The Holocene Infill of Lake Conjola, a Narrow Incised Valley System on The

Quaternary International 221 (2010) 23–35

Contents lists available at ScienceDirect

Quaternary International

journal homepage: www.elsevier.com/locate/quaint

The Holocene inﬁll of Lake Conjola, a narrow incised valley system on the southeast coast of Australia

Craig R. Sloss a,*, Brian G. Jones b, Adam D. Switzer c, Scott Nichol d, Alastair J.H. Clement e, Anthony W. Nicholas b a School of Natural Resource Sciences, Queensland University of Technology, GPO Box 2434, 2 George Street, Brisbane, Queensland 4001, Australia b School of Earth and Environmental Sciences, University of Wollongong, NSW 2522, Australia c Department of Earth Sciences, The University of Hong Kong, Hong Kong SAR, China d Petroleum and Marine Division, Geoscience Australia, GPO Box 378, Canberra, ACT 2601, Australia e School of People, Environment & Planning, Private Bag 11-222, Massey University, Palmerston North, New Zealand article info abstract

Article history: A detailed Holocene sedimentological and geomorphological history of the sedimentary infill of Lake Available online 9 July 2009 Conjola, a barrier estuary on the southeast coast of Australia, is presented. Results show that a remnant Last Interglacial barrier system is preserved in the mouth of a narrow incised valley. During the early stage of Holocene sedimentary infill, a laterally extensive transgressive sand facies was deposited as rising post-glacial sea-level breached remnants of the Last Interglacial barrier ca. 7500 cal BP. From 7500 to 4000 cal BP sediment continued to accumulate within the mouth of the incised valley, forming an extensive flood-tide delta within the drowned river estuary. Marine influences were restricted by further sediment accumulation at the mouth of the estuary, leading to the development of mid-Holocene barrier and back-barrier depositional environments. This research adds detail to stratigraphic models of the sedimentary infill and geomorphological evolution of barrier estuaries formed in narrow incised valley systems on the southeast coast of Australia, and provides a global model for estuarine deposition in regions that have been tectonically stable over the late Quaternary. Ó 2009 Elsevier Ltd and INQUA. All rights reserved.

1. Introduction have similar sedimentological, geomorphological, and chronolog- ical responses to sea-level changes over the last full glacial cycle Models that summarise the geomorphologic evolution of barrier (Sloss et al., 2004, 2005, 2006a). Limited work in narrow (<2km estuaries on the southeast coast of Australia have now developed to wide), relatively shallow (<40 m deep) estuaries (e.g. Burrill Lake; the stage of including details of the sedimentary infill that relate to Sloss et al., 2006b) suggests a similar situation. the transgressive phase of the early Holocene. In earlier models, the This investigation of the sedimentary infill and geomorpholog- transgressive marine facies was spatially restricted to the mouths of ical evolution of Lake Conjola provides an opportunity to further the incised valleys and interfingered landward with back-barrier assess whether the infill and evolution of estuaries formed within central basin mud facies that unconformably overlie the antecedent narrow incised valley systems is consistent with the Burrill Lake Late Pleistocene land surface (e.g., Roy et al., 1980, 2001; Chapman study, and with results from estuaries that formed in broad incised et al., 1982; Roy, 1984a,b, 1994; Dalrymple et al., 1992). Elaborating valleys, such as Lake Illawarra and St Georges Basin. This case study on these earlier models of wave-dominated barrier estuaries, Sloss also presents the opportunity to develop a more detailed concep- et al. (2005, 2006a,b, 2007) have shown that the Holocene trans- tual model of the estuarine evolution and sedimentary infilling of gressive facies is more extensive than previously anticipated, narrow incised valley systems that have developed on tectonically forming a basal, near basin-wide shell-rich sandsheet that lies stable wave-dominated coasts. unconformably over the Late Pleistocene antecedent land surface. These studies have shown that estuaries formed in broad (>10 km wide) and relatively shallow (<30 m deep) incised valley systems 2. Study site

Lake Conjola, located approximately 200 km south of Sydney on * Corresponding author. Tel.: þ617 313 82610; fax: þ617 313 81535. the southeast coast of Australia, represents one of several wave- E-mail address: [email protected] (C.R. Sloss). dominated barrier estuaries that lie between the Eastern Highlands

1040-6182/$ – see front matter Ó 2009 Elsevier Ltd and INQUA. All rights reserved. doi:10.1016/j.quaint.2009.06.027 24 C.R. Sloss et al. / Quaternary International 221 (2010) 23–35 and the continental shelf (Fig.1; Roy et al.,1980, 2001). Lake Conjola complex, and has formed an elongate delta in the northwest of the formed in a relatively shallow (<40 m) and narrow (no more than basin (Fig. 2). The estuary is connected to the Pacific Ocean by 1 km at its widest) incised valley, cut into Permian sandstone a narrow and extensively shoaled (<2 m deep) sinuous channel bedrock (Snapper Point Formation) during previous sea-level approximately 3.5 km long (Fig. 2). This channel is sufficiently long lowstands. Around the margin of the estuary, the sandstone crops to reduce the tidal range within the estuary to a few centimetres. out as low sub-horizontal rock benches or small cliffs. Seaward of The restricted inlet also results in an average water level within the Lake Conjola, the coast is bordered by a narrow (<50 km wide) and estuary complex of þ27 cm above present mean sea level (PMSL; relatively deep (approximately 200 m) continental shelf (Roy et al., Manly Hydraulic Laboratory; Sloss et al., 2007). 1980). To the west, the catchment of Lake Conjola is constrained by the Eastern Highlands, which form a steep escarpment roughly 3. Methods parallel with the main trend of the coastline (Fig. 1). This coastal margin has experienced relative tectonic stability during the 3.1. Core collection and sediment analysis Quaternary (Murray-Wallace and Belperio, 1991; Murray-Wallace, 2002), making the southeast coast of New South Wales an ideal Surface sedimentary facies mapping was made using a combi- setting in which to examine the influence of sea-level fluctuations nation of aerial photography and field observations (Fig. 2). The over the most recent glacial cycle on the sedimentary infill of sedimentary infill and geological evolution of Lake Conjola were incised valley systems and the geomorphological evolution of reconstructed using the facies associations and faunal analysis of estuarine embayments. 27 largely undisturbed cores of unconsolidated sediment collected The barrier estuary comprises three depositional basins (Fig. 2): using a mechanically operated vibracorer. Cores were collected Lake Conjola itself, with a surface area of 5.8 km2 and water depths from the modern marine-influenced facies and the modern fluvial reaching 10 m; Lake Berringer, a northern limb of the estuary with bay-head delta (Fig. 2; Table 1). Cores recovered ranged from 1.50 m a surface area of 0.8 km2 and depth <5 m; and Pattimores Lagoon, to a maximum of 6.30 m of sediment. The cores were opened and a small coastal lagoon forming a southern limb with a surface area visually logged for colour, sediment texture, composition and of 0.3 km2 and maximum water depth of 3 m. Together, the three significant facies changes. The cores were levelled to Australian depositional basins act as a sediment sink for a 145 km2 river Height Datum (AHD), which is equivalent to mean sea level on the catchment. Conjola Creek is the main fluvial inlet to the estuary southeast coast of Australia, and were adjusted for compaction

WOLLONGONG Lake Illawarra

NSW Illawarra Escarpment Minnamurra River

Shoalhaven Bight South Pacific New South Shoalhaven River Ocean Wales SYDNEY 35°S Jervis Bay St Georges Basin

Swan Lake Lake Conjola N Narrawallee Inlet

Burrill Lake Continental shelf margin Tabourie Lake (200 m contour) Eastern Highlands (200 m contour)

20 km

Batemans Bay

Fig. 1. Map of study area showing the location of the Lake Conjola and other wave-dominated barrier estuaries on the southeast Australian coast. C.R. Sloss et al. / Quaternary International 221 (2010) 23–35 25

Fig. 2. Sedimentary facies divisions and vibracore locations within the Lake Conjola barrier estuary.

(measured core penetration vs. recovered depth). Core data were vibracores. The relative abundance of individual molluscan species plotted using the graphic logging program WinLoG 3.12 (GAEA for each facies was then determined (Table 3). Technologies). From each core, w5 g of sediment was collected every 10 cm, and 3.3. Optically stimulated luminescence dating (OSL) at locations of significant facies change, for sediment analysis. Sedi- ment samples were first visually inspected using a binocular micro- Samples were prepared at the Luminescence Dating Laboratory at scope to determine sediment constituents and roundness. Sediment The University of Hong Kong with techniques modified from (Li and collected for quantitative analysis was disaggregated in water by Sun, 2006). Raw samples were initially treated with 20% H2O2 and 10% immersion in an ultrasonic bath. Sodium hexametaphosphate was HCl to remove organic material and carbonates. Grains of 150–180 mm added to prevent flocculation of the fine-grained sediment prior to were selected by dry sieving. Sodium polytungstate heavy liquid analysis using a Malvern Mastersizer 2000 laser particle size analyser. (density between 2.62 and 2.70 g/cm3) was used to separate quartz Mean grain size, sorting and skewness were recorded to determine grains which were then treated with 40% hydrofluoric acid for 90 min sediment characteristics (Table 2), and to distinguish between sedi- to destroy any remaining feldspar, followed by 10% HCl acid etch to ments from different depositional environments. remove fluoride precipitates. Separated quartz grains were mounted on 10 mm diameter aluminum discs with ‘‘Silkospray’’ silicon oil. The 3.2. Faunal assemblages purity of quartz grains was tested by monitoring for the presence of feldspar using infrared stimulated luminescence (Aitken, 1998). OSL Faunal assemblages from the major sub-surface sedimentary measurements were made using an automated Risø TL-DA15 OSL facies were described to determine palaeo-depositional environ- reader (Markey et al., 1997). The equivalent doses (De) were deter- ments of sedimentary successions preserved in Lake Conjola. A mined by the SAR protocol (Murray and Wintle, 2000). visual assessment of the nature of preservation and relative The environmental dose rate was measured using a variety of abundance of macrofossil populations was made on the collected techniques. Thick-source alpha counting (TSAC) was used to measure 26 C.R. Sloss et al. / Quaternary International 221 (2010) 23–35

Table 1 Vibracore location and details (Grid Zone 56H).

Core Code Easting Northing Water depth (m) Core recovery (m) Compaction (m) CON1 268230 6098539 0.55 3.60 0.90 CON2 268059 6098321 1.30 4.24 0.95 CON3 268098 6098031 1.60 3.50 1.30 CON4 268123 6097785 2.15 4.36 0.23 CON5 267921 6097926 1.25 3.72 0.90 CON6 268253 6097562 2.40 3.51 1.13 CON7 268310 6097407 1.88 2.38 1.08 CON8 268837 6097468 1.70 4.94 3.70 CON9 268593 6097669 0.30 4.15 0.80 CON10 268157 6097354 2.70 3.02 0.15 CON11 268863 6097360 2.50 1.70 0.85 CON12 267058 6094898 2.75 4.06 0.55 CON13 267038 6094888 2.65 4.70 0.30 CON14 267018 6094990 2.60 4.82 0.30 CON15 272489 6096089 2.50 6.30 0.35 CON16 271526 6095200 2.60 5.97 0.58 CON17 272040 6095067 0.30 2.30 0.70 CON18 277962 6094915 0.32 3.08 1.20 CON19 271829 6094704 0.25 3.31 1.85 CON20 271596 6094402 0.50 1.50 0.25 CON21 270524 6094559 0.32 2.17 0.30 CON22 270391 6094604 0.30 2.43 0.70 CON23 270012 6094671 2.10 2.68 0.75 CON24 270101 6094930 2.10 3.86 0.90 CON25 269821 6094520 1.70 2.90 0.45 CON26 269780 6094537 1.20 2.80 0.55 CON27 270063 6094400 0.40 1.90 1.80

contributions from the U and Th decay chains (Aitken, 1985). Calibrated radiocarbon ages (cal BP) are presented using a 2-sigma Concentrations of U and Th were checked using X-ray fluorescence uncertainty term (95% degree of confidence; Table 4). (XRF) which was also used to determine potassium (K) content. The cosmic-ray dose rates were estimated from equations related to 3.5. Amino acid racemisation geomagnetic latitude and altitude (Prescott and Hutton, 1994). Fifteen samples of fossil molluscs were dated utilising the 3.4. Radiocarbon age determinations aspartic acid racemisation dating method. This dating method has proven to provide a useful geochronological tool for fossil material Radiocarbon (AMS) ages were obtained from fossil molluscs preserved in sedimentary successions spanning the early Holocene collected from sedimentary successions preserved in the incised to relatively recent (e.g., Goodfriend, 1991, 1992; Goodfriend and valley-fill (Table 4). Ages obtained from the Waikato University Stanley, 1996; Sloss et al., 2004, 2006a). Numeric ages for this study Radiocarbon Laboratory, New Zealand, were calibrated to sidereal have been determined based on the degree of aspartic acid race- years using the radiocarbon calibration program CALIB REV5.0.1 misation using an apparent parabolic kinetic model (Table 5; (Stuiver and Braziunas, 1993; Stuiver and Reimer, 1993). The marine Murray-Wallace and Kimber, 1987; Goodfriend et al., 1992; Murray- model calibration curve (Marine04) was used together with a DR Wallace, 1993; Sloss et al., 2004, 2006a; Sloss, 2005). Average value of 11 85 years to correct the marine reservoir effect for amino acid D/L ratios for each sample analysed were based on at southeastern Australia and to convert ages into sidereal years least three replicate injections on a reverse-phase high perfor- (Gillespie, 1977; Gillespie and Polach, 1979; Stuiver et al., 1998). mance liquid chromatograph in the Amino Acid Dating Laboratory,

Table 2 Summary of sediment analysis from successions preserved in Lake Conjola.

Facies code Main constituents Grain size Sorting Skewness Age range (years before present) Late Pleistocene barrier Quartz sand Fine- to medium- Well to poorly sorted Fine to coarse skewed Last Interglacial sand (PBS) grained Marine transgressive Quartz sand Medium- to coarse- Moderately to poorly Near symmetrical to coarse 7500–6500 sandsheet (MTS) and shell hash grained sorted skewed Flood-tide delta (FTD) Quartz sand Medium-grained Moderately to poorly Coarse to very coarse skewed 6500 to present sorted Back-barrier Quartz sand Medium-grained Moderately to well Fine skewed to near ? to present sand-flat (BBSF) sorted symmetrical Central basin mud Silt Very fine- to fine- Poorly to very poorly Fine skewed to near 4000 to present facies (CBM) grained sorted symmetrical Fluvial pro-delta/ Silt, quartz Fine- to medium- Poorly to very poorly Fine to very fine skewed Modern baskswamp and lithic clasts grained sorted (FPD/FBS) Fluvial bay-head Quartz and Medium- to coarse- Poorly to very poorly sorted Coarse skewed 2000 to present delta (FBD) lithic clasts grained C.R. Sloss et al. / Quaternary International 221 (2010) 23–35 27

Table 3 Holocene sedimentary succession (Table 4). Samples collected from Summary of the faunal distribution in facies preserved in Lake Conjola. the lower mottled unit 2.48–2.60 m and 2.75–2.90 m below the Species PBS HMTS FTD BBSF CBM FBD FPD/FBS sediment–water interface yielded OSL ages of 126 ka and 130 ka Anadara trapezia –Aa,b,c Aa,c Aa,b,c Rb,c Aa,c Aa,b,c respectively (Fig. 3). An additional OSL age from the poorly devel- Astele subcarinata –C C– – –– oped soil profile overlying the mottled unit (1.87–2.00 m below Austrocochlea constricta –C C– – –– sediment–water interface, Figs. 3 and 4) yielded an OSL age Batillaria australis –A AA R VCC of 61 ka. Brachidontes rostratus – R–Cb,c,d –– – –– Dosinia crocea – R–Cb,c –– – –– Eumarcia fumigate –Rc Rc –––– 4.2. Marine transgressive sand (MTS) Fulvia tenuicostata –Rc Rc –––– Nassarius burchardi –C CC C CC In cores collected from the mouth of the estuary, Lake Bellinger Nassarius jonasi –C CC C CC and along the southern arm of Lake Conjola, unconsolidated quartz Notospisula trigonella –Rb,c Cb,c Cb,c Ca,b,c Cc Rc Ostrea angasi –Cc –– – –– and carbonate-rich marine sand lies unconformably over the Pectan fumatus –Cc –– – –– antecedent Late Pleistocene substrate (Figs. 3–5). Sediment analysis Polinices conicus –C C– – –– shows that this unit is dominated by medium- to coarse-grained, Polinices sordidum –C C– – –– rounded to sub-rounded, moderately to poorly sorted and coarse Pyrazus ebeninus –C R– – –– Tellina deltoidalis –– –Cb,c Cb,c Cc VCb,c skewed to near symmetrical sand, suggesting rapid deposition or a mixed-energy regime (Table 2). This facies was recovered from VR ¼ Very rare; R ¼ Rare; C ¼ Common; VC ¼ very common; A ¼ Abundant. a Dominant species. cores collected from the marine-influenced facies (CON16–27), b Mainly articulated. ranged in thickness from 50 cm to 10 cm, and was recovered from c Mainly disarticulated. 5.60 m to 1.96 m below AHD. At Yooralla Bay in the western d Mainly fragments. extremity of the southern arm of Lake Conjola the marine transgressive sand forms a thicker (2 þ m) possible beach deposit where University of Wollongong. For a full discussion of the methods and it is confined by a rising shore (Fig. 5). Based on facies character- numeric age determinations see Sloss et al. (2004, 2006a) and Sloss istics and mineralogy, the source of this unit is interpreted to have (2005). been sediment stored on the continental shelf, which was trans- ported shoreward during the most recent post-glacial marine 4. Results transgression, rather than the surrounding catchments. The faunal population in the marine transgressive sand is domi- Seven individual facies were identified, based on sedimento- nated by the semi-infaunal estuarine bivalve Anadara trapezia and the logical data, faunal assemblages and geochronology. epifaunal gastropod Batillaria australis. Also found within this facies are common specimens of molluscs that typically inhabit low- to 4.1. Last Interglacial (LIG) remnant barrier sands high-energy sandy shores in the lower littoral zone in nearshore environments. These include the bivalves Dosinia crocea, Pecten In vibracores that penetrated the complete Holocene succession fumatus, Ostrea angasi, Brachidontes rostratus and the gastropods in the mouth of Lake Conjola (CON16, 19, 24, 23, 25, 26; Figs. 2–4), Astele subcarinata and Pyrazus ebeninus (Table 3; Ludbrook, 1984; the basal facies retrieved in the lower part of each profile comprises Yassini, 1986; Jensen, 1995, 2000; Sloss et al., 2006b, 2007). Age fine- to medium-grained quartzose sand that probably represents constraints for this facies are based on radiocarbon and amino acid a LIG remnant barrier. These sands are typically moderately to racemisation derived ages from fossils preserved in this unit range poorly sorted (Table 2) and white, yellow or light grey with minor from 6535 215 to 7330 390 cal BP (Figs. 3–5; Tables 5 and 6). mottling. This facies has very few lithic constituents, very little carbonate content and is dominated by rounded to well-rounded 4.3. Flood-tide delta sands (FTD) frosted quartz grains suggesting significant reworking. In CON25 the top of the LIG remnant barrier exhibits a rudi- This facies is composed of moderately to very poorly sorted fine- to mentary soil profile with a leached ‘‘A’’ horizon above a ‘‘B’’ horizon medium-grained sand, suggesting a wide variation of energy levels comprising poorly sorted dark brown to black medium- to fine- within different parts of the flood-tide delta. This facies was recovered grained humate-rich sand, or a pale grey to white sand with a clay from cores collected from the mouth of the inlet to Roberts Point and matrix (Fig. 3). Leaching of the ‘‘A’’ horizon of these strata and the Lake Berringer (CON16-25; Figs. 2 and 4). The measured thickness of accumulation of organic matter and/or clay minerals farther down this facies ranges up to 3 m but it may be thicker in the mouth of the the profile has resulted in textural inversion, and indicates trans- incised valley. The faunal elements of this facies are dominated by location of organic matter and clay minerals through the porous common estuarine molluscan species including the bivalves sand. The development of the proto-sol explains the greater range A. trapezia and Notospisula trigonella as well as common specimens of of particle sizes, sorting and skewness observed in this facies the gastropods B. australis, Nassarius burchardi, Nassarius jonasi, (Table 2). Polinices sordidus and Polinices conicus (Table 2). A. trapezia collected 14 The Late Pleistocene age for this facies is supported by OSL from this facies yielded a C age of 4850 300 cal BP This facies analysis of the pale mottled quartz sand facies that underlie the (Wk23267; Table 5) and amino acid racemisation age determinations range from 5750 270 to 320 20 cal BP.

Table 4 4.4. Muddy sand and reworked back-barrier sand-ﬂats (BBSF) Optical simulated luminescence (OSL) ages obtained from the Late Pleistocene successions from Lake Conjola. This facies is spatially restricted to the periphery of the lagoonal Core code Sample depth in core (m) Sample depth (below AHD) OSL age (ka) system in water depths generally <2 m, and hence it is prone to CON25 1.87–2.00 3.30–3.47 61 9 reworking due to internal wind-generated wave action and weak CON25 2.48–2.60 3.91–4.03 124 11 wind-generated currents. It is composed of medium-grained grey/ CON25 2.75–2.90 4.18–4.43 130 14 brown to olive/brown mottled sand with minor muddy fraction. 28 C.R. Sloss et al. / Quaternary International 221 (2010) 23–35

Fig. 3. Representative vibracore (CON25) collected from the inlet channel and ﬂood-tide delta region of the Lake Conjola barrier estuary (Figs. 2 and 4). The core shows the sequences starting in mottled Late Pleistocene sediments overlain by marine transgressive sands (MTS) and ﬂood-tide delta facies (FTD).

The sediments are moderately to well sorted with fine to near wood and shell hash. A mid to late Holocene age has been assigned symmetrical skewness suggesting significant reworking of this to the back-barrier sand-flat facies on the basis of stratigraphic facies (Table 2). A. trapezia is the dominant fauna, B. australis is position. abundant, N. trigonella becomes more common in the finer deeper areas and there are minor occurrences of Tellina deltoidalis, N. 4.5. Central basin mud facies (CBM) burchardi and N. jonasi (Table 3). The fossil shells preserved in this facies are typically disarticulated, chalky, degraded and frag- Coring in the central basin of Lake Conjolawas limited byexcessive mented, suggesting significant reworking of the bioclasts that are water depth. However, this facies was samples in cores collected from therefore unsuitable for dating. This unit also contains a quantity of the fluvial pro-delta regions near Conjola Creek (CON2-11) and C.R. Sloss et al. / Quaternary International 221 (2010) 23–35 29

Fig. 4. Core locations (A) and schematic cross-section (B) through the marine-influenced facies showing the Last Interglacial barrier deposits and Holocene sedimentary facies associations in the entrance to Lake Conjola. surface samples described by Packwood (1999).Thisfaciesis environment within the estuary (as it does at present) and would not composed of very fine-grained grey/black estuarinemud consisting of have been flushed from the system by circulating tidal currents. The a poorly to very poorly sorted silty clay, with a high concentration of age of this facies is based on its stratigraphic position above the organic matter characteristic of anoxic environments. This facies is marine transgressive sand; it accumulated in the low-energy central indicative of a very low-energy environment (Table 2). N. trigonella basin following the formation of the Holocene proto-barrier (between dominates these strata, occurring as occasional dense shell beds with about 5000 and 3000 cal BP). abundant articulated shells. Organic-rich layers are also interbedded within the estuarine mud closer to the fluvial margins of the estuary 4.6. Fluvial bay-head delta sands (FBD) (Fig. 6). The silty mud comprises fine-grained terrigenous detritus supplied from the freshwater streams entering the estuaries. The fine This facies was recovered from cores collected from near the silt would have rapidly flocculated in the brackish to fully saline mouth of Conjola Creek (CON1–5, 7, 8 and 10) and at Yooralla Bay 30 C.R. Sloss et al. / Quaternary International 221 (2010) 23–35

This facies typically contains interbedded organic lenses at the base of the unit, displaying similar characteristics to the pro-delta sandy mud, indicating that ﬂuvial bay-head delta prograded over the ﬂuvial pro-delta facies into the central basin (Figs. 2 and 6).

4.7. Fluvial backswamp deposits and pro-delta sandy mud (FBS and FPD)

These two facies consist of sandy mud or muddy sand composed mainly of poorly sorted and fine skewed fine-grained sand and silt, but in places containing rounded to sub-rounded quartz and sub- rounded to sub-angular lithic granules. These facies also have a high organic fraction with allochthonous wood and other organic matter; the backswamp facies commonly displays rudimentary peat development. These two facies are spatially restricted to inter- distributary bays, overbank swamps and the fluvial pro-delta environment at the mouth of Conjola Creek, where it enters the lagoon, and they are up to at least 1.5 m thick (Figs. 2 and 6). Faunal elements within the fluvial pro-delta sandy muds are dominated by the estuarine bivalves A. trapezia and N. trigonella, along with T. deltoidalis. The fossil shells preserved in the pro-delta facies are typically articulated and fresh. However, there are also common chalky, degraded and fragmented specimens, especially in the backswamp facies, indicating a mixed assemblage of in situ and reworked molluscan fauna. A radiocarbon age determination on an articulate A. trapezia (assumed to be in life position) collected from the fluvial pro-delta yielded an age of 155 155 cal BP (Table 5) indicating that the facies in CON11 is a modern depositional envi- Fig. 5. Schematic cross-section through the marine transgressive sand (MTS) and fluvial bay-head delta (FBD) facies in Yoorala Bay. Southwestern Lake Conjola (for core ronment at the front of the current delta. These two facies were locations see Fig. 2 and Table 1). deposited in low-energy regimes with occasional higher energy flood events.

(CON13–15; Figs. 2, 5 and 6). The thickness of this facies ranges up to at least 3 m but is probably thicker adjacent to the main channel 5. Discussion of Conjola Creek. The strata located in the bay-head delta are composed of olive/brown poorly sorted medium- to coarse-grained 5.1. Infill of narrow incised valley systems sand that is coarse skewed with minor quantities of silt and clay and a large component of sub-angular to rounded quartz and lithic Lake Conjola estuary fills a narrow and relatively shallow low- clasts. However, within the main channel the sediment is very stand-incised valley system eroded into the underlying Permian coarse-grained quartz and lithic-rich sand with sub-rounded to bedrock. Within the incised valley sediments extend back to 130 ka, rounded clasts up to 2 cm diameter. The fluvial channel sands also and thus preserve a record of sea-level regression and transgression contain a minor component of reworked carbonate shell hash. The over the last full glacial cycle. FBD facies is restricted to the channel margins and fluvial delta. Based on facies associations, fossil faunal assemblages and Within the delta sand, wood and other organic matter are common. geochronological data the Holocene depositional history and Fossil shells preserved in this facies are dominated by A. trapezia geomorphological evolution of the Lake Conjola barrier estuary has and T. deltoidalis with common B. australis and N. trigonella been identified. This sedimentary infill and geomorphological (Table 3). N. burchardi and N. jonasi are less common. However, evolution is similar to results from Burrill Lake 10 km to the south many shells are disarticulated, chalky, degraded and fragmented, (Sloss et al., 2006b). Both barrier estuaries represent narrow incised suggesting significant reworking of the bioclasts. Due to significant valley systems with infill histories that can be divided into five reworking of sediment and bioclasts it is difficult to assess the age distinct phases associated with sea-level fluctuations during the of this facies but all the analysed shells are less than 3000 years old. last glacial–interglacial cycle.

Table 5 Radiocarbon ages obtained from fossil molluscs collected in Lake Conjola.

Core code Species Sample depth Sample depth Radiocarbon dating Facies code Radiocarbon age Calibrated radiocarbon Radiocarbon age in core (m) (AHD) laboratory code age range cal yr BP CON11 A. trapezia 0.56 2.79 Wk23263 FPD 597 30 310–0 155 155 CON13a A. trapezia 2.15 4.52 Wk23264 MTS 6573 32 7280–6840 7060 220 CON16a P. fumatus 4.10 6.43 Wk23265 MTS 6645 32 7360–6930 7145 215 CON19a A. trapezia 2.48 2.46 Wk23266 MTS 6122 32 6750–6320 6535 215 CON21 A. trapezia 1.48 1.53 Wk23267 FTD 4638 32 5150–4550 4850 300 CON22 A. trapezia 2.28 2.31 Wk23268 MTS 6283 34 6960–6490 6725 235

a Denotes samples that have had both radiocarbon and amino acid racemisation analysis. C.R. Sloss et al. / Quaternary International 221 (2010) 23–35 31

Table 6 Amino acid (aspartic) recemisation derived ages obtained from fossil molluscs collected in Lake Conjola.

Core code Species Sample depth in core (m) Sample depth (m AHD) Facies code Laboratory code Average Asp D/L ratio AAR age CON5 B. australis 0.32 1.30 FBD UWGA-7487 0.313 0.043 1120 60 CON11 A. trapezia 0.56 2.79 FBD UWGA-7488 0.210 0.010 1170 60 CON12 N. trigonella 0.57 3.05 FBD UWGA-7496 0.202 0.023 1110 60 CON13 B. australis 0.36 2.74 FBD UWGA-7489 0.329 0.059 2910 180 CON13a A. trapezia 2.20 4.58 MTS UWGA-7490 0.500 0.030 6800 340 CON14 B. australis 0.64 2.97 FBD UWGA-7492 0.308 0.022 1075 55 CON16a P. fumatus 4.10 6.43 MTS UWGA-7497 0.488 0.044 7330 390 CON18 B. australis 0.95 1.00 FTD UWGA-7493 0.191 0.015 320 20 CON19 B. australis 0.42 0.40 FTD UWGA-7494 0.439 0.013 2440 120 CON19a A. trapezia 2.48 2.46 MTS UWGA-7498 0.540 0.015 6800 320 CON21 A. trapezia 1.03 1.08 FTD UWGA-7495 0.534 0.026 3770 190 CON21 B. australis 1.64 1.69 FTD UWGA-7483 0.648 0.019 5750 270 CON22 A. trapezia 2.93 2.96 FTD UWGA-7486 0.442 0.070 5300 320

a Denotes samples that have had both radiocarbon and amino acid racemisation analysis.

5.2. Last Interglacial (LIG) barrier system 3.4 m AHD; Fig. 3) yielded an OSL age of 61 9 ka, supporting the hypothesis that this basal unit was partially exposed and reworked Facies analysis and OSL ages obtained from the Late Pleistocene during a post-LIG period. succession recovered from the Conjola estuary complex indicate During this time a fluvial channel would have incised into the that a barrier system formed within the mouth of the incised valley Pleistocene sediments creating a lowstand-incised valley. However, during the Last Interglacial (Figs. 3, 4 and 7). As with the Holocene fluvial erosionwas not sufficient to remove all of the remnant barrier barrier system, it is assumed that sediment stored on the continental system. As a result the remnant barrier still partly fills the present shelf during the penultimate glacial phase would have moved mouth of the estuary and provided a core on which the Holocene landward with rising sea level as a transgressive systems tract. barrier and flood-tide delta has formed (Fig. 7). This is consistent Following the transgression and during the LIG sea-level highstand with research in other estuarine systems on the southeast Australian sediments accumulated in the mouth of the incised valley system, coast that shows LIG remnant barriers underlying all the investi- resulting in the stabilisation of a barrier and back-barrier lagoon gated Holocene barrier systems (Sloss et al., 2006a,b, 2007). similar to the Holocene lagoon that presently fills the incised valley. Roy and Thom (1981; also see Thom and Roy, 1983) suggested 5.4. Holocene marine transgression that on the south coast of New South Wales (south of 33S) LIG deposits had been removed from incised valley systems during Between ca. 7800 and at least 6500 cal BP, the lowstand-incised periods of lower sea-levels. However, similar LIG remnant barrier valley was inundated by rising sea-level during the most recent systems have subsequently been identified in Burrill Lake (Sloss post-glacial marine transgression (Sloss et al., 2007). During this et al., 2006b), the Minnamurra estuary (Boyle, 2004) and in the phase sea-level attained sufficient elevation to breach the remnant broader, shallow incised valleys now occupied by Lake Illawarra LIG barrier and resulted in the deposition of a transgressive sand and St Georges Basin (Sloss et al., 2004, 2005, 2006a). Evidence of facies (MTS facies, 2.10 m to 5.83 m AHD; Figs. 3–5 and 7). The partially preserved LIG estuarine deposits has also been reported shell-rich MTS facies, with a diverse mix of marine and estuarine from Narrawallee Inlet, 5 km south of Lake Conjola (Fig. 1; Nichol molluscan fauna, indicates that during the early- to mid-Holocene and Murray-Wallace, 1992). The presence of estuarine clays indi- Lake Conjola was more open to direct ocean influences and oper- cates that a LIG barrier would have been present beneath the ated as a narrow sheltered coastal embayment or drowned river Holocene barrier system in a more seaward locality than investi- estuary. This is consistent with results from Burrill Lake, Minna- gated by Nichol and Murray-Wallace (1992). These estuarine clays murra River and the broader incised valleys now filled by Lake underwent diagenetic alteration when subaerially exposed Illawarra and St Georges Basin. All these valley-fill successions following the LIG sea-level highstand. Similar weathered and record the deposition of transgressive sand facies and more open mottled clays containing ferruginous or calcareous nodules and marine conditions during the Holocene marine transgression and scattered roots were identified in Lake Illawarra and have also been early sea-level highstand (Sloss et al., 2006a,b, 2007). assigned a LIG age based on their stratigraphic position (Sloss, 2005; Sloss et al., 2006a). Hence LIG deposits on the south coast are much more common than Roy and Thom (1981) inferred. 5.5. Holocene sea-level highstand In Lake Conjola LIG deposits are represented by a remnant barrier sand facies that would have been deposited during the Last The FTD facies is interpreted to have been deposited as sediment Interglacial sea-level maximum (wþ5 m AHD). Specifically, the LIG continued to accumulate in the drowned river valley during the facies most likely represents sand deposited as transgressive and Holocene highstand (ca. 6500–2500 cal BP; Sloss et al., 2007). This flood tidal delta deposit during the LIG sea-level highstand ca. facies represents a transition between the wave-dominated near- 125–130 ka (Figs. 3–5 and 7; Table 4). shore and more sheltered back-barrier depositional environments. At present this facies is restricted to the mouth of Lake Conjola. However, during the early- to mid-Holocene this facies also 5.3. Lowstand-incised valley system extended throughout the Lake Berringer depositional basin (Fig. 4). Based on radiocarbon and amino acid racemisation derived ages on Following the LIG sea-level highstand the remnant barrier A. trapezia and B. australis, the FTD facies ranges in age from system experienced sub-aerial exposure and reworking resulting in 5750 270 to 320 20 cal BP (Figs. 2 and 4; Tables 5 and 6). This minor post-emplacement diagenetic alteration and rudimentary indicates that the flood-tide delta continued to provide a positive soil development. The poorly developed soil profile in CON25 (ca. sediment supply following the culmination of the Holocene marine 32 C.R. Sloss et al. / Quaternary International 221 (2010) 23–35

Fig. 6. Core locations (A) and schematic cross-section (B) showing the facies associations from the ﬂuvial-dominated facies adjacent to Conjola Creek. C.R. Sloss et al. / Quaternary International 221 (2010) 23–35 33

Fig. 7. The geomorphological evolution of Lake Conjola showing: (a) lowstand fluvial incision into the bedrock basement and the antecedent Pleistocene land surface; (b) deposition of the Holocene marine transgressive sandsheet from ca. 7500 to 5500 years ago and subsequent sea-level highstand; (c) restriction of the open ocean marine influence associated from ca. 3000 years ago due to the growth of an Holocene proto-barrier resulting in the development of the low-energy back-barrier lagoon; and (d), further restriction of marine influences associated with the fully emergent Holocene barrier, the shoaling of the inlet channel and the initiation of the progradation of fluvial bay-head deltas from ca. 3000 years ago. transgression. The continued aggradation of the flood-tide delta and two smaller creeks in the northwest of the estuary complex. facies during the mid-Holocene highstand would have eventually The initial sedimentation consists of backswamp and deltaic resulted in restricted tidal flow and the development of barrier, deposits that extend 2–4 km down the creeks to the present inlet channel and back-barrier depositional environments from at northern margin of Lake Conjola. The current delta associated with least 3000 years ago. Conjola Creek consists of spatially restricted fluvial channel sands The presence of the transgressive facies (ca. 7500–5500 cal BP) and that extend 1.5 km south along the western margin of the lagoon the initial highstand flood-tide delta deposits (ca. 5500–3000 cal BP) forming an elongate delta. The fluvial sands grade laterally into are consistent with results from Lake Illawarra, St Georges Basin and delta front sands and pro-delta sandy mud that extend a farther Burrill Lake. These estuaries also record a shift from open marine 800 m into the lagoon. An amino acid derived age on B. australis conditions to more sheltered back-barrier depositional environments, (1120 60; UWGA-7487) and A. trapezia (1170 60; UWGA-7488) and fine-grained estuarine mud then accumulated in the deeper parts collected from fluvial influenced facies indicate that timing of the of the incised valley from ca. 4500 cal BP (Sloss et al., 2006a,b, 2007). present progradation of this fluvial system in Lake Conjola occurred sometime before 1100 years ago (Fig. 6; Tables 5 and 6). Delta 5.6. Fluvial progradation progradation in Yooralla Bay occurred at essentially the same time (Fig. 5; Tables 5 and 6). Related sedimentological and stratigraphic Apart from shoaling in the inlet channel, sediment infilling of studies on fluvial progradation in Lake Illawarra (Sloss et al., 2005, the depositional basin is presently concentrated at the landward 2006a; Hopley and Jones, 2006), St Georges Basin (Sloss et al., margins of the estuary and is dominated by fluvial activity 2006b; Hopley et al., 2007), and Burrill Lake (Jones et al., 2003; (Figs. 5–7). The main source of terrigenous detritus is Conjola Creek Sloss et al., 2006b) indicate that major fluvial progradation into the 34 C.R. Sloss et al. / Quaternary International 221 (2010) 23–35

Fig. 8. Stratigraphic model of the evolutionary stages of barrier estuaries that have formed in both broad and narrow relatively shallow (<40 m deep) incised valleys showing: (a) the lowstand-incised valley system and remnant interglacial barrier; (b) more open marine conditions during the Holocene transgression and the initial stages of the Holocene sea- level highstand ca. 8000–4000 years ago; (c) sedimentary infilling during the latter stages of the Holocene sea-level highstand and slight sea-level regression from ca. 2500 years ago (modified after Roy, 1984a; Sloss et al., 2006a,b, 2007). present estuarine basins and the deposition of fluvial pro-delta and The other major diversion from the previous stratigraphic bay-head delta sands occurred at least 2500 cal BP. The details of models is seen with the deposition of the transgressive facies and or the fluvial and estuarine interface are one area that requires addi- highstand facies that extends farther landward as a near basin- tional upstream research in the future. wide deposit (Fig. 8). The reason for the greater extent of the transgressive deposit is due to the system operating as an open coastal embayment as rising sea level inundated the incised valley 6. Conceptual models for the geomorphological and during the most recent post-glacial marine transgression (ca. sedimentological histories of barrier estuaries 8000–6500 cal BP). During this early stage of infill sediment supply on tectonically stable margins was not sufficient to fill the accommodation space until sea-level stabilised during the Holocene sea-level highstand (ca. 6500– The stratigraphy recorded in the infill of narrow incised valley 2500 cal BP). During the highstand marine sediment supply systems that are now occupied by Lake Conjola and Burrill Lake is exceeded accommodation space resulting in the deposition of an consistent with the sedimentary infill and geomorphological extensive flood-tide delta and barrier system that eventually filled evolution of barrier estuaries that have formed in broad, shallow the mouth of the incised valley (Fig. 8). incised valleys (Sloss et al., 2005, 2006a,b). Results from this and related studies into the infill of incised valley systems adds greater detail to conceptual models for the 7. Conclusions geomorphological and sedimentological histories of barrier estuaries on relatively tectonically stable coastal margins (Fig. 8). In The sedimentary infill and geomorphological evolution of the particular, results from Lake Conjola show that the barrier complex Lake Conjola barrier estuary is consistent with results from extends much further landward than in earlier stratigraphic models a previous study in Burrill Lake. Both estuarine systems represent which show it to be restricted to the mouth of the incised valley and barrier estuaries that have formed in narrow and relatively shallow no farther landward than the inlet (Chapman et al., 1982;(Roy, incised valleys. Both have similar geological settings and experi- 1984a,b) 2001; Dalrymple et al., 1992; Roy, 1994). enced the same sea-level histories over the most recent full glacial The revised conceptual model also has a greater emphasis on cycle. In summary this sedimentological and geomorphological the role that the antecedent Late Pleistocene land surface and the history includes: inherited geomorphology of the incised valley system plays on the sedimentary infill and geomorphological evolution of the barrier - Narrow and relatively shallow incised valleys eroded into estuary (Fig. 8). In this regard, preservation of LIG marine sediments Permian bedrock. overlain by Holocene transgressive and highstand deposits, illus- - The preservation of sediment infill that extends back to at least trates that incised valley fills on the south coast of NSW formed over the LIG. at least two glacio-eustatic sea-level cycles (Nichol and Murray- - LIG sediments are represented by remnant barrier and back- Wallace, 1992; Sloss et al., 2006a,b). Work in narrow incised valley barrier facies. estuaries in New Zealand also highlights this control of antecedent - The late Pleistocene deposits are unconformably overlain by valley fill on modern facies organisation (e.g. Heap and Nichol,1997). the near basin-wide transgressive sand facies that contains C.R. Sloss et al. / Quaternary International 221 (2010) 23–35 35

a diverse mix of estuarine and shallow marine faunal assem- Hopley, C.A., Jones, B.G., Puotinen, M., 2007. Assessing the recent (1834–2002) blages. This transgressive facies was deposited between 7500 morphological evolution of a rapidly prograding delta within a GIS framework: Macquarie Rivulet delta, Lake Illawarra, New South Wales. Australian Journal of and 5500 cal BP. Earth Sciences 54, 1047–1056. - Open marine conditions continued during the early stage of the Jensen, P.,1995. Seashells of Central New South Wales. Townprint, Townsville. p. 129. Holocene sea-level highstand (ca. 5500–3000 cal BP) indicative Jensen, P., 2000. Seashells of South-Eastern Australia. Capricornica Publications, Sydney, p. 118. of a more open marine embayment or drowned river estuary Jones, B.G., Killian, H.E., Chenhall, B.E., Sloss, C.R., 2003. Anthropogenic effects in that occupied the shallow incised valleys for much of the a coastal lagoon: geochemical characterization of Burrill Lake, NSW, Australia. Holocene highstand. Journal of Coastal Research 19, 621–632. Li, S.H., Sun, J., 2006. Optical Dating of Holocene dune sands from the Hulun Buir - The extension of a relatively recent elongate fluvial delta has Desert, northeastern China. The Holocene 16 (3), 457–462. dominated sedimentary and geomorphological change in the Ludbrook, N.H., 1984. Quaternary Molluscs of South Australia. Department of Mines inner part of the estuary. and Energy, Handbook No. 9. Government Printer, Adelaide, p. 327. - The sedimentological and geomorphological histories of the Markey, B.G., Bøtter-Jensen, L., Duller, G.A.T., 1997. A new flexible system for measuring thermally and optically stimulated luminescence. Radiation narrow and shallow incised valleys now occupied by Burrill Measurements 27, 83–90. Lake and Lake Conjola are similar to those histories identified Murray, A.S., Wintle, A.G., 2000. Luminescence dating of quartz using an in the broader incised valleys now occupied by Lake Illawarra improved single-aliquot regenerative-dose protocol. Radiation Measurements 32, 57–73. and St Georges Basin. Accordingly, results from this study Murray-Wallace, C.V., Belperio, A.P., 1991. Last Interglacial shoreline in Australia – provides support the revised model of estuarine evolution on a review. Quaternary Science Reviews 10, 441–461. the southeast coast of Australia and provide a framework for Murray-Wallace, C.V., Kimber, R.W.L., 1987. Evaluation of the amino acid racemization reaction in studies of Quaternary marine sediments in South Australia. other regions that have similar sea-level histories on tectoni- Australian Journal of Earth Sciences 34, 279–292. cally stable margins. Murray-Wallace, C.V., 1993. A review of the application of the amino acid racemisation reaction to archaeological dating. The Artefact 16, 19–26. Acknowledgements Murray-Wallace, C.V., 2002. Pleistocene coastal stratigraphy, sea-level highstands and neotectonism of the southern Australian passive continental margin – a review. Journal of Quaternary Science 17, 469–489. We thank the School of Earth and Environmental Sciences, Nichol, S.L., Murray-Wallace, C.V., 1992. A partially preserved last interglacial University of Wollongong; and GeoQuEST, University of Wollon- estuarine fill: Narrawallee Inlet, New South Wales. Australian Journal of Earth Sciences 39, 545–553. gong. Optical stimulated luminescence analysis was undertaken at Packwood, A., 1999. An environmental investigation of Lake Conjola, South Coast, the University of Hong Kong. Conventional radiocarbon ages were NSW. B.Sc. (Hons) thesis, University of Wollongong, Wollongong (unpubl.). p.131. obtained from the Australian National University, Canberra; and Prescott, J.R., Hutton, J.T., 1994. Cosmic ray contributions to dose rates for luminescence and ESR dating: large depths and long-term time variations. Radiation Waikato University, New Zealand. Amino acid racemisation analysis Measurements 23, 497–500. was undertaken at the Amino Acid Racemisation Dating Laboratory, Roy, P.S., Thom, B.G., 1981. Late Quaternary marine deposition in New South Wales University of Wollongong. Optical stimulated luminescence anal- and southern Queenslanddan evolutionary model. Journal of the Geological Society of Australia 28, 417–489. ysis was undertaken at the University of Hong Kong by Anchuan Roy, P.S., Thom, B.G., Wright, L.D., 1980. Holocene sequences on an embayed high- Fan with the assistance of Annie Lau and Holly Wong. We also thank energy coast: an evolutionary model. Sedimentary Geology 26, 1–19. Massey University for travel assistance for A. Clement (Graduate Roy, P.S., Williams, R.J., Jones, A.R., Yassini, I., Gibbs, P.J., Coates, B., West, R.J., Scanes, P.R., Hudson, J.P., Nichol, S., 2001. Structure and function of south-east Research Fund, 2007). This paper is a contribution to IGCP Project Australian estuaries. Estuarine, Coastal and Shelf Science 53, 351–384. 495 ‘‘Quaternary Land–Ocean Interactions’’ and the INQUA working Roy, P.S., 1984a. New South Wales estuaries: their origin and evolution. In: group on ‘‘Coastal and Marine Processes’’. Thom, B.G. (Ed.), Coastal Geomorphology in Australia. Academic Press, Sydney, pp. 99–212. Roy, P.S., 1984b. Holocene sedimentation histories of estuaries in southeastern References Australia. In: Hodgkins, E.P. (Ed.), Estuarine Environments of the Southern Hemi- sphere. Department of Conservation and Environment Bulletin 161,Perth, pp.1–59. Aitken, M.J., 1985. Thermoluminescence Dating. Academic Press, London, p. 359. Roy, P.S., 1994. Holocene estuary evolution – stratigraphic studies from south- Aitken, M.J., 1998. An Introduction to Optical Dating. Oxford University Press, eastern Australia. In: Dalrymple, R., Boyd, R., Zaitlin, B.A. (Eds.), Incised-Valley Oxford, p. 267. Systems: Origin and Sedimentary Sequences. SEPM Society of Sedimentary Boyle, J., 2004. Late Quaternary geomorphological evolution of Minnamurra Geology Special Publication 51, pp. 241–264. estuary, New South Wales. B.Sc. (Hons) thesis, University of Wollongong, Sloss, C.R., Murray-Wallace, C.V., Jones, B.G., Wallin, T., 2004. Aspartic acid race- Wollongong (unpubl.). p. 213. misation dating of mid-Holocene to recent estuarine sedimentation in New Chapman, D.M., Geary, M., Roy, P.S., Thom, B.G., 1982. Coastal Evolution and Coastal South Wales, Australia: a pilot study. Marine Geology 212, 45–59. Erosion in New South Wales. Coastal Council of New South Wales, Sydney. p. 341. Sloss, C.R., Jones, B.G., Murray-Wallace, C.V., McClennen, C.E., 2005. Holocene sea Dalrymple, R.W., Zaitlin, B.A., Boyd, R.,1992. Estuarine facies models: conceptual basis level change and the evolution of a barrier estuary: a case study, Lake Illawarra, and stratigraphic implications. Journal of Sedimentary Petrology 62, 1130–1146. NSW, Australia. Journal of Coastal Research 21, 943–959. Gillespie, R., Polach, H.A., 1979. The suitability of marine shells for radiocarbon Sloss, C.R., Murray-Wallace, C.V., Jones, B.G., 2006a. Aminostratigraphy of two dating of Australian prehistory. In: Berger, R., Suess, H.E., (Eds.). Radiocarbon Holocene wave-dominated barrier estuaries in southeastern Australia. Journal Dating, International 14C Conference 9th, Proceedings. Berkeley, University of of Coastal Research 22, 113–136. California Press, pp. 404–421. Sloss, C.R., Jones, B.G., McClennen, C.E., de Carli, J., Price, D.M., 2006b. The Gillespie, R., 1977. Sydney University natural radiocarbon measurements IV. geomorphological evolution of a wave-dominated barrier estuary: Burrill Lake, Radiocarbon 19, 101–110. New South Wales, Australia. Sedimentary Geology 187, 229–249. Goodfriend, G.A., Stanley, D.J., 1996. Reworking and discontinuities in Holocene Sloss, C.R., Murray-Wallace, C.V., Jones, B.G., 2007. Holocene sea-level change on the sedimentation in the Nile delta: documentation from amino acid racemization southeast coast of Australia: a review. The Holocene 17, 1001–1016. and stable isotopes in mollusk shell. Marine Geology 129, 271–283. Sloss, C.R., 2005. Holocene sea-level change and the aminostratigraphy of wave- Goodfriend, G.A., Hare, P.E., Druffel, E.R.M., 1992. Aspartic acid racemization and dominated barrier estuaries on the southeast coast of Australia. Ph.D. thesis, protein diagenesis in corals over the last 350 years. Geochimica et Cosmochi- University of Wollongong, Wollongong (unpubl.). p. 485. 14 14 mica Acta 56, 3847–3850. Stuiver, M., Braziunas, T.F., 1993. Modelling atmospheric C influences and C ages Goodfriend, G.A., 1991. Patterns of racemization and epimerization of amino acids in of marine samples to 10,000 BC. Radiocarbon 35, 137–189. 14 land snail shells over the course of the Holocene. Geochimica et Cosmochimica Stuiver, M., Reimer, P.J., 1993. Extended C database and revised CALIB radiocarbon Acta 55, 293–302. calibration program. Radiocarbon 35, 215–230. Goodfriend, G.A., 1992. Rapid racemization of aspartic acid in mollusc shells and Stuiver, M., Reimer, P.J., Braziunas, T.F., 1998. High-precision radiocarbon age cali- potential for dating over recent centuries. Nature 357, 399–401. bration for terrestrial and marine samples. Radiocarbon 40, 1127–1151. Heap, A.D., Nichol, S.L., 1997. The influence of limited accomodation space on the Thom, B.G., Roy, P.S., 1983. Relative sea level change in New South Wales over the stratigraphy of an incised-valley succession: Weiti River estuary, New Zealand. past 15,000 years. In: Hopely, D. (Ed.), Australian Sea Levels in the Last 15,000 Marine Geology 114, 226–252. years: a Review, Monograph Series, Occasional Papers, vol. 3. Department of Hopley, C.A., Jones, B.G., 2006. Holocene stratigraphic and morphological evolution Geography, James Cook University, Townsville, pp. 64–84. of the Wandandian Creek delta, St Georges Basin, New South Wales. Australian Yassini, I., 1986. Shelled Molluscs of Lake Illawarra. Lake Illawarra Management Journal of Earth Sciences 53, 991–1000. Committee and Wollongong City Council, Wollongong, p. 41.