South Coast Of Western Australia Research Articles

Introduction to the special issue of The Natural History of Two Peoples Bay Nature Reserve, Western Australia

Context This paper introduces the special issue of Pacific Conservation Biology devoted to the natural history of Two Peoples Bay Nature Reserve on the south coast of Western Australia. Methods This paper provides the background to the special issue. Key results Two Peoples Bay Nature Reserve was gazetted in 1967 for the conservation of the native biota, including two species; the Djimaalap/noisy scrub-bird (Atrichornis clamosus) and Ngilgaitch/Gilbert’s potoroo (Potorous gilbertii), both believed extinct for over 100 years before being rediscovered on the Reserve. The Reserve is 4774.7 ha in area, with wetlands, heathlands, granite outcrops, sand dunes, beaches, cliffs, and islands. Since it was established, mean annual rainfall has decreased by 16.8%, mean annual maximum temperature has increased by 0.2°C, and mean annual minimum temperature has increased by 0.7°C. Conclusions The paper poses the question: what do the changes of drier winters, hotter summers, and more extreme weather events mean for managers of conservation areas such as Two Peoples Bay? Implications Changing climate will pose problems for the managers of Two Peoples Bay Nature Reserve in ensuring the conservation of the Djimaalap/noisy scrub-bird and Ngilgaitch/Gilbert’s potoroo.

Basin testing of the 1-2-1 M4 WEC

The M4 family of Wave Energy Converters consist of 3 rows of floats, with the front two rows rigidly connected and a hinged connection(s) to the back row. The various possible configurations are commonly identified by the number of floats in each row – hence 1-2-1 has 1 float in front, 2 in the middle, and 1 at the rear. A study by Stansby et al 2017 [1] showed that the 1-2-1 and 1-3-2 variants had the lowest cost of energy of all configurations studied. The 1-3-2 variant has subsequently been extensively studied as it provides greater power per machine. However, the 1-2-1 machine has received less attention. In this paper we report, for the first time, wave basin testing of a 1-2-1 variant. The design is a 1:15 scaled version of a 1-2-1 M4 suitable for deployment in the prevailing short period wind waves in King George Sound, Albany, on the south coast of Western Australia. 
 
 The tests were carried out in the Model Test Basin at the Australian Maritime College, Tasmania. This basin is 35 m x 12 m and tests were run with a water depth of 0.8 m. For modelling operational conditions, the power take-off was represented by a pneumatic ram; in extreme seas the power take-off was removed.
 
 Decay tests, irregular operational seas and irregular extreme seas were tested. All waves were long crested. Sea states tested were taken from the scatter diagram for the deployment site in King George Sound. Body displacements, mooring loads, run-up on the middle floats and forces in the PTO (where installed) were measured. Measured motions and power were compared to a linear model. The level of agreement is compared with previous tests on other variants of M4 in the published literature, including the 1-3-2 variant tested in Carpintero-Moreno et al [2] and the 1-1-1 variant tested in Stansby et al [3]. Compared to some other configurations (such as 1-3-2) the 1-2-1 M4 is more prone to roll. Implications of the test results for deployment in King George Sound are discussed.
 
 [1] Stansby, P., Moreno, E.C. and Stallard, T., 2017. Large capacity multi-float configurations for the wave energy converter M4 using a time-domain linear diffraction model. Applied Ocean Research, 68, pp.53-64.
 
 [2] Carpintero-Moreno, E. and Stansby, P., 2019. The 6-float wave energy converter M4: Ocean basin tests giving capture width, response and energy yield for several sites. Renewable and Sustainable Energy Reviews, 104, pp.307-318.
 
 [3] Stansby, P., Moreno, E.C. and Stallard, T., 2015. Capture width of the three-float multi-mode multi-resonance broadband wave energy line absorber M4 from laboratory studies with irregular waves of different spectral shape and directional spread. Journal of Ocean Engineering and Marine Energy, 1, pp.287-298.

Phylogenetic position, validity and diversity of the genus Milnesioides (Eutardigrada: Apochela)

Abstract The order Apochela, the only exclusively carnivorous tardigrade lineage, comprises four genera, of which Milnesium contains multiple species and is common and cosmopolitan, whereas the remaining genera (Bergtrollus, Limmenius and Milnesioides) are monotypic, rare and have restricted geographical distributions. More importantly, although there are ample genetic data for numerous Milnesium species, no other apochelan genus has been sequenced so far, which limits our understanding of milnesiid evolution. In this contribution, we analysed two populations of Milnesioides from the south coast of Western Australia. The obtained molecular phylogenetic tree clearly indicated Milnesioides as a sister lineage to all remaining Milnesium species, supporting the validity of the genus. Moreover, the sister relationship of Milnesioides and Milnesium lends support to the Gondwanan origin of the order Apochela. Phenotypic differences between the type population of Milnesioides exsertum from New South Wales and the populations from Western Australia analysed in this study suggest that the latter represent a new species. The new data and morphological differences between populations reported in the original description of Milnesioides strongly suggest that the genus is not monotypic.

Ichthyofaunas of nearshore, shallow waters of normally-closed estuaries are highly depauperate and influenced markedly by salinity and oxygen concentration

This study determined the ichthyofaunal characteristics of the nearshore, shallow waters of three normally-closed estuaries (Stokes, Culham and Hamersley inlets) on the south coast of Western Australia over three years, during which each system remained closed to the ocean through the recent formation of a sand bar at its mouth. The ichthyofauna in each estuary was depauperate (6 or 7 species) and overwhelmingly dominated by small euryhaline atherinid and gobiid species and a larger sparid, which each complete their life cycle within their natal estuary. The atherinid Atherinosoma elongatum contributed between 74.5 and 94.5% to the ∼168,000 fish collected from these three estuaries. In contrast, marine species were represented solely by six Aldrichetta forsteri (Mugilidae), likely derived from overwash of the bar. The degree to which salinity increased and oxygen declined during the three years of closure varied markedly among the three estuaries. Among estuary basins, the number of species and density of fishes declined most rapidly in Culham Inlet, where mean salinity rose sharply from 52 to 293 and oxygen concentration fell precipitously to 0.6 mg L−1, with only A. elongatum present in salinities up to 147 and oxygen concentrations down to 2.4 mg L−1. In contrast, number of species and density of fishes remained relatively constant in the basin of Stokes Inlet, where salinity rose to only 64 and oxygen concentration declined to only 5.5 mg L−1, with ichthyofaunal and environmental changes in the basin of Hamersley Inlet intermediate between those in Culham and Stokes. While species were variably partitioned between the basin and river, certain species, when subjected to extreme salinities in the basin, moved into the less saline riverine reaches of the estuary, with the isolated pools that form upstream in estuaries during very dry periods providing refugia. In estuaries on the extensive south-western Australian coastline, the number of fish species, and particularly the number and abundance of marine species, undergo an overall progressive decline down the lower west coast and eastwards along the southern coast where they eventually fall to minimal levels. This reflects the overall trend for estuaries to change from permanently-open to the ocean to intermittently-open, to seasonally-open and finally normally-closed.

Hibbertia aplacophylla (Dilleniaceae), a new species from south-western Western Australia segregated from H. notibractea

Hibbertia aplacophylla K.R.Thiele sp. nov. is here segregated from H. notibractea J.R.Wheeler. It comprises plants from a disjunct population on the far south coast of Western Australia that differ most significantly from H. notibractea in having leaves with a distinct midrib and recurved margins (cf. flat with neither midrib nor recurved margins), sepals that are quite glabrous (cf. ciliate-margined), and anthers held erect at the ends of the fused filaments (cf. deflexed).

The spatiotemporal dynamics, distribution, and characteristics of beached plastics along the remote south coast of Western Australia

Understanding the accumulation mechanism for beached plastics is important for marine debris research. Similar to the global accumulation pattern for beached plastics, we find that along the remote south coast of Western Australia (SCWA) white, hard, microplastics dominate the microplastic pollution accumulating on beaches. We estimate that along the SCWA, plastics are present at a density of 2.01 items·m-2, but also find that the density of plastic pollution is higher at the eastern end of bays. Significantly fewer plastics were found after easterly winds (austral summer-prevailing winds), and regional physical ocean process, including the Leeuwin Current, and the Ekman transport effect may be relevant to the rate of plastic accumulation on SCWA beaches.

Measuring a Rogue? An Investigation into an Apparent Giant Wave

Abstract An apparent giant wave event having a maximum trough-to-crest height of 21 m and a maximum zero-upcrossing period of 27 s was recorded by a wave buoy at a nearshore location off the southwestern coast of Australia. It appears as a group of waves that are significantly larger both in height and in period than the waves preceding and following them. This paper reports a multifaceted analysis into the plausibility of the event. We first examine the statistics of the event in relation to the rest of the record, where we look at quantities such as maximum-to-significant wave height ratios, ordered crest–trough statistics, and average wave profiles. We then investigate the kinematics of the buoy, where we look at the relationship between the horizontal and vertical displacements of the buoy, and also attempt to numerically reconstruct the giant event using Boussinesq and nonlinear shallow water equations. Additional analyses are performed on other sea states where at least one of the buoy’s accelerometers reached its maximum limit. Our analysis reveals incompatibilities of the event with known behavior of real waves, leading us to conclude that it was not a real wave event. Wave events similar to the one reported in our study have been reported elsewhere and have sometimes been accepted as real occurrences. Our methods of forensically analyzing the giant wave event should be potentially useful for identifying false rogue wave events in these cases.

Variability of wave power production of the M4 machine at two energetic open ocean locations: Off Albany, Western Australia and at EMEC, Orkney, UK

Since intermittent and highly variable power supply is undesirable, quantifying power yield fluctuations of wave energy converters (WECs) aids with assessment of potential deployment sites. This paper presents analysis of 3-hourly, monthly, seasonal, and inter-annual variability of power output of the M4 WEC. We compare expected performance from deployment at two wave energy hotspots: off Albany on the south-western coast of Australia and off the European Marine Energy Centre (EMEC) at Orkney, UK. We use multi-decadal wave hindcast data to predict the power that would have been generated by M4 WEC machines. The M4 machine, as a floating articulated device which extracts energy from flexing motion about a hinge, is sized according to a characteristic wavelength of the local wave climate. Using probability distributions, production duration curves, and coefficients of variation we demonstrate larger variability of the 3-hourly power yield at Orkney compared to Albany. At longer timescales, seasonal trends are highlighted through average monthly power values. From a continuity of supply perspective, we investigate occurrences of low production at three different threshold levels and calculate duration and likelihood of such events. Orkney is found to suffer from more persistent lows, causing a more intermittent power output. We also consider the effect of machine size on its power performance. Smaller machines are found to more effectively smooth out the stochastic nature of the underlying wave resource.

Dietary characteristics of the ecologically-important fish species Centroberyx gerrardi, including discussion of resource partitioning among species of Berycidae in Australia

Data for the Berycidae, collected during extensive past scientific surveys, were used to quantify the depth distributions of the four species of Centroberyx and two of Beryx found in Australian coastal waters and thus elucidate the extent to which these species are partitioned by region and depth. The dietary, jaw and dentitional characteristics of the ecologically and fishery-important Centroberyx gerrardi were then determined, providing the first such account for any Centroberyx species. While Centroberyx gerrardi, Centroberyx lineatus, Beryx splendens and Beryx decadactylus are found throughout southern Australia, the last two species extend further up the west and east coasts. Centroberyx australis occurs on the lower half of the west coast eastwards to the central south coast and Centroberyx affinis on the lower half of the east coast. The four Centroberyx species typically occur at depths <350 m and the two Beryx species at >350 m. On the south coast of Western Australia, depth distributions undergo an overlapping progressive gradation, from C. lineatus in inshore and nearshore shallow waters, to C. gerrardi and C. australis in nearshore deep waters, and then B. splendens and B. decadactylus in offshore deep waters. The main dietary categories of C. gerrardi change with increasing body size from crabs and isopods in small fish to teleosts in the largest fish, in which volumetrically they constituted >60% of the stomach contents. The wide range of teleost prey (at least 39 species from 33 families) ingested by C. gerrardi would be valuable to this species if continuing climate change or other anthropogenic effects lead to alterations in the composition of potential prey. Differences between depth distributions account for the fish prey of C. gerrardi comprising nearshore species, such as those of clupeids, congrids, pomacentrids and platycephalids, whereas those of B. splendens (from studies elsewhere) are dominated by myctophids, which are abundant in deeper waters. The combination of a large mouth and numerous, exclusively small teeth (edentulate morphotype) strongly suggest that C. gerrardi is a suction feeder adapted to engulfing larger prey. While the co-occurring and likewise commercially-fished Oplegnathus woodwardi also ingests substantial volumes of crabs and teleosts, its diet is distinguished from C. gerrardi by large volumes of poriferans and appreciable volumes of echinoderms, likewise reflecting feeding specialisations. Although differing in depth distributions and dietary compositions, berycid species in general are close to the apex of the food web.

The Beauty of Terror

For several decades I had a series of recurring numinous dreams about drowning and tidal waves. Curious about their symbolic significance, and inspired by Jung’s theory of archetypes, I responded imaginally to a spectacular wild site known as “The Gap” on the south coast of Western Australia. I chose this site because—as a physical equivalent of the abyss and an imaginal embodiment of the Void—it elicited similar emotional responses to my numinous dreams. This is an account of my journey as I peered into that physical void and entered an imaginal one.

Mafic intrusions in southwestern Australia related to supercontinent assembly or breakup?

Variably oriented dolerite intrusions outcrop in the Albany–Fraser Orogen along the south coast of Western Australia with previously unknown ages but where previous studies interpreted Mesoproterozoic to Cretaceous emplacement. Here, we place temporal constraints on seven mafic intrusions across ∼150 km of coast using zircon U–Pb, apatite U–Pb, and plagioclase 40Ar/39Ar geochronology, coupled with whole-rock major and trace-element geochemistry, that reveal late Mesoproterozoic to potentially Early Cretaceous crystallisation ages. Three intrusions metamorphosed to greenschist facies are likely associated with either the emplacement of the ca 1210 Ma Marnda Moorn large igneous province or Stage II Albany–Fraser Orogeny, both of which were associated with the assembly of Rodinia. Three unmetamorphosed dykes have (probable) Neoproterozoic to lower Cambrian emplacement ages, likely associated with the ca 550–500 Ma Kuunga Orogeny during Gondwana assembly. The final sill, also unmetamorphosed, strikes perpendicular to the other six intrusions, shows unusual Pb anomalies and contains inherited zircon that has been reset by a Permian or younger event, pointing towards magmatism in southwestern Australia during the breakup of Gondwana. The new results provide hitherto unrecognised mafic intrusive evidence for modification of Proterozoic crust, potentially associated with Rodinia assembly, Gondwana assembly and Gondwana breakup in southwestern Australia. KEY POINTS Variably oriented mafic dykes in southwest Australia are dated by zircon U–Pb, apatite U–Pb and plagioclase 40Ar/39Ar methods. The dykes are related to Rodinia assembly (ca 1200 Ma), Gondwana assembly (ca 550 Ma) and, probably, Gondwana breakup (ca 135 Ma). These new ages provide evidence for mafic activity clearly linked to the supercontinent cycle.

Salted mullet: Protracted occurrence of Mugil cephalus under extreme hypersaline conditions

The fish faunas of eight estuaries along 130 km of the south coast of Western Australia were sampled seasonally for one year, during which Beaufort Inlet became markedly hypersaline (salinities up to 122 and > 100 for six months). These conditions were caused by a combination of low amounts of saline river flow, the bar of this shallow estuary remaining closed for 27 months and high rates of evaporation. Fish faunas in the nearshore, shallow and offshore, deeper waters of Beaufort Inlet were depauperate compared to nearby estuaries. The number of fish species declined as salinity increased, with the highly euryhaline, estuarine-resident atherinid Atherinosoma elongata being the only species to survive throughout the study. The cosmopolitan flathead mullet Mugil cephalus survived for the next longest period, living in salinities in excess of 100 for at least four months and in a maximum salinity of 122. This is the highest known salinity in which a marine-spawning fish species has been found globally. This finding provides support for the cryptic species complex hypothesis pertaining to M. cephalus and that individuals in south-western Australia may be a seperate species. The survival of these species for a relatively protracted time reflects the fact that they are euryhaline and have a suite of adaptations that allow them to occupy environments from freshwater to extreme hypersaline conditions. The longer occurrence of M. cephalus in the extreme salinities than Acanthopagrus butcheri and Aldrichetta forsteri, is likely also related to their primary diet of detritus, particulate organic matter and diatoms, all of which are abundant in Beaufort Inlet. In contrast, piscivorous and zoobenthivorous fish were depauperate and in low abundances, which may reflect limited food resources during hypersaline conditions, and/or more reduced euryhalinity by these species. Clearly, hypersalinity has a marked effect on the faunas and thus ecosystem functioning of estuaries, and with declines in rainfall and hotter temperatures projected in future climate change scenarios, more estuaries are likely to become increasingly hypersaline.

New records of the diving beetle Rhantus simulans R&amp;eacute;gimbart, 1908 in south-western Australia (Coleoptera, Dytiscidae, Colymbetinae)

New distributional records of the rarely collected diving beetle Rhantus simulans R&amp;eacute;gimbart, 1908, an endemic species of south-western Australia, are presented. We also summarize what is known about its habitat. The occurrence of R. simulans indicates a high conservation value of the sampled wetland. For easier identification, we provide photographs of the habitus and male genitalia of R. simulans and R. suturalis (Macleay, 1825). Rhantus simulans is now recorded from 17 localities along the coast of south-western Australia. Furthermore, data on the location of other 31 diving beetle species are provided.

Evaluating candidate wetlands for the assisted colonization of the western swamp turtle Pseudemydura umbrina in a changing climate: Macro‐invertebrate food resources and turtle diet

Abstract The natural habitat of the western swamp turtle (Pseudemydura umbrina Siebenrock, 1901) – the ephemeral, winter wet swamps north of Perth, Australia – is in danger owing to climate change and habitat fragmentation. The decline in rainfall in this area over the last five decades is predicted to continue, shortening the annual activity period for the turtles and potentially shifting their optimal climate zone to the south. Assisted colonization to wetlands in the cooler far south west of the state is one management response. As a contribution to such a measure, the diversity and abundance of food resources and consumption by turtles were evaluated at two potential and one existing colonization site. Thirty‐five captive‐bred juvenile P. umbrina were temporarily released into three sites: Moore River Nature Reserve north of Perth (into which the species had already been successfully translocated) and Meerup and East Augusta in the cooler far south of Western Australia. Food resources were assessed using sweep nets to sample invertebrates on two occasions at each wetland. Separate samples were collected for biomass determination and for assessing invertebrate diversity. Feeding by turtles was assessed by stomach flushing. Neither biomass nor biodiversity differed significantly between the southern sites and the reference site north of Perth. Stomach contents varied greatly, from 0 to 62 animals per turtle. The main prey items were beetles, ostracods, isopods and tadpoles. Each candidate wetland provided adequate food resources, indicating that assisted colonization to the cooler south coast of Western Australia has the potential to become a reasonable conservation tool to ensure the long‐term survival of P. umbrina.

Soil Management Systems to Overcome Multiple Constraints for Dryland Crops on Deep Sands in a Water Limited Environment on the South Coast of Western Australia

Deep sands on the south coast sandplain of Western Australia (WA) have multiple soil constraints including water repellence, high soil strength, low nutrient levels and subsoil acidity. The aim of the study was to test contrasting methods of managing water repellence and to assess their impacts on one or more soil constraints to crop production. These methods included seeding tyne design (knife point, winged points, paired row), soil wetting agent addition, strategic inversion tillage (rotary spading, mouldboard ploughing to 0.35 m) and clay-rich subsoil addition (170 t ha−1 with incorporation by spading to 0.20 or 0.35 m). Limesand (2 t ha−1) was applied as a split plot treatment prior to tillage. Cumulative crop yields were increased by 2.1–2.6 t ha−1 over five years by the strategic deep tillage and clay application treatments compared to the control. Water repellence was reduced by the inversion ploughing and subsoil clay addition treatments only. The effect of water repellence on crop establishment was expressed only in low rainfall years (Decile &lt; 4) and mitigated by the paired row, wetting agent, spader and clay-amended treatments. In all years, plant numbers were adequate to achieve yield potential regardless of treatment. Soil K and plant tissue K and B were increased where clay had been applied. Inversion tillage reduced soil pH, organic carbon (OC) and macro nutrients in the 0–0.1 m layer although in most years there was no significant decline in plant tissue macro nutrient levels. Soil strength was reduced as a result of the inversion tillage to a depth of 0.35 m. However, the alleviation of soil strength and the crop yield responses diminished with time due to re-compaction. No crop response to the applied lime was found over five years at this site since the soil pHCaCl2 exceeded 4.7 within the root zone. In terms of soil constraints, we conclude that compaction was the dominant constraint at this site followed by water repellence and K deficiency.

Assisted colonisation trials for the western swamp turtle show that juveniles can grow in cooler and wetter climates

Species with restricted ranges and long generation times are vulnerable to climate change due to limited opportunity to disperse or adapt. Australia’s rarest reptile, the western swamp turtle Pseudemydura umbrina, persists naturally in only one seasonal swamp that holds water in the Austral winter and spring. A marked reduction in winter rainfall in recent decades has shortened the swamp hydroperiod, restricting when turtles are able to feed, grow and reproduce. To mitigate possible future loss of reproductive capacity in the native habitat, assisted colonisation was trialled in 2016 using 35 captive-bred juveniles. Here, we report the outcomes of this 6 mo trial, which compared the growth of turtles released approximately 300 km south of the species’ indigenous range with growth of turtles released at an existing northern translocation site. We showed that growth rates comparable to those at warmer northern translocation sites can be achieved in the south, even in an atypically cool spring as occurred in 2016. Microclimates available to P. umbrina at 2 southern sites were suitable for foraging and growth in late spring and early summer, but juvenile growth at one southern site was significantly better than at the other, likely due to higher prey biomass when water temperatures were suitable for foraging. These early results suggest that introduction of P. umbrina to seasonal wetlands near the south coast of Western Australia could be considered in the immediate future, but further trials are recommended to assess growth and survivorship over longer periods.

Integrating feral cat (Felis catus) control into landscape-scale introduced predator management to improve conservation prospects for threatened fauna: a case study from the south coast of Western Australia

Abstract ContextFeral cat predation has had a significant impact on native Australian fauna in the past 200 years. In the early 2000s, population monitoring of the western ground parrot showed a dramatic decline from the pre-2000 range, with one of three meta-populations declining to very low levels and a second becoming locally extinct. We review 8 years of integrated introduced predator control, which trialled the incorporation of the feral cat bait Eradicat® into existing fox baiting programs. AimsTo test the efficacy of integrating feral cat control into an existing introduced predator control program in an adaptive management framework conducted in response to the decline of native species. The objective was to protect the remaining western ground parrot populations and other threatened fauna on the south coast of Western Australia. MethodsA landscape-scale feral cat and fox baiting program was delivered across south coast reserves that were occupied by western ground parrots in the early 2000s. Up to 500000ha of national parks and natures reserves were baited per annum. Monitoring was established to evaluate both the efficacy of landscape-scale baiting in management of feral cat populations, and the response of several native fauna species, including the western ground parrot, to an integrated introduced predator control program. Key resultsOn average, 28% of radio-collared feral cats died from Eradicat® baiting each year, over a 5-year period. The results varied from 0% to 62% between years. Changes in site occupancy by feral cats, as measured by detection on camera traps, was also variable, with significant declines detected after baiting in some years and sites. Trends in populations of native fauna, including the western ground parrot and chuditch, showed positive responses to integrated control of foxes and cats. ImplicationsLandscape-scale baiting of feral cats in ecosystems on the south coast of Western Australia had varying success when measured by direct knockdown of cats and site occupancy as determined by camera trapping; however, native species appeared to respond favourably to integrated predator control. For the protection of native species, we recommend ongoing baiting for both foxes and feral cats, complemented by post-bait trapping of feral cats. We advocate monitoring baiting efficacy in a well designed adaptive management framework to deliver long-term recovery of threatened species that have been impacted by cats.

A rare capture of two Japanese rubyfish (

Due to advances in fish-finding equipment and vessel capabilities, commercial and recreational fishers are now regularly accessing deep waters off the edge of the continental shelf and catching fish species that are rarely encountered in shallower waters or that have not previously been caught. This study details the capture of two Japanese rubyfish (Erythrocles schlegelii) in deep, offshore waters on the south coast of Western Australia, and in waters further south than previously encountered. This study also provides the first age estimates from counts of growth (opaque) zones in sectioned sagittal otoliths. The estimated ages of 8 years for both individuals, one female and the other male, are much lower than what would have been expected based on age estimates for this species derived from scales undertaken in an earlier study. Understanding the biological characteristics of these deepwater fish species will assist in future management of these resources.

Non-Linear Modes of Narrative in the Disruption of Time and Genre in Ambelin Kwaymullina’s &lt;em&gt;The Interrogation of Ashala Wolf&lt;/em&gt;

Non-Linear Modes of Narrative in the Disruption of Time and Genre in Ambelin Kwaymullina’s &lt;em&gt;The Interrogation of Ashala Wolf&lt;/em&gt;

Find a match with triple-dating: Antarctic sub-ice zircon detritus on the modern shore of Western Australia

In this work we present a novel zircon triple-dating approach (Lu-Hf – U-Pb – (U-Th)/He), complimented with grain shape and trace element chemistry to test models of trans-continental transport of ultimately Gondwana interior derived detritus. Our integrated fingerprinting approach on single zircon grains provides the opportunity for robust source correlations as each isotopic system provides temporal constraints on distinct geological processes, ranging from source age (Lu-Hf), through crystallization age (U-Pb) to exhumation age ((U-Th)/He). Collectively, this detailed level of grain characterisation is much more diagnostic of source region than any single tracer alone, and together with grain shape, helps to constrain intermediate detrital grain histories between source and sink. Applying this approach to an enigmatic detrital zircon population from a modern beach sand on the south coast of Western Australia reveals a dominant 700-500 Ma U-Pb component, with a bimodal Hf-isotope composition and Silurian (U-Th)/He cooling age, all of which is strongly correlated with inferred sub-ice basement of East Antartica and the geodynamic setting of unexposed components of the Kuunga Orogen. Our work points towards multicycle sediment processing, and ongoing reworking of poorly known supra-Yilgarn Craton vestiges of Antarctica-derived sediment that became isolated during Cretaceous break-up of East Gondwana. Furthermore, Hf isotopes in these zircon grains suggest that the Kuunga Orogen in Antarctica was rooted on Archean crust.