Wedge-shaped microblade cores are typical representatives of Upper Paleolithic microlithic assemblages in Northeast Asia. Core reduction technology of these nuclei has been investigated for over a century generating many noteworthy achievements. However, disputes regarding some fundamental aspects of this technology are still under discussion. This paper documents pressure flaking experiments on wedge-shaped microblade cores replicating artifacts discovered in Upper Paleolithic sites in the Nihewan Basin. Experiments were designed to test relationships between technological and morphological variables and microblade morphology. Such variables included the working point of pressure-flaking implements, width of the flaking surface, arris height, and vices or other means of securing nuclei in place. Based on these variables, five groups were compared with one another. Microblade cores in the standard group have a narrower working face and higher arris, and were fixed in a V-shaped device with microblades produced by use of a thin-tipped pressure flaker. Other groups showed differences in one of these variables otherwise keeping consistent with the standard group. For example, microblade cores in the low arris group only made the arris itself lower, while their working face, method of fixing and pressure flaking tool utilized are same as the standard group.
Conventional linear and geometric morphometric data on microblades were collected to analyze the degree of standardization of microblade morphology among different experimental groups. The main linear measurements were width and thickness of microblades and platform width and thickness. Geometric morphometric analysis was undertaken using Elliptic Fourier Analysis (EFA). All results revealed specific group-level differences regarding shape and standardization of microblades.
Microblade morphology is affected by several factors such as arris height, working face width, diameter of the pressure-flaker point, the form of vice employed, etc. Regular microblades can be continually produced only by utilizing a higher arris, which is achieved by ensuring the working face of microblade cores is not too wide, otherwise the height of the arris would decrease and interfere with subsequent manufacture of microblades. A thin, pointed pressure-flaking tool makes more effective use of the arris than a thick, pointed tool to remove microblades. Experiments with various means of fixing wedge-shaped microblade cores demonstrates that the core’s bottom edge is primarily employed to stabilize the stone nucleus throughout the process of microblade production. Results of the experiments reported here provide new information on microblade production and sheds light on the dispersal of microblade technology in Northeast Asia.