Fig 1.
Location of Riwi Cave.
Fig 2.
(A) Plan and (B) profile. CAD by Dorcas Vannieuwenhuyse.
Fig 3.
Stratigraphic profile and description of (A) squares 1 and 4, and (B) square 3. The location of OSL samples is marked in red, and the location of radiocarbon charcoal samples in yellow. Charcoal samples recovered from the sieve are given in italics, and charcoal samples taken from the section are marked with an arrow. CAD by Dorcas Vannieuwenhuyse.
Table 1.
Published dates from Riwi [15].
Table 2.
New radiocarbon dates from Riwi Cave.
Fig 4.
The OSL decay curves for representative samples of grains from (a) Riwi-4 and (c) Riwi-27 that span the range of luminescence sensitivities (‘relative brightness’). (b) and (d) show the corresponding dose response curves for those grains shown in (a) and (c).
Fig 5.
Radial plot of the De distribution for the accepted grains in a (A) mixed (Riwi-6) and a (B) scattered (Riwi-18) sample. The grey bands in (A) are centred on the weighted mean De determined for each dose population using the Finite Mixture Model. The grey band in (B) is centred on the weighted mean De determined using the central age model after the rejection of outliers (shown as open triangles). Radial plots for all 37 samples are presented in S1 Fig.
Table 3.
Dose rate data, equivalent doses and OSL ages for sediment samples from Riwi.
Fig 6.
Bayesian model of the radiocarbon dates from Riwi.
Dates have been calibrated against SHCal13 [30] and modelled in OxCal v.4.2 [31]. Pale probability distributions represent the calibrated, unmodelled date, whilst dark grey distributions represent the modelled date. The two brackets beneath the distributions represent the 68.2% and 95.4% probability ranges. Prior and posterior outlier probabilities are given in brackets following the sample name in the form [O: posterior/prior]. A ‘?’ implies the date was not included in the model.
Fig 7.
Bayesian model of the OSL dates from Riwi.
Only random errors are included. For explanation of figure interpretation, see Fig 6.
Fig 8.
A comparison of Boundaries generated by the radiocarbon and OSL Bayesian models.
(A) illustrates the Boundaries of the radiocarbon and OSL models, alongside the estimated Boundaries if the systematic error is included in the OSL model, and (B) the Difference between the Boundaries calculated in the radiocarbon model and the OSL model with and without the systematic error estimation.
Table 4.
Difference between Boundaries from the models of the radiocarbon and OSL ages calculated in OxCal.
If zero is included in the probability range the two probability distributions are considered indistinguishable.