Cooloola Sand Mass Research Articles

Reconstructing Holocene fire records using dune footslope deposits at the Cooloola Sand Mass, Australia

AbstractIn this study, we assess charcoal records from eolian deposits within the Cooloola Sand Mass, a subtropical coastal dune system in eastern Australia, to determine whether they can be used as a proxy for Holocene fire history. We excavate four profiles in depositional wedges at the base of dune slipfaces (footslope deposits) and calculate charcoal concentrations for three size classes (180–250 μm, 250–355 μm, and 355 μm–2 mm) at predetermined depth intervals. Age–depth models are constructed for each profile using radiocarbon measurements (n = 46) and basal optically stimulated luminescence ages (n = 4). All records appear intact with little evidence of postdepositional mixing as demonstrated by minimal age reversals and consistent trends in charcoal concentration and accumulation rates (CHAR) among size classes. Combining all four records, we generate a ca. 7 cal ka BP terrestrial fire history that depicts distinct peaks representing periods of increased local fire activity at <0.3, 1.1–0.4, 2.2–1.6, 3.4–2.6, and 6.7–5.3 cal ka BP. Our findings parallel regional records and highlight the utility of dune footslopes as ecological and sedimentary archives. As dune fields are much more common than wetlands and lakes in semiarid and arid areas, these deposits have the potential to increase the spatial resolution of fire records globally.

Fraser Island (K'gari) and initiation of the Great Barrier Reef linked by Middle Pleistocene sea-level change

The eastern Australia coastline is characterized by impressive coastal landforms and an extensive northward-moving longshore drift system that have been influenced by a stable, long-term tectonic history over the Quaternary period. However, the timing and drivers of the formation of two conspicuous landscape features—Fraser Island (K’gari) and the Great Barrier Reef—remain poorly understood. Here we use optically stimulated luminescence and palaeomagnetic dating to constrain the formation of the extensive dunes that make up Fraser Island, the world’s largest sand island, and adjacent Cooloola Sand Mass in southeastern Queensland. We find that both formed between 1.2 Ma and 0.7 Ma, during a global climate reconfiguration across the Middle Pleistocene transition. They formed as a direct result of increased amplitude of sea-level fluctuations associated with increasing global ice volume that redistributed previously stored sediment across the continental shelf. The development of Fraser Island dramatically reduced sediment supply to the continental shelf north of the island. This facilitated widespread coral reef formation in the southern and central Great Barrier Reef and was a necessary precondition for its development. This major reorganization of the coastal sedimentary system is probably not unique to eastern Australia and should be investigated in other passive-margin coastlines.

Using calibrated surface roughness dating to estimate coastal dune ages at K'gari (Fraser Island) and the Cooloola Sand Mass, Australia

AbstractHere we present a novel application of landscape smoothing with time to generate a detailed chronology of a large and complex dune field. K'gari (Fraser Island) and the Cooloola Sand Mass (CSM) dune fields host thousands of emplaced (relict) and active onlapping parabolic dunes that span 800 000 years in age. While the dune fields have a dating framework, their sheer size (~1930 km2) makes high‐resolution dating of the entire system infeasible. Leveraging newly acquired (n = 8) and previously published (n = 20) optically stimulated luminescence (OSL) ages from K'gari and the CSM, we estimate the age of Holocene dunes by building a surface roughness (σC)–age relationship model. In this study, we defineσCas the standard deviation of topographic curvature for a dune area and we demonstrate an exponential relationship (r2 = 0.942, RMSE = 0.892 ka) betweenσCand timing of dune emplacement on the CSM. This relationship is validated using ages from K'gari. We calculateσCutilizing a 5 m digital elevation model and apply our model to predict the ages of 726 individually delineated Holocene dunes. The timing of dune emplacement events is assessed by plotting cumulative probability density functions derived from both measured and predicted dune ages. We demonstrate that both dune fields had four major phases of dune emplacement, peaking at <0.5, ~1.5, ~4, and ~8.5 ka. We observe that our predicted dune ages did not create or remove major events when compared to the OSL‐dated sequence, but instead reinforced these patterns. Our study highlights thatσC–age modelling can be an easily applied relative or absolute dating tool for dune fields globally. This systematic approach can fill in chronological gaps using only high‐resolution elevation data (3–20 m resolution) and a limited set of dune ages.

Measuring landscape evolution from inception to maturity: Insights from a coastal dune system

The concept of the geomorphic cycle is a foundational principle in geology and geomorphology, but the topographic evolution of a single landscape from inception to maturity has been difficult to demonstrate in nature. The onlapping dunes of the Cooloola Sand Mass (CSM) in eastern Australia provide an ideal chronosequence to evaluate landscape evolution. Here commonly assumed properties on which landscape models are based (i.e., conservation of mass and major factors contributing to landscape change) can be physically measured and accounted for. Our field based measurements and forward numerical models demonstrate that dunes, like other landscapes, relax in an exponential manner. The emplaced dunes evolve through an initial phase of rapid topographic adjustment associated with the dominance of landsliding. This phase continues for ∼1 kyr until hillslope gradients are lowered below their angle of repose (0.65 m m−1 or 33°). Once sufficiently lowered, the dunes evolve through slow, soil creep processes. These findings of dual transport regimes are validated by stratigraphic records at all excavated dune foot-slopes and we propose that this evolution can be measured by the distribution of curvature (C) of a landform, specifically its standard deviation (σC), as a measure of surface roughness. Surface roughness smooths with time through diffusional sediment transport that lowers local relief. The value and its rate of smoothing can define the stage in evolutionary development and help infer processes, which makes it an important morphometric tool for understanding landscapes. These observations highlight that under stable evolutionary conditions, the development of the landscape is governed by the physical properties of the dune's parent material. In addition, our findings support landscape evolution inferences from numerical and physical models and the coupling of granular material physics with landscape change.

Holocene evolution of a barrier-spit complex and the interaction of tidal and wave processes, Inskip Peninsula, SE Queensland, Australia

This paper presents a reconstruction of the Holocene evolution of the Inskip Peninsula in SE Queensland. The peninsula links two major dune fields, the Cooloola Sand Mass to the south and K’gari (Fraser Island) to the north. Geomorphic features of this peninsula include remnant parabolic dunes, numerous beach ridges with foredunes, and a series of spits. Together these features provide insight into Holocene coastal evolution and changing marine conditions. A remnant beach ridge/foredune complex at the northern portion of Inskip may have been connected to K’gari and a river/tidal channel near Rainbow Beach township which separated it from the Cooloola Sand Mass to the south. This channel avulsed northward in the early mid-Holocene (after 8.8 ka) with spit development from the south. This was followed by a phase of beach-ridge/foredune complex development that started by ~6.7 ka. Stratigraphic evidence from the highest and best developed parabolic dunes in the northern portion of Inskip Peninsula indicates dune development from the mid-Holocene beach complex by 4.8 ka. Beach ridges with foredunes continued to prograde but notably declined in size during the late-Holocene. In the latest Holocene (<4.8 ka) many of the late-Holocene beach ridges/foredune complexes have been truncated by a re-orientation of the shoreline and longshore sediment transport has promoted the growth of the modern spit at the northern end of the peninsula. Erosive and longshore processes continue to be highly active because of tidal interactions between Great Sandy Strait and the Coral Sea. This detailed study of Inskip Peninsula’s evolution aids significantly in future coastal management decisions, and provides evidence for World Heritage Area extension for the Cooloola Sand Mass, including the incorporation of Inskip Peninsula itself. It also contributes to the global understanding to coastal evolution in an area of strong wave and tidal interaction.

The Teewah Transect: GPR-Derived Insights into the Younger Dune Morphosequences on the Great Sandy Coast, Queensland, Australia

Gontz, A.; McCallum, A.; Ellerton, D.; Patton, N., and Shulmeister, J., 2020. The Teewah Transect: GPR-Derived Insights into the Younger Dune Morphosequences on the Great Sandy Coast, Queensland, Australia. In: Malvarez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 500-504. Coconut Creek (Florida), ISSN 0749-0208. The world's largest sand islands lie off the coast of southeast Queensland, Australia. Between these islands, mainland coastal sand masses, bedrock promontories and rivers exist in low-lying areas. Sediment is sourced from one of the world's longest downdrift systems, transporting sand eroded from sandstones in New South Wales north over 1000 km. Recent work has shown the coastal dune fields have been periodically active for the last million years, at times of high and intermediate sea-levels, and identified a series of aeolian morphosequences that exhibit an onlapping relationship with evidence of significant reworking of more seaward morphosequences to create more landward low-relief aeolian landscapes. In 2012, a campaign that collected over 300 km of ground penetrating radar data was begun to understand the stratigraphic framework of this sand-rich system.. One of the surveys acquired a transect over the dune environment of the southern tip of the Cooloola Sand Mass near the town of Teewah. At this location, the dune field narrows to less than 1.5 km with 20-25 m of relief. The seaward side is characterized by eroding dunes and high bluffs. Moving inland over the highest portion of the dune field, the landscape slopes gently to a near sea level with a pluvial-fluviallacustrine dominated system that drains directly to the Noosa River and the Coral Sea. GPR surveys revealed a complex stratigraphy including primary sediment structures related to aeolian processes overprinted with podzol soil development resulting in post depositional features that range from well-developed soil sequences to incipient horizons. Recent GIS mapping has identified this area as consisting of primarily Holocene systems. The Teewah Transect is presented as a case study demonstrating a spatial relationship of the morphosequences and examines the aeolian-soil relationships at the far southern tip of the Cooloola Sand Mass.

An 800 kyr record of dune emplacement in relationship to high sea level forcing, Cooloola Sand Mass, Queensland, Australia

The Cooloola Sand Mass is a large coastal dune field situated in southeast Queensland, Australia and is part of a much larger system of coastal dune fields, including the world's largest sand Island, Fraser Island, as well as Moreton Island and Stradbroke Island. Cooloola is characterised by a sequence of onlapping, parabolic dune units that have been emplaced episodically over the Pleistocene and Holocene. The tectonically stable coastline of SE Queensland is an ideal area to study the driving mechanisms of coastal dune development, as sea level variability is driven primarily by glacial eustasy. Geomorphic and chronostratigraphic analyses have identified seven major periods of dune activity with the earliest phase of deposition occurring ca. 800 ka. Subsequent periods of dune emplacement date to about ca. 150 ka, 110 ka, 10–6 ka, 5–3.5 ka, ca. 2 ka and 0.4–0.2 ka.The Holocene dune activity coincides with the last stages of post-glacial marine transgression and suggests these large parabolic dunes formed in response to rising sea levels. It is likely that this pattern is consistent through the Pleistocene, and the MIS 5 interglacial period is also recorded. For earlier events the large absolute errors on the ages make interpretation difficult. There is a notable absence of OSL ages dating to the Last Glacial Maximum and no ages that are unambiguously associated with lowstand periods. This is most likely because the coast would have been 60 km offshore of its current position during lowstands, limiting sediment supply and wind energy at the modern coast. These results provide strong evidence that coastal dune fields in SE Australia are predominantly emplaced during sea-level rise, as originally proposed in the Cooper-Thom model.

Rapid Assessment of Shoreline Changes Induced by Tropical Cyclone Oma Using CubeSat Imagery in Southeast Queensland, Australia

Kelly, J.T. and Gontz, A.M., 2020. Rapid assessment of shoreline changes induced by Tropical Cyclone Oma using CubeSat imagery in southeast Queensland, Australia. Journal of Coastal Research, 36(1), 72–87. Coconut Creek (Florida), ISSN 0749-0208.Tropical Cyclone Oma hit the SE Queensland coast of Australia in February 2019. Significant wave heights exceeding 10 m were further amplified by a king tide. Satellite remote sensing of pre- and post-Oma shoreline positions was performed because storms hindered the ability to acquire field-based data. The high spatial and temporal resolution of PlanetScope imagery enabled mapping of the high water line (HWL), which was used as a shoreline indicator across 200 km of shoreline. Given that this is the first use of PlanetScope imagery to map shoreline positions, the positional uncertainty was assessed. Comparison to a temporally coincident, LIDAR-derived mean high water (MHW) shoreline at a distant site showed an average horizontal offset of 9 m with the HWL shoreline. The Oma-affected shoreline uncertainty ranged between ±13.86 and 23.28 m, primarily influenced by the geometric accuracy of the data used, as well as the pixel size of the imagery and the horizontal offset between the HWL and MHW elevations. The net shoreline movement (NSM) was calculated every 200 m along the study area by the Digital Shoreline Analysis System. Only transects with NSM values greater than the uncertainty of their associated shoreline compartment were used to assess change. The spatial distribution of erosion and accretion was similar across the SW–NE-oriented shorelines as the southern ends of Fraser Island and the Cooloola Sand Mass eroded while their northern ends prograded. Wave data shows that the wave direction rapidly shifted 56° in an anticlockwise direction during Oma. Wave propagation came primarily from the SE, and the direction of longshore transport likely turned northward, leading to the shoreline rotation observed in the imagery. This study demonstrates the significant improvement on assessments of regional-scale shoreline changes in the aftermath of an episodic event using new satellite products.

High-resolution remapping of the coastal dune fields of south east Queensland, Australia: a morphometric approach

ABSTRACT The sand islands and shore-attached dune fields of south east Queensland form the world’s oldest and largest coastal sand dune system. Here we present updated morphological maps for the dune fields based on topographic expression and geomorphic relationships. Individual dunes were delineated using high-resolution elevation data and were grouped into morphosequences based on the elevation, drainage characteristics and slope characteristics of the individual dunes. The slope characteristics focussed on high resolution derived slope-curvature and slope-elevation parameters. Morphosequences were recognised from cross-cutting relationships and relative position in the dune field. Our method was developed for the Cooloola Sand Mass and then applied to Fraser Island, Moreton Island and North Stradbroke Island, the other major sand islands in south east Queensland. In total, five Holocene and four Pleistocene units have been identified. The new mapping underpins current work on the geomorphic evolution of the dune fields.

Bimodal climate control of shoreline change influenced by Interdecadal Pacific Oscillation variability along the Cooloola Sand Mass, Queensland, Australia

Wave climate in southeast Queensland, Australia has been correlated to changes in the Southern Oscillation Index (SOI), but observations of shoreline change associated with the variable wave climate have been limited due to a paucity of aerial photography, LiDAR, and other beach profiling datasets in this region. A multi-decadal, sub-annual temporal resolution shoreline dataset spanning 1996 to 2017 was produced using satellite imagery collected by Landsat 5, 7, and 8. A total of 147 shoreline positions were delineated using the Modified Normalized Difference Water Index on cloud-free imagery and corrected for horizontal offsets forced by variable tide stages at the satellite flyover time. The relative influence of SOI, the Southern Annular Mode (SAM), Pacific Decadal Oscillation (PDO), and Subtropical Ridge Latitude (STR-L) and Pressure (STR-P) on shoreline dynamics along the Cooloola Sand Mass in Queensland are assessed by performing cross correlations between their respective index values and shoreline change distances calculated by the Digital Shoreline Analysis System. A bimodal climate control of shoreline change is observed dependent upon the phase of the Interdecadal Pacific Oscillation (IPO). IPO modulates the impacts of ENSO on eastern Australia through its control over the position of the South Pacific Convergence Zone and elevating/lowering of tropical Pacific sea surface temperatures. During negative IPO, SOI is negatively correlated to the Cooloola Sand Mass shoreline indicating that the shoreline retreats during negative SOI phases. During positive IPO, the impacts of SOI are weakened and the STR becomes the primary driver of shoreline change with shoreline response being contingent upon its orientation. The SW-NE aligned Noosa North shoreline erodes in response to poleward movement of the STR, likely due to the enhanced cross-shore wave attack as a result of anti-clockwise wave rotation. The opposite response is shown at the SE-NW aligned Rainbow Beach shoreline, which is oriented almost parallel to the incident wave direction and is sheltered by the Double Island Point headland. These results suggest that climate control on shoreline change at Cooloola Sand Mass, and likely other sand islands in the region, is two-tiered, whereby interdecadal variability of the IPO governs the relative influence of SOI and STR under the different IPO phases. The linked climate and shoreline variability correlation shown in this study provides significant insight into how the Cooloola Sand Mass shoreline will respond to future climate changes under a global warming scenario.

Geomorphology of the Inskip Peninsula, Queensland, Australia

ABSTRACT The Inskip Peninsula is the link between two major coastal dune fields; Fraser Island (the world’s largest sand island) and the adjacent Cooloola Sand Mass. There has been a notable lack of research into the geomorphology of the sand masses and the relationship between the two dunefields. This paper presents a detailed geomorphological map of the Inskip Peninsula at a scale of 1:10,000. The Peninsula can be divided into three parts; an eastern section dominated by late Holocene strandlines and foredunes with an active spit at the northern limit of the peninsula; a central zone composed of broader foredune ridges and swales and an eastern zone comprised of remnants of older parabolic sand dunes and foredune remnants. The map provides a framework for ongoing work on landscape reconstruction.

Late-Holocene cliff-top blowout activation and evolution in the Cooloola Sand Mass, south-east Queensland, Australia

Cliff-top dunes are a locally important geomorphic features of sedimentary coasts. They are traditionally interpreted as being sourced by (or with) sand derived from the beach below the cliff. This paper presents the results of a stratigraphic and geochronological study of Carlo Sand Blow, a coastal blowout that has developed on top of a high sandy cliff in the Cooloola Sand Mass, south-east Queensland. We use a combination of sedimentological, pedological and geophysical techniques along with optically stimulated luminescence dating to determine the depositional history and evolution of the blowout. We demonstrate that the blowout is dominantly nourished by sand eroded from its floor rather than the adjacent beach. The original dune surface dates to the first half of the last glacial period (c. 40–70 ka) and this dune was deflated in the late-Holocene. Dune activity is directly associated with cliff undercutting because of coastal retreat in the late-Holocene, but coastal erosion on its own is not capable of maintaining aeolian activity. Blowout activity occurred between 2.6 and 2.3 ka and again at 0.3 ka with aeolian sand burying palaeosols. Both soil surfaces contained charcoal and tree stumps in growth position and our study suggests that fire is the immediate trigger for blowout reactivation. It is likely that these fires were anthropogenic in origin, because the site is somewhat protected from natural fire and the ages coincide with intensification of human use of coastal sites in the area.

Patterned fen formation and development from the Great Sandy Region, south-east Queensland, Australia

The Great Sandy Region (incorporating Fraser Island and the Cooloola sand-mass), south-east Queensland, contains a significant area of Ramsar-listed coastal wetlands, including the globally important patterned fen complexes. These mires form an elaborate network of pools surrounded by vegetated peat ridges and are the only known subtropical, Southern Hemisphere examples, with wetlands of this type typically located in high northern latitudes. Sedimentological, palynological and charcoal analysis from the Wathumba and Moon Point complexes on Fraser Island indicate two periods of swamp formation (that may contain patterned fens), one commencing at 12 000 years ago (Moon Point) and the other ~4300 years ago (Wathumba). Wetland formation and development is thought to be related to a combination of biological and hydrological processes with the dominant peat-forming rush, Empodisma minus, being an important component of both patterned and non-patterned mires within the region. In contrast to Northern Hemisphere paludifying systems, the patterning appears to initiate at the start of wetland development or as part of an infilling process. The wetlands dominated by E. minus are highly resilient to disturbance, particularly burning and sea level alterations, and appear to form important refuge areas for amphibians, fish and birds (both non-migratory and migratory) over thousands of years.

Observations on the boletes of the Cooloola Sand-mass, Queensland and notes on their distribution in Australia: Part 3. Lamellate taxa

The lamellate boletes found in the Cooloola Sand-mass, Queensland are described and discussed in the light of earlier Australian records of paxilloid fungi. Nine species of Paxillus are discussed, two in Tapinella, which is maintained as a separate entity, and 11 are assigned to Phylloporus. Of the last, eight are new records to Australia and two are new species. Three appendices cover various aspects of studies on Australian boletes which have come to light since the publication of this series, including notes on the host-range of the parasitic hyphomycete Sepedonium.

SomeCortinarius spp. (Agaricales) of the Cooloola Sand-Mass, Queensland, Australia

Four distinct species ofCortinarius referable to subg.Dermocybe are described from the Cooloola Sand-Mass, Queensland; two are formally recognized asC. alkalivirens, spec. nova andC. chromobasis, spec. nova, whilst notes are provided for the other two. Chemical methods and cladistic studies are applied and indicate a new section of the subgenus is required.Australodermocybe sect. nova is proposed.

Morphological Differences in Lignotubers of Eucalyptus intermedia R.T. Bak. And E. signata F. Muell. Associated With Different Stages of Podzol Development on Coastal Dunes, Cooloola, Queensland

The sandmass at Cooloola comprises a series of overlapping aeolian dune systems that extend in age from the present back more than 100 000 years. Podzols are the dominant soils, forming a sequence from rudimentary through to giant forms, according to age. The lignotuber morphology of Eucalyptus signata and E. intermedia was examined within each dune system across the chronosequence, at sites in which most factors affecting plant growth (available soil water status, drainage, light, temperature, fire regimes, exposure to wind and/or salt spray) other than a declining soil nutrient supply were similar. Three lignotuber morphologies were identified: (1) a single-stemmed (SS) form; (2) a multi-stemmed (MS) form with stems originating from a lignotuber only slightly larger than a main stem; and (3) a multi-stemmed plate-like form (MSP) with individual stems separated and growing from a plate-like lignotuber. Multi-stemmed forms of the two eucalypts occur along the coastal margin and on the most nutrient- poor dunes; at all other sites single-stemmed forms are dominant. The most nutrient-poor site had only MS and MSP forms, whilst in sheltered areas the coastal margin had SS individuals. We conclude that in the Cooloola sandmass the development of multi-stemmed forms in both E. signata and E. intermedia may be induced by a variety of factors, including very low nutrient status, but the multi-stemmed plate-like form of E. intermedia is most likely a response to an exceptionally low nutrient supply.