determination of palaeoenvironments in coastal areas. Living and recently dead aragonitic gastropods (Coxiella spp.) from Old Man Lake sediments luminesce bright apple‐green whereas the same species from the nearby saline environment of the Coorong Lagoon shows no luminescence. Following diagenetic alteration to calcite, as confirmed by X‐ray diffraction analysis, the gastropods show characteristic orange cathodoluminescence in both environments.

Holocene sediments from southern Spencer Gulf are cool‐water carbonate‐rich gravels and sands, dominated by molluscs and Bryozoa. Five sedimentary fades are recognized: (i) molluscan gravel; (ii) branching coralline‐algal gravel, associated with shallow partially protected environments; (iii) molluscan‐biyozoan sand; (iv) mixed bioclastic sand, representative of the deeper central region of the lower gulf; and (v) bryozoan gravel, an isolated fades developed in a semi‐protected micro‐environment. The southern gulf is characterized by complex oceanographic conditions together with variations in water depth and substrate. The sediments share the characteristics of both the southern shelf and upper Spencer Gulf. Grain‐size distribution and sedimentary facies are controlled by a combination of all the above processes. Past sea level fluctuations are recognized from sea floor strand‐line deposits. The relic component of the palimpsest sediments has eroded from the Pleistocene aeolianite dunes. The sediments, t...

Benthic foraminifera are abundant in surficial sediment of Gulf St Vincent and the distribution of many species is related to water depth. For example, Nubecularia lucifuga is most abundant in shallow northern waters while Ammobaculites reophaciformis is more common in deeper southern parts of the gulf. Elphidium crispum, a shallow‐water species, and E. macelliforme, favouring deeper water, provide a useful numerical ratio. Their logarithmic relative abundance in the sediment size fraction 0.50–0.25 mm correlates closely with water depth, particularly for southern Gulf St Vincent. Vibrocore SV23 recovered an undisturbed section of Quaternary strata from one of the deepest parts (40 m) of the gulf. Late Pleistocene sediment (oxygen isotope stage 3) was in turn overlain by rapidly deposited lacustrine and restricted marginal marine sediment before development of more open Holocene marine conditions. Using the Elphidium ratios and other supporting foraminiferal data on a framework of 14C dates, a palaeosea‐l...

Concordant results for the extent of racemization of the amino acids, aspartic acid, leucine and valine and isoleucine epimerization in several mollusc genera support radiocarbon data that indicate an interstadial age (oxygen isotope stage 3: 45,000 to 30,000 yr B.P.) for a sequence of mollusc-rich, carbonate muds in Gulf St. Vincent, South Australia. A numeric age of 46,500 ± 9100 yr B.P. was obtained on marine molluscs from these sediments, using a model based on “apparent” parabolic racemization kinetics. In a global context, the sequence represents one of the few well documented occurrences of marine strata of this age from a tectonically quiescent setting. A sea level as high as −22 m is indicated for this interval. Amino acid racemization provides an important method for validating conventional, “finite” radiocarbon ages close to the practical limits of radiocarbon dating and in studies of reworking.

The wide Lacepede Shelf and narrow Bonney Shelf are contiguous parts of the south-eastern passive continental margin of Australia. The shelves are open, generally deeper than 40 m, covered by waters cooler than 18°C and swept by oceanic swells that move sediments to depths of 140 m. The Lacepede Shelf is proximal to the ‘delta’of the River Murray and the Coorong Lagoon. Shelf and upper slope sediments are a variable mixture of Holocene and late Pleistocene quartzose terrigenous clastic and bryozoa-dominated carbonate particles. Bryozoa grow in abundance to depths of 250 m and are conspicuous to depths of 350 m. They can be grouped into four depth-related assemblages. Coralline algae, the only calcareous phototrophs, are important sediment producers to depths of 70 m. Active benthic carbonate sediment production occurs to depths of 350 m, but carbonate sediment accumulation is reduced on the open shelf by continuous high energy conditions. The shelf is separated into five zones. The strandline is typified by accretionary sequences of steep shoreface, beach and dune carbonate/siliciclastic sediments. Similar shoreline facies of relict bivalve/limestone cobble ridges are stranded on the open shelf. The shallow shelf, c.40–70 m deep, is a wide, extremely flat plain with only subtle local relief. It is a mosaic of grainy, quartzose, palimpsest facies which reflect the complex interaction of modern bioclastic sediment production (dominated by bryozoa and molluscs), numerous highstands of sea level over the last 80 000 years, modern mixing of sediments from relatively recent highstands and local introduction of quartz-rich sediments during lowstands. The middle shelf, c.70–140 m deep, is a gentle incline with subtle relief where Holocene carbonates veneer seaward-dipping bedrock clinoforms and local lowstand beach complexes. Carbonates are mostly modern, uniform, clean, coarse grained sands dominated by a diverse suite of robust to delicate bryozoa particles produced primarily in situ but swept into subaqueous dunes. The deep shelf edge, c. 140–250 m deep, is a site of diverse and active bryozoa growth. Resulting accumulations are characteristically muddy and distinguished by large numbers of delicate, branching bryozoa. The upper slope, between 250 and 350 m depth, contains the deepest platform-related sediments, which are very muddy and contain a low diversity suite of delicate, branching cyclostome bryozoa. This study provides fundamental environmental information critical for the interpretation of Cenozoic cool water carbonates and the region is a good model for older mixed carbonate-terrigenous clastic successions which were deposited on unrimmed shelves.

— Spherules and irregular shard-like particles consisting of authigenic mineral phases have been identified in the Acraman impact ejecta horizon preserved within the late Proterozoic shales of the Adelaide Geosyncline, South Australia. The spherules (150 μm to 1 mm diameter) range in shape from near-spherical through ellipsoidal to extended ellipsoidal-dumbbell. The distinctive morphology of the spherules and shard-like particles and their restriction to the ejecta horizon, suggest that they were deposited initially as glassy bodies which subsequently have been pseudomorphed by more stable authigenic phases like calcite, quartz, albite, and barite.

In an attempt to understand the origin of an Ir-rich unit near the Late Devonian Frasnian-Famennian (F/F) boundary in the Canning basin of Western Australia, we have examined two lithologically similar Early Cambrian and late Oligocene age horizons from southeastern Australia. Both consist of stromatolitic iron oxide and carbonate petrographically similar to the Ir-rich Frutexites microstromatolites near the F/F boundary. Significant siderophile and chalcophile element anomalies (Ir, Pt, and Ru up to 1.1, 14, and 1.2 ppb, respectively) at both horizons have a geochemistry similar to that of the F/F Frutexites anomaly. As with the F/F bed, the Cambrian and Oligocene stromatolitic beds are closely associated with synsedimentary hardgrounds that contain evidence of subaerial exposure. We suggest that all of these Ir-rich stromatolitic beds developed in response to relative sea-level change and represent periods of condensed marine sedimentation. It is probable that condensation was produced by rapid drowning following subaerial exposure.

Geochemical investigations of a widely dispersed Late Proterozoic impact ejecta horizon and its host shales (Bunyeroo Formation, Australia) have provided strong evidence for low-temperature mobilization of the platinum group elements (PGE), including Ir. PGE anomalies are associated with both the ejecta horizon (Ir up to 2.0 ppb, Pt up to 270 ppb) and the green shales that envelop it. Several PGE anomalies (0.073-0.45 ppb Ir, 3.11-314 ppb Pt) also occur in thin green shale beds at other stratigraphic levels within a predominantly red shale sequence (average red shale background of 0.019 ppb Ir and 0.89 ppb Pt). All green shale horizons analyzed, regardless of their stratigraphic position, have relatively high levels of Ir and other PGE. The nonextraterrestrial, postdepositional origin of the PGE at other stratigraphic levels away from the impact ejecta horizon is indicated by their occurrence in thin, permeable, green beds in a predominantly red shale sequence, their association with enrichments in Cu-V-Zn-Ni, and their nonchondritic PGE interelement ratios. The impact ejecta horizon has a more chondritic PGE geochemistry consistent with a meteoritic origin. A redox precipitation model similar to that invoked for redbed Cu-U-V deposits is proposed to explain the PGE anomalies in the green shales.

Stratigraphic and chronologic studies of the coastal sediments of northern Spencer Gulf in the vicinity of Redcliff are described. Two Pleistocene marine units are recognised beneath an extensive Holocene peritidal sequence. The Holocene sequence is dominated by sediments of the Posidonia australis seagrass facies which form a distinctive carbonate bank fringing the coastline. Peritidal sedimentation commenced prior to 6600 radiocarbon yrs B.P. and a + 2.5 m higher relative sea level existed from about 6000 until around 1700 yrs B.P. The subsequent relative fall to present level probably resulted from local tectonic uplift. After the regression, mangrove and samphire colonization, and beach ridge progradation, occurred over the former seagrass bank.

Carbonate-dominant sediments are currently forming and accumulating over the extensive marine shelf of the passive margin of southern Australia. A dearth of continental detritus results from both a very low relief and a predominantly arid climate. The wide continental shelf is bathed by cold upwelling ocean waters that support luxuriant growths of bryozoans and coralline algae, together with sponges, molluscs, asteroids, benthic and some planktonic foraminifera. The open ocean coast is battered by a persistent southwest swell, resulting in erosion of calcrete-encrusted Pleistocene eolianites. Much sediment is reworked and overall shelf sedimentation rates are low. High-energy microtidal beach/dune systems occur between headlands and along the very long ocean beach in the Coorong region. The northern, more arid coastal areas also contain saline lakes that precipitate gypsum from infiltrated sea water, and display marginal facies of aragonite boxwork to fenestral carbonate crusts, with stromatolites and tepee structures. In contrast, the southern, seasonally humid Coorong region, has a predominantly continental groundwater regime where sulphate is rare, and the high summer evaporation precipitates dolomite, magnesite and aragonite muds. Fenestral crusts, breccias, tepees and some stromatolites are also present. St. Vincent and Spencer gulfs both afford some protection from ocean swell, but tidal amplitude and currents increase, and a depth and inundation-related zonation of plants and animals is established. Muddy carbonate sand accumulates on the sea floor below 30 m, where filter-feeding bryozoans, bivalves and sponges dominate. In shallower regions, seagrass meadows contain a rich fauna that results in rapid accumulation of an unsorted muddy bioclastic sand. Mangrove woodlands backed by saline marsh with cyanobacterial mats are common, and accumulate mud-rich and gastropod-bearing sediment. As tidal amplitude and desiccation increase northward into both gulfs, a supratidal zone bare of vegetation (sabkha) becomes the site for deposition of gypsum-rich and fenestral calcitic mud.

The seafloor morphology and lithology of northern Spencer Gulf, South Australia, is related to successive transgressions and regressions accompanying glacial and non-glacial periods. Vibrocoring has revealed a veneer of Holocene bioclastics and a sequence of Pleistocene marine strata which display varying degrees of pedogenesis, oxidation, decalcification and clay illuviation. The contact between the Holocene and Pleistocene sediments is marked by either a thin alluvial or aeolian horizon or by a soil horizon of variable development. The Pleistocene marine strata have been assigned to four Formations (older Pleistocene marine beds, Mambray Fm., False Bay Fm., and Lowly Point Fm.) based on superposition of lithofacies and intervening pedogenic horizons. A sequence of slightly altered, laminated lagoonal clays (Lowly Point Formation) and bryozoan rich limestones (False Bay Formation) has been encountered in deeper parts of the Gulf. Stratigraphically below these is a widespread, weathered marine unit (Mambray Formation) which contains abundant remains of the bivalve Anadara trapezia and the foraminifer Marginopora vertebralis, species absent from the present biota. This unit, in turn, is underlain by a sedimentary sequence strongly altered by pedogenesis and clay illuviation (older Pleistocene marine beds); its original marine character has been largely obliterated. A dearth of fluvial gravels and sand from the vibrocores, as well as evidence from palaeosols, indicate that a predominantly semi-arid to arid climate has persisted in the northern Gulf region since ca. 125,000 yrs ago, and that there has been little subsequent terrigenous material transported to the Gulf.

The dispersed carbonaceous matter (kerogen), illite, and magnetic response of the Tindelpina Shale Member in the lower part of the thick, extensive Tapley Hill Formation provide three complementary methods for zoning the incipient metamorphic character of rocks comprising the late Precambrian Adelaide System where they crop out between Adelaide, Olary, and Marree in the Adelaide Geosyncline. The methods are based on the following parameters: kerogen structure (as determined by X-ray diffraction) and composition (percentage carbon, hydrogen to carbon atomic ratio, δ 13CPDB); illite crystallinity; and amplitude and type of aeromagnetic anomalies. Kerogen is the most definitive indicator of metamorphic change in the Tindelpina Shale. It has been used to delineate a western subgraphitic zone (85–91%C, H/C > 0.10) which is separated from an eastern graphitic zone (91–98%C, H/C < 0.10) by a north-trending line through Adelaide, Mintaro, Orroroo, and Baratta. A similar two-fold zonation appears to exist in the Mouth Painter—Copley—Marree area. Metamorphic adjustment of the stable carbon isotopic composition of the kerogen is also evident. Kerogen rank correlates well with illite crystallinity. Illites in the western zone have Weaver indices of less than six. Crystallinity increases to the east where 2M illite becomes the dominant illite polymorph. The eastern graphitic zone largely coincides in location and extent with a zone of linear aeromagnetic anomalies of amplitude exceeding 100 gammas. In the lower Tapley Hill Formation the anomaly is attributed to remanent magnetism, probably associted with metamorphic growth of magnetite. All three indicators suggest an increase in metamorphic grade from west to east across the geosyncline, in agreement with published observations based on conventional petrographic analysis of pelitic (and to a lesser extent, carbonate) rocks. Illite and chlorite, characteristic of the anchizone of burial diagenesis, are the dominant sheet silicates in the shales studied, although incipient metamorphic alteration of chlorite to biotite has occurred in some specimens from the graphitic zone. The subgraphitic and graphitic facies of the Tindelpina Shale correspond with the chlorite and biotite (and higher) zones, respectively, of low-pressure intermediate-type metamorphism previously established for the Mount Lofty and Flinders Ranges. Greater depth of burial of the lower Tapley Hill Formation in the eastern half of the geosyncline would account for the metamorphic trend observed in its organic matter and clay mineral content. Differential burial does not, however, adequately explain the magnetics, nor the absence of biotite-grade rocks in the central Flinders Ranges. Other magnetically anomalous beds are found throughout the Adelaide System and in overlying Cambrian strata. For the magnetism in these different stratigraphic intervals to be of metamorphic derivation, a regional thermal event, perhaps related to the Cambro-Ordovician Delamerian Orogeny, must be postulated.

The late Proterozoic Sturtian succession in the northern part of the Adelaide ‘Geosyncline’ is disposed in a southward-closing arcuate outcrop belt that is largely fault-bounded on its southern margin. On the west side the glacigenic portion of the Sturtian succession is between 100 and 800 m thick. A thin discontinuous basal breccia is present on the older rocks of the Burra Group. This is followed by a locally developed diamictite with associated lenticular sandstones, interpreted as a tillite and glacial outwash deposits, respectively. The succeeding Sturtian units are much more widespread. Unit 2 is a mudstone-dominated heterogeneous succession of siliciclastic rocks formed by traction currents, gravity flows and rain-out from floating ice. A second diamictite (Unit 3) is massive in the southeasterly part of the study area near the town of Copley, but is stratified and heterogeneous in an area to the northwest. This diamictite is probably a marine deposit formed in the south by rapid rain-out from floating ice and in the north by a variety of processes that largely reworked the glacigenic sediment. The topmost unit (4) is also heterogeneous and resulted from the interplay of gravity flows, traction currents and ice rain-out. Palaeocurrents indicate a dominantly southeasterly transport but some herringbone cross bedding suggests tidal activity. Dolostones are present in Unit 4 and stromatolitic bioherms were noted in the basal diamictite. In this region the Sturtian succession is considered to be the product of glaciation centred to the west and north, feeding into an elongate basin here termed the ‘North Flinders Basin’. Palaeocurrent data and thickness changes suggest that the basin may have opened to the east. In late Proterozoic time this basin may have been separated from the main part of the Adelaide ‘Geosyncline’ to the southeast by the shallow-to-emergent Central Flinders zone.

The Serle Conglomerate is a lenticular unit (8 km × 160 m) at the top of the Late Proterozoic (Sturtian) glacigenic Yudnamutana Subgroup in the northeastern part of the Adelaide “Geosyncline”. In its type area at the west end of the Fitton Trough it can be subdivided into five stratigraphic units interpreted as the products of deposition in the mid-to-upper portions of a submarine fan complex. Progradation of submarine fans under conditions of eustatic sea-level rise was probably due to concomitant fault activity and isostatic readjustments(?) along the basin margins. In an area about 10 km west of the type area, similar conglomerates overlie glacigenic rocks of the Yudnamutana Subgroup with an erosional contact and therefore are younger than them. There is no definitive evidence of glacial influence during deposition of the Serle Conglomerate, so that previous correlations with glacigenic diamictites elsewhere in the Adelaide “Geosyncline” are unlikely. There is no justification, in this area, for inferring two separate early Sturtian glaciations.

The Yudnamutana Subgroup is a thick succession of upper Proterozoic (Sturtian) glacigenic rocks preserved in the Yudnamutana trough in the northeastern part of the Adelaide "geosyncline." In ascending order, the subgroup comprises the Fitton, Bolla Bollana, and Lyndhurst Formations. The name "Hamilton Creek Member" is proposed for a locally developed conglomeratic facies at the base of the Fitton Formation. These rocks are interpreted as the products of two glacial advances. The first is evidenced by the Hamilton Creek Member, which includes sediment gravity flows derived from subaqueous glacial outwash. The Fitton Formation is composed mainly of basinal siltstones and mudstones with associated coarser-grained rocks that are largely sediment gravity flows. Diamictites in the upper part of the formation signify the onset of a second glacial advance. Thick diamictites of the Bolla Bollana Formation are interpreted as rainout deposits from floating ice derived from ice streams debouching from a steep and high hinterland into a fault-controlled basin. The Lyndhurst Formation is mainly fine-grained rocks. Dropstones and sparse diamictites attest to the presence of some floating ice, but some of the diamictites are probably mass-flow deposits. Paleocurrent data from the Yudnamutana Subgroup indicate transport to the west-northwest. The Sturtian glacigenic rocks are overlain by a transgressive shale. Stratigraphic similarities exist between the Yudnamutana Subgroup and thinner successions to the west. These stratigraphic similarities probably reflect paleoclimatic changes. The twice-repeated sequence of diamictite followed by mudstone is attributed to two glacial advance-retreat cycles. Local variations in thickness and stratigraphic succession are probably related to contemporaneous faulting.

Heavy mineral studies on Pleistocene tills from North America, Upper Palaeozoic tillites of South Africa and Australia, and late Precambrian tillites of South Australia show that the heavy mineral suites of the Pleistocene tills are dominated by amphiboles, the Upper Palaeozoic tillites by garnet, and the late Precambrian tillites by zircon and tourmaline. About half of the garnets in the Upper Palaeozoic tillites show evidence of having been rounded, and retain delicate surface chattermark trails, which indicates that these garnets have not undergone chemical attack since deposition. Although the remainder of the garnets show, by way of etching, that intrastratal solutions were active in the sediments, it is suggested that amphiboles, pyroxenes and epidote, which must have been present in the original Upper Palaeozoic heavy mineral suites, were lost primarily by the action of sorting and mechanical abrasion in beach environments prior to, and during interglacial periods. The absence of garnet and the etching of tourmaline and zircon in the late Precambrian tillites is attributed to the action of alkaline intrastratal solutions over the long time interval during which the tillites were buried in the Adelaide Geosyncline.

Deep-sea drilling in the Southern Ocean south of Australia and New Zealand shows that the Circum-Antarctic Current developed about 30 million years ago in the middle to late Oligocene when final separation occurred between Antarctica and the continental South Tasman Rise. Australia had commenced drifting northward from Antarctica 20 million years before this.

Four dating methods have been used to obtain chronological information about Holocene and Pleistocene coastal marine sediments in South Australia, and to check the stratigraphic reliability of each dating technique. Estimates of accumulation rates for Holocene seagrass bank deposits vary according to the time period over which they are averaged. The estimates vary from 2.0 to 2.7 mm yr −1 for measurements by the Pb-210 method (averaged over about 100 years) to 1.4-0.2 mm yr −1 for C-14 derived measurements (averaged over a period of 1000–7000 yrs). Radiocarbon age determinations on carbonate and organic fractions do not date the true sediment age. Shells, shell fragments and calcareous fines predate the sediment whereas organic and seagrass detritus postdate it. By dating sample pairs, their age can be adequately defined. Thermoluminescence age estimates correlate well with available C-14 ages where the sediment grains have experienced good exposure to sunlight prior to deposition. Amino acid racemization and thermoluminescence measurements indicate a late Pleistocene age of ca. 110,000 yrs for the Mambray Formation of Spencer Gulf. Amino acid racemization data also support a correlation with the late Pleistocene Glanville Formation of Adelaide.

Analyses of major oxides and some trace elements (Ga, Rb, Sr, and B) were carried out on 25 samples of tillite matrix materials of the major Late Precambrian glacial episode in South Australia. The results indicate the dominantly granitic nature of the source rocks and suggest deposition under marine glacial conditions.

The U‐Pb ages of zircons from a tuff‐like layer in the Late Precambrian Bunyeroo Formation in the central and southern Flinders Ranges, South Australia, show that the layer was not formed from volcanic detritus contemporaneous with sedimentation. The ages, dominantly 1575 ± 11 Ma, are consistent with the layer having been derived largely from the Gawler Range Volcanics. On this and other evidence, the layer has been identified as the ejecta blanket from a large bolide impact (Gostin et al 1986). Zircons from a second tuff‐like layer in the Bunyeroo Formation from the northern Flinders Ranges are dominantly much younger, 1143 ± 26 Ma, and have been abraded by sedimentary processes, indicating that that layer is not part of the same blanket.

High-resolution continuous seismic reflection profiles of northern Spencer Gulf, which is shallower than 25 m, show seismic discordances and bed reflectors to depths of 20 m below the seafloor. Comparison with vibrocore data indicates a correspondence of seismic discordances with major stratigraphic boundaries, often enhanced by pedogenesis. Holocene marine sediments generally form a thin ( During each successive Quaternary marine inundation, the broad and generally flat seafloor became covered by thin sheet drapes of muddy sand and sandy mud. Such flat areas became progressively restricted by the encroaching growth of marginal accretionary platforms and seagrass banks. Ephemeral lakes or sabkhas were established as well as beach ridges, aeolian sand dunes and distal alluvial fans.

Surficial sediments of Gulf St. Vincent, South Australia, are predominantly bioclastic, cool-temperate carbonates. Benthic foraminifera are abundant and distribution of species is closely related to water depth. For example, Massilina milletti is most common at depths ca. 40 m, while Discorbis dimidiatus is characteristics of shallow, subtidal environments. Elphidium crispum, a shallow-water species, and E. macelliforme, favoring deeper water, provide a useful numerical ratio. Their logarithmic relative abundance, in the sediment size fraction 0.50–0.25 mm, correlates strongly with water depth. Vibrocores SV 4 and SV 5 recovered undisturbed sections of Quaternary strata from the deepest part (ca. 40 m) of Gulf St. Vincent. Amino acid racemization and radiocarbon age determinations show that late Pleistocene sections of the cores were deposited over the time ca. 45,000 to 30,000 yr B.P. Species of fossil foraminifera, recovered from these sections, are mostly extant in modern Gulf St. Vincent, thus allowing paleoecological inferences of late Pleistocene sea levels. These inferred sea-level maxima can be correlated with those determined from study of Huon Peninsula coral reef terraces. Initial estimates of tectonically corrected sea levels for transgressions in Gulf St. Vincent at 40,000 and 31,000 yr B.P. are −22.5 m and −22 m, respectively. The intervening regression lowered sea level to −28 m.

Northern Spencer Gulf is the landward extremity of a shallow marine embayment which occupies a structural depression that overlies a major Precambrian lineament. Situated in a warm temperate climate, the low rainfall and high evaporation have created high salinities resulting in an hydrological inverse estuary. Modern sedimentation is dominantly biogenic carbonate to mixed terrigenous-carbonate. It is controlled by a mesotidal regime with occasional storm surges, minor wave activity, and a prolific growth of seagrass in shallow water. The skeletal detritus consists of bivalves, gastropods, forams, echinoids, coralline algae and bryozoa. The subtidal zone between 10–25 m is divided morphologically into two provinces. The wide southern part has a relatively smooth floor, but the northern part is narrower, and the seafloor is either scoured free of loose sediment, or covered with wide belts of megaripples. The subtidal zone between 0–10 m is everywhere dominated by seagrass meadows. The seagrasses are largely Posidonia australis and P. sinuosa and occupy broad depositional platforms, and discrete offshore banks. The seagrass meadows produce and trap mollusc/foram detritus, resulting in the accumulation of very poorly sorted, organically bound structureless carbonate muddy sand. Intertidal and supratidal zone sediments are very extensive. The intertidal zone includes bare sand flats or those covered by the seagrass Zostera . Dense mangroves ( Avicennia marina ) from mean sea level to spring high-tide level are followed progressively by a halophytic (samphire) association and an Atriplex (saltbush) association. Extensive algal mats occur with the halophytes and extend into the mangrove forests. The sediments are muddy and only moderately calcareous. The supratidal zone consists mainly of bare carbonate flats, some stranded beach ridges, and coastal dunes. The carbonate flats contain discoidal gypsum crystals in weakly layered, fenestral, calcitic mud. Coastal changes during historic time are limited, and the dominant sedimentary regime in northern Spencer Gulf is the vertical growth of seagrass areas to form intertidal sand flats.

A study of the stratigraphic units within the southern Sydney Basin has led to the recognition of Upper Carboniferous and Lower Permian sediments. Terrestrial valley-fill sediments up to 228 m thick define a palaeodrainage system active during the Upper Carboniferous. These sediments belong to the proposed Talaterang Group and comprise the Yadboro Conglomerate, Tallong Conglomerate, Burrawang Conglomerate, Yagers Conglomerate, Pigeon House Creek Siltstone, and Badgerys Breccia. Palynological data indicate that at least the lower part of the Talaterang Group can be correlated with the Seaham Formation of the Hunter Valley. The Talaterang Group is overlain disconformably by the Clyde Coal Measures (up to 41 m thick) and the Yarrunga Coal Measures, which are in part laterally equivalent to, and overlain by, the Conjola Sug-Group (lower part of the Shoalhaven Group). The Clyde Coal Measures may be correlated with the interval extending from the Rutherford Formation to the Greta Coal Measures of the H...

An assumed glacial pavement at the base of a Late Proterozoic glacigene sequence in the Wooltana district is explained as a tectonic feature. Similar surfaces, not associated with glacigene sedimen...

An inexpensive, portable cutter, which can be used in laboratories and on board research vessels, has been designed to cut liner tubes longitudinally without touching the core material. The principal advantages of the cutter are: 1) a cutting head that automatically adjusts to accommodate any variations in the roundness of liner tubes regardless of their length; 2) a cutting head that can be adjusted for variations in the wall thickness of liners; 3) the speed with which liners can be cut on two sides simultaneously.

(1989). Geological Note: Discovery of the acraman impact ejecta blanket in the officer basin and its stratigraphic significance. Australian Journal of Earth Sciences: Vol. 36, No. 4, pp. 585-587.