Chronostratigraphy and geomorphology of washover fans in the Exmouth Gulf (NW Australia) – A record of tropical cyclone activity during the late Holocene

May, Simon Matthias; Brill, Dominik; Leopold, Matthias; Callow, Nik; Engel, Max; Scheffers, Anja; Opitz, Stephan; Norpoth, Maike; Brückner, Helmut

doi:10.1016/j.quascirev.2017.05.023

Cited by 29 publications

(54 citation statements)

References 81 publications

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“…This has supported a more informed approach to understanding conditions associated with TC events, fan topography and depositional processes, and in planning field sampling and prioritising collected field samples for dating May et al, 2017). This allows unique insight into the likely sequences of inundation and dynamics that control the sedimentary processes that have created this (and potentially other) washover landforms.…”

Section: Resultsmentioning

confidence: 95%

“…Beyond the scope of this paper is the presentation of detailed stratigraphic and dating evidence, which is the focus of the work by May et al (2017) and Brill et al (2017), but is supported by the work detailed in this paper. DSM).…”

Section: Introductionmentioning

confidence: 94%

“…TC Olwyn generated a storm surge of approximately 1 m and the storm tide peaked at 3.5 m AHD at the Exmouth tidal gauge (Western Australian Department of Transport, unpublished data), and May et al (2017) report storm surge elevations of 4.3 m AHD at the landward margin of supratidal mudflats in Giralia Bay. in the form of new sand lobes and/or erosion in the washover channel, along the western bank of the fan, and in the southern part of the central channel.…”

Section: Recent Washover Activitymentioning

confidence: 99%

“…The topographic inundation analysis using the DEM connectivity mapping ( Figure 5), while containing some uncertainties and simplifications, has made a significant contribution to informing where field efforts for dating and detailed stratigraphic analysis should be prioritised to investigate the contemporary or more recent history of the washover fan archives (see Brill et al, 2017;May et al, 2017). However, this approach requires detailed and site-specific sea level and wave height data during inundation events that can resolve the transition, timing, duration and nature of the 'overwash' inundation and transition to the 'inundation' regime and the associated flow velocities, connectivity sequence and sediment dynamics during such an event.…”

Section: Washover Fan Archive and Dynamicsmentioning

confidence: 99%

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Drone photogrammetry and KMeans point cloud filtering to create high resolution topographic and inundation models of coastal sediment archives

Callow

May

Leopold

2018

Earth Surf Processes Landf

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Coastal areas are vulnerable to the impacts of tropical cyclones (TC), tsunamis and other water super‐elevation events, but the frequency of these events is often poorly represented by conventional records. Coastal overwash deposits (including washover fans) can provide a longer‐term archive of event frequency. Because of their low‐gradient geomorphic form, washover fans require high accuracy (centimetre‐resolution) topographic models to understand patterns of connectivity and dynamics that control archive formation. Using images collected by a remotely piloted aircraft system (RPAS, or ‘drone’) and Structure‐from‐Motion (SfM) photogrammetry techniques, we apply a novel point‐cloud filtering technique based on KMeans classification of the R‐G‐B colour of each X‐Y‐Z point to remove vegetation and create a centimetre‐resolution and accuracy bare‐earth digital terrain model (DTM) of a washover fan in Exmouth Gulf (Western Australia). Using the RPAS‐SfM orphophoto and DEM data, supported by ground‐penetrating radar (GPR) and field stratigraphic analysis, we show how this approach can be applied to understand dynamics controlling low‐gradient geomorphic landforms, using an example of a washover fan sedimentary archive in northwestern Australia created by extreme overwash events. Our approach reveals the likely role of backflooding and terrestrial runoff in creating backwater environment for sub‐aqueous deposition and good sediment preservation and identifies key areas to target for detailed dating and stratigraphic analysis of a potentially decadal to sub‐millennial resolution sediment archive of TC activity. Copyright © 2018 John Wiley & Sons, Ltd.

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Section: Resultsmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 94%

Section: Recent Washover Activitymentioning

confidence: 99%

Section: Washover Fan Archive and Dynamicsmentioning

confidence: 99%

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Drone photogrammetry and KMeans point cloud filtering to create high resolution topographic and inundation models of coastal sediment archives

Callow

May

Leopold

2018

Earth Surf Processes Landf

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“…Major and rapid change is intrinsic to many coastlines, sometimes linked to El Nino Southern Oscillation (ENSO) or some other atmospheric-ocean interaction (Woodroffe & Murray-Wallace, 2014) as well as changes in the delivery and the coastal configuration of sediments (e.g., Lewis, Olley, Furuichi, Sharma, & Burton, 2014;Stanley & Clemente, 2017). Storms, tropical cyclones and other ENSO-related events can have an immediate impact on coastal geomorphology, water circulation, and ecology in coastal estuarine systems, because of inundation, barrier overwash or breaching (Hopley, 1974;Filgueira et al, 2013;May et al, 2017). In terms of coastal dynamics, key parameters include the intensity and repetition of those events that dictate whether the change is short-term or chronic.…”

Section: The Example Of Estuariesmentioning

confidence: 99%

Physical sedimentary controls on subtropical coastal and shelf sedimentary systems: Initial application in conceptual models and computer visualizations to support archaeology

Larcombe¹,

Ward

Whitley

2018

Geoarchaeology

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Advances in digital spatial analysis and 3D photorealistic modeling offer the potential to create virtual interpretations of the now inundated landscapes of NW Australia. While this provides a useful template for potential late Pleistocene and early Holocene coastal occupation on the shelf, we stress the importance of understanding sediment dynamics as a primary control for terrain modelling, particularly at the scale of human ecosystem dynamics. We briefly review six major drivers of change upon tropical and semi‐tropical continental shelves and coastlines, and some of the typical coastal geomorphologies associated with each. We then hypothesize how these drivers might have varied on the NW Shelf of Australia since 65 ka, and then apply the logic to the Barrow Island region, to form some “end‐member” visualizations of coastal change in the early Holocene. The visualizations indicate a high degree of variability in coastal morphology, particularly through the post‐glacial period, which is likely to have radically changed the capacity of the coastline to provide resources for human use during that period. Hence, rather than considering any single visualization as being absolute, end‐member visualizations should be used to generate testable hypotheses that are reviewed repeatedly in the light of new physical, environmental, and archaeological information.

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Reef island evolution in a turbid‐water coral reef province of the Indo‐Pacific

Bonesso

Cuttler

Mather

et al. 2023

The Depositional Record

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Coral reef islands are vulnerable landforms to environmental change. Constructed of largely unconsolidated reef‐derived sediments, they are highly sensitive to variations in metocean boundary conditions, raising global concern about their future resilience and stability in the face of increased natural hazards, sea‐level rise and anthropogenic climate change. This study examines the evolution of an inshore turbid reef island from the southern Pilbara region of Western Australia (Indo‐Pacific) using detailed analyses of island chronostratigraphy (composition, texture) and geochronology (21 in‐situ radiometric dates) from Eva Island. Downcore, composition of island‐grade (reef‐derived) sediments were homogenous, dominated by molluscan (37%–42%) and coral (32%–37%) constituents. The 14C radiometric dating of island sediments, beachrock and coral microatolls identified five stages of island formation across changing sea‐level regimes over the mid to late Holocene: (1) limestone platform accretion at ca 6,000 cal yr BP, coinciding with reef decline or ‘give‐up’ on neighbouring Exmouth Gulf reefs; (2) sand cay (i.e. core) initiation and vertical aggregation at ca 5,000 cal yr BP during the point of sea‐level regression to current levels; (3) major accretion and lateral progradation of the island between 3,500 cal yr BP and 2,500 cal yr BP including the modification of island shorelines through alongshore reworking of sediment; (4) lateral accretion and minor expansion to the north and formation of beachrock pavement between 2,500 and 650 cal yr BP; and (5) planform adjustment (erosion of the north‐west island) and backstepping under stabilised sea levels over the past 650 years. While this model is comparative to studies on island formation following incremental sea‐level fall following the mid‐Holocene highstand, it demonstrates active landform readjustment under stabilised sea levels over the past 2,000 years, probably the influence of local‐scale metocean boundary conditions within climate windows across the mid to late Holocene period (i.e. independent of sea‐level fluctuations). Importantly, while sediment production rates are predicted to be lower in turbid‐water reef systems than clear water, Eva Island shows no change in carbonate producers (i.e. proportion of mollusc and coral) over the course of island building, indicating the carbonate factory has not experienced significant adjustments in reef ecology, but has remained stable despite low water quality.

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Chronostratigraphy and geomorphology of washover fans in the Exmouth Gulf (NW Australia) – A record of tropical cyclone activity during the late Holocene

Cited by 29 publications

References 81 publications

Drone photogrammetry and KMeans point cloud filtering to create high resolution topographic and inundation models of coastal sediment archives

Drone photogrammetry and KMeans point cloud filtering to create high resolution topographic and inundation models of coastal sediment archives

Physical sedimentary controls on subtropical coastal and shelf sedimentary systems: Initial application in conceptual models and computer visualizations to support archaeology

Reef island evolution in a turbid‐water coral reef province of the Indo‐Pacific

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