Fig 1.
Map of the Tankwa Karoo and relevant sites in South Africa.
Site abbreviations (west to east): DRS Diepkloof, VAR Varsche Rivier, KKH Klein Kliphuis, ORV Olifants River Valley, PUT Putslaagte 1, MRS Mertenhof, UPK Uitspankraal 7, TWF Tweefontein, BOS Bos River, DRI Driekoppen, ORA Orangia 1. Open-source spatial data from NaturalEarthData.com, NASA SRTM Version 3.0, and South African National Biodiversity Institute (bgis.sanbi.org). Vegetation data from the National Vegetation Map Project 2012 (VEGMAP), after [18].
Fig 2.
Schematic of Levallois and Nubian production methods (modified from [28, 29]).
Fig 3.
(a) South-east of Tweefontein from the high ridge to the north; (b) north at the site showing flagged artefacts on the desert pavement; (c) aerial view showing silcrete artefacts recorded in 2014 transects and Nubian cores recorded in both 2014 and 2015. Aerial image supplied by National Geo-Spatial Information (Department of Rural Development and Land Reform, Mowbray, South Africa).
Table 1.
Sampling and recording methods employed at Tweefontein.
Fig 4.
Schematic of the 2015 sampling grid showing mapped Nubian cores, points and radial cores.
Table 2.
Artefact frequencies recorded in complete grid squares 18/-1, 18/+1, 18/+2, sampling all artefacts >10mm, in all raw materials.
Table 3.
Artefact frequencies recorded in complete grid squares 18/+3, 18/+4 and 18/+5, sampling all artefacts >20mm hornfels and >10mm all other raw materials.
Fig 5.
Bar graphs showing artefact size fractions in the sampling grid.
(a) By grid square, (b) by raw material. Grid squares refer to column 18 and row number (see Fig 4); raw material abbreviations H hornfels, Q quartzite, S silcrete, C CCS, D dolerite, O other.
Fig 6.
(a) Nubian Type 1, (b-d) Type 1/2, (e-i) Type 2; (j) Type 2 core with refitting (broken) point. Raw material: (a-d) hornfels, (e) dolerite, (f) quartz breccia, (g-i) silcrete, (j) CCS.
Table 4.
Frequencies of Nubian core shapes at Tweefontein by raw material.
Table 5.
Frequencies of Nubian core types at Tweefontein by raw material.
Table 6.
Frequencies of distal median ridge angles on Tweefontein Nubian cores.
Table 7.
Frequencies of distal platform angles on Tweefontein Nubian cores.
Fig 7.
Raw material: (a-j) hornfels, (k-p) silcrete, (q) Dwyka quartzite, (r-v) CCS.
Table 8.
Frequencies of point fragmentation at Tweefontein by raw material.
Fig 8.
Diagrams of dorsal scar patterning on Tweefontein points related to Nubian Type 1 reduction.
Points also illustrated in Fig 7 are indicated. Retouch and edge-damage scars are shaded in grey. Artefacts are not to scale.
Fig 9.
Diagrams of dorsal scar patterning on Tweefontein points related to Nubian Type 1/2 reduction.
Points also illustrated in Fig 7 are indicated. Retouch and edge-damage scars are shaded in grey. Artefacts are not to scale.
Fig 10.
Diagrams of dorsal scar patterning on Tweefontein points related to Nubian Type 2 reduction.
Points also illustrated in Fig 7 are indicated. Retouch and edge-damage scars are shaded in grey. Artefacts are not to scale.
Table 9.
Frequencies of point platform types by raw material.
Table 10.
Frequencies of point dorsal scar patterns by raw material.
Table 11.
Frequencies of retouch type for complete and fragmentary points by raw material.
Fig 11.
Scatter plots showing artefact length by width.
(a) Nubian cores and (b) points.
Fig 12.
Box plots showing artefact length by raw material.
(a) Nubian core and (b) points.
Table 12.
Summary of descriptive statistics for Tweefontein Nubian cores.
Table 13.
Summary of descriptive statistics for Tweefontein complete points.
Fig 13.
Bar graphs showing artefact cortex percentage.
(a) Nubian cores and (b) points.
Fig 14.
Map of occurrences of Nubian technology in the Tankwa Karoo.
Survey walk paths are shown in white. Open-source spatial data from NaturalEarthData.com, NASA SRTM Version 3.0, and the South African National Biodiversity Institute (bgis.sanbi.org).
Fig 15.
(a-k) Points, (l, p) overshot flakes from Nubian cores, (m, n) reworked Nubian core fragments, (o) Nubian Type 2 core. Raw material: (a, d, i-k, m-p), silcrete, (b-c, f-g, l) hornfels, (e) quartzite, (h) CCS.
Table 14.
Sites with Nubian technology (by raw material and core type) and associated unretouched and unifacial points in the Tankwa Karoo.
Sites listed from west to east, locations shown in Fig 14.
Fig 16.
(a-c) Nubian Type 1/2 cores, (d-g) points with informal retouch or edge-damage. Raw material: (a-b, g) hornfels, (c-d) CCS, (e) Dwyka quartzite, (f) silcrete.
Fig 17.
Nubian core surface finds in the Tankwa Karoo region.
(a-d) Nubian cores; (e) point from Nubian core; (f) Olifants River core; (g) Bos River core. Raw material: (a) Dwyka quartzite, (b-d) hornfels, (e-g) silcrete. Locations of (a-e) shown in Fig 14 and (f-g) in Fig 1.
Fig 18.
Map showing sites with Nubian technology in relation to Köppen-Geiger climate zones.
BSh, BSk and BWh are arid climate areas. Koppen-Geiger Climate data from CliMond.org, after [140]. Open-source spatial data from NaturalEarthData.com. Site numbers refer to Table G in S1 Appendix.
Fig 19.
Sites with Nubian technology in relation to rainfall models.
(a) Last Interglacial (140–120 ka, the age of many northern sites), and (b) Last Glacial Maximum (22 ka). Red areas receive less than 300 mm rainfall. Annual precipitation taken from bioclimatic data downloaded from Woldclim.org, after data from [143, 144]. Open-source spatial data from NaturalEarthData.com.