Fig 1.
Location of Lake Mungo and the extent of its shorelines based on digital elevation models (DEMs).
A. DEMs illustrating the Mungo lake shorelines during the mega-lake (75 m AHD) and main high lake phases (68–70 m AHD). The locations of surveyed transects of the shorelines are shown, including the lateral 75 m AHD beach transect (WOC beach transect), the dating and sedimentology transects (1. Northern lunette; 2. Central lunette). The location of channel sediment dating is also shown (3). B. Location of Lake Mungo within the Willandra Lakes system, and within Australia (inset). C. DEM of the northern Mungo lunette island during the mega-lake phase, showing the extent of the two connecting channels. The locations of the northern lunette transect (1) and channel dating study (3) are also shown.
Fig 2.
Schematic cross-sections showing the chronostratigraphy of the Lake Mungo lunette.
A. Stratigraphy, OSL ages and sampling positions of the central lunette transect, linking the RL beach with its backdune. B. Stratigraphy, OSL ages and sampling positions (both for OSL dating and particle-size analyses) of the northern lunette transect. Uncertainties of the OSL ages are 1σ. The 75 m AHD shoreline is marked in both transects as a dotted line.
Table 1.
Equivalent dose (De), dose rate data and OSL age estimates for the Lake Mungo lunette transects and Leaghur Channel samples.
Fig 3.
Lake Mungo chronostratigraphy and palaeohydrology, compared with palaeoenvironmental conditions in the Murray-Darling Basin (MDB).
The likely duration of the mega-lake phase (within 2σ of its weighted-mean age) is highlighted by dotted lines. A. Age-ranked chronology and relative probability distributions for the stratigraphic units at Lake Mungo, based on combined OSL ages from this study and [6]. The numbers of age estimates are: Reactivated Unit H (2), Arumpo (13), RL (4), Upper (7), Lower Mungo (4). The interpreted duration of the different stratigraphic units, and the palaeoenvironmental summary, is shown at the top of the diagram. The weighted-mean ages for each of the units are shown at the base. Uncertainties of the OSL ages are 1σ. B. Probability density distribution of sandy bedload units from MDB rivers (N = 73; after [16]). Age-ranked individual OSL ages for increased fluvial activity in the Lachlan River (N = 10; [15]) are also shown. Global marine oxygen isotope chronozones [53] are shown for context.
Fig 4.
Surveyed archaeological traces and OSL sampling sites in the northern, former island, transect.
A number of these traces are illustrated in the Supplementary Information. The context for A3 and A4 are shown in S17A Fig; the baked sediment hearthstones are shown in detail in S17B Fig, and its full assemblage in S17C Fig; A8 is shown in S17D Fig; the context for A5 and A6 is pictured in S17E Fig; A7 and A8 are shown in S18 Fig.