The Shuidonggou (SDG) site complex, located in the Ningxia Hui Autonomous Region of Northwest China and yielded Middle-Upper Paleolithic transitional blade-rich assemblages, has been given more and more focuses since its discovery and first excavation in the 1920s. This paper presents a specific lithic analyses (core reduction and tool modification) on the stone artefacts yielded by three years of systematic and advanced excavations at Shuidonggou locality 7 (SDG7), an important locality within the SDG site cluster.
As shown by the characteristics of the cores and flakes from SDG7, direct hammer percussion was the dominant flaking technique, but the bipolar technique was also used on a small-scale, especially for some high-quality and small-sized cherts. As for the core reduction strategy, most of the cores, including simple flake cores (free-hand direct hammer percussion), discoid cores and bipolar cores, show the features of flake production without core preparation.Compared to the centripetal reduction of discoid cores, the reduction strategy of simple flake cores is to look for the most suitable platforms and working surfaces by changing flaking direction. However, it should be noted that there are four flat-faced cores that display consistent features of the Levallois-like blade assemblage with the ones identified at other localities like SDG1, 2 and 9, which have been described as an intrusive large blade technology with characteristics of initial Upper Paleolithic from the Siberian/Mongolian region.
There are five kinds of tool forms (scrapers, points, notches, denticulates and choppers) identified at SDG7, most of which are small in size and made by complete flakes. The predominant tool forms are scrapers (n=105; 86.77%), most of which are side scrapers. Most working edges of the tools appear to be unifacially and lightly retouched by direct hammer percussion. However, the presence of some finely retouched tools (end scrapers and some side scrapers) made from high quality raw materials may indicate the technological innovations of local industry during the Upper Paleolithic.
Above all, based on the detailed lithic analyses, two distinct technological assemblages are identified at SDG7. One is a flake-tool technology, which is the local and dominant technological assemblage in North China, characterized by free-hand core reduction without preparation and simple tool modification. The other is an intrusive Levallois-like blade technology, which is represented by flat-faced cores with preparation of platforms and working surfaces for the production of blades and/or elongated flakes. We believe the detailed study of the lithic materials from SDG7 would be of a great relevance for the comprehensive understanding of the whole technological complex at SDG site region and its role in the Upper Paleolithic of North China.