Coastal Landscapes of South Australia

This book aims to assist people in interpreting coastal landforms in South Australia, revealing how the coast has evolved and is continuing to do so under the influences of a range of processes acting upon a variety of geological settings. 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. 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. This book is a landmark study into the variable character of the South Australian coast and its long-term evolution

Coastal Landscapes of South Australia

This book aims to assist people in interpreting coastal landforms in South Australia, revealing how the coast has evolved and is continuing to do so under the influences of a range of processes acting upon a variety of geological settings. 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. 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. This book is a landmark study into the variable character of the South Australian coast and its long-term evolution

Using LiDAR to assess the effect of fire and floods on upland peat bogs, Waterfall Gully, Mount Lofty Ranges, South Australia

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\u27s 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

Last interglacial (MIS 5e) sea-level determined from a tectonically stable, far-field location, Eyre Peninsula, southern Australia

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 with the last interglacial maximum, but further highlight the complexity in dating fossil molluscs by the U-series method in view of their open-system behaviour. The shelly successions of the Glanville Formation occur at elevations higher than attained by sea-level in the current, Holocene interglacial. A higher sea-level of between 2.1 ± 0.5 and 4 ± 0.5 m above present sea-level is inferred for the last interglacial maximum (MIS 5e) along this coastline based on the elevation of sedimentary successions host to the shallow subtidal¿intertidal fossil molluscs Katelysia sp., and Anadara trapezia. The paleosea-level observations place a lower limit on the sea-level attained during the last interglacial maximum and suggest that caution be exercised in the definition of the upper limit of sea-level during this interglacial

A review of laterite studies in southern South Australia

Volume: 119Start Page: 1End Page: 2

Inselbergs and monoliths: a comparative review of two iconic Australian landforms, Uluru (Ayers Rock) and Burringurrah (Mount Augustus)

The concept of \u27monolith\u27 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 \u27largest monolith in Australia\u27. 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 \u27monolith\u27 has been used to describe such a wide range of features involving so many criteria that we prefer not to use \u27monolith\u27 as a geomorphic term. In relation to the inselbergs described here, the use of the term \u27monolith\u27 has led to needless and unhelpful comparisons between these two remarkable landforms