Microlithic Technology in Northern Asia: A Risk-Minimizing Strategy of the Late Paleolithic and Early Holocene

Microblade technology was important in hunter-gatherer adaptations throughout northern Asia from the late Pleistocene through the Pleistocene/Holocene transition and beyond. To date, most studies from the region are concerned with origins, technological lineages, and culture history. In contrast, we direct attention to issues involving the role of microlithic technology in adaptive strategies and problem solution among north Asian hunter-gatherers by looking at artifact design and risk analysis. First we discuss the function of Asian microblades and outline the general costs and benefits of organic points with microblade insets over simple organic points and flaked stone points, as well as the relative advantages of wedge-shaped and split-pebble microcores in terms of the Z-score model. We conclude with a review of the role of microlithic technology as a risk-minimizing strategy of Arctic and sub-Arctic large-game hunters in northern Asia and suggest further lines of inquiry. M technology was important in hunter-gatherer adaptations throughout northern Asia from the latter part of the late Pleistocene through the Pleistocene/ Holocene transition and beyond (Chard 1974; Chen 1984; Chen and Wang 1989; Derev’anko 1998; Gai 1985; Goebel 1995; Goebel et al. 2000; Goebel and Slobodin 2001; Hoffecker et al. 1993; Kobayashi 1970; Kuzmin and Orlova 1998; Lu 1998; Seong 1998). To date, researchers in the region have focused primarily on issues of culture history, in which questions of culture origin and typology are foremost (Seong 1998). Consequently, we are faced with a welter of type lists, divided and subsumed into archaeological cultures that never quite account for everything—always some assemblage or date falls outside the general pattern. The failure of the archaeological record to conform to such categories is not a reflection of our excavation or typological skills. Rather, it is the inevitable result of variability in past human behavior that is not categorical, but situational. While the distribution and variability of microlithic technology remain important variables to track, we direct attention to issues involving the role of microlithic technology in adaptive strategies. In other words, what were the major problems microlithic technologies solved for north Asian hunter-gatherers? Answering this question will help explain the emergence, spread, and persistence of microlithic technology in northern Asia. We approach the question from the vantage point of artifact design (Bamforth and Bleed 1997; Bleed 1987; Ellis 1997; Knecht 1993, 1997) and risk analysis employing the Z-score model (Bettinger 1991; Stephens 1981; Stephens and Charnov 1982; Winterhalder et al. 1999). First we discuss the function of Asian microblades and outline the general costs and benefits of three as104 Robert G. Elston and P. Jeffrey Brantingham pects of microlithic technology: (1) the advantages of organic points with microblade insets over simple organic points and flaked stone points, (2) the relative efficiency of biface and microblade production, and (3) the relative advantages of wedge-shaped and split-pebble microcores in terms of the Z-score model. We conclude with a review of the role of microlithic technology as a strategy to cope with increasing variability in late Pleistocene environments of northern Asia and, finally, suggest further lines of inquiry. The Function of Asian Microblades Late Paleolithic Asian microlithic technology was employed to produce stone insets for the margins of composite tools made of organic materials such as bone, antler, and ivory. No Late Paleolithic organic components of composite weapons have been recovered in China, but Late Paleolithic examples of inset projectile points are known from Siberia (Chard 1974:fig. 1.16; Derev’anko 1998:figs. 87, 127). Both composite points and knives have been recovered from Neolithic sites in Siberia and northeast China (Chard 1974:figs. 2.14, 2.16; Guo 1995:fig. 1.11; Lu 1998:92). Modified, end-hafted microblades were also sometimes used as scrapers, drills, knives, and projectile points (Elston et al. 1997; Gai 1985; Lu 1998:92; Madsen et al. 1998). There is no evidence that inset tools were ever used as sickles in the Chinese Neolithic, where this function was performed by serrated implements of ground stone, bone, or shell (Chang 1986:figs. 49, 52, 126; Shih 1992:figs. 8, 9; Underhill 1997:fig. 4). Thus, we follow Lu (1998) and others in assuming that most Asian pre-Neolithic microblades were intended to be used as marginal insets for projectile points made of bone, antler, or ivory. In this chapter, we refer to such points without insets as organic points (Knecht 1997) and to organic points with insets as inset points. The costs and benefits of inset points are best understood in comparison with the alternatives: simple organic points and flaked stone points. Performance of Organic and Flaked Stone Points The performance characteristics of organic and flaked stone points are known from experimental replication and use, and as reflected in the ethnographic record. Both aspects have been covered recently in papers by Heidi Knecht (1993, 1997) and Christopher Ellis (1997). Their findings are summarized briefly as follows (Table 8.1). Flaked stone points are relatively fragile and often fail catastrophically in use. Breakage is particularly common when they hit the ground or impact trees or rocks. Importantly, stone points apparently become brittle and easily damaged in severe cold. Spears and arrows with stone points are composite weapons in which the stone component is expendable (Bamforth and Bleed 1997:129) and probably expected to fail. Some ethnographic hunters believe that stone points are more lethal when they break up on penetration, because the fragments increase tissue damage and bleeding. Compared to the costs of fabricat ing shafts , with their nocks or sockets , fletching, and hafts, flaked stone points are cheap and quick to make. The stone-tipped projectile is designed to allow replacement of a damaged point without having to create an entirely new weapon. The use of a foreshaft may offer additional protection to the main shaft, as well as increased ease in point replacement. However, making foreshafts for stone points and fitting the points to them are additional costs in manufacture, and the use of a foreshaft produces a weaker weapon than one with a solid shaft. Organic points are made by splitting the bone or antler and shaping it by scraping and grinding. Organic points are more durable than stone points, less likely to break in use, and more easily repaired if dulled or broken. The time required to make an organic point is greater than that for most flaked stone points. However, organic points have longer use-lives, and one may spend more time making a series of expendable stone points than making one organic point (Knecht 1997). Organic points cause less lethal wounds than stone points with their sharp cutting edges that promote tissue damage and bleeding. As summarized in Table 8.2, Ellis (1997) has evaluated the factors influencing choice of stone or organic points in a survey of over 100 ethnographic cases. He found that stone arrow and spear points are used almost exclusively for large and dangerous game (bears and large herd animals) and in warfare where killing the enemy is the object. However, the use of thrusting spears with stone points tended to be limited to situations in which there was little danger to the user or in which a number of replacement weapons were available. Organic points were used when wielding thrusting spears against smaller herd animals, against dangerous animals when no replacement weapons were available, when multiple thrusts were to be given in warfare, on arrows used in cold weather (when stone points are brittle and easily broken), and when throwing spears in heavy underbrush. Microlithic Technology in Northern Asia 105 Ellis’s review of ethnographic data suggests that various factors including ambient temperature and prey type condition the selection and use of organic or flaked stone points. The primary factor underlying these situational decisions appears to be the cost or risk associated with weapon failure (Bamforth and Bleed 1997; Torrence 1989). When the potential cost is relatively low, stone points tend to be used. When the cost of failure is high, reliable weapons are called for (sensu Bleed 1987), and organic points are more likely to be employed. Costs and Benefits of Inset Points Creating inset points involves manufacturing, using, and maintaining a complex toolkit in which we might find hard and soft hammers, pressure tools, holding devices, anvils, splitting wedges, grinders, scrapers, slotting tools (burins, gravers, saws), and mastic (Flenniken 1987; Tabarev 1997). Toolkits for either flaked stone or organic points contain fewer items. The use of inset points in a weapons system is costly. It requires a large investment to learn how to produce microblades of a consistent width and thickness and how to do it quickly enough to meet demands in field conditions (Bamforth and Bleed 1997:132). Making microblades takes more time than producing bifaces from comparable amounts of raw material (Flenniken 1987). Making appropriate insets from microblade blanks and installing them in the margins of slotted organic points requires still more time. It may also be costly to learn to create slots of consistent width and depth and time consuming to produce them. Ellis (1997) does not cite ethnographic cases of inset point use. However, his review of ethnographic uses of organic points and flaked stone points suggests that the best design features of both are combined in inset points. Inset organic points can cause tissue damage and bleeding similar to that caused by stone points with less likelihood of breaking; they are both strong and lethal (Figure 8.1). Inset points can be used more than once, eliminating the need for frequent tip replacement and use of foreshafts. At the same time, inset points are highly maintainable, requiring only replacement of lost or broken insets and occasional tip resharpening. Batches of insets can be produced in anticipation of need (Bamforth and Bleed 1997:132; Kuhn 1994). As we have suggested, however, the cost of producing inset points is much higher than that for weapons with organic or flaked stone tips. The payoff for the increased cost of inset weapons is their performance in situations in which the cost of failure is catastrophic and/or deadly: when they must be used multiple times without replacement, when the prey is a key resource that must be taken during a limited time, when the prey is a dangerous animal or a human enemy to be engaged at close quarters, or when the weapon is used in very cold environments. Organic Points Stone Points Material limits morphology More varied morphology possible Considerable time to manufacture Can be made relatively quickly Cause less tissue damage Cause great tissue damage, bleeding More durable: Less durable: • unaffected by cold weather • more brittle in cold weather • rarely damaged in transport • easily damaged in transport • rarely break in use • invariably break on missed shot • frequently shatter when penetrating prey Easily repaired/resharpened Difficult or impossible to repair Less likely to be used with foreshaft More often used with foreshaft Reusable Expendable Table 8.1. Performance characteristics of organic and flaked stone points Organic Points Used Stone Points Used On thrusting spears without foreshafts against herd animals When hunting large game Against large/dangerous animals without replacement weapons When attacking dangerous solitary animals (bears) On thrusting spears used in hand-to-hand fighting On thrusting spears when danger to user is slight On arrows used in cold weather For killing enemies at a distance On spears cast in heavy brush Table 8.2. Ethnographic situational use of organic and flaked stone points 106 Robert G. Elston and P. Jeffrey Brantingham Relative Efficiency of Bifaces and Microblades in Production of Cutting Edge After raw material is procured, the first step in preparation of virtually all varieties of wedge-shaped cores involves some degree of bifacial reduction (see Bleed, this volume). Thus, we must assume that all prehistoric knappers who made microblades from wedge-shaped cores could have produced bifaces to use as tools if they had chosen to do so. In some cases, bifaces used as tools and points do accompany microblades in lithic assemblages (Dyuktai Cave, Siberia; Uenodaira and Araya, Japan; Hutouliang and Pigeon Mountain Basin, China); in others, unifacially modified flakes (Afontova Gora-2, Siberia) and macroblades (Kokorevo-2, Siberia) serve the same functions as bifacial knives and points. While this variability is no doubt multidimensional, we explore a few aspects of it by comparing the costs and benefits of producing bifaces and microblades. Our analysis makes use of experimental data (Table 8.3) provided by Flenniken (1987). To compare time and raw material consumption of the two techniques, Flenniken experimentally produced microblades from replicate Dyuktai bifacial cores, and, as well, made finished bifaces. As blanks to start the reduction process, he used large flakes of comparable size for both the wedge-shaped cores and bifaces. Flenniken (1987:122–132) concluded from his experiment that production of bifaces is the least economical use of toolstone because, while usable microblades (average 101 per core) comprised 41.6 percent of prepared core weight, finished bifaces comprised only 29.5 percent of blank weight. However, our analysis suggests this conclusion may be incorrect because Flenniken apparently did not calculate wastage of each technique as a proportion of the original weight of the raw material blank, nor did he include the final production step of microblade production. Flenniken (1987) does not report the mean weights of the flake blanks used as the initial starting points of reduction. We are able to estimate, however, the weights of key products and by-products by using the mean weights of Stage 2 bifaces as a starting point and working back through the process using the proportions of products and debitage reported. Flenniken reports a mean weight of 219.1 gm for the Stage 2 biface “blanks” used to make microblade cores. We assume that when Flenniken refers to “blanks” for the biface trajectory, he also means Stage 2 bifaces. This assumption is important and reasonable given (1) the statement that the reduction process started in each case with flakes of comparable size and (2) that the reported starting weights for microblade cores (Stage 2 biface) and formal bifaces (“blank”) are equivalent. Comparisons based on these assumed equivalencies indicated that as much as 69.85 percent of the initial raw material is wasted in microblade core preparation, reduction, and maintenance; 30.15 percent of the initial raw material is converted into microblades. The production of completed bifaces uses 70.5 percent of the initial raw material; 29.5 percent of the initial blank weight is retained in the final biface. This comparison suggests that there is no clear advantage in raw material economy between the two techniques. However, there are further potential costs and benefits associated with these technologies. Importantly, a handful of microblades is merely a bundle of stone splinters, not a finished tool. Insets, commonly made by snapping off both ends of the microblade, comprise about one-third to one-half of the intact microblade weight. Thus, 33 gm of snapped microblade insets from 66 gm of microblades per core in Flenniken’s experiment is only 15.06 percent of the initial blank weight, less than half the yield of finished bifaces. Flenniken also points out that microblades cost more in time to produce; he took 51 minutes on average to make about 100 microblades, or about twice the time per core (exclusive of heat treatment) used to make each biface. Thus, compared with microblade production, biface production appears to take less time and to make a more economical use of raw material. Figure 8.1. Organic, stone, and inset organic points compared. Microlithic Technology in Northern Asia 107 At the same time, we are aware that bifaces and microblades may represent different technological modalities that are not directly comparable in terms of a general economic currency such as raw material weight. Recall that the focus of our discussion has been on the relative performance characteristics of inset and flaked stone points. Flaked stone points are so effectively lethal because of their cutting edges. If we assume that length of usable cutting edge is the currency to be maximized (Kuhn 1994), and production time is the cost to be minimized, we now have an equivalent basis for comparison. Flenniken’s experimental bifaces averaged about 15 cm in length, thus yielding a maximum of 30 cm of cutting edge (less if hafted) per biface. The mean microblade yield per core was 101. Assuming each microblade could provide an inset 2 cm long, the average core would provide 202 cm of cutting edge, nearly seven times that of the experimental biface for just twice the cost in time and the same cost in raw material. Nevertheless, one might argue that the ability to resharpen a biface adds utility. While it is true that a biface used as a scraper or knife can be resharpened many times over a long use-life, a bifacial projectile point is likely to catastrophically fail after at most a few uses (Rondeau 1996). Most bifacial stone points probably could not be resharpened enough to match the 202 cm of inset cutting edge utility produced by microblade core reduction in the previous example. Additional utility may accrue from employing a biface as a tool prior to its service as a microblade core, as was sometimes the case in Japan (Bamforth and Bleed 1997) and China (Lu 1998), and by using biface thinning flakes and ski spalls as tools or tool blanks. While such recycling can reduce raw material demands, and can provide additional cutting edge (cf. Kelly 1988; Kuhn 1994), it is not edge of the same uniform quality provided by insets, and it does not serve the same purpose as projectile point edges. Such cost and benefit analysis seems ripe for further exploration through experimental replication and modeling. Relative Efficiency of Boat-Shaped and Wedge-Shaped Microcores Asian microblade cores are frequently divided into a large number of types (Chen and Wang 1989; Morlan 1976), though Seong (1998) has made a significant contribution by reducing these bewildering type lists to four basic variants. For the purposes of this chapter, we will distinguish between two basic approaches: boat-shaped cores made on split pebbles or thick flakes, and wedgeshaped cores made on bifacial blanks (Figure 8.2, A, B) (Kobayashi 1970). Microblades can be produced from boat-shaped cores in a few steps (Morlan 1976). One primary advantage of boat-shaped cores is that they are usually produced from small, pebble-sized toolstone packages locally available in many geomorphic contexts. The use of a minimal number of technical steps in preparing boat-shaped cores appears to allow a large proportion of the pebble blanks to be turned into microblades (Seong 1998:272–274). Fewer steps in preparation may also reduce the risk of core failure since fewer things can go wrong. In conReduction Stage Mean Weight (g) Previous Stage % of Previous Stage