by Aaron Jonas Stutz

Research on big issues in human evolution–like how Neandertals contributed to our own genetic diversity and to ancient cultural diversity … before they went extinct–certainly involves a level technical nitty gritty that even specialists in the field get worn down by. But sooner or later, we get back up, ready to geek out on the details again. For those of you interested and with institutional access, please check out our newly published article on radiocarbon dating the earliest Upper Paleolithic in the Levant. This is the first major publication on our work on the Mughr el-Hamamah site–work that has been led my Liv Nilsson Stutz and myself … but which has depended on and succeeded thanks to extensive collaboration (Stutz et al., in press). The article may be viewed here, although–as noted above–full access to this Journal of Human Evolution content requires a subscription, so you may be limited to the abstract:

http://www.sciencedirect.com/science/article/pii/S0047248415001050?np=y

Liv Nilsson Stutz provides a narrated overview of the article here:

http://audioslides.elsevier.com//ViewerLarge.aspx?source=1&doi=10.1016/j.jhevol.2015.04.008

In addition, Emory University’s inimitable Carol Clark has published an great overview of the work here: http://esciencecommons.blogspot.com/2015/06/stone-tools-from-jordan-point-to-dawn.html

In this post, I emphasize the key findings from our collaborative research on the Mughr el-Hamamah site, Jordan, and its importance for understanding the beginning of the Upper Paleolithic. I also offer a brief peek at work to come. The main take-home point can be summarized succinctly. It is not easy to obtain consistently accurate C14 measurements on really really old charcoal, but due to excellent preservation and just as excellent, careful technical skill–thanks to the excavation team including co-authors Trina Arpin and Jamie L. Clark and radiocarbon-dating specialist co-authors Jason Rech, Jeff Pigati, and Jim Wilson–we can report that the Early Upper Paleolithic artifacts stratigraphically associated with the charcoal-rich hearths at Mughr el-Hamamah (Caves of the Doves), Jordan, date to ca. 45,000-39,000 years ago. It may be a narrower range within that overall span. It may be a few separate episodes of intense occupation. Or it may be pretty slow and steady over most of that time frame. But here it is, folks. With all of the remaining technical limitations to state-of-the-art measurements of C14 levels; with all of the assumptions that still go into the statistical models for converting raw C14 measurements to calibrated calendar ages; with all of the uncertainties over whether we removed enough contaminating carbon, whatever its isotopic composition … we show that oldest dated charcoal material–out of the nine Early Upper Paleolithic charcoal fragments tested–probably falls between about 45 and 43 thousand years ago.

The secondary take-home finding is that the stone tools–consistently Early Upper Paleolithic in their technology and form, including flint endscrapers, burins, a few pointed blades, and numerous retouched blades–are surprisingly diverse. And there are a couple of ways that this diversity shows itself in the Mughr el-Hamamah assemblage. One is that co-author John Shea has identified approximately the same number of prismatic blade and bladelet cores as he has identified Levallois cores. All of these different kinds of flint cores–for removing flakes and blades alike–are found throughout the stratigraphically intact, single Early Upper Paleolithic layer, dominated by successively stacked hearths and ash accumulations. Thus, we preliminarily report evidence for use of so-called Initial Upper Paleolithic (IUP), Levallois-like core preparation and flake removals … alongside production of straight, narrow blades from narrow-fronted Early Ahmarian (that is, Protoaurignacian-like) cores.

Now, remember: this is a hypothesis. We’re nearing the completion of the analysis of the flint tool assemblage and associated provenience information. All indications so far are that the stratigraphic association of IUP and Early Ahmarian technologies reflects roughly contemporaneous human use of those technologies in the 45-39 kya timeframe. But we will test this hypothesis with careful examination of the Levallois cores, the unmodified flakes and blades, and their stratigraphic relationships. At present, it is certainly hard to rule out that the Levallois cores have been disturbed and redeposited from an older, underlying IUP or Late Middle Paleolithic layer, perhaps still intact in an unexcavated part of the cave. From this perspective, there is also good reason to continue excavations at Mughr el-Hamamah–which has only been subject to the test excavations that we carried out in 2010, providing the basis for the ongoing analyses we are conducting.

The other way that the stone tool technological diversity manifests itself is the surprising fact that scaled pieces and other bipolar cores on flakes far outnumber either blade/bladelet cores or Levallois. This was one of John Shea’s main findings that we describe in the new paper. Along with the usual endscrapers, burins and retouched blades, the scaled pieces provide evidence for intense onsite task activities. Scaled pieces are cores where flakes and small bladelets can be quickly removed, as the core is struck with a hammer or other percussor, while the knapper balances it with her fingers on an anvil. The resulting flakes and bladelets would have been one-time, throw-away cutting or piercing implements. In general, there is less focus by the Early Upper Paleolithic inhabitants of Mughr el-Hamamah on preparing portable, multi-use thicker flakes and points for unpredictable hunting and gathering tasks. More focus is on using materials at hand to carry out food and materials processing tasks on the site. Mughr el-Hamamah is small, so it would have comfortably sheltered only a small number of families. But we can make the logical inference that members of those families were consistently spending more time on site doing work than they might have done in previous time periods, perhaps with their stays lasting a few more days, weeks or even months than would have occurred during the preceding Middle Paleolithic period (see Kuhn & Stiner, 2006, for a thoughtful, important discussion of this point).

Other notable finds from the Early Upper Paleolithic layer (Layer B) of Mughr el-Hamamah include: a small number of bone point or needle fragments, a fragment of human atlas (1st cervical vertebra), and a possible marine shell bead. As noted above, John Shea’s analysis of the stone tools is nearing completion, and we look forward to submitting the results of that study for publication as soon as possible.

Ongoing work involves study of the animal bones recovered in place with the stone tools and the hearths (led by Jamie L. Clark, in collaboration with Gideon Hartman and Miriam Belmaker), study of the sediment microstructure, plant phytolith content, and chemical composition (Trina Arpin, Rosa Maria Albert, and Dan Cabanes), charred wood remains (Chantel E. White), and landscape geomorphology (Fuad Hourani). Feedback and inquiries about the article and our project are welcome: astutz@emory.edu

References

Kuhn, S. L., & Stiner, M. C. (2006). What’s a Mother to Do? The Division of Labor among Neandertals and Modern Humans in Eurasia. Current Anthropology, 47(6), 953–981. http://doi.org/10.1086/507197

Stutz, A. J., Shea, J. J., Rech, J. A., Pigati, J. S., Wilson, J., Belmaker, M., Albert, R. M., Arpin, T., Cabanes, D., Hartman, G., Hourani, F., White, C. E., Nilsson Stutz, L. (n.d.). Early Upper Paleolithic chronology in the Levant: new ABOx-SC accelerator mass spectrometry results from the Mughr el-Hamamah Site, Jordan. Journal of Human Evolution. http://doi.org/10.1016/j.jhevol.2015.04.008