Fig 1.
Summary of stratigraphic sections from the Toumboura, TMBI-2017 and Ravin de Sansandé sites.
Fig 2.
Sedimentary, stratigraphic, and chronocultural synthesis of Toumboura I and Toumboura- 2017.
Table 1.
OSL and radiocarbon ages obtained for the sedimentary units at Toumboura I. Toumboura I-2017 was excavated from the top of the colluvium down to UG sample T7 represents age provided directly from the Later Stone Age archaeological horizon.
SU: Sedimentary Unit.
Fig 3.
(A) View of the excavation from the South. (B) Stratigraphic sequence from E-W section.
Table 2.
Summary of artefacts finds per sedimentary unit at Toumboura I-2017.
Table 3.
Composition of the Late Stone Age lithic assemblage at Toumboura I-2017.
Table 4.
Cores attributes, Toumboura I-2017 site.
(A) Dimensions of cores per raw material. (B) Cores reductions modalities per core main production objectives and numbers of striking platforms.
Fig 4.
Different core exploitation modalities at Toumboura I-2017.
(1) peripheral core, chert. (2) frontal core, quartz. (3) semi-rotating core, chert. (4) frontal core, greywacke.
Fig 5.
Flake blanks at Toumboura I-2017 site.
(1) Débordant flake, greywacke. (2) Simple flake, chert. (3) Semi-cortical flake, chert. (4) Simple flake, greywacke.
Fig 6.
Blade and bladelet blanks at Toumboura I-2017 site.
(1) Blade, chert. (2) Semi-cortical blade, chert. (3) Flank blade, quartz. (4, 5, 6) Bladelet, chert.
Table 5.
Types and numbers of blanks used per raw materials.
Table 6.
Dimensions of flakes, blades, bladelets, segments and backed bladelets per raw material at Toumboura I-2017.
Fig 7.
Example of segments at Toumboura I-2017.
(1) On bladelet. (2, 3, 5) On flakes. (4) On undetermined blank. (1, 3, 5) Segments with discontinuous retouch and irregular cutting edges. (2, 4) Segments with abrupt retouch and straight cutting edge. (1, 2, 3, 4) Chert. (5) Quartz.
Fig 8.
Global view of the three excavation campaigns at the Ravin de Sansandé site.
Table 7.
Results of radiocarbon and OSL analyses at the Ravin of Sansandé site per sedimentary unit (US).
Depths indicated from the surface.
Table 8.
Composition of artifacts per stratigraphic unit at the Ravin de Sansandé site.
Fig 9.
Schematics of the different interventions, stratigraphic units and OSL samples at the Ravin de Sansandé site.
Table 9.
Composition of the Late Stone Age lithic assemblage at Ravin of Sansandé, 2020 excavation.
Fig 10.
Different core exploitation modalities at Ravin of Sansandé.
(1) Semi-rotating core, quartz. (2, 3) Frontal core, chert. (4) Peripheral core, chert. (5) Frontal core, greywacke.
Table 10.
Cores attributes in Ravin of Sansandé site.
A) Dimensions of cores per raw material. B) Cores reduction modalities per cores main objectives and numbers of striking platforms.
Fig 11.
Flakes at the Ravin of Sansandé site.
(1,3) flakes, chert. (2,4) Débordant flakes, greywacke.
Table 11.
Raw materials and dimensions of flakes, blades, bladelets, segments and end-scrapers of Ravin de Sansandé site.
Fig 12.
Blades and bladelets at the Ravin of Sansandé site.
(1,3) blades, chert with patina. (2) blade, quartz. (4,6) bladelets, chert.
Fig 13.
End-scrapers and Segments at the Ravin de Sansandé.
(1,2) End-scrapers on a chert with rectangular and convex shapes with abrupt to semi-abrupt faces. (3) End-scraper on a greywacke with circular and convex shapes with abrupt to semi-abrupt faces. (4, 8) Segments with abrupt retouch and rectilinear edges. (5, 6) Segments with discontinuous retouch and irregular edges. (5, 8) Greywacke made on a flake. (4, 6, 7) Chert made on a bladelet.
Table 12.
Segments at Ravin de Sansandé.
Types and numbers of blanks used per raw materials.
Fig 14.
Location of Toumboura I-2017 and Ravin de Sansandé sites with MSA and LSA sites in West and Central Africa mentioned in the text.
Table 13.
OSL and C 14 dates from MSA and LSA sites cited in the article.
We used OxCal to provide calibrated Before Present dates. The OSL ages from Scerri and al. 2017 and 2021 have been rounded to the first decimal. https://c14.arch.ox.ac.uk/oxcal/OxCal.html.*: OSL ages from Bayesian analyses, 95% credibility interval.