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© 2020, © 2020 Geological Society of Australia. Quaternary alluvial and colluvial sediments infill major river valleys and form alluvial fans and colluvium-filled bedrock depressions on the range fronts and within the Mount Lofty Ranges of southern Australia. A complex association of alluvial successions occurs in the Sellicks Creek drainage basin, as revealed from lithostratigraphy, physical landscape setting and optically stimulated luminescence (OSL) ages. Correlation of OSL ages with the Marine Oxygen Isotope record reveals that the alluvial successions represent multiple episodes of alluvial sedimentation since the penultimate glaciation (Marine Isotope Stage 6; MIS 6). The successions include a penultimate glacial maximum alluvium (Taringa Formation; 160 ± 15 ka; MIS 6), an unnamed alluvial succession (42 ± 3.2 ka; MIS 3), a late last glacial colluvial succession within bedrock depressions (ca 15 ka; MIS 2) and a late last glacial alluvium (ca 15 ka; MIS 2) in the lowest, distal portion of Sellicks Creek. In addition, the Waldeila Formation, a Holocene alluvium (3.5 ± 0.3 ka; MIS 1), and sediments deposited during a phase of Post-European Settlement Aggradation (PESA) are also identified. The age and spatial distribution of the red/brown successions, mapped as the Upper Pleistocene Pooraka Formation, directly relate to different topographic and tectonic settings. Neotectonic uplift locally enhanced erosion and sedimentation, while differences in drainage basin sizes along the margin of the ranges have influenced the timing and delivery of sediment in downstream locations. Close to the Willunga Fault Scarp at Sellicks Creek, sediments resembling the Pooraka Formation have yielded a pooled mean OSL age of 83.9 ± 7 ka (MIS 5a) corroborating the previously identified extended time range for deposition of the formation. Elsewhere, within major river valleys, the Pooraka Formation was deposited during the last interglacial maximum (128–118 ka; MIS 5e). In general, a

2019 Surficial iron-rich deposits (ferricretes) occur on and around Burringurrah (Mount Augustus), a huge, remote inselberg in the Gascoyne district of Western Australia. Oriented NW-SE, Burringurrah is approximately 14 km long, 5 km wide, rises to 1105 m above sea level and stands some 700 m above the surrounding plain. The majority of the ferricretes occupy bedrock valley bottom floors on the southern side of the inselberg at Edney Springs, Flintstone Creek, and on the Edney Trail where they have formed on unweathered quartzose Mount Augustus Sandstone, which only contains a few percent Fe2O3. At 'The Pound', a boulder ferricrete overlies deeply weathered igneous bedrock, unroofed by erosion of the overlying Mount Augustus Sandstone, exposing the unconformity between the weathered granitic bedrock and the Mount Augustus Sandstone in the core of a broad, asymmetrical and doubly plunging anticline. On the northern, steeper, side of the mountain, vermiform and conglomeratic ferricretes are sparsely exposed in drainage lines. Ferricrete mineralogy is dominated by goethite with only small amounts of hematite. Oxygen isotope inferred ages of weathered monzogranite produced a top-down weathering front extending up to the Neogene at an elevation coincident with the ferricretes within bedrock valley bottoms. Beyond the mountain, the age of ferricreted sandy alluvium was established by thermoluminescence polymineral fine grain dating. These produced a minimum depositional age of >37.6 ± 2.6 ka and a second finite age of 139 ± 44 ka, suggesting ferricrete formation here may have begun during the last interglacial period and continued throughout the late Pleistocene. Formation of ferricretes on top of iron-poor quartzites is unusual. It reflects not only the absolute accumulation of iron oxides derived from the Mount Augustus Sandstone but possibly the additional contributions of iron-bearing aeolian dust from the surrounding plains subsequently washed down drainage lines to

Alluvial sequences proximal to coastlines offer opportunities to establish associations between terrestrial, sea-level and climatic events. South Australia hosts a globally significant Pleistocene interglacial sea-level record and numerous terrestrial sediment sources. However, only fragmentary evidence of pre-Last Interglacial alluvium has been identified. This paper presents the first definitive recognition of MIS 7 alluvium in South Australia, which occurs beneath the surface of extensive river terraces flanking Currency Creek and the Finniss River, between the Mount Lofty Ranges and the River Murray Lakes. A thermoluminescence age, 227 ± 24 ka, correlates with the penultimate interglacial global sea-level highstand. Nearby, last interglacial fossils of the estuarine bivalve Spisula trigonella at 2.53 ± 0.25 m APSL occupy a hollow eroded into the MIS 7 alluvium. Increasing aridity and decreased fluvial activity in the late Quaternary have preserved the MIS 7 alluvium. The fragmentary record of alluvium pre-dating the Last Interglacial is attributed to three principal causes: (1) tectonic subsidence of the Murray Estuary, which increased the potential for burial or coastal erosion of sediments; (2) erosion and reworking of previously existing alluviums, especially during low sea levels of glacial times; (3) the absence of reliable dating controls on the potentially older alluvial sediments.

The last interglacial maximum (Marine Isotope Substage 5e [MIS 5e], 128¿116 ka) is a distinctive event in recent Earth history. Shoreline successions of this age are important for calibrating climate models and defining the overall behaviour of the crust¿mantle system to fluctuating ice and ocean-water volumes. In a global context, the recently intensified interest in last interglacial shoreline successions has revealed considerable variability in the magnitude of sea-level rise during this time interval and highlighted the need to examine paleosea-level evidence from tectonically stable, far-field settings. Situated in the far-field of continental ice sheets and on the tectonically stable Gawler Craton, the 300 km coastal sector of western Eyre Peninsula between Fowlers Bay and Lake Newland in southern Australia represents an important region for defining the glacio-eustatic (ice-equivalent) sea-level attained during the last interglacial maximum based on the relative sea-level observations from this region. Low-energy, shoaling upward, peritidal bioclastic carbonate successions of the last interglacial (locally termed Glanville Formation) formed within back-barrier, estuarine¿lagoonal environments in the lee of eolianite barrier complexes (locally termed Bridgewater Formation) along this coastline. The well-preserved shelly successions (coquinas) contain diverse molluscan fossil assemblages including species no longer living in the coastal waters of South Australia (e.g. the Sydney cockle Anadara trapezia and the benthic foraminifer Marginopora vertebralis). The extent of amino acid racemisation (a measure of fossil age based on increasing d/l value) in a range of species, and in particular A. trapezia and Katelysia sp., confirms the time equivalence of the isolated embayment-fill successions, correlated with the informal type section of the Glanville Formation at Dry Creek, north of Adelaide. Preliminary U-series analyses on A. trapezia also suggest a correlation

Geologically, the South Australian coast is very young, having evolved over only 1% of geological time, during the past 43 million years since the separation of Australia and Antarctica. It is also very dynamic, with the current shoreline position having been established from only 7000 years ago. The South Australian mainland coast is 3816 km long, with islands providing an additional 1251 km of coast, giving a total coastline of just over 5000 km. South Australian coastal landforms include cliffs, rocky outcrops and shore platforms, mangrove woodlands, mudflats, estuaries, extensive sandy beaches, coastal dunes and coastal barrier systems, as well as numerous near-shore reefs and islands. This book is a landmark study into the variable character of the South Australian coast and its long-term evolution.

The concept of 'monolith' is considered with reference to two imposing inselbergs in semi-arid Australia, Uluru (Ayers Rock) and Burringurrah (Mount Augustus). Individually each has been described as the 'largest monolith in Australia'. To assess this comparison we outline the geology, morphology and geomorphic history of each. Both consist of sedimentary rock, but they differ in almost all other aspects including dimensions, lithological variations, geological evolution, tectonics, rock structures, operating processes and ages of both the landforms and the underlying rocks. The term 'monolith' has been used to describe such a wide range of features involving so many criteria that we prefer not to use 'monolith' as a geomorphic term. In relation to the inselbergs described here, the use of the term 'monolith' has led to needless and unhelpful comparisons between these two remarkable landforms.

A geochronological framework for the sequential development of coastal barrier aeolianite complexes in the mouth region of the River Murray, Australia's largest river system is presented based on amino acid racemization and thermoluminescence dating. The sedimentary successions represent a foreshortened and condensed sequence of coastal barriers compared with those of the Coorong Coastal Plain in southern South Australia where the barrier complexes are more widely separated in response to tectonic uplift. The barriers have formed during interglacial sea-level highstands and are correlatives of genetically equivalent landforms of the Coorong Coastal Plain. Thermoluminescence dating and the extent of amino acid racemization in aeolianite ‘whole-rock’ sediment samples, reveal a general increase in age of the barriers landwards from the modern coastline. In detail, however, the individual barriers represent composite structures having formed in more than one interglaciation, due to the reoccupation of Pleistocene shoreline positions during sea-level highstands of similar amplitude, in a zone of gradual basin subsidence. The most seaward Pleistocene aeolianite at Surfer Beach is of interstadial age (Marine Isotope Stage 5c, 105 ± 5 ka; MIS 5c), and correlates with the Robe Range of the Coorong Coastal Plain. The last interglacial shoreline (130 ± 15 ka; MIS 5e) is particularly well-defined in the River Murray mouth region. It is represented by a complex association of coastal parabolic dunes superimposed on a transverse dune system, which runs parallel with the former coastline, and also includes associated estuarine, lagoonal and open ocean beach facies. Landward of the last interglacial succession are distinct barriers relating to the penultimate interglaciation (215 ± 35 ka; MIS 7), as well as earlier interglaciations (350 ± 65 ka; MIS 9 or 11 and 470 ± 70 ka; MIS 11 or 13). The coastal barriers have been successively breached by the ancestral River Murray at times of

A flood exceeding the 100 year average recurrence interval in November 2005 led to the failure of an upland peat bog in Waterfall Gully. The area is prone to severe bushfire and flood events and the control dam at the base of First Falls was filled with sediment sourced from Wilson Bog. A resistant quartzite bar at Fourth Falls has formed a natural constriction point against which burnt logs and debris have collected following previous fire events forming a natural dam resulting in sediment/peat accumulation upstream. The failure of the bog was inevitable as the vegetative material in the log-jam progressively weakened and rotted. Intense flooding triggered the failure but it was augmented by the build up of a critical mass of sediment upstream of the restriction point. The downstream force of the flood waters and the weight of the saturated bog sediments was enough to overcome the basal frictional forces resulting in slumping and headward erosion. LiDAR data clearly shows an erosion channel scoured out by the flood. Approximately 5000 m3 of sediment (-10,100 tonnes) was washed downstream. LiDAR coupled with a tri-spectral scanner has the capacity to identify other upland peat bogs due to their high NDVI value and assess their stability on steep slopes or narrow valleys. Fire is another risk to the stability of these bogs as it has the potential to remove binding vegetation and expose unconsolidated sediments to erosion during subsequent rain events. Groundsurface and vegetation surface DEM's generated from LiDAR combined with NDVI maps derived from a tri-spectral scanner provide an ideal tool to monitor and assess the risk of slumping in other upland peat bogs.