Japanese archaeologist explores prehistoric transitions in southern Jordan

AMMAN — The archaeological journey of Professor Seiji Kadowaki in Jordan started in 2000 when he became a member of the archaeological project at a Neolithic site of Ayn Abu Nukhayla in Wadi Rum. This project was led by Professor Donald O. Henry of the University of Tulsa, Kadowaki said.

Kadowaki added that he also participated in several other archaeological projects, such as those at Baja, Dhra’, Hemmeh and Wadi Ziqlab. For decades Kadowaki studied prehistoric past of the southern Levant.

Regarding the Middle and Upper Palaeolithic sites in southern Jordan, they have been originally investigated by Henry since the 1970s.

"Professor Henry discovered more than 100 prehistoric sites in the western Hisma Basin and excavated several Middle Palaeolithic sites [Tor Faraj and Tor Sabiha] and Upper Palaeolithic sites [Wadi Aghar, Tor Fawaz, Tor Hamar, Tor Aeid, and Jebel Humaima]. He established a chrono-cultural framework of these sites by examining lithic techno-typology and radiometric dating," Kadowaki underlined.

The professor added that in 2016, he started collaboration with Professor Henry and re-excavated some of these sites, including Tor Faraj, Tor Sabiha, Wadi Aghar, Tor Fawaz, and Tor Hamar, in order to refine chronology and cultural changes from the Middle Palaeolithic to the Upper Palaeolithic and to obtain paleoenvironmental data for these time periods."

Kadowaki re-excavated two Middle Paleolithic sites (Tor Faraj and Tor Sabiha) and three Upper Palaeolithic sites (Wadi Aghar, Tor Fawaz, and Tor Hamar). All of them are rock-shelter sites, where Paleolithic hunter-gatherers had their camps, in which they left material remains of their activities, such as stone tools, animal bones, shell beads and hearth. 

They made and used stone tools and butchered some hunted animals, and also used shell beads.

Furthermore, the modern climate in southern Jordan is very dry, and food resources are limited, but many Palaeolithic sites remaining in this area indicate that during the Palaeolithic period, this area was more humid and hosted more animal and plant sources, which were exploited by Palaeolithic hunter-gatherers. 

"The late Middle Palaeolithic and early Upper Palaeolithic periods are known to correspond to important paleoanthropological processes, such as the dispersals of modern humans [Homo sapiens] from Africa and the extinction of Neanderthals. Rich Palaeolithic records in southern Jordan allow us to study what was happening during this dynamic period in human history," Kadowaki elaborated.

Their research confirmed changes in stone tool typology and technology at the transition from the Middle to Upper Palaeolithic.

"We demonstrated that the efficiency in stone tool production, as measured by the production rate of lithic cutting edge, increased not at the conventional boundary between the Middle and Upper Palaeolithic, but a little later in association with the miniaturisation of stone tools." 

"In addition, we found that long-distance transportation of sea shells [from Red Sea] emerged at the beginning of the Upper Palaeolithic, indicating the range expansion of resource procurement and/or the development of social interaction with other groups," Kadowaki, who is teaching Prehistoric Archaeology at Nagoya University Museum, said.

He said that scholars think that in Upper Palaeolithic humans had more frequent opportunities to exploit resources from diverse environmental/ecological settings. 

Such opportunities may have worked as buffers against risk in semiarid environments, such as in southern Jordan, he concluded.

The Middle to Upper Palaeolithic transition (has long been known as a key prehistoric cultural process or chronological range to investigate human bio-cultural evolution due to its temporal proximity to the wide geographic expansion of Homo sapiens ca. 50–40 thousand years ago and concomitant demise of archaic humans, Kadowaki underlined. 

The professor noted that mainly based on European records, the Middle Palaeolithic to Upper Palaeolithic cultural transition was conventionally regarded as a discontinuous process or “revolution” marked by the introduction of new cultural/behavioural packages associated with a wave of dispersing Homo sapiens population. 

“However, more recent increase in the recovery of archaeological records, particularly in Africa and Asia, has suggested geographically diverse cultural patterns that involve both continuous and discontinuous aspects as well as various timings of change depending on cultural elements,” Kodowaki said.

The professor added that the cultural framework of the transition has been effectively delineated by techno-morphological attributes of stone tools, which constitute the most abundant cultural remains at Palaeolithic sites, and detailed examinations of lithic techno-morphology led researchers to reassess the conventional view and propose more complicated cultural processes at the Middle to Upper Palaeolithic transition. 

In order to compare variations of lithic assemblages over different periods or regions, it remains a methodological challenge for archaeologists to establish consistent and quantitative criteria (rather than descriptions) that allow objective illustration and assessment of temporal/spatial cultural dynamics, the professor said. 

He noted that scholars present a quantitative examination of diachronic changes in stone tool assemblages at the Middle to Upper Palaeolithic transition by focusing on the production rate of stone tool cutting edges. 

“Most Palaeolithic stone artefacts have sharp edges as their functional parts [e.g., for cutting and scraping], and sharp edges are created by knapping off flakes from silicious rocks, such as obsidian and flint." 

"Thus, the length of cutting edge per mass of stone has been used in numerous studies to quantify the efficiency in stone tool production, in other words, the efficiency in the consumption of raw rock material,” Kadowaki underlined.

Although the cutting-edge production rate has been widely recognised as a consistent and quantifiable aspect of prehistoric human technological evolution, there remains uncertainty about how the rate actually changed during the transition. 

Conventionally, a shift from dominant Levallois technology in the Middle Palaeolithic to the blade technology in the Upper Palaeolithic was considered to have increased the cutting-edge production rate, he said, adding that uncritical recourse to such a progressive view is currently being reconsidered under recent recognition of Palaeolithic technological variability and insights from lithic experimental studies.

Kadowaki's major publications in academic journals include Nature Communications, Journal of Human Evolution, Journal of Palaeolithic Archaeology, Journal of Archaeological Science, Archaeometry, Archaeological Research in Asia, Quaternary International, Quaternary Science Reviews.