Environmental factors in human evolution and dispersals in the Upper Pleistocene of the western Mediterranean
Our project examined the early human occupation of Morocco in the Upper Pleistocene, with the broad aims of identifying changes in the archaeological and environ-mental records and assessing whether these may be correlated with global climatic events.
Northern and eastern Morocco are of critical interest because they lie on a potentially important human dispersal route extending from the Maghreb westwards along the Mediterranean coast and close to the narrow strait that separates Africa from Europe.
Yet, despite the distinctiveness of its geographical location, it is unclear whether cultural successions in this region were predominantly local events, indicative of isolation and endemism, or influenced by demographic movements from outside.
In particular, surprisingly little is known about the chronology of the Middle and Upper Palaeolithic or of the palaeoenvironmental background to human occupation during this time.
Photograph: Taforalt Cave, interior view.
Our study has focused principally on caves in the north and east of the country. Here there is a wealth of Palaeolithic evidence, often in well-preserved contexts and with possibilities for obtaining dating analyses and multi-proxy data to reconstruct former environments.
These data include a wide range of materials such as charcoals and phytoliths, small and large fossil mammals, reptiles, amphibians, birds and molluscs.
One of the key sites is Grotte de Pigeons at Taforalt, near the border with Algeria. Our excavations and sampling of this cave have produced over 40 AMS radiocarbon determinations, OSL, TL and U-series dates from cultural and other horizons spanning the Middle and Upper Palaeolithic.
This work is still ongoing but already provides one of the longest dated sequences for these periods from anywhere in the North African Maghreb.
Results and future directions
1. We have demonstrated that the Upper Palaeolithic, locally known as the Ibero-maurusian, probably dates no earlier than 17.085ka (YS occupation horizon 2).
However, artefacts in the underlying YS occupation horizons 3 (22.2ka) and 4 (25.76ka) neither fall within the Ibero-maurusian nor do they seem to fit the description of the Middle Palaeolithic Aterian described by earlier excavators.
While it is possible that the types found belong to hitherto unrecognised 'transitional Middle-Upper Palaeolithic industries', we believe it more prudent at the moment to leave any precise attribution until further work has been completed.
These results nevertheless refute the view still held by some archaeologists that the Maghreb was abandoned by humans between 40-20ka.
2. Using the calibrated age scales it is possible to show that Upper Palaeolithic Iberomaurusian and earlier human activities at Taforalt were broadly contemporary with a number of presumed cooling episodes in the oceanic record.
However the exact status of Heinrich Events and Dansgaard-Oeschger cycles in relation to climatic change still needs to be fully clarified and it may be too simplistic to interpret all of these episodes in the same way and purely in terms of major cooling and drying.
Thus although it seems reasonable to acknowledge a correlation between Heinrich Events and occupation episodes at Taforalt, the case for climate change as a dominant factor in this process cannot be fully tested until further work on reconstructing the palaeoenvironmental sequence has been completed.
3. Evidence of human mortuary activity in the Iberomaurusian Upper Palaeolithic comes from undisturbed human burials at the back of the cave.
Excavations in 2005 and 2006 revealed the partially articulated skeletons of four adults.
Individuals were buried in a crouched or seated position and are closely associated with horn cores of various sizes, which are absent elsewhere in the deposit.
Photograph: Iberomaurusian burial from Hattab 2 Cave. This site was also investigated by the project. The cranium reveals the same pattern of incisor extraction as seen in the burials from Taforalt.
Other burials have been identified but not yet fully excavated, including those of infants, children and adults.
We do not have direct dating evidence for the burials yet, but it is clear from thicker sequences of sediments preserved elsewhere in the cave that they come from within grey ashy deposits (overlying the YS series).
The earliest date of 12.675ka from the base of the grey sequence provides a likely maximum age for the burials.
The new excavations provide the first opportunity to record human mortuary activity at Grotte de Pigeons in detail and may contribute to a revised interpretation of the existing osteological sample.
We will now study the human fossils for evidence of diet, activity patterns, skeletal and dental disease, and cultural modification in order to develop an overall understanding of human lifestyle during this period.
We will also try to establish the relationship between the Iberomaurusian people of Taforalt and other previous and subsequent human groups within the region.
4. Investigation of the lower sequence of Middle Palaeolithic layers at Taforalt has revealed a major series of archaeological horizons in ashy deposits with associated faunal and botanical remains.
Preliminary dating based on luminescence and U-series determinations suggests human occupation occurred during late MIS6 and continued intermittently until <40ka.
One of the most interesting layers contains evidence of thin, bifacially worked foliate points, normally indicative of the Aterian (Middle Palaeolithic), and numbers of perforated marine shells. The latter appear to have been imported from a contemporary coastline which would have been approximately 35km from the cave in the Upper Pleistocene.
We are waiting for further results of dating this layer, which may eventually provide evidence of a similarly early use of personal ornaments as recorded at Blombos Cave, South Africa and Es Skhul, Israel.
This summary was compiled by Nick Barton, who is also the PI for this project, with help from Louise Humphrey, Simon Collcutt and Jalil Bouzouggar.
The research was undertaken by:
Lithics and excavations: Nick Barton (Oxford) and Jalil
Bouzouggar (Ministère de la Culture, Morocco).
Dating: Robert Hedges (Oxford), Tom Higham (Oxford), Ed Rhodes (Australian National University) and Jean-Luc Schwenninger (Oxford).
Human remains: Chris Stringer (Natural History Museum) and Louise Humphrey (Oxford).
Fauna: Elaine Turner (RGZM, Mainz), Cath Price (Oxford) and Simon Parfitt (Natural History Museum & University College, London).
Isotopic analyses: Tim Atkinson (University College, London).
Palaeobotany: Steven Ward (Oxford), Kathy Willis (Oxford).
Sedimentary analysis: Simon Collcutt (Oxford Archaeological Associates Ltd).
Other collaborators: Silvia Bello, Simon Blockley, Adrian Parker, Gideon Henderson, Julie Ferguson, Edward Hodge, Alistair Pike, Marian Vanhaeren, and Francesco d'Errico.
Co-funding: The British Academy, Institut National des Sciences de l'Archéologie et du Patrimoine, Ministère de la Culture, Morocco, and the Oxford University Development Research Fund.