Dissertations / Theses on the topic 'Beaches Australia'

Longshore sediment transport rate was measured during energetic sea breeze activity, on intermediate-to-reflective sandy beaches in Southwestern Australia. Estimates of suspended load were obtained using backscatter sensors, current meters and streamer traps. Total load was determined using fluorescent tracer sand and an impoundment study. The measurementsw ere cross-compareda nd usedt o evaluates everalw idely-used longshore transport equations. The streamer trap measurement revealed an exponential distribution of the suspended sediment flux with vertical mixing decreasing in the onshore direction. A continuous time series of the longshore suspended sediment flux across the surf zone was obtained by combining the streamer trap measurements with data collected using surf zone instruments. Comparison of the suspended longshore flux with the total longshore flux derived from the dispersal of the sand tracer indicated that the relative contribution of the suspendedlo ad to the total load was at least 59 %. The movement of sandt racer on four different beaches demonstrated that nearshore sediments were transported obliquely across the surf zone, challenging our conventional view of dividing nearshore sediment transport into cross-shore and longshore components. Furthermore, tracer was found to move from the outer surf zone to the swash zone and vice versa, indicating a cross-shore sediment exchange. The contribution of the swash zone to the total longshore flux was estimated around 30-40 %. Despite large differences in the temporal and spatial scales of the measurement techniques, the littoral drift rates are comparable, suggesting a northward transport rate of 138,000-200,000 m3 year-1. Longshore sediment transport during sea breezes is mainly the result of a high longshore energy flux exerted by wind waves. This is accurately predicted by the equations of Inman and Bagnold (1963) and CERC (1984). The bimodal wave field, characteristic of Southwestern Australia, renders the Kamphuis (1991b) formula unsuitable in this instance.

Accumulations of seagrass, macroalgae and other matter, collectively known as wrack, commonly occur on many sandy beaches, and can play an important role in coastal and nearshore ecosystems. Despite this, wrack removal from sandy beaches is a widespread and increasingly common practice globally, and there is little information regarding the ecological effects of such wrack removal on sandy beaches. The aim of this thesis was to establish the ecological importance of wrack in South Australian (SA) sandy-beach ecosystems. As a first step in furthering our understanding of the effects of wrack removal, I aimed to assess the importance of wrack, independent of the effects of wrack removal. The second over-riding aim of this thesis was to assess the ecological effects of wrack removal on aspects of these systems. To date, the methods used for quantifying the size of wrack deposits on sandy beaches have had limited use due to the time and expertise required to conduct thorough sampling. In Chapter 2, I thus tested the accuracy of a rapid “photopoint” method to visually estimate percentage wrack cover as well as provide an archived record. Comparisons of results obtained from conventional transects with those from photopoints indicated that the photopoint technique can be used to rapidly and accurately estimate % wrack cover on sandy beaches. The photopoint method has a wide range of potential applications and represents a valuable advance in the field. Currently our knowledge of the amounts and types of wrack on SA shores is limited, despite these accumulations being a feature of some SA beaches. Wrack deposits in three biogeographical regions of SA were thus repeatedly surveyed to assess spatial (between and within regions) and temporal (seasonal and inter-annual) variation (Chapter 2). Both wrack cover and the composition of wrack deposits varied spatially and temporally. Wrack deposits contained a diverse array of seagrass, algal, other biotic materials and anthropogenic debris. The South East region of SA had distinctly-different wrack deposits compared to the Metropolitan and Fleurieu Peninsula regions; in general, the cover of wrack was higher, and the diversity and biomass of kelps, red algae and green algae was higher in this region compared to the other two regions. South Australian wrack deposits are thus dynamic and complex. The amount of wrack deposited and retained on a beach may be affected by the beach morphology but, to date, few studies have investigated this link. I assessed wrack cover on beaches with a range of morphodynamic types and found that beaches that were more dissipative in nature had a greater cover of wrack than beaches of the reflective type. I also examined whether wrack deposits affected the sediment characteristics of underlying and nearby sediments. Wrack deposits had little measurable effect on underlying sediments and did not affect particle-size distribution or organic-matter content. There was, however, a trend for beaches in the South East region of SA to have higher organic matter content in their sediments, and these beaches also have higher wrack cover and higher proportions of algae in their deposits. There was also a trend for beaches with higher wrack cover to have less compacted sediments, although this trend was not consistent. Overnight pit-fall trapping surveys of the macrofauna on four SA sandy beaches indicated that local macrofaunal communities were diverse (representing 72 species from 19 Orders in total), abundant, and variable in both time and space. The macrofauna encountered were mostly terrestrial taxa with only 2 truly marine species, and spanned multiple trophic levels, concurring with the results of previous studies. Macrofaunal abundances were higher where associated with wrack than in bare sand, and macrofaunal communities differed between the driftline of wrack and wrack patches away from the driftline. Within the driftline itself, there were few differences between bare sand and wrack-covered areas, suggesting that the entire driftline area is important as a habitat and food resource. Thus, wrack deposits provide an important habitat and food source for macrofauna, and the driftline provides an area of beach with concentrated resources, which in turn concentrates a distinct macrofaunal community. Wrack deposition on sandy beaches varies spatially and is affected by morphological features on the beach-face such as cusps. In Chapter 5, I thus tested a series of hypotheses regarding the differences in wrack deposits, sediments and macrofaunal communities between cusp bays and horns. Bays had greater cover and larger pieces of wrack than horns. Sediment organic-matter content was greater on horns than in bays but mean particle size did not differ consistently between bays and horns. Macrofaunal diversity was higher in bays and this pattern was probably driven by differences in the cover of wrack between bays and horns. Cusp morphology thus influences the distribution of wrack on the beach-face, which in turn influences the distribution of macrofauna. Studies of sandy beaches with cusps should therefore be explicitly designed to sample cusp features and their associated wrack deposits. Chapter 6 assesses the incorporation of wrack into beach and nearshore ecosystems via two pathways: decomposition and incorporation into trophic webs. I assessed the decomposition of algal and seagrass wrack using litterbag experiments and found that after a very rapid initial loss of mass, likely due to cell lysis and leaching, the rate of decomposition of wrack was much slower. Most release of nutrients from organic matter decay thus appears to occur in the first few days after deposition and the processes affecting the rate and nature of wrack decomposition vary among taxa (i.e. algal versus seagrass and among species). Stable isotopes of C and N were used to assess whether beach macrofauna or nearshore macro-invertebrates and fish might rely on wrack as a source of nutrition. I found that seagrasses did not provide a food source for any consumers but algae, particularly brown algae including kelps, appeared to be potential sources of nutrition for beach and nearshore consumers. The incorporation of wrack into beach and nearshore ecosystems may thus occur primarily through consumption of algal wrack by herbivores such as amphipods and dipterans, with predation on them being important pathways for the transfer of nutrients and energy into higher trophic levels. The amount of wrack in the surf zone did not affect the abundance and species richness of fish and invertebrates netted there. The aim of Chapter 7 was to determine the effects of wrack removal on sandy beach macrofaunal communities. In the first study the effects of large-scale commercial harvest of wrack on the macrofaunal communities at Kingston were assessed. The macrofaunal communities present in the ‘Natural’ area of Kingston beach were far more diverse and abundant, and included different species, compared to the ‘Cleared’ area at Kingston. In the second part of Chapter 7, I experimentally removed wrack from the driftline of beaches to assess short-term effects on macrofaunal communities. The experimental treatment did not appear to have any measurable effects on the macrofaunal communities. I also analysed material that was removed from the beach in the raking experiments and found that a large proportion of the material (e.g. 81% of the DW) was sand. I recommend that future studies into the effects of wrack removal use large cleared areas of beach, attempt to use the same wrack removal methods and/or machinery used locally, and assess the macrofaunal communities repeatedly and over longer times following wrack removal activities. In Chapter 8, I attempt to assess the effects of removal of wrack for beach ‘cleaning’ or commercial ‘harvest’ of wrack by comparing key indicators from Chapters 2 to 7. Implications and recommendations for the management of wrack are discussed, including with regard to the techniques used in this thesis and their applicability in managing wrack deposits. I attempt to identify the shortcomings of this research as well as directions for further research. Thus I have demonstrated that wrack in SA provides an important link between offshore habitat and nearshore, beach and terrestrial habitats via the transfer of organic matter and nutrients. Wrack interacts with beach morphology and sediments, provides habitat for macrofauna, remineralises nutrients through its decomposition, and provides the basis of a complex trophic web. I conclude that wrack is a key component in beach ecosystems.

The Australian beach is a significant component of the Australian culture and a way of life. The Australian Beachspace explores existing research about the Australian beach from a cultural and Australian studies perspective. Initially, the beach in Australian studies has been established within a binary opposition. Fiske, Hodge, and Turner (1987) pioneered the concept of the beach as a mythic space, simultaneously beautiful but abstract. In comparison, Meaghan Morris (1998) suggested that the beach was in fact an ordinary or everyday space. The research intervenes in previous discussions, suggesting that the Australian beach needs to be explored in spatial terms as well as cultural ones. The thesis suggests the beach is more than these previously established binaries and uses Soja's theory of Thirdspace (1996) to posit the term beachspace as a way of describing this complex site. The beachspace is a lived space that encompasses both the mythic and ordinary and more. A variety of texts have been explored in this work, both film and literature. The thesis examines textual representations of the Australian beach using Soja's Thirdspace as a frame to reveal the complexities of the Australian beach through five thematic chapters. Some of the texts discussed include works by Tim Winton's Breath (2008) and Land's Edge (1993), Robert Drewe's short story collections The Bodysurfers (1987) and The Rip (2008), and films such as Newcastle (dir. Dan Castle 2008) and Blackrock (dir. Steve Vidler 1997). Ultimately The Australian Beachspace illustrates that the multiple meanings of the beach's representations are complex and yet frequently fail to capture the layered reality of the Australian beach. The Australian beach is best described as a beachspace, a complex space that allows for the mythic and/or/both ordinary at once.

Thesis (B. Sc.(Hons.))--University of Adelaide, Dept. of Geology and Geophysics, 1996.
National Grid reference (SI-54)6527 - II, (SI-54) 6627 - III 1:10 000 sheet. Includes bibliographical references (leaves 32-39).

I investigated the past, present and possible futures of Australia’s ocean pools, over a hundred public seawater pools sited on rocky surfcoasts, so that waves wash over their walls. My interdisciplinary analysis informed by actor-­‐network theory explored their contributions to surf, beach, pool and body cultures and recreational coasts. Ocean pools have since the nineteenth century been far more significant in the surf, beach, pool and body cultures of Australia and South Africa, than in those of Britain and the United States. Most of Australia’s ocean pools lie within state of New South Wales, and my work strengthens the case for recognising Australian and NSW ocean pools as having distinct collective identities and affinities with their South African counterparts. Ocean pools are sites of social and environmental learning that challenge efforts to establish human mastery over wild natures and depictions of coastal environments as mere stages for enacting human activities unconstrained by non-­‐human nature. They also challenge the notion that people prefer to swim and bathe at patrolled beaches or in private or public pools far less wild than an ocean pool. They are evidence that supervision by suitably trained and equipped lifeguards or lifesavers is not the only or the most satisfactory way to adequately safeguard bathers and swimmers from the dangers of the sea. Australia’s ocean pools demonstrate that regardless of race, class, gender, age or ability, people can and do make themselves at home in pools shared convivially with wild nature and well-­‐suited for sustained, unsupervised recreation and sport on rocky surfcoast. Ocean pools serve as places of refuge, therapeutic and restorative environments, adventure playgrounds, convivial public spaces, visually appealing cultural landscapes, brands, icons and symbols. Australia’s ocean pools are unified by their sites, their affordances and core actor-­‐ networks linked to their fundamental and enduring identity as ‘wild but safe enough surfside pools’. Rocky shores and coastal waters characterised by surf, sharks and rips are among the most persistent macro-­‐actors in these networks that include bathers, swimmers, tourism and transport networks, news media, local councils and progress associations. Australian ocean pools that gained a further identity as ‘public pools for competition and carnivals’ acquired additional actor-­‐networks strongly linked since the late nineteenth century to amateur swimming clubs and schools, and since the twentieth century to surf lifesaving clubs and winter swimming clubs. Those ocean pools nevertheless, remained predominately recreational facilities. As other types of public pools became more affordable, Australia’s ocean pools remained popular despite gaining new identities as an ‘unusually hazardous type of public pool’ and ‘a type of facility no longer created’. The growing threats to ocean pools and their actor-­‐networks are a further unifying factor. As sport and recreation venues cultivating healthy, convivial relationships with wild nature and possessing unrealised potential as centres for community engagement, learning and research, ocean pools are worth emulating on other rocky shores and in other public places. My work strengthens efforts to sustain and create ocean pools and supports further studies on seawater pools and their actor-­‐networks.

The nesting demographics of sea turtles using beaches within the Barrow, Lowendal, Montebello (B-L-M) island complex on the North West Shelf of Western Australia were examined in the context of their spatial and temporal distribution and potential for exposure to industrially based artificial light sources. The distribution of overnight turtle tracks throughout the island complex confirmed high density nesting of Chelonia mydas (green turtles) on deep, sandy and high energy beaches and Natator depressus (flatback turtles) on deep, sandy and low energy beaches, while Eretmochelys imbricata (hawksbill turtle) tracks were most visible on shallow, sandy beaches adjacent to near shore coral reef habitat. The three species exhibited a summer nesting peak. Hawksbill turtles commenced nesting in September and continued through to January, green turtles commenced in November and decreased in March. Flatback turtles displayed the most constrained nesting season reported to date in Australia with 86% of the animals visits recorded in December and January only. Nesting population sizes estimated for the three species suggest that on a national scale the B-L-M complex is a moderately large green turtle and a large flatback rookery site. The hawksbill rookery is large on an international scale. While none of the green turtle nesting beaches fell within a 1.5 km radius of industrially based artificial light sources an estimated 42% of nesting flatback turtles and 12% of nesting hawksbill turtles were potentially exposed to these light sources. Testing of green turtle and hawksbill hatchling response to different wavelengths of light indicate that hatchlings from the B-L-M region respond to low wavelength much like hatchlings tested in North America (Witherington 1992a). Flatback hatchlings displayed a similar preference for low wavelength light however their responses to discrete light wavelengths between 400 nm and 700 nm suggest that this species may not discriminate well between wavelengths that lie between 450 nm and 550 nm. This response may be related to the rapid attenuation of visible light that occurs in the turbid near shore habitats favoured by this species. Field based arena studies carried out to investigate hatchling behaviour on nesting beaches with light types commonly used in industrial settings found green turtle and flatback hatchlings are significantly attracted to these lights compared to controls. Lights that emit strongly in the low wavelength range (i.e. metal halide and fluorescent) caused hatchling misorientation at lower intensities than the test light that emitted relatively poorly in this range (high pressure sodium vapour). Hawksbill hatchlings tested in situ under the influence of actual oil and gas onshore and offshore facility based lighting were disrupted from the most direct line to the ocean by these light emissions. Emergence fan mapping methods that measure hatchling orientation on nesting beaches were refined and are proposed as an alternative monitoring tool for use on beaches that are logistically difficult to access for large scale experimental orientation studies. The hatchling behaviour was clearly complicated by beach topography and moon phase. Satellite tracking of post nesting female green and hawksbill turtles from North West Shelf rookeries has identified the Western Australian location of migratory corridors and foraging grounds for these species while Scott Reef turtles migrate from their south Timor Sea rookery to Northern Territory waters. Green turtle nesting on Barrow Island and Sandy Island (Scott Reef) forage at feeding grounds 200 – 1000 km from their nesting beaches. Hawksbill turtles nesting at Varanus Island and Rosemary Islands forage at locations 50 – 450 km from their nesting beaches. While all of the nesting beaches within the B-L-M island complex are protected under the Barrow-Montebello Marine Conservation Reserves, the only foraging ground similarly protected is the Northern Territory foraging ground used by Scott Reef green turtles. None of the foraging grounds used by North West Shelf green or hawksbill turtles is currently protected by conservation reserves.

Thesis (B. Sc.(Hons.)--University of Adelaide, Dept. of Geology and Geophysics, 1993.
On title page: National Grid reference (51-53) 6326-4 (1-50,000). Includes bibliographical references (leaves 45-50).

no
This paper analyses the verbal and textual hostility employed by rioters, politicians and the media in Sydney (Australia) in December 2005 in the battle over Sutherland Shire¿s Cronulla Beach. By better understanding the linguistic conventions underlying all forms of maledictive hate, we are better able to address the false antimonies between free speech and the regulation of speech. It is also argued that understanding the harms of hate speech provides us with the tools necessary to create a more responsive framework for criminalising some forms of hate speech as a preliminary process in reducing or eliminating hate violence.

Ces travaux visent à inscrire le monitoring des plages récifales de l'île de La Réunion dans la « Stratégie Nationale de Gestion Intégrée des Zones Côtières » (2012). Elle oriente les recherches vers une démarche labellisée sur le long terme qui se concrétise par la mise en place de protocoles de mesures normalisés déployés sur des sites ateliers. Le site de l'Ermitage devient, en 2012, le premier site atelier en zone tropicale et de type bioclastique labellisé à l'échelle nationale (AllENVI, puis INSU en 2014). La dynamique des plages d'arrière-récif demeure à ce jour peu étudiée à travers le monde. Les plages bioclastiques de La Réunion sont le produit de récifs coralliens décrits comme dégradés par les biologistes depuis les années 80. Elles sont confrontées à une très forte anthropisation. Des formes marquées d'érosion se lisent dans ces paysages littoraux. La révision des protocoles de suivi de la topographie des plages tout en exploitant les suivis historiques, vise à illustrer la pluralité des dynamiques en contexte d'arrière-récif. La diversité des processus et des échelles spatio-temporelles impliqués dans le fonctionnement hydro-sédimentaire des plages récifales nécessite la mise en œuvre de méthodes d'observation in situ adaptées, comparables et reproductibles. Dans cette étude nous exploitons surtout les suivis topographiques des plages à l'échelle évènementielle, saisonnière et pluriannuelle. Par l'analyse morphologique et volumétrique des séries de profils topographiques, la variabilité morphosédimentaire en zone intertidale et supratidale est décrite. La significativité de la mesure de la mobilité du trait de côte est également questionnée
Long-term assessment of beach morphodynamic is a great challenge to understand future trajectories of these landforms. In France, in 2012, a national strategy for an integrated management of shoreline has been adopted. This one lead to creation of research labels (SOERE and SNO) which aim to sustain scientific researches dedicated to sandy beach morphodynamic in response to various hydrodynamics forcing. Shoreline monitoring on selected pilot sites is conducted within network where normalized protocols and high quality data are guaranteed at long-term scale. The French coastline also extend in tropical zone through its ultramarine territories. Tropical shoreline are among the most sensitive environment however they remain poorly studied. Since, 2012, Reunion island, a French department in Indian Ocean, integrated the SOERE network. Coral reef and coral beaches which preferentially developed on the western coast are frequently threatened by major swell event associated with tropical cyclones or long period swell. Since now, the beach trend evolution and morphogenic processes have not been quantified. However past monitoring exists which has consisted in topographic measurement along beach profile based on empirical protocols which produced biaised data. Since its integration within SOERE network, DGPS survey are now conducted along the different coral beach compartments of Reunion Island at seasonal and post-storm scale. This study aims to capitalize historical and DGPS beach topographic data in order to quantify long term and post-storm beach response and recovery from Cap Champagne to Trou d'Eau

Although the physical characteristics of surfing breaks are well described in the literature, there is little specific research on surfing and coastal management. Such research is required because coastal engineering has had significant impacts to surfing breaks, both positive and negative. Strategic planning and environmental impact assessment methods, a central tenet of integrated coastal zone management (ICZM), are recommended by this thesis to maximise surfing amenities. The research reported here identifies key oceanographic considerations required for ICZM around surfing breaks including: surfing wave parameters; surfing break components; relationship between surfer skill, surfing manoeuvre type and wave parameters; wind effects on waves; currents; geomorphic surfing break categorisation; beach-state and morphology; and offshore wave transformations. Key coastal activities that can have impacts to surfing breaks are identified. Environmental data types to consider during coastal studies around surfing breaks are presented and geographic information systems (GIS) are used to manage and interpret such information. To monitor surfing breaks, a shallow water multibeam echo sounding system was utilised and a RTK GPS water level correction and hydrographic GIS methodology developed. Including surfing in coastal management requires coastal engineering solutions that incorporate surfing. As an example, the efficacy of the artificial surfing reef (ASR) at Mount Maunganui, New Zealand, was evaluated. GIS, multibeam echo soundings, oceanographic measurements, photography, and wave modelling were all applied to monitor sea floor morphology around the reef. Results showed that the beach-state has more cellular circulation since the reef was installed, and a groin effect on the offshore bar was caused by the structure within the monitoring period, trapping sediment updrift and eroding sediment downdrift. No identifiable shoreline salient was observed. Landward of the reef, a scour hole ~3 times the surface area of the reef has formed. The current literature on ASRs has primarily focused on reef shape and its role in creating surfing waves. However, this study suggests that impacts to the offshore bar, beach-state, scour hole and surf zone hydrodynamics should all be included in future surfing reef designs. More real world reef studies, including ongoing monitoring of existing surfing reefs are required to validate theoretical concepts in the published literature.

In Australia today, beach-going is a major pastime but a poorly understood activity. A large number of stereo-types and images have been used to characterize beach-going and beach-goers. There have been images of national types, such as life savers; images of groups, such as willowy board riders; images of sex, such as bikini-girls; and images of character, such as lazy workers who take sick-days off to go the beach. Such stereo-types suggest th a t beach-going is an important aspect of Australian life yet, because they deal only with isolated aspects of beach-going, they do not significantly advance our overall understanding of beach-goers and beach life. This history will try to provide a general understanding of the changing character and role of beach-going in Australian life.

Includes bibliographical references (leaves 136-154) Aims to determine the effects of an outfall discharging secondarily treated wastewater effluent on benthic communities at Christies Beach with the specific objectives of: characterising the physical, biological and chemical environment of Gulf St Vincent and the study area region; ascertaining the extent to which effluent outfall has affected the macrobenthic infaunal community structure; characterising the structure of macrobenthic infaunal communities in the near shore water of the Adelaide metropolitan coast; and, determining the functional response through measurements of sediment community respiration to these changes.

Includes bibliographical references (leaves 136-154)
xvii, 171 leaves ; ill. (some col.), maps ; 30 cm.
Aims to determine the effects of an outfall discharging secondarily treated wastewater effluent on benthic communities at Christies Beach with the specific objectives of: characterising the physical, biological and chemical environment of Gulf St Vincent and the study area region; ascertaining the extent to which effluent outfall has affected the macrobenthic infaunal community structure; characterising the structure of macrobenthic infaunal communities in the near shore water of the Adelaide metropolitan coast; and, determining the functional response through measurements of sediment community respiration to these changes.
Thesis (Ph.D.)--University of Adelaide, Dept. of Environmental Biology, 2001

Turquesa Beach is a start-up dedicated to manufacturing and selling premium children’s swimwear through its website in Portugal. Although it was founded in 2016 and is still establishing itself in the Portuguese market, the company wants to expand its sales period to the whole year. As such, Turquesa Beach wants to expand to Southern Hemisphere countries, in which the high season is between December and February. Consequently, this dissertation’s objective is to analyze the possibility of an internationalization to Australia by understanding how the Australian Swimwear Market is structured, which marketing strategy can be recommended for an online-based company such as Turquesa Beach, and the investment necessities that the company might have. Through extensive research on online platforms and interviews with the owner of Turquesa Beach, it was possible to gather crucial information to better understand the position of the company as well as the Australian market. Finally, after conducting the market analysis and financial forecasts, it was recommended to Turquesa Beach to enter the Australian market by using marketing tools such as Google AdWords and Facebook Ads, add new features to the swimsuits – such as SPF/UV protection –, and hire a fulfilment agency in Australia.
A Turquesa Beach é uma start-up que produz e comercializa fatos-de-banho para crianças até aos 10 anos de idade através do seu site, em Portugal. Apesar de ter sido fundada em 2016 e de se estar a estabelecer no mercado Português, a empresa quer conseguir ampliar o seu período de vendas, não só durante o verão, mas para o ano todo. Como tal, a Turquesa Beach pretende expandir para o Hemisfério Sul, onde o verão começa em Dezembro e acaba em Fevereiro. A presente tese visa avaliar a possibilidade de internacionalização para a Austrália, através da análise da estrutura do mercado Australiano, da análise das potenciais estratégias de Marketing que poderão ser usadas por uma empresa online como a Turquesa Beach, e da análise do possível investimento que a empresa terá de sustentar. Toda a informação analisada no presente estudo foi recolhida através de pesquisas extensas em variadas plataformas online, assim comontrevistas com a fundadora da Turquesa Beach. Depois de conduzida a análise, recomendou-se que a Turquesa Beach use plataformas de anúncios como o Google AdWords e o Facebook Ads, que adicione proteção SPF/UV aos seus fatos-de-banho e que contrate uma agência que possa armazenar e transportar os produtos na Austrália.

The stranding of crude oil on the beaches of southern Australia was first recorded approximately 150 years ago. This material, locally known as coastal bitumen, was used by the early maritime visitors and settlers to caulk their vessels and is the first recorded commercial use of crude oil in Australia. Historical records indicate that the greatest amount of coastal bitumen strands along the coasts of South Australia and western Victoria. The Otway Basin, which straddles part of this shoreline, is one of a series of basins located along the southern passive margin of the Australian continent. These basins formed during the Late Jurassic-Early Cretaceous in response to the rifting and final breakup of eastern Gondwanaland 95 million years ago. The circumstantial evidence of coastal bitumen, and the more recent discovery of offshore gas seeps, have been used to promote petroleum exploration in the Otway Basin. As a result, several small but commercial gas fields and numerous oil shows have been discovered. The moderate success of exploration in the Otway Basin may not be a true indication of its ultimate reserves, given that Australia’s most prolific petroleum province, the Gippsland Basin, lies immediately to the east. The aims of this study were twofold: to appraise the hydrocarbon potential of the western Otway Basin, and to identify the origin(s) of the coastal bitumen. Source rocks were identified using an interdisciplinary approach which included wireline log interpretation, lithological descriptions, organic petrology (viz. maceral analysis, vitrinite reflectance) and organic geochemical analyses (viz. TOC and Rock-Eval pyrolysis). Oil-source rock and oil-oil correlations were attempted using carbon isotope mass spectrometry, gas chromatography and gas chromatography-mass spectrometry. In the western Otway Basin the most important hydrocarbon plays occur within the Early Cretaceous Otway Group (Crayfish Subgroup and Eumeralla Formation). Terrigenous source rocks with potential to generate both oil and gas were identified in the lower Eumeralla Formation. The waxy paraffinic-naphthenic crude oils recovered from Windermere-1 and 2, Lindon-1 and Port Campbell-4 have biomarker signatures that are indicative of a terrestrial source to which conifer resins made a significant contribution. These oils have been correlated with coaly facies of the lower Eumeralla Formation. In the Crayfish Subgroup, lacustrine mudstones in the Pretty Hill Sandstone contain kerogen derived from a mixture of algal and biodegraded plant remains which appears to have generated significant volumes of gas (Katnook-Ladbroke Grove Gas Field; Troas-1) and minor quantities of oil (Sawpit-1). Reservoir bitumens occur in the Pretty Hill Sandstone at Crayfish-A1 and Zema-1. These bitumens are unlike any other oil found within the Otway Basin. Their distinctive biomarker assemblage indicates that they were derived from algal and bacterial remains preserved in carbonate-evaporite sediments. Although no such source rocks have yet been penetrated by any exploration well, it is believed that they may be located within either the lower Crayfish Subgroup or the Casterton beds. These inferred source rocks are likely to be overmature in most areas of the western Otway Basin, precluding any significant future hydrocarbon generation. However, their required presence indicates that hydrocarbons were generated very early in the history of the basin. A bimonthly survey documenting the stranding of coastal bitumen between Kangaroo Island, South Australia and Cape Otway, Victoria was carried out from September 1990 to September 1991. The physical characteristics of the coastal bitumens collected during this period enabled three categories of beached petroleum to be identified: waxy bitumen, asphaltite and oil slicks. Elemental, isotopic and biomarker analyses of representative samples confirmed that these three categories of petroleum are not geochemically related. Of extreme significance is the fact that they bear no resemblance to oil discoveries in the Otway Basin. Waxy bitumens are the most common type of coastal bitumen, accounting for 90% of the total beached petroleum. They represent the weathered remains of paraffinic-naphthenic crude oils which have low to moderate sulphur (0.1-2.6%) contents. Their medium to low density (10-40°API) ensures that they float in sea water. These waxy bitumens contain a unique association of source-specific biomarkers, notably botryococcane, oleanane, isomeric bicadinanes and 4-methyl steranes, which is not found in any indigenous Australian oils. The biological precursor of botryococcane is synthesized only by the freshwater green alga Botryococcus sp. and 4-methyl sterols are abundant in dinoflagellates. Oleanane originates from angiosperms which first appeared in the Late Cretaceous. High concentrations of bicadinane are derived from the resins (dammars) of the fossil angiosperm family Dipterocarpaceae. In terms of their biogeographic range, both extant and fossil dipterocarps are confined to the tropics of Southeast Asia, although their dammars have been found on South Australian beaches. Together, these biomarkers imply that the waxy bitumens were derived from Tertiary lacustrine source beds which were deposited at low palaeolatitudes. When the effects of extensive weathering and biodegradation are taken into account, the waxy bitumens are similar to bitumens stranded on the coasts of the Northern Territory and Western Australia, and to Tertiary crude oils produced from Sumatra. Hence, it has been deduced that the waxy bitumens originate from oil seeps within the Indonesian Archipelago. These crude oils are transported into southern Australian waters as flotsam by a complex system of surface ocean currents which include the South Equatorial Current, Leeuwin Current and West Wind Drift. Asphaltite is the least common variety of coastal bitumen. These jet black bitumens are heavy (~8°API) and characteristically exhibit deep desiccation cracks on their upper surface. The oldest asphaltite analysed in this study was collected before the year 1900 on Kangaroo Island, and the stranding of comparable samples continues to the present day. The asphaltites have a uniform aromatic-asphaltic composition and are rich in sulphur (S=3-6%). Their unimodal n-alkane distribution centred about C¹⁵, the predominance of cholestane among their C ₂₇-C ₂₉ desmethyl steranes and the presence of dinosterane (a marine dinoflagellate biomarker) as the major C₃₀4-methyl sterane, highlight the marine source affinity of the asphaltites. The presence of rearranged steranes and hopanes indicates that their parent crude oils were generated from clay-rich sediments. The asphaltite samples are isotopically light (δ¹³Csat~-30.0‰; δ¹³Carom~-29.5‰) relative to the waxy bitumens. These depleted δ¹³C values, combined with the presence of dinosterane and C₂₈ /C₂₉ sterane ratios ranging from 0.7 to 1.2, suggests that their source rocks are of Mesozoic age. The South Australian and Victorian asphaltites are almost identical to asphaltic bitumen which strands on the west and south coasts of Tasmania. The biomarker geochemistry of the asphaltite was compared with those of many other Australian and non-Australian marine sediments and oils. However, no matching signatures were found and so the source of the asphaltite could not be identified. Nevertheless, the long stranding history of the asphaltite suggests that it is a natural phenomenon. A third group of ‘coastal bitumens’ represents stranded oil slicks. These films and sheets of liquid oil are of sporadic occurrence and have been linked to local maritime operations. The bitumens assigned to this category have variable geochemical signatures depending on the type of oil discharged; both refined and unrefined crude oils were among the samples collected. The majority of these crude oils originated from either Southeast Asia or the Middle East, the two main provinces from which oil is imported into Australia. The stranding of coastal bitumen along the southern margin of Australia can be attributed to both natural and anthropogenic causes but not, as first suspected, to oil seepage from the offshore sector of the Otway Basin.
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Thesis (Ph.D.) -- University of Adelaide, Department of Geology and Geophysics, 1995