Geomorphological evidence for late Quaternary ...

Geomorphology 241 (2015) 160–174

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Geomorphological evidence for late Quaternary tectonic deformation of the Cape Region, coastal west central Australia Beau B. Whitney ⁎, James V. Hengesh Centre for Offshore Foundation Systems, The University of Western Australia, M053, 35 Stirling Highway, Crawley, Perth, Western Australia 6009, Australia

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Article history: Received 9 August 2014 Received in revised form 23 January 2015 Accepted 5 April 2015 Available online 18 April 2015 Keywords: Coastal geomorphology Active tectonics Stable continental regions MIS 5e paleo sea level Western Australia

a b s t r a c t A late Pleistocene (Marine Isotope Stage 5e) emergent marine sequence fringes the coastline of the Cape Region of coastal west central Australia and provides elevation and age control to characterize the locations and rates of crustal deformation. There is a systematic measurable change in relative paleo sea-level elevations across the Cape Region. High-precision leveling of modern and Pleistocene shoreline features indicates the minimum elevation range of MIS 5e shoreline features along the coast is 10.4 m. This compares with the 2.5 m elevation range for observed modern shoreline analogs. The lack of continuity of MIS 5e shoreline elevations along 300 km of coastline demonstrates continuing tectonic deformation along coastal anticlines in the Cape Region. Topographic expression of MIS 5e features indicates tectonic uplift consistent with late Neogene to Quaternary deformation on the Cape Cuvier and Cape Range anticlines. Post-MIS 5e tectonic uplift rates are up to 0.054 ± 0.035 mm/yr at fold axial locations. Estimated subsidence rates are − 0.013 ± 0.034 mm/yr on fold limbs. While the estimated vertical tectonic deformation is small and the rates are low, the geomorphological data also demonstrate tectonic activity, not stability. © 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

1. Introduction This study investigates elevations of previously dated paleoshoreline features and rates of neotectonic deformation within the onshore Carnarvon basin in coastal west central Australia. The study area extends along the coast from Cape Cuvier to the northern tip of the Cape Range (~21.5°S to 25°S) and is herein referred to as the Cape Region (Fig. 1). The generally low-lying landscape of the Cape Region is punctuated by a series of topographically prominent anticlines that deform the Miocene Trealla and Tulki limestones and other undifferentiated Miocene to younger sedimentary deposits (e.g., Hocking et al., 1987). We utilize coastal geomorphology and nearshore stratigraphy related to the last interglacial (LIg) period to assess whether the late Neogene folds in the Cape Region have been tectonically active since Marine Isotope Stage 5e (MIS 5e). The MIS 5e shoreline sequence is characterized by a fringing reef platform, nearshore sediments, a geomorphologically distinct abrasion surface, a paleo-shoreline angle, and the adjacent paleo sea cliff or terrace riser. Geomorphic features of both the modern (active) shoreline and the emergent MIS 5e paleoshoreline were mapped and surveyed to document the relative positions and elevations of shoreline features and to determine the elevations of paleo sea-level indicators. ⁎ Corresponding author. Tel.: +61 4 1221 4726. E-mail addresses: [email protected], [email protected] (B.B. Whitney), [email protected] (J.V. Hengesh).

Elevations from LIg shoreline features are compared with analog features from the modern (active) shoreline in order to assess the variability in elevations (or unit thicknesses) within the late Quaternary section. Survey points were located on in situ corals, nearshore deposits, marine abrasion surfaces, and wave-cut notches. Preservation of the late Pleistocene section varies along the coast, as does the range of elevations for various components within the coastal sequence. Although the thicknesses and elevations of individual components within the late Pleistocene section vary, the stratigraphic positions of individual components are consistent and can be correlated from site to site. The positions and elevations of coastal features were analyzed at individual study sites, across folds, and across the 300 km-long study area. These elevation data were then compared to a range of eustatic sea-level estimates for the LIg (MIS 5e) highstand in order to establish the range of possible rates of tectonic uplift and subsidence. 2. Background A number of researchers have addressed the topics of tectonic stability and paleo sea level using data gathered from the MIS 5e features preserved in the Cape Region (e.g., Denman and van de Graaff, 1977; Kendrick et al., 1991; O'Leary et al., 2008a). The products of these investigations are two contrasting sets of literature: the first recognizes late Quaternary tectonic deformation in the region; while the second considers western Australia as tectonically stable and thereby providing a paleo sea-level datum.

http://dx.doi.org/10.1016/j.geomorph.2015.04.010 0169-555X/© 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

B.B. Whitney, J.V. Hengesh / Geomorphology 241 (2015) 160–174

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Fig. 1. Regional map showing principal geological provinces and structural trends. For legibility, individual structures within the WASZ are omitted. The principal structural fabric within the WASZ is parallel to the Darling fault and NWSM trends. Plate motion data from Bock et al. (2003).

Many researchers have documented evidence for Late Neogene and younger deformation within the extended crust of the Carnarvon basin both onshore and offshore (Table 1). In addition, a number of researchers have documented evidence for Quaternary tectonic activity

Table 1 Literature that present data for Quaternary tectonic deformation the Carnarvon Basin. Raggatt (1936), Clarke (1938), Teichert (1948), Condon et al. (1955), Condon et al. (1956), McWhae et al. (1956), Boutakoff (1963), Raynor and Condon (1964), Baxter (1967), Wyatt (1967), Hancock (1969), Allen (1972b), van de Graaff et al. (1976), Denman and van de Graaff (1977), Veeh et al. (1979), Megallaa (1980), Hocking (1985), Hocking et al. (1987), Hocking (1988), Malcolm et al. (1991), Kendrick et al. (1991), Wyrwoll et al. (1993), Baillie and Jacobson (1995), Crostella (1995), Logan (1987), Crostella and Iasky (1997), Keep et al. (1998), O'Brien et al. (1999), Keep et al. (2000), Ellis and Jonasson (2001), Hearty et al. (2002), Keep et al. (2002), Longley et al. (2002), Cathro and Karner (2006), Clark (2006), Keep et al. (2007), Hillis et al. (2008), Revets et al. (2009), Hengesh (2010), Hengesh et al. (2011a, b), Clark et al. (2011), Keep et al. (2012), Müller et al. (2012), McPherson et al. (2013), Whitney and Hengesh (2013), Whitney et al. (2014), Hengesh and Whitney (2014).

in the Cape Region (e.g., Condon et al., 1955, 1956; Boutakoff, 1963; Hancock, 1969; Logan et al., 1970; Allen, 1972b; van de Graaff et al., 1976; Denman and van de Graaff, 1977; Veeh et al., 1979; Kendrick et al., 1991; Clark, 2010; Clark et al., 2012). Folding of late Quaternary sediments in the Cape Range and Carnarvon Basin (Whitney and Hengesh, 2015), the presence of fault scarps (Whitney and Hengesh, 2013), and the occurrence of several historical large magnitude earthquakes (McCue, 1990; Leonard, 2008) clearly indicate that although western Australia may have low rates of tectonic deformation, it is not stable. Neotectonic deformation of this region has been recognized for more than 75 years. However, an influx of recent literature uses paleo sea-level data from western Australia under the assumption that the coastline is tectonically stable (e.g., Stirling et al., 1995, 1998; Hearty et al., 2007; Siddall et al., 2007; O'Leary et al., 2008a, 2008b; Kopp et al., 2009). Moreover, two recent studies refute the concept of stable continental marine platforms altogether in terms of providing a datum around which eustatic sea level oscillates (Moucha et al., 2008; Pedoja et al., 2011). The opposing views of tectonic stability vs. tectonic activity have significant implications for studies of paleo sea level, intraplate tectonics, and seismic hazard.

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13 o

Range Anticline

SYMBOLS Anticline axis and plunge Coast parallel slope of MIS 5e platform. Arrow points downslope. This is effectively an apparent dip direction

Antic line

Rang e Roug h

11

Ningaloo

Giralia Anticline

12

Cape

Cape

Range

Coast

22

o

23

Coast

WESTERN AUSTRALIA

Minilya folds

10 9 8 7

Gnaraloo

4-6 3 2

Quobba

Lake Macleod

in e

Cape Cuvier

t i cl Cape C uvier An

Red Bluff

o

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Although there are two contrasting views presented in the literature, it is misleading to characterize the opposing views as comparable in terms of their breadth and volume of research. We have found only two published papers that specifically interpret data from the Cape Region as indicating tectonic stability, i.e. Hearty et al. (2007) and O'Leary et al. (2008a). Both are widely cited, both assert tectonic stability of the WA coastline, and both conclude that there are two eustatic MIS 5e highstands (two distinct LIg marine terraces) evident in the Cape Region. It appears intrinsic to their conclusions that either the coast is tectonically active or there were two highstands. We do not agree that these conditions are mutually exclusive. 3. Geologic and tectonic setting The study area lies within the onshore part of the Carnarvon basin (Fig. 1). The Carnarvon basin occupies the southern portion of the Westralian Superbasin (Yeates et al., 1987) and is filled with up to 15 km of Paleozoic to recent sedimentary rocks overlying crystalline basement (Baillie et al., 1994). The Paleozoic section is unconformably overlain by up to 4 km of Mesozoic marine sequences (Playford and Johnstone, 1959; Hocking et al., 1987). Structural elements within the Carnarvon Basin developed as a result of Late Triassic to Early Jurassic rifting during large-scale supercontinent fragmentation (e.g., Teichert, 1948; Konecki et al., 1958; Arrington, 1966; Allen, 1972a, 1972b; Hocking et al., 1987). The dominant structural architecture is controlled on the eastern margin by continental-scale, terrane-bounding fault systems such as the Darling fault system to the south and the North West Shelf Megashear (NWMS) to the northeast (AGSO, 1994; Kennett and Abdullah, 2011) (Fig. 1). The NWMS separates sedimentary rocks of the Westralia Superbasin from Proterozoic Pilbara and Kimberley cratons and adjacent orogenic terranes. The fault systems follow the extended margin of western Australia and include a zone of late Neogene to Recent folding and faulting referred to as the Western Australia Shear Zone (WASZ) (Whitney and Hengesh, 2013; Whitney et al., 2014; Whitney and Hengesh, 2015). The WASZ comprises both onshore and offshore recently reactivated structures along the formerly rifted margin including well documented folds within the Cape Region (e.g., Malcolm et al., 1991) (Fig. 2). Throughout the WASZ, Mesozoic rift-related normal faults have been reactivated to accommodate oblique crustal shortening (Sykes, 1978; Crone et al., 1997; Cathro and Karner, 2006; Revets et al., 2009; Keep et al., 2012; Müller et al., 2012; McPherson et al., 2013). Reverse reactivation has occurred along offshore structures such as the Barrow Island anticline, Rowley Shoals Ridge, and Scott Reef (e.g. Boutakoff, 1963; Keep et al., 2007), along the coastal anticlines of the Cape Range (van de Graaff et al., 1976; Malcolm et al., 1991), and folds within the Carnarvon alluvial plain (Whitney and Hengesh, 2015). Anticlines in the Carnarvon basin have formed as fault propagation folds above blind, oblique reverse faults (McWhae et al., 1956; Hocking, 1988; Hillis et al., 2008). The folds generally are asymmetrical hanging wall anticlines and the underlying structures are west-dipping listric faults (Condon et al., 1956; Malcolm et al., 1991). Many of these faults show little evidence for net reverse slip motion (Iasky and Mory, 1999) indicating limited reverse slip or recent onset of reverse reactivation. The most topographically prominent folds in the Carnarvon basin occur in the Cape Region and include the Cape Range, Rough Range, Giralia Range, Cape Cuvier, and Minilya anticlines. A hillshade digital elevation

1 Quobba

o

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Fig. 2. Digital elevation model (SRTM 3 arc sec) of the Cape Region showing major anticlines and study locations discussed in text. Study sites are: (1) Cape Cuvier, (2) Korean Star, (3) Korean Star North, (4) Red Bluff South, (5) Red Bluff, (6), Red Bluff North, (7) Turtles, (8) Tombstone, (9) 3 Mile Camp, (10) 3 Mile Camp North, (11) Yardie Creek, (12) Grindstone Quarry, and (13) Vlaming Head. Note that the topographic expression of the anticlines decreases from northwest to southeast with the Cape Range being the most prominent.


model of the onshore Carnarvon basin shows a general decrease in the topographic expression of folds from northwest to southeast (Fig. 2). 4. Methods Elevation and geomorphological data were collected from both modern and MIS 5e shoreline features in the Cape Region. These data document the relative positions and the associated range of elevations of sea-level indicators across the late Neogene to Quaternary folds. Four sources of uncertainty relate to our methods and are discussed in detail in the following sections. Two sources of uncertainty in our data acquisition are: (1) the precision of the survey device, which is reported as ±0.1 m; and (2) the degree of preservation of paleo-shoreline indicators. The remaining two sources of uncertainty affect the estimated rates of tectonic deformation. They are: (1) uncertainty in the dating process used to estimate the age of the MIS 5e highstand; and (2) the global MIS 5e sea-level elevation estimates. 4.1. Site surveying Elevation data were collected using a Hemisphere R120 differential global positioning system (DGPS) equipped with an Allegro CX data collector. The Omni STAR HP subscription service was used to maximize vertical accuracy; the expected 2-sigma uncertainty in vertical measurements is less than 0.1 m. In order to verify the accuracy of the DGPS measurements, repeated measurements were collected over a two-week period and yielded results within the range of accuracy reported by the system provider. Survey elevations were collected in coordinate system WGS 1984 corrected in real-time to AUSGeoid09 UTM 49S and 50S, using the Australian Height Datum (AHD). 4.2. Age control on the LIg shoreline An MIS 5e age is firmly established for the emergent marine shore platform in the study area based on 102 dated coral samples (Veeh et al., 1979; Kendrick et al., 1991; Stirling et al., 1998; Hearty et al., 2007; Hearty and O'Leary, 2008; O'Leary et al., 2008a). The ages of these samples are presented in Fig. 3 and have an average of 128.6 ka (SD = 7.5 ka). The age range of a more comprehensive global dataset is similar to the age range derived from local data and is used herein. The age of the global MIS 5e highstand (also referred to here as the LIg highstand) has been constrained based on 711 U–Th ages collected from 16 sample locations around the globe (Dutton and Lambeck, 2012). They conclude

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that the peak LIg sea-level highstand occurred 117–130 ka. For the purpose of computing vertical deformation rates we have adopted this period as the age of the LIg sea-level highstand. This 13,000 yr uncertainty (123.5 ± 6.5 ka) in the age of the highstand is incorporated into our derived tectonic rates and affects them by approximately ±5%. 4.3. Elevation of the LIg sea level MIS 5e shoreline features from ‘tectonically stable’ coastlines of the western Atlantic Ocean have elevations that range from + 3 to +8 m (Muhs, 2002). Elevations of MIS 5e shoreline features from tectonically ‘stable’ southern Australia are +2 m (Murray-Wallace, 2002). We use the range from non-western Australian sites and ‘stable’ coastal sites for the MIS 5e sea-level highstand elevation range. This range captures a sea-level elevation uncertainty of 6 m (2 to 8 m elevation); we present the range of LIg sea-level elevations as 5 ± 3 m. The vertical deformation rates for our study area are calculated based on the 5 ± 3 m range of MIS 5e sea-level elevations from Muhs (2002) and MurrayWallace (2002), and 117–130 ka BP (123.5 ± 6.5 ka) as the age of the LIg sea-level highstand (Dutton and Lambeck, 2012) (Table 2). 4.4. Preservation of LIg shoreline indicators Shoreline angles are well known indicators of sea level (e.g., Lajoie, 1986; Pirazzolli, 1986) and are observed at two of the study sites. The shoreline angle is the best indicator for mean low water springs (MLWS) level, in that wave cut notches could be related to high tide, storm events, or bioerosional processes (e.g., Fischer, 1980; Kershaw and Guo, 2001). Likewise, distal seaward elevations taken on the marine shore platform surface will be lower in elevation than the corresponding shoreline angle. Most elevation control was acquired on the emergent marine shore platform. The error between the platform elevations and MLWS level was therefore considered in each applicable case. Marine shore platforms are seaward sloping surfaces that can have several meters of relief in the direction normal to the shoreline (Lajoie, 1986) (Table 3). Erosional processes require shore platforms to be at or just below sea level when they form. The highest surveyed shore platform elevations, therefore, only provide lower bound or limiting maximum elevations (i.e., sea level may have been above this elevation). As a consequence, the tectonic uplift rates we present based on platform elevation data are minimum rates. Where the shoreline angle is observed an upper bound limiting elevation is available, and therefore this uncertainty is minimized. In the absence of a shoreline angle (which can be buried by dunes or talus), we use the highest elevation of the emergent shore platform or

Fig. 3. Aggregate U-series data from sites within this study area. Uncertainty bars omitted for 1979 and 1991 studies as values exceed the range of the graph. One age from Hearty et al. (2007), taken from a sample collected at the Korean Star, exceeded the range of the graph (191.7 ka) and is not presented. Data are from: Veeh et al. (1979); Kendrick et al. (1991); Stirling et al. (1998); Hearty et al. (2007); O'Leary et al. (2008a); and Hearty and O'Leary (2008).

In order to provide a framework for a discussion of individual site locations, we first describe the types of stratigraphic and morphological features found in the survey areas. A composite type-section for the study area is presented in Fig. 4 and the numbers in brackets in the

– – – – – – – – – – – – – 9.4 9.0 10.0 4.6 7.1 10.4 3.1 7.7 3.4 4.6 2.5 7.9 10.5 – – 9.0 10.0 4.6 7.1 10.4 3.1 7.7 3.4 4.1 – – – – – – – – – – – – – – – – – – – 5.3 6.3 3.5 5.3 7.5 2.8 5.5 2.6 2.9 – – – – – 45 47 16 40 68 16 50 10 18 – – – – – 5.9 4.5 3.9 2.6 2.4 1.1 2.9 4.5 3.8 – – – – – 10.7 backedge 11.3 backedge –

11.5′ 14.5 12.2 – – 8.5 – 12.5 4.8 7.2 – – 10.3 – 11.0 11.8^ backedge 12.2 backedge – – – –

– – 10.0 – – – – 10.6 5.3 – – 7.9 – – 9.4 9.0 9.0 4.6 7.1 10.4 3.1 7.7 3.4 4.1 2.5 – – 2.9 – 9.0 10.0 4.6 7.1 10.4 3.1 7.7 3.4 4.6 2.5 7.9 10.5 2.9 3.7 notch – – – – 3.5 notch 4.1 – – – – – – – 2.5 – Submerged Submerged 2.0 Submerged 0.9 – – – – 2.2 berm – 1.6

The MIS 5e platform is locally cut into eolian sandstone. ^The high tide notch at Cape Cuvier was measure off-section to the south. The beach rock at the Cape Cuvier tip is a coralline algal boundstone with cobbles and gravel. MIS 5e sea level estimates delineated with an (*) indicate a 2 m addition of water depth above the highest observed in situ coral.

5.1. The coastal type-section

Cape Range

5. Results: coastal stratigraphy and geomorphology

Active shoreline characteristics

The contemporary tidal range in the study area is approximately 1.5 m (Bureau of Meteorology: http://www.bom.gov.au/oceanography/ tides/). Mean low water springs (MLWS) level is used locally to compare morphostratigraphic relations with sea level and to compare elevations between active shoreline and emergent shoreline features. The largest discrepancy observed during our investigation between 0 m AHD and MLWS level was 1.0 m. We observed a paired set of wave cut notches at several locations that generally coincide with low tide and high tide levels. On the modern coastline, the low tide notch or shoreline angle occurs between 0 and 1 m AHD. The high tide notches range between 0.9 and 2.5 m AHD (Table 3). A third higher wave-cut notch that we interpret as a storm event notch is observed at a few locations. To correlate our observations with previous sea-level estimates that use MLWS level as a datum, we define the lowest of the wave-cut notches found along the MIS 5e shoreline assemblage as the paleo-shoreline angle and paleoMLWS level.

Table 3 Elevation data on geomorphic surfaces from this survey.

4.5. Tidal variations and sea-level indicators

1.0 – – Submerged Submerged Submerged Submerged – 0.3 – – – – –

MIS 5e platform characteristics

highest in situ coral as the minimum limiting sea-level indicator at that site. Coral elevations provide a minimum estimate, but corals require a sufficient depth of water for habitat. The most conservative approach to estimating water level at the time of reef growth is to use the shallowest optimum growth depths of the highest elevation in situ corals (Muhs et al., 2011). The coral assemblage along the Cape Region coast commonly includes Porites in the upper reef section, which commonly live in 5 to 10 m water depths, but can live in shallow water up to the tide line (McCulloch, M. personal communication, 2014). As none of the corals observed in our study area show evidence of die-off or formation of micro-atolls we assume that a sufficient depth of water was maintained to preserve the coral habitat, in this case a minimum water depth of 2 m. At locations where geomorphic sea-level indicators provide only a minimum sea-level elevation, we assume a limiting water depth of 2 m above the highest in situ coral elevation to provide a maximum estimate for MIS 5e sea level. This approach is used in the absence of geomorphic indicators of maximum sea level.

1 Cape Cuvier Tip 1.0 Platform – 2 Korean Star – 3 Korean Star North – 4 Red Bluff South 1.9 5 Red Bluff 1.9 6 Red Bluff North 0.1 7 Turtles – 8 Tombstone 0.3 9 3 Mile Camp – 10 3 Mile Camp North – 11 Yardie Creek 0.2 12 Grindstone Quarry – 13 Vlaming Head 1.5

±0.035 ±0.031 ±0.034 ±0.034 ±0.035 ±0.034 ±0.038 ±0.034 ±0.032 ±0.034 ±0.038 ±0.030 –

Quobba Coast

0.042 0.046 0.005 0.026 0.054 −0.008 0.035 −0.005 0.003 −0.013 0.037 0.049 –

Coast perpendicular elevations (m)

11.0 11.0 6.6 9.1 12.4 5.1 10.6 5.3 6.1 4.5 10.7 11.3 –

Exposed platform width (m)

Max

9.0 10.0 4.6 7.1 10.4 3.1 7.7 3.4 4.6 2.5 7.9 10.5 –

Exposed platform slope (degrees)

Min

Beach rock/cemented marine sand (m)

Cape Cuvier Korean Star Korean Star North Red Bluff South Red Bluff Red Bluff North Turtles Tombstone 3 Mile Camp 3 Mile Camp North Yardie Creek Grindstone Quarry Vlaming Head

Storm Platform/bar Coral Low tide notch High tide berm/notch crest (m) (shoreline angle) notch (m) (m) (m) (m)

Cape Range

1 2 3 4 5 6 7 8 9 10 11 12 13

Uplift or subsidence rate (mm/yr)

High tide notch/platform (m)

Quobba Coast

Limiting elevations of MIS 5e shoreline features (m)

Water Low tide level notch/platform (m) (m)

Site

MIS 5e sea level estimate (m)

Table 2 Tectonic uplift and subsidence rates based on a 5 ± 3 m MIS 5e sea level elevation and 117–130 ka MIS 5e age.

11.0 11.0 11.0* 6.6* 9.1* 12.4* 5.1* 10.6 5.3 6.1* 4.5* 10.7 11.3 –


Site

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Fig. 4. Composite type-section of Pleistocene emergent shoreline features. 1) Abrasion platform cut into regional bedrock; 2) basal lag; 3) coralline algae; 4) coral reef; 5) fossil beach; 6) fossil dune; 7) low-tide notch; 8) high-tide notch; and 9) storm notch. Not all features are present everywhere. Coralline algae locally infills basal lag (during transgression) and encrusts coral platform (during regression).

following paragraphs refer to specific features in the coastal section. This composite section illustrates a single-peak MIS 5e sea-level highstand with systematic transgressive and regressive sequences. These sequences are preserved locally as ‘type’ examples and illustrate the impact that sea-level change has on sedimentary or biosedimentary facies. Not all of these nine features are present at all of the sites due to either lack of initial development or poor preservation. During the MIS 5e transgression wave energy planed an abrasion platform in the substrate [1]. A basal lag of sands and gravels representing variable wave energy environments overlies this shore platform [2]. Locally the basal lag is cemented and infilled with coralline algae forming a boundstone [3]. With rising sea level the shoreline moves landward providing vertical accommodation space for fringing coral reef growth [4]. Fossil beach deposits are landward and at higher elevations than the reef [5]. Coralline algae or boundstone is found concomitant with fossil beach deposits [3]. Locally, the beach sands fine upward into eolian sands (fossil dunes) and represent the transition from sublittoral to eolian processes [6]. Landward of the fossil beach is the MIS 5e paleo sea cliff. The abrasion platform meets the base of this sea cliff at the shoreline angle [7]; the shoreline angle represents the MLWS level. At some locations additional wave-cut notches are preserved above the shoreline angle. We interpret the notch above the shoreline angle as the high tide notch [8] and, where present, the next higher notch as the storm notch [9]. In most places the base of the paleo sea cliff is buried by younger eolian dunes or talus and the shoreline angle is not exposed. At some locations coralline algae encrusts the surface of the fringing reef platform. Coralline algae can live in periodically-exposed intertidal settings (Johnson, 1961; Adey and Macintyre, 1973; Steneck, 1986), flourish in high energy environments, and are early colonizers during marine transgression (Johansen, 1981; Kendrick et al., 1991). Thus, coralline algae delimit the prograding front (and during regression, receding limit) of coral on high energy shorelines (Ghose, 1977). The landward extent and maximum elevation of the coralline algae coincide with the maximum periodically exposed intertidal setting (i.e., paleo high tide). During sea-level regression the marine limit occupied by coralline algae migrates seaward and encrusts the coral platform in a coralgal veneer. 5.2. The Quobba Coast Ten sites were investigated along the Quobba Coast (Fig. 2). These include from south to north: Cape Cuvier, Korean Star, Korean Star North, Red Bluff South, Red Bluff, Red Bluff North, Turtles, Tombstone, 3 Mile Camp, and 3 Mile Camp north. These sites are described in the following sections.

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5.2.1. Cape Cuvier Cape Cuvier is a rocky headland (24.22°S, 113.39°E) located on the coast approximately 15 km west of Lake MacLeod. At Cape Cuvier, the generally north–south oriented coastline makes an abrupt turn and trends east–west for approximately 4 km before returning to a north– south orientation. The mapped axis of the Cape Cuvier anticline trends parallel to the coast except where it intersects the north-facing shore of the headland (Hocking et al., 1987) (Fig. 5). The anticline axis is onshore south of shoreline and offshore north of the shoreline. The modern coast is a high energy environment with a modern marine abrasion surface beveled into the emergent MIS 5e deposits. The MIS 5e surface comprises a b55 m-wide, seaward-sloping coralline algae encrusted reef platform that is continuously exposed for ~ 2 km to the south of Cape Cuvier (Fig. 6A). The shore platform has a seaward slope with coast perpendicular elevations that range from 5.3 to 9.0 m (Table 3). Platform elevations are sub-horizontal in a coast parallel direction. The MIS 5e shore platform is a planar abrasion surface on a constructional reef assemblage that consists of both in situ and detrital corals. These corals were sampled and dated to 137 to 118 ka (O'Leary et al., 2008a). Due to the high energy shoreline environment, the Cape Cuvier section is more complex than elsewhere along the coast. At the tip of the cape, paleo sea-level indicators are preserved in two separate outcrops. A small sea stack lies 25 m seaward of the active sea cliff. The sea stack preserves an isolated remnant of the MIS 5e section that consists of the abrasion platform and basal lag overlain by a coralline algal boundstone (Fig. 5, cross-section C; Fig. 6B). The boundstone is a fining-upward marine sequence overlying a seaward-dipping abrasion platform cut into eolianite bedrock. The basal part of the boundstone unit contains numerous eolianite boulders between 2 and 3 m in diameter cemented by a matrix of coralline algae. Boulders within the boundstone unit on the sea stack originated from the sea cliff and were reworked in the surf zone. The elevation of the contact between the boundstone and abrasion platform ranges from 3.5 to 4.5 m. The eroded top of the boundstone (remnant MIS 5e shore platform) on the sea stack is at an elevation of 6.5 m. The boundstone and underlying Pleistocene abrasion surface preserved in the sea stack has been eroded by wave action and now is separated from the sea cliff by a 25 m-wide modern abrasion surface (2.5 m elevation at its inner edge) cut into bedrock. At the sea cliff, the same stratigraphic succession found on the sea stack is present, but at a higher elevation. The contact between the abrasion platform and marine deposits (boundstone) is between 9 and 11 m (Figs. 5C, D, 6C). The boundstone at this higher elevation contains coarse gravels and small boulders, but no clasts larger than 0.2 m (Fig. 6C). We interpret the boundstones at these two outcrops as being part of the same unit. Reconstructing the basal abrasion surface and overlying boundstone units yields an average dip of 11°. The actual dip is likely flatter near the sea stack and steeper (ramps up) toward the sea cliff. This is similar to observations made by Denman and van de Graaff (1977) a few hundred meters to the south of the site where finer grained (lower energy) paleo beach deposits have dips up to 20° seaward. Fig. 7 compares the shoreline morphology and deposits from both the modern and MIS 5e paleo-shoreline assemblages at this location. The modern beach preserves geomorphic evidence of both low and high tide strandlines, and higher storm deposits. The 1 m notch measured on the modern shoreline represents the MLWS level and the 2.5 m notch represents high tide level. The highest notch at 3.7 m represents the storm notch and upper limits of the swash zone. The MIS 5e shoreline has wave-cut notches and associated beach deposits at 9.0 and 11.0 m, and a higher notch with beach sands at 11.8 m (Fig. 7 and Table 3). We interpret the 9.0 m elevation of the MIS 5e shore platform as a minimum paleo MLWS level. The higher wave-cut notch (11.0 m) represents a paleo high-tide level and an overlying coralline algae boundstone up to 11.5 m limits the high-tide wetting depth.

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N

113.40o E

Korean Star 6.3-10.0m

24.22 oS

Indian Ocean

Tip 9.4m Anticline Platform slope direction

C D

Cape Cuvier

Apparent bedrock dip MIS 5e Coral/Platform

Platform 5.3-9.0m

Undifferentiated (Quaternary) Trealla Limestone (Miocene)

1 km

Giralia Calcarenite (Eocene)

C West

_ = 2.5 V H Terrace Deposits CBS

Erosional terrace

5.4 m

?

Erosional Terrace Level

b`

? Scree

Eolianite

10m 5

Red algal limestone

MLWS 0

e

0.3 m red algal Eolianite rock stack limestone over 0.2 m 15m 20 m north of section conglomerate 10.5 10 Conglomerate & reef debris (some in situ ?) ‘Intertidal’ terrace 5 (Not measured) Modern Beach Eolianite MLWS ? ? 0

_ V H= 2.5

Sc

re

D

East In situ coral 9.4 m

Slope less than 1o

Scree

A

B

Fig. 5. (A) Geologic map of Cape Cuvier, showing study sites, images, and topographic profiles. Star symbol indicates location of 14.5 m elevation carbonate sand deposits. Map adapted from Hocking (1985). (B) Photograph showing the ‘red algal limestone’ referenced in profile D. Profiles C and D are redrawn from Denman and van de Graaff (1977). In profile C, the projected correlation of boundstone overlying the erosional terrace is shown as a dashed line labeled with b′. The label was added in order to reference the profile to Fig. 6B; b′ also is shown in Fig. 6B.

Approximately 500 m south of the Cape there is a wave-cut notch at 11.8 m, which we interpret as the MIS 5e storm notch. Carbonatecemented marine sands were measured at 14.5 m approximately 650 m south of the Cape (Fig. 6). These sands are paleo storm deposits or swash zone deposits from a beach face. The estimated uplift rate for the Cape Cuvier site is summarized in Table 2. An uplift rate of 0.042 ± 0.035 mm/yr was calculated using paleo-shoreline elevations of 9.0 and 11.0 m which correspond to the MIS 5e shore platform and notch elevations, respectively. Previous researchers interpreted two Pleistocene marine terraces at this location (Denman and van de Graaff, 1977; O'Leary et al., 2008a). Denman and van de Graaff (1977) measured a ‘lower’ wave cut notch in the sea cliff at ‘5 m’ elevation (their measurement from MLWS level). They speculate that the boundstone preserved on the sea stack

is the same unit as the higher elevation boundstone on the sea cliff. Ultimately they correlate the lower (5 m) notch, which they interpret as a second Pleistocene terrace, to the ‘lower’ boundstone unit (Fig. 5C, D). We did not observe this ‘lower’ 5 m notch during our investigation. However, we measured an active notch at 3.7 m and modern storm run-up deposits that buttress the base of the sea cliff at 5.7 m. The ‘lower’ notch may have been buried by these sands. Alternatively, at this site, the modern MLWS level is 1.0 m AHD based on our survey data. Therefore, the ‘+5 m lower terrace’ observed by Denman and van de Graaff (1977), likely is 4 m elevation within the AHD reference frame. This elevation is similar to the 3.7 m storm notch we surveyed. Similarly, we surveyed the coralline algae rim at 9.4 m (Fig. 5B) and they measured it at 10.5 m. As the MLWS level at this site is 1.0 m AHD, their elevations are 1 m higher than the AHD reference frame.


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Fig. 6. Images of Cape Cuvier. Photo A: aerial photograph of Cape Cuvier showing photo B and C locations (“V” opens toward the view); (r) eolianite rock stack; (d) northern limit of continuous coralline platform at Cape Cuvier. Photo B: (a) coralline algal boundstone with gravel clasts up to 3 m in diameter; (b) contact between boundstone and MIS 5e abrasion platform; a person is standing on an active wave-cut platform. Photo C: (a) coralline algal capstone and boundstone with gravel clasts up to 0.2 m in diameter; (b) contact between boundstone and MIS 5e abrasion platform (b′, projected; same b′ shown in Fig. 5 profile C); (c) active high tide abrasion platform; (s) eolianite sea cliff; (r) off-section eolianite rock stack from Denman and van de Graaff (1977).

We interpret their ‘lower’ notch as an active Holocene storm notch. This elevation fits within the ranges of storm notch and storm berm elevations observed elsewhere along the coast (Table 3). O'Leary et al. (2008a) also interpret two sea-level stillstands based on a subtle inflection point on the terrace surface at 5.1 m elevation. They interpret the inflection point as a shoreline angle formed during a brief stillstand. We did not observe an inflection point in the terrace

surface along the Cape Cuvier coastline. Unfortunately, the location of their surveyed transect is not shown in their paper so we could not reoccupy the location. 5.2.2. Korean Star The Korean Star shipwreck is located approximately 3 km northeast of Cape Cuvier (24.21°S, 113.42°E) (Fig. 5). The Korean Star North site is

14.5m

d c

11.8m

b

d

5.7m

c

3.7m

11.0m

b a

2.5m

9.4m 9.0m

a Paleo shoreline elevations

1.0m

Modern shoreline elevations

Fig. 7. Paleo- and modern shoreline feature elevations at Cape Cuvier. The range of paleo features is 5.5 m. The range of modern features is 4.7 m. (a) MLWS level; (b) high-tide notch; (c) storm notch; (d) limit of storm run-up.

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Fig. 8. View to the south of the coastline between the Korean Star Memorial Site and Cape Cuvier. Photo shows the folded Miocene section (see white unit) in the sea cliff. Bottom photo is annotated: red line overlays folded Miocene unit; (a) indicates up to 6.6 m coral platform surface that decreases to the north (left); shoreline angle is 10.0 m at the Korean Star site. Anticline axis shown with symbol. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

5.2.3. Red Bluff Red Bluff is a promontory with a northwest-facing shoreline (24.03°S, 113.44°E) located approximately 22 km north of Cape Cuvier (Figs. 2, 9). The axis of the Cape Cuvier anticline trends parallel to the coast and intersects the northwest facing shoreline (Hocking, 1985). The modern shoreline consists of a marine abrasion surface that is beveled into the emergent MIS 5e reef assemblage. The 5e surface comprises an up to 70 m-wide, seaward sloping coralline algae encrusted

113.45 oE

3 Mile Camp 2.9-4.1m

Anticline Platform slope direction Apparent bedrock dip Tombstone 2.6-3.4m

MIS 5e Coral/Platform Undifferentiated (Quaternary)

Turtles 5.5-7.7m

Trealla Limestone (Miocene)

anticline

Giralia Calcarenite (Eocene)

Cape

Cuvier

Indian Ocean

Red Bluff North 2.8-3.1m

24.0 oS

located 4.5 km north of the Korean Star. The Pleistocene section at the Korean Star site includes a marine abrasion surface and coralline platform, beach deposits, and a wave-cut notch. The erosional platform is between 6.3 and 10.0 m elevation, steepening at the paleo sea cliff to the base of a wave-cut notch at 12.2 m (Table 3). The landward portion of the shore platform above an elevation of 9.0 m is an erosional surface cut into fossiliferous Tertiary limestone bedrock. Below 9.0 m the platform is a flat eroded surface of a boulder-rich coralline algae cemented boundstone with boulders up to 5 m in diameter. The boulders originated from the adjacent sea cliff and subsequently have been reworked in the surf zone. The seaward edge of the shore platform drops abruptly into the active surf zone. Most of the landward part of the platform is covered with colluvium from rock falls along the paleo sea cliff. However, cemented marine sands are preserved at the base of the wave-cut notch and immediately downslope beneath large boulders. Colluvium covers the landward part of the platform except at the 12.2 m wave-cut notch. We interpret the step in the platform surface at 10.0 m elevation as the paleo-shoreline angle and paleo MLWS level indicator and the 12.2 m notch as the paleo high-tide notch. The positions and range of elevations of these features are consistent with the range of elevations of modern coastal features observed elsewhere along the coast. Survey data from the Korean Star and Korean Star North sites are presented in Tables 2 and 3. The marine abrasion platform slopes gently (b0.2°) to the north for approximately 6 km where it is covered by Holocene dunes and intertidal swash zone sands. A lateral facies change occurs within the shore platform substrate along this sloping surface. At the Korean Star shipwreck monument the reef facies comprises boundstone dominated by boulders and coralline algae. To the north the boulder component decreases and grades into a coral-dominated reef platform. The boulder component decreases as the height of the paleo sea cliff decreases and diverges from the active shoreline. Along this stretch of coastline the northeast sloping shore platform coincides with the eastern limb of the Cape Cuvier anticline. The orientation of the MIS 5e surface is consistent with the dip of the Tertiary bedrock exposed in the sea cliff between the Korean Star and Cape Cuvier (Fig. 8). There are no published ages for the coralline platform at the Korean Star site. However, Hearty et al. (2007) assign a MIS 5e age for the platform. Based on the preservation and morphology of the emergent shoreline features compared to the emergent shoreline deposits elsewhere in the study region, we agree with their interpretation. The estimated uplift rates for the Korean Star site are summarized in Table 2. An uplift rate of 0.046 ± 0.031 mm/yr was calculated using a paleo-shoreline elevation of 10.0 m and maximum coral elevation of 9.0 m plus an assumed 2 m water depth. Along the eastern limb of the anticline, the elevation of the MIS 5e surface decreases systematically toward the Korean Star North site (Table 3) and thus the post-MIS 5e deformation rates vary depending on the position of the platform with respect to the anticlinal axis. We estimate an uplift rate of 0.005 ± 0.034 mm/yr at the Korean Star North site. Further north, the platform becomes buried by dunes and swash zone sands.

Red Bluff South 5.3-7.1m

Red Bluff Camp

Red Bluff 7.5-10.4m

2 km Fig. 9. Geologic map of the Red Bluff region, adapted from Hocking (1985) showing study sites with minimum and maximum platform elevations.


reef platform. The MIS 5e paleo-reef fringes the western and northern sides of the promontory and slopes gently to the north for approximately 7 km before being buried by Holocene dune and beach sands. Geomorphic, stratigraphic, and elevation data were gathered along 4.5 km of coastline near the Red Bluff campground. The base of the section consists of an abrasion platform cut into Tertiary bedrock. A variably thick (b0.5 m) coarse gravel lag overlies and locally infills undulations in the abrasion platform. The gravel lag grades into a conglomeratic coralline mass (boundstone) that becomes less gravelly and fines up-section. Favids, Porites, and Acropora in growth positions comprise the upper reef section. Large (N 2 m diameter) Tertiary limestone boulders eroded from the adjacent paleo sea cliff are incorporated within the coral assemblage. The top of the reef is abraded and now forms a sub-horizontal erosion surface or platform. Locally, this shore platform is overlain by a sequence of sands and corals in growth position. The sand unit that overlies the boundstone is coarse grained and shell-rich in the bottom 20 cm and then progressively fines upsection. This sand unit represents a swash zone that grades into windblown facies and is preserved only in local paleo ‘pocket beach’ environments. Several shore platform elevation transects were measured along the Red Bluff coast on both the east and west sides of the Cape Cuvier anticline as mapped by Hocking (1985). Coast perpendicular elevations of this platform range from 5.3 to 7.1 m west of the axis (the Red Bluff South site), from 7.5 to 10.4 m near the axis of the anticline (the Red Bluff site), and from 2.8 to 3.1 m east of the axis (the Red Bluff North site) (Fig. 9).

169

The LIg shore platform along the Red Bluff coast is a nearly continuously exposed gently north-dipping surface with no observed steps or bevels. Changes in elevation across the coast-parallel slope of the platform demonstrate subtle anticlinal folding. The estimated uplift rates for the Red Bluff site are summarized in Table 2. Uplift rates of 0.054 ± 0.035 mm/yr were calculated using paleo-shoreline elevations of 10.4 m and 12.4 m. The 10.4 m elevation was measured on an in situ Porites at the upper limit of the exposed reef platform. The 12.4 m elevation incorporates an assumed 2 m water depth required for coral habitat. At the Red Bluff North site a subsidence rate of − 0.008 ± 0.034 mm/yr is calculated where the coral platform elevation is 3.1 m. This rate also incorporates a 2 m minimum assumed water depth above the coral to provide a maximum limiting elevation of 5.1 m. This rate suggests that the net late Pleistocene subsidence is occurring on the eastern limb of the anticline. 5.2.4. Turtles and tombstone sites Turtles is a picturesque 150 m-wide paleo pocket beach and emergent reef platform 5 km south of 3 Mile Camp on Gnaraloo Station (23.90°S, 113.47°E) (Figs. 9, 10A). The emergent MIS 5e marine shore platform consists of both in situ and detrital coral encrusted with coralline algae. Platform elevations vary from 5.5 m at the seaward edge to 7.7 m at the landward edge. A fossil beach locally overlies the platform surface (Table 3). A wave-cut notch in Tertiary eolianite was measured at an elevation of 10.6 m. Tertiary bedrock exposed in the sea cliff at Turtles dips eastward indicating the hingeline of the anticline is offshore (Fig. 10B).

Fig. 10. Images of Turtles and Tombstone. Photo A: shows oblique air photo of Turtles with (c) coral platform; (e) 5.5 m coral platform seaward edge; (f) 7.7 m coral platform/fossil beach contact; (g) 10.6 m wave-cut notch; (h) 12.5 m landward limit of fossil beach; and (x) paleo sea cliff. Photo B: shows perspective views of Turtles with (c) coral platform; and (d) eastwardly dipping bedrock in sea cliff. Photo C: shows view to the north of 2.8–4.0 m-high coral platform at Tombstones with: (a) fossil beach rock; and (b) 0.3 m wave-cut notch, base obscured by beach sand. Photo A courtesy of the Geological Survey of Western Australia, Department of Mines and Petroleum. © State of Western Australia 2013.

170


The shore platform between Turtles and 3 Mile Camp is composed of cemented in situ and detrital corals. Approximately 1.7 km north of Turtles at the Tombstone site the MIS 5e platform outcrops at elevations between 2.6 and 3.4 m and is overlain by fossil beach rock (Fig. 10C). From Tombstone to 3 Mile Camp platform elevations are consistently within a 2 m range. Near 3 Mile Camp the platform is cut into eolianite at an elevation of 4.6 m. The adjacent coral platform is at 4.1 m elevation. At 3 Mile Camp North the reef platform surface decreases to an elevation of 2.5 m and is modified by active shoreline processes. Three photographs in Fig. 11A–C) show a range of the LIg fossil reef platform characteristics and active shoreline processes. The photographs are, in succession, north to south. At some locations (Fig. 11A) no riser exists and the fossil platform has been reoccupied by the modern shoreline. Where the MIS 5e platform is emergent yet within the range of modern tides and storm surges, the platform is being reoccupied (Fig. 11B). Where the MIS 5e platform surface is above the reach of wave energy, the modern riser is eroding into the MIS 5e reef assemblage and the emergent platform is retreating landward (Fig. 11C). The overall decrease in platform elevation from Turtles northward to 3 Mile Camp North is consistent with the dip observed in underlying Tertiary bedrock further indicating that the axis of the anticline is west of the coastline and trends northward obliquely away from this stretch of coast (Fig. 9). The Turtles site is closer to the axis of the fold than the Tombstone site. The estimated uplift/subsidence rates for the Turtles and Tombstone sites are summarized in Table 2. At Turtles an uplift rate of 0.035 ± 0.038 mm/yr was calculated using paleo-shoreline elevations of 7.7 m and 10.6 m. At Tombstone a subsidence rate of −0.005 ± 0.034 mm/yr was calculated using the maximum coralline platform elevation of 3.4 m and the 5.3 m wave-cut notch. At 3 Mile Camp an uplift rate of 0.003 ± 0.032 mm/yr was calculated using the 4.6 m abrasion platform elevation and 6.1 m limiting shoreline elevation. At 3 Mile Camp North a subsidence rate of − 0.013 ± 0.034 mm/yr was calculated using 2.5 m coralline platform elevation and a 4.5 m limiting elevation. The 6.1 m and 4.5 m elevations incorporate the assumed 2 m minimum water depth above the coralline platform.

between 3° and 6° east. The fold has a northward plunge of up to 3° and a southward plunge of less than 1° (Condon et al., 1955). There is a broad gently seaward-dipping carbonate platform with multiple marine abrasion surfaces on the western limb of the anticline. The youngest of these marine abrasion surfaces, the Tantabiddi terrace (van de Graaff et al., 1976), has a MIS 5e age (Fig. 3) (Veeh et al., 1979; Stirling et al., 1998).

5.3. The Cape Range

5.3.2. Grindstone Quarry Grindstone Quarry is a small sand and gravel pit located 44 km north of Yardie Creek and 1.3 km inland from the coast (21.95°S, 113.96°E) (Fig. 12). The quarry exposes a thinly bedded westward dipping (~10°) weakly cemented shell rich calcarenite sand. The sand reaches a maximum elevation of 10.3 m. The sands terminate approximately 40 m west of a coast parallel bar in the underlying calcrete surface. This bar has a crest elevation of 10.5 m (Table 3). A trough east of the bar has an elevation of 10.0 m. The landward margin of the trough is marked by a prominent shoreline angle that is cut into the margin of the older (Jurabi) terrace deposits at 11.3 m. We interpret the

Three sites were investigated on the western flank of the Cape Range anticline; these include: Yardie Creek, Grindstone Quarry and Vlaming Head (Fig. 12). The Cape Range anticline is a 130 km-long, 32 kmwide structure that has folded Miocene and younger deposits (Condon et al., 1955). The Cape Range anticline has the highest topographic expression (N 300 m) of all mapped anticlines within the Carnarvon basin. These anticlines have a marked linear arrangement such that the Cape Range anticline aligns with the Cape Cuvier anticline. The limbs of the Cape Range anticline dip between 3° and 8° west and

5.3.1. Yardie Creek Yardie Creek is the largest drainage on the western flank of the Cape Range (22.32°S, 113.81°E) (Fig. 12) and incises the Neogene through Quaternary section. In the Yardie Creek area a series of four marine terrace abrasion surfaces and risers are cut into Tertiary bedrock. The Tantabiddi is the lowest terrace. We surveyed a transect across the Tantabiddi terrace on the south side of Yardie Creek. There is a step in the MIS 5e abrasion surface at 7.9 m and the back edge of the surface is at an elevation of 10.7 m (Table 3). The 7.9 m step might be a geomorphologically analogous feature to the more subtle ‘inflection point’ (5.1 m elevation) that O'Leary et al. (2008a) observed at Cape Cuvier. However, it is at a higher elevation and is a clearly expressed step in the terrace platform surface. A several meter-high terrace riser and a platform surface were observed upslope of the Tantabiddi terrace. This higher surface previously has been mapped as the Jurabi terrace, which is older than MIS 5e (van de Graaff et al., 1976) and possibly MIS 7 (Clark et al., 2012). The western end of the transect terminated at the modern low tide strandline (MLWS level) at the mouth of Yardie Creek. The MLWS level was surveyed at 0.2 m AHD elevation. The active high-tide strandline at the mouth of the creek was measured at an elevation of 2.2 m. Thus, the modern beach preserved geomorphic evidence of a 2 m tidal range. Using modern strandlines as an analog, we interpret the two erosional steps at and near the back edge of the MIS 5e surface as the low-tide and high-tide shoreline angles. The lower shoreline angle at 7.9 m correlates to the paleo MLWS level. The estimated uplift rates for the Yardie Creek site are summarized in Table 2. An uplift rate of 0.037 ± 0.038 mm/yr was calculated at Yardie Creek using paleo-shoreline elevations of 7.9 m and 10.7 m.

Fig. 11. Photographs of the coastline near 3 Mile Camp and 3 Mile Camp North (from North to South). Dashed line in photo A indicates limit of modern marine organisms encrusted on fossil reef. Riser height in photo B is approximately 1 m. Boulder in foreground of photo C is approximately 1 m high. The arrow points to a dune which is visible on all three photos showing the decreasing elevation of the fossil reef along the coast.


171

114 o E

Anticline

Vlaming Head 2.9m

Platform slope direction MIS 5e Coral/Platform

0 00

1

e

Exmouth Gulf

Rang 100

Girali a anticlin e

20 km

Ro

ug

hR

an

ge

ant

iclin

e

Yardie Creek 7.9-10.7m

500

Indian Ocean

Ant i

Structural contours of the top of Miocene Tulki Limestone redrawn from Condon et al., 1955. Contour interval 100 ft.

22 oS

Undifferentiated (Cretaceous)

Grindstone Quarry 10.5-11.3m

clin e

Undifferentiated (Miocene)

Cape

Undifferentiated (Quaternary)

Fig. 12. Geologic map of the Cape Range region, showing study sites (adapted from Hocking, 1985). Structural contours of the Miocene Tulki Limestone redrawn from Condon et al. (1955).

10.5 m bar crest elevation and the 11.3 m wave-cut notch as the low and high tide strandlines, respectively. The paired shoreline features observed at Grindstone Quarry and Yardie Creek are not preserved everywhere along the west side of the Cape Range. In map view they repeatedly join and bifurcate along trend, likely as a consequence of subtle variations in the coastline morphology, similar to the active shoreline. Based on similarities in geomorphic expression and relative elevations of the paired features, we correlate the two paleo-shoreline features observed at the Grindstone quarry to the shoreline angles observed at Yardie Creek. The estimated uplift rates for the Grindstone Quarry site are summarized in Table 2. An uplift rate of 0.049 ± 0.030 mm/yr was calculated using the paleo-shoreline elevations of 10.5 m and 11.3 m.

5.3.3. Vlaming Head Vlaming Head is located at the northern tip of the Cape Range (21.80°S, 114.12°E) (Fig. 12). At this location an approximately 15 m-wide MIS 5e reef occurs at an elevation of 2.9 m. The paleoshoreline angle is buried beneath dunes. The active high tide shoreline angle is cut into this exposed reef at 1.6 m AHD. This elevation coincided with high tide at the time of our survey. Using the seaward edge of the shore platform elevation provides only a minimum estimate of the MIS 5e sea-level elevation at this location. Unlike all of the other sites, the exposed reef at Vlaming Head is a considerable distance from the paleo sea cliff and shoreline angle (N500 m). The greatest coast-perpendicular elevation change we observed across the shore platform surface anywhere in the study area is 3.7 m, at Cape Cuvier and the Korean Star—high energy environments—it is reasonable to assume that the elevation of the shoreline angle at Vlaming Head is less than 10.5 m (its elevation at Grindstone Quarry). This estimate is consistent with the late Neogene deformation and the northward plunge of the Cape Range anticline (Fig. 12). Given the limited data, we do not estimate an uplift or subsidence rate for Vlaming Head.

The vertical deformation rates along the Cape Range since MIS 5e are variable along the trend of the structure, which is consistent with the long-term style of deformation observed by Condon et al. (1955) (Fig. 12). The greatest uplift (doming) is in the central part of the Cape Range anticline and decreases to the north and south. The sequence of older marine terrace surfaces also is highest in the central part of the range and decreases in elevation at the northern and southern ends of the anticline. 6. Discussion of tectonic deformation Surveyed paleo-shoreline elevations provide evidence of Quaternary deformation across the Cape Range and Cape Cuvier anticlines in the Cape Region. The elevations of relative sea-level indicators from our 13 sites range from approximately 0 m to 10.4 m. Unlike the stable Gawler Craton that contains a LIg shoreline at a consistent elevation of 2 m over a 500 km-long stretch of coastline (Murray-Wallace, 2002), the shoreline features along the 300 km-long stretch of coastline in the Cape Region have elevations that vary by more than 10 m. The positions and elevations of LIg sea level indicators are consistent with the long-term pattern of late Neogene to Quaternary deformation along the coast (Fig. 13) (cf. Clark et al., 2012). The highest observed MIS 5e shoreline features coincide with the locus of maximum uplift on the Cape Cuvier anticline (i.e. fold axial location) and the minimum elevations coincide with locations on the fold limbs or noses, as seen along the Cape Cuvier and Cape Range anticlines, respectively. Because the LIg abrasion surface trends obliquely to the dip of the Cape Cuvier and Cape Range fold limbs (Fig. 13) the slope of the shore platform surface represents the apparent dip on the LIg section of the fold limb in a coast parallel direction. The folds exhibit a few meters of vertical displacement over a few kilometers of coastline, as is most evident at Red Bluff, where the platform elevation changes ~ 7 m over 3 km of a continuously exposed abrasion surface (eroded reef platform). This elevation change is approximately double what is observed at any individual coast perpendicular transect (Fig. 13).

172


Anticline Platform slope direction

24 o

10 km

Red Bluff

Cu v ier

3M

3M

Ca pe

n rea h Ko Nort ar St

Indian

Ocean

Quobba

e anticlin

Cu vi

er 12.0 10.0 8.0 6.0 4.0 2.0

7360000

7355000

7350000

7345000

7340000

7335000

7330000

7325000

7320000

7315000

0.0 7310000

AHD Elevation (Meters)

C a pe

ile

Ca mp No ile r th Ca m p To mb sto ne Tu rtle s

Gnaraloo

Maximum MIS 5e Coral /

Platform Edge

UTM Northing (Meters)

Fig. 13. Structural map of the Quobba Coast showing inferred anticline axis and plunge based on Tertiary outcrops near Cape Cuvier and MIS 5e platform elevations measured at the study sites. Small (coast parallel) arrows indicate MIS 5e platform slope (apparent dip). Graph shows limiting coral/platform elevations.

At a few locations, MIS 5e shoreline features intersect the active shoreline, notably north of 3 Mile Camp North site where the northward-sloping shore platform has been reoccupied during the Holocene transgression (Fig. 11A, B). At locations similar to this (e.g., Red Bluff North and north of Korean Star North) the platform surface elevations are no longer representative of paleo-shoreline elevations as the Pleistocene sections have been modified. For this reason, the lowest surveyed MIS 5e shore platform elevations we present are 2.8–3.1 m at Red Bluff North and 2.5 m at 3 Mile Camp North. Where the MIS 5e platform is lower than approximately 2.5–3 m elevation it is susceptible to reoccupation. The interaction between the paleo-shoreline and the modern shoreline precludes more definitive resolution of elevations at these locations. Therefore, these are minimum values. However, the lateral variability in height of MIS 5e platform and shoreline angles (e.g. Fig. 11A–C) suggests that the MIS 5e platform surface drops to near modern sea level and is possibly locally submerged. The relative sealevel change across the study region ranges from ~0 m at 3 Mile Camp North to N10.4 m at Red Bluff. Clark et al. (2012) estimate 10–15 m of uplift of the Jurabi (ca. MIS 7) terrace along the Cape Range since ~200 ka. This terrace age and elevation range yield late Pleistocene uplift rates of 0.05 to 0.07 mm/yr, decreasing to the north. These rates are best estimates that incorporate large uncertainties in age data (Clark, D. personal communication, 2014). Even so, at Yardie Creek, their rate estimate is within the upper range of our estimated rates (0.074 mm/yr). The pattern of deformation on the Cape Range anticline described in the Clark et al. (2012) study is consistent with the pattern identified in this study. Both are consistent with the underlying pattern of late Neogene deformation that indicates a north-plunging Cape Range anticline. The assumed MIS 5e age of 123.5 ± 6.5 ka, paleo sea levels of 5 ± 3 m, and our measured relative sea-level elevations yield estimated tectonic uplift and subsidence rates that range from 0.089 mm/yr to −0.047 mm/yr. These end-member rates are derived from the minimum and maximum limiting elevations of MIS 5e shoreline features observed at each site (Table 2). The end-member rates for all 13 sites are presented in Table 4. In our calculations, the high end of the LIg sea-level range (8 m) yields rates which suggest that net subsidence should be occurring along most of the Cape Region coastline (at 8 of the 13 study sites). Notably, at the Cape Range, a + 8 m MIS 5e sea-

level datum suggests late Quaternary subsidence at Yardie Creek (− 0.001 mm/yr) rather than uplift. These estimates are untenable with the longer term expression of Neogene deformation observed in the Cape Region. Therefore, we surmise that MIS 5e sea-level highstand was on the low-end of global estimates in this region of coastal west central Australia. 7. Conclusions This paper quantifies the locations and rates of late Quaternary deformation in the Cape Region of coastal west central Australia. Elevations of paleo-shoreline features collected from 13 sites along a 300 km section of coastline provide evidence of tectonic deformation since the LIg MIS 5e sea-level highstand (~130 to 117 ka). The elevations of the paleo-shoreline features indicate that late Quaternary deformation patterns are consistent with the longer term patterns of late Neogene to Quaternary folding. Table 4 End-member uplift rates derived from highest and lowest MIS 5e sea level estimates from the literature.

Quobba Coast

1 2 3 4 5 6 7 8 9 10

Cape Range

11 12 13

Cape Cuvier Korean Star Korean Star North Red Bluff South Red Bluff Red Bluff North Turtles Tombstone 3 Mile Camp 3 Mile Camp North Yardie Creek Grindstone Quarry Vlaming Head

Minimum estimated uplift rate (− denotes subsidence) from +8 m sea level

Maximum estimated uplift rate from +2 m sea level

0.008 0.015 −0.029

0.077 0.077 0.039

−0.008 0.018 −0.042 −0.003 −0.039 −0.029 −0.047

0.061 0.089 0.026 0.074 0.029 0.035 0.021

−0.001 0.019

0.074 0.079

–

–


Measurements of paleo-shoreline features normal to the coastline indicate that there is an approximate 2.5 m range in elevations at any of our investigation sites (Fig. 13). This is similar to the variability seen in modern shoreline features. However, the elevations of MIS 5e relative sea-level indicators along the coast range from approximately 0 m to greater than 10.4 m. The total elevation range of MIS 5e shoreline features is significantly greater than the 2.5 m elevation range for observed modern shoreline analogs. Further, the variations in platform elevations change predictably according to position relative to fold axes defined in the underlying Neogene deposits. In the Cape Region, the pattern of MIS 5e surface elevations is consistent with the wavelength of Neogene folds. We view this as evidence for progressive late Quaternary deformation of the LIg coastal section across the folds. The Cape Cuvier and Cape Range anticlines are tectonically active, low slip-rate structures. Vertical deformation rates were computed using limiting maximum marine shore platform and/or paleo-shoreline angle elevations, MIS 5e sea-level elevations of 5 ± 3 m, and MIS 5e age estimates of 123.5 ± 6.5 ka. These parameter values yield tectonic uplift rates at fold-axial locations of 0.054 ± 0.035 mm/yr at Red Bluff, 0.046 ± 0.031 mm/yr at Korean Star, and 0.049 ± 0.030 mm/yr at Cape Range. Tectonic subsidence may be occurring along fold limbs at rates of up to approximately −0.013 ± 0.034 mm/yr. The rates of deformation are low, but non-negligible and indicate that post-MIS 5e tectonic deformation has occurred. Regardless of whether LIg sea level was +2 or + 8 m or somewhere in between, the strain gauge provided by the LIg shoreline features is deformed systematically along wavelengths consistent with longer term deformation of Neogene strata. We provide new elevation and stratigraphic information on last interglacial shoreline features in the Cape Region of coastal west central Australia. Although the data we present indicate that the gross tectonic deformation is small and the rates are low, the data also demonstrate tectonic activity, not stability, within the formerly extended margin of coastal west central Australia. The evidence for tectonism is compelling, and though minor in absolute terms, the contribution of tectonism to relative sea-level change in the Cape Region must be recognized.

Acknowledgments We are very appreciative to the owners of Red Bluff camp and Gnaraloo Station for allowing access to their properties. We gratefully acknowledge the generous financial support provided by the Chevron Australia Business Unit (Project PDEP AES 12-P1ABU-82) and the genuine interest and support for this research shown by Dan Gillam and Jill Jensen. We thank Dr. Karl-Heinz Wyrwoll for introducing us to a number of the study locations in the Cape Region. We also appreciate the valuable knowledge, insights, and field discussions shared by Prof. Malcolm McCullough, and Prof. Ben Greenstein regarding the coral reef ecology and radiometric dating of corals in the Cape Region. Dr. Greenstein also provided valuable comments to an earlier draft of this manuscript. We also thank Dr. Derek Booth, Dr. Dan Muhs, Dr. Dan Clark, Dr. Colin Murray-Wallace, Dr. Vincent Regard, and two anonymous reviewers who provided detailed comments and feedback to earlier drafts. All of the reviews helped to greatly improve this manuscript. This work forms part of the activities of the Centre for Offshore Foundation Systems (COFS), currently supported as a node of the Australian Research Council Centre of Excellence for Geotechnical Engineering and as a Centre of Excellence by the Lloyd's Register Foundation. The Lloyd's Register Foundation invests in science, engineering and technology for public benefit, worldwide. The lead author is the recipient of a SIRF scholarship from The University of Western Australia.

References Adey, W.H., Macintyre, I.G., 1973. Crustose coralline algae: a re-evaluation in the geological sciences. Geol. Soc. Am. Bull. 84, 883–904.

173

AGSO North West Shelf Study Group, 1994. Deep reflections on the North West Shelf: changing perceptions of basin formation. In: Purcell, P.G., Purcell, R.R. (Eds.), The North West Shelf. Australia, Proceedings of the Petroleum Exploration Society of Australia symposium, pp. 63–76. Allen, J., 1972a. Groundwater resources along the lower Gascoyne River—a summary. W. Aust. Geol. Surv. Annu. Rep. 23–25. Allen, J., 1972b. Cretaceous–Holocene stratigraphy and structure, lower Gascoyne River, Carnarvon Basin. W. Aust. Geol. Surv. Annu. Rep. 17–22. Arrington, R.N., 1966. The Southern Carnarvon Basin, Western Australia. Aust. Pet. Explor. Soc. J. 6, 12–16. Australian Government Bureau of Meteorology website, d. accessed 20 June 2013. http:// www.bom.gov.au/oceanography/tides/. Baillie, P.W., Jacobson, E., 1995. Structural evolution of the Carnarvon terrace, Western Australia. Aust. Petrol. Explor. Assoc. J. 35, 321–332. Baillie, P., Powell, C., Li, Ryall, A., 1994. Tectonic framework of Western Australia's neoproterozoic to recent sedimentary basins. In: Purcell, P.G., Purcell, R.R. (Eds.), The North West Shelf Australia, Proceedings of the Petroleum Exploration Society of Australia Symposium, pp. 45–62. Baxter, J.L., 1967. The geology of the Rocky Pool dam site. Geological Survey of Western Australia, Report 16. Bock, Y., Prawirodirdjo, L., Genrich, F., Stevens, W., McCaffrey, R., Subarya, C., Puntodewo, S.O., Calias, E., 2003. Crustal motion in Indonesia from global positioning system measurements. J. Geophys. Res. 108. http://dx.doi.org/10.1029/2001JB000324. Boutakoff, N., 1963. Geology of the off-shore areas of North-Western Australia. Aust. Pet. Explor. Soc. J. 7, 44–49. Cathro, D.L., Karner, G.D., 2006. Cretaceous–tertiary inversion history of the Dampier Subbasin, northwest Australia: insights from quantitative basin modelling. Mar. Pet. Geol. 23, 503–526. Clark, D., 2006. A seismic source model based on neotectonic data. Proceedings, Earthquake Engineering in Australia: Canberra, pp. 69–73. Clark, E., 2010. Identification of Quaternary scarps in southwest and central west Western Australia using DEM-based hill shading: application to seismic hazard assessment and neotectonics. Int. J. Remote Sens. 31, 6297–6325. Clark, D., McPherson, A., Collins, C.D.N., 2011. Australia's seismogenic neotectonic record: a case for heterogeneous intraplate deformation. Geosci. Aust. Rec. 11. Clark, D., McPherson, A., Van Dissen, R., 2012. Long-term behaviour of Australian stable continental region (SCR) faults. Tectonophysics http://dx.doi.org/10.1016/j.tecto. 2012.07.004. Clarke, E. de C., 1938. Middle and west Australia regionale geologie der erde (Andree, Brouwer u. Bucher). (Die alten Kerne), (Abschnitt VII 1:62). Condon, M.A., Johnstone, D., Perry, W.J., 1955. The Cape Range structure Western Australia. Commonwealth of Australia Department of National Development Bureau of Mineral Resources Geology and Geophysics Bulletin. 21 p. 107. Condon, M.A., Johnstone, D., Prichard, C.E., Johnstone, M.H., 1956. The Giralia and Marrilla anticlines. Commonwealth of Australia Department of National Development Bureau of Mineral Resources Geology and Geophysics Bulletin 25, 96. Crone, A.J., Machette, M.N., Bowman, J.R., 1997. Episodic nature of earthquake activity in stable continental regions revealed by paleoseismicity studies of Australian and North American Quaternary faults. Aust. J. Earth Sci. 44, 203–214. Crostella, A., 1995. Structural evolution and hydrocarbon potential of the Merlinleigh and Byro sub-basins, Carnarvon Basin, Western Australia. Geol. Surv. W. Aust. Rep. 45, 41. Crostella, A., Iasky, R.P., 1997. Structural interpretation and hydrocarbon potential of the Giralia area. Carnarvon Basin, Western Australia Geological Survey Reportp. 52. Denman, P.D., van de Graaff, W.J.E., 1977. Emergent Quaternary marine deposits in the Lake MacLeod area, WA. W. Aust. Geol. Surv. Annu. Rep. 1976, 32–37. Dutton, A., Lambeck, K., 2012. Ice volume and sea level during the last interglacial. Science 337, 216–219. Ellis, G.K., Jonasson, K.E., 2001. Western Australia – Atlas of Petroleum Fields – Onshore Carnarvon Basin. Department of Mineral and Petroleum Resources Petroleum Division. 2 p. 2. Fischer, R., 1980. Recent tectonic movements of the Costa Rican Pacific coast. Tectonophysics 70, T25–T33. Ghose, B.K., 1977. Paleoecology of the Cenozoic reefal foraminifers and algae—a brief review. Palaeogeogr. Palaeoclimatol. Palaeoecol. 22, 231–256. Hancock, P.M., 1969. Regional geologic implications, Rocky Pool dam site investigation. Carnarvon Basin: Geological Survey of Western Australia Annual Report for the Year 1968, pp. 42–45. Hearty, P.J., O'Leary, M.J., 2008. Carbonate eolianites, quartz sands, and Quaternary sealevel cycles, Western Australia: a chronostratigraphic approach. Quat. Geochronol. 3, 26–55. Hearty, D.J., Ellis, G.K., Webster, K.A., 2002. Geological history of the western Barrow Subbasin: implications for hydrocarbon entrapment at Woollybutt and surrounding oil and gas fields. In: Keep, M., Moss, S.J. (Eds.), Proceedings of the Petroleum Exploration Society of Australia Symposium. The Sedimentary Basins of Western Australia 3, pp. 577–598. Hearty, P.J., Neumann, A.C., Hollin, J.T., O'Leary, M.J., McCulloch, M.T., 2007. Global sea level fluctuations during the last interglaciation (MIS 5e). Quat. Sci. Rev. 26, 2090–2112. Hengesh, J.V., 2010. Seismic source model development for Australia's northwest shelf. Proceedings of the Australian earthquake engineering society conference, Paper No. 22. Hengesh, J.V., Whitney, B.B., Rovere, A., 2011a. A Tectonic Influence on Seafloor Stability Along Australia's North West Shelf, Proceedings of the Twenty-first International Offshore and Polar Engineering Conference. ISBN: 978-1-880653-96-8, pp. 596–604 (ISSN 1098-6189).

174


Hengesh, J.V., Whitney, B.B., Clark, D., 2014. Quaternary Reactivation of Australia's Western Passive Margin: Inception of a New Plate Boundary? INQUA Focus Group on Paleoseismology and Active Tectonics. 5th INQUA Meeting on Paleoseismology. Active Tectonics and Archeoseismology (PATA), 21-27 September 2014, Korea, pp. 207–210. Hengesh, J.V., Wyrwoll, K.H., Whitney, B.B., 2011b. Neotectonic deformation of northwestern Australia and implications for oil and gas development. In: Gourvenec, White (Eds.), Proc. 2nd International Symposium on Frontiers in Offshore Geotechnics (ISFOG). Hillis, R.R., Sandiford, M., Reynolds, S.D., Quigley, M.C., 2008. Present-day stresses, seismicity and Neogene-to-Recent tectonics of Australia's ‘passive’ margins: intraplate deformation controlled by plate boundary forces. In: Johnson, H., Doré, A.G., Gatliff, R.W., Holdsworth, R., Lundin, E.R., Ritchie, J.D. (Eds.), The Nature and Origin of Compression in Passive Margins: Geological Society of London Special Publication. 306, pp. 71–90. Hocking, R.M., 1985. Geology of the Carnarvon Basin, Geological Survey of Western Australia, 1:1,000,000 scale map. Hocking, R.M., 1988. Regional geology of the northern Carnarvon Basin. In: Purcell, P.G., Purcell, R.R. (Eds.), Proceedings of the North West Shelf Symposium Petroleum Exploration Society of Australia, pp. 97–114. Hocking, R.M., Moors, H.T., van de Graaff, W.J.E., 1987. Geology of the Carnarvon Basin, Western Australia. Geol. Surv. W. Aust. Bull. 133. Iasky, R.P., Mory, A.J., 1999. Geology and petroleum potential of the Gascoyne platform southern Carnarvon basin Western Australia. Geol. Surv. W. Aust. Rep. 69, 51. Johansen, H.W., 1981. Coralline Algae, a First Synthesis. CRC Press, Inc. Boca Raton, Florida. Johnson, J.H., 1961. Limestone-building Algae and Algal Limestones. Johnson Publishing Company, Boulder. Keep, M., Powell, C.M., Baillie, P.W., 1998. Neogene deformation of the North West Shelf, Australia. In: Purcell, P.G., Purcell, R.R. (Eds.), Proceedings of the Petroleum Exploration Society of Australia. The Sedimentary Basins of Western Australia 2, pp. 81–91. Keep, M., Bishop, A., Longley, I., 2000. Neogene wrench reactivation of the Barcoo Subbasin, northwest Australia: implications for Neogene tectonics of the northern Australian margin. Pet. Geosci. 6, 211–220. Keep, M., Clough, M., Langhi, L., 2002. Neogene tectonic and structural evolution of the Timor Sea region, NW Australia. In: Keep, M., Moss, S.J. (Eds.), Proceedings of the Petroleum Exploration Society of Australia Symposium. The Sedimentary Basins of Western Australia 3, pp. 341–353. Keep, M., Harrowfield, M., Crowe, W., 2007. The Neogene tectonic history of the North West Shelf, Australia. Explor. Geophys. 38, 151–174. Keep, M., Hengesh, J., Whitney, B., 2012. Natural seismicity and tectonic geomorphology reveal regional transpressive strain in northwestern Australia. Aust. J. Earth Sci. 59, 341–354. Kendrick, G.W., Wyrwoll, K.-H., Szabo, B.J., 1991. Pliocene–Pleistocene coastal events and history along the western margin of Australia. Quat. Sci. Rev. 10, 419–439. Kennett, B.L.N., Abdullah, A., 2011. Seismic wave attenuation beneath the Australasian region. Aust. J. Earth Sci. 58, 285–295. Kershaw, S., Guo, L., 2001. Marine notches in coastal cliffs: Indicators of relative sea level change Perachora Peninsula, central Greece. Mar. Geol. 179, 213–228. Konecki, M.C., Dickins, J.M., Quinlan, T., 1958. The Geology of the Coastal Area Between the Lower Gascoyne and Murchison Rivers. Australia Bureau Mineral Resources, Western Australia 37. Kopp, R.E., Simons, F.J., Mitrovica, J.X., Maloof, A.C., Oppenheimer, M., 2009. Probabilistic assessment of sea level during the last interglacial stage. Nature 462, 863–868. Lajoie, K., 1986. Coastal tectonics. In: Wallace, R.E. (Ed.), Active Tectonics. National Academy Press, Washington, DC, pp. 95–124. Leonard, M., 2008. One hundred years of earthquake recording in Australia. Bull. Seismol. Soc. Am. 98, 1458–1470. Logan, B.W., 1987. The MacLeod evaporate basin, Western Australia. AAPG Mem. 44, 140. Logan, B.W., Read, J.F., Davies, G.R., 1970. History of carbonate sedimentation, Quaternary Epoch, Shark Bay, Western Australia. AAPG Mem. 13, 38–84. Longley, I.M., Buessenschuett, C., Clydsdale, L., 2002. The North West Shelf of Australia—a Woodside perspective. In: Keep, M., Moss, S. (Eds.), The Sedimentary Basins of Western Australia 3: Petroleum Exploration Society of Australia. 3, pp. 27–88. Malcolm, R., Pott, M., Delfos, E., 1991. A new tectonostratigraphic synthesis of the North West Cape area. Aust. Petrol. Prod. Explor. Assoc. J. 31, 154–176. McCue, K., 1990. Australia's large earthquakes and recent fault scarps. J. Struct. Geol. 12, 761–766. McPherson, A., Clark, D., Whitney, B., 2013. Neotectonic evidence for a crustal strain gradient on the central-west Western Australian margin. In: Moss, S., Keep, M. (Eds.), Proceedings of the Western Australian Basins Symposium (16 pp.). McWhae, J.R.H., Playford, P.E., Lindner, A.W., Glenister, B.F., Balme, B.E., 1956. The stratigraphy of Western Australia. J. Geol. Soc. Aust. 4, 1–153. Megallaa, M.N., 1980. A geophysical study of the central-southern Carnarvon Basin. Geol. Surv. W. Aust. Rep. 10. Moucha, R., Forte, A.M., Mitrovica, J.X., Rowley, D.B., Quere, S., Simons, N.A., Grand, S.P., 2008. Dynamic topography and long-term sea-level variations: there is no such thing as a stable continental platform. Earth Planet. Sci. Lett. 271, 101–108.

Muhs, D., 2002. Evidence for the timing and duration of the last interglacial period from high-precision Uranium-series ages of corals on tectonically stable coastlines. Quat. Res. 58, 36–40. Muhs, D.R., Simmons, K.R., Schumann, R.R., Halley, R.B., 2011. Sea-level history of the past two interglacial periods: new evidence from U-series dating of reef corals from south Florida. Quat. Sci. Rev. 30, 570–590. Müller, R.D., Dyksterhuis, S., Rey, P., 2012. Australian paleo-stress fields and tectonic reactivation over the past 100 Ma. Aust. J. Earth Sci. 59, 13–28. Murray-Wallace, C.V., 2002. Pleistocene coastal stratigraphy, sea-level highstands and neotectonism of the southern Australian passive continental margin—a review. J. Quat. Sci. 17, 469–489 (ISSN 0267–8179). O'Brien, G.W., Morse, M., Wilson, D., Quaife, P., Colwell, J., Higgins, R., Foster, C.B., 1999. Margin-scale, basement involved compartmentalization of Australia's North West Shelf: a primary control on basin-scale rift, deposition and reactivation histories. Aust. Petrol. Prod. Explor. Assoc. 39, 40–63. O'Leary, M.J., Hearty, P.J., McCulloch, M.T., 2008a. Geomorphic evidence of major sea level fluctuations during marine isotope substage-5e, Cape Cuvier, Western Australia. Geomorphology 102, 595–602. O'Leary, M.J., Hearty, P.J., McCulloch, M.T., 2008b. U-series evidence for widespread reef development in Shark Bay during the last interglacial. Palaeogeogr. Palaeoclimatol. Palaeoecol. 259, 424–435. Pedoja, K., Husson, L., Regard, V., Cobbold, P.R., Ostanciaux, E., Johnson, M., Kershaw, S., Saillard, M., Martinod, J., Furgerot, L., Weill, P., Delcaillau, B., 2011. Relative sea-level fall since the last interglacial stage: are coasts uplifting worldwide? Earth-Sci. Rev. 108, 1–15. Pirazzolli, P.A., 1986. Marine notches. In: van de Plassche, O. (Ed.), Sea-level Research: A Manual for the Collection and Evaluation of Data. Geo Books, Norwich. Playford, P.E., Johnstone, M.H., 1959. Oil exploration in Australia. Bull. Am. Assoc. Pet. Geol. 43, 397–433. Raggatt, H.G., 1936. Geology of the north-west basin, Western Australia, with particular reference to the stratigraphy of the Permo-Carboniferous. R. Soc. N. S. W. LXX, 100–174. Raynor, J.M., Condon, M.A., 1964. Summary of data and results, Carnarvon Basin, Western Australia, Exmouth Gulf marine seismic survey Whaleback seismic survey. West Australian Petroleum Pty. Publication. 49 p. 23. Revets, S.A., Keep, M., Kennett, B.L.N., 2009. NW Australian intraplate seismicity and stress regime. J. Geophys. Res. 114, B10305. http://dx.doi.org/10.1029/2008JB006152. Siddall, M., Chappell, J., Potter, E.-K., 2007. Eustatic sea level during past interglacials. Dev. Quat. Sci. 7, 75–92. Steneck, R.S., 1986. The ecology of coralline algal crusts: convergent patterns and adaptive strategies. Annu. Rev. Ecol. Syst. 17, 273–303. Stirling, C.H., Esat, T.M., McCulloch, M.T., Lambeck, K., 1995. High-precision U-series dating of corals from Western Australia and implications for the timing and duration of the Last Interglacial. Earth Planet. Sci. Lett. 135, 115–130. Stirling, C.H., Esat, T.M., Lambeck, K., McCulloch, M.T., 1998. Timing and duration of the Last Interglacial: evidence for a restricted interval of widespread coral reef growth. Earth Planet. Sci. Lett. 160, 745–762. Sykes, L., 1978. Intraplate seismicity, reactivation of pre-existing zones of weakness, alkaline magmatism, and other tectonism postdating continental fragmentation. Rev. Geophys. Space Phys. 16, 621–688. Teichert, C., 1948. Younger tectonics and erosion in Western Australia. Geol. Mag. 85, 243–246. van de Graaff, W.J.E., Denman, P.D., Hocking, R.M., 1976. Emerged Pleistocene marine terraces on Cape Range, Western Australia. W. Aust. Geol. Surv. Annu. Rep. 1975, 62–70. Veeh, H.H., Schwebel, D., van de Graaff, W.J.E., Denman, P.D., 1979. Uranium-series ages of coralline terrace deposits in Western Australia. J. Geol. Soc. Aust. 26, 285–292. Whitney, B.B., Hengesh, J.V., 2013. Geological constraints on Mmax values from Western Australia: implications for seismic hazard assessments. Aust. Geomech. J. 47, 15–25. Whitney, B.B., Hengesh, J.V., 2015. Geomorphological evidence of neotectonic deformation in the Carnarvon Basin, Western Australia. Geomorphology 228, 579–596. Whitney, B.B., Hengesh, J.V., Clark, D., 2014. The Western Australia Shear zone. INQUA Focus Group on Paleoseismology and Active Tectonics. 5th INQUA Meeting on Paleoseismology. Active Tectonics and Archeoseismology (PATA), 21-27 September 2014, Korea, pp. 162–165. Wyatt, J.D., 1967. Geological Investigations of the Kennedy Range Dam Site: Geologic Survey of Western Australia Report. p. 34. Wyrwoll, K.-H., Kendrick, G.W., Long, J.A., 1993. The geomorphology and Late Cenozoic geomorphological evolution of the Cape Range–Exmouth Gulf region. In: Humphreys, W.F. (Ed.), The Biogeography of Cape Range, Western Australia, Records of the Western Australian Museum Supplement. 45, pp. 1–23. Yeates, A., Bradshaw, M., Dickens, J., 1987. The Westralian superbasin, as Australian link with Tethys. In: McKenzie, K. (Ed.), Shallow Tethys 2, 2nd International Symposium on Shallow Tethys, pp. 199–213.