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Show pecking, and abrasion or grinding. In this order there is an inverse relationship between the quantity of material removed and production investment (time and energy), with flaking generally resulting in more for less and grinding resulting in less for more. This inverse relationship is also expressed within each technique: for flaking the difference between percussion and pressure methods of force application, for pecking the difference between using sharp and blunt percussors and ones of different weight/size, and for grinding the difference between coarse and fine abrasives. This relationship is one means for monitoring the relative production costs of various stone artifacts. Flaking is the best method to remove large amounts of material to quickly alter the plan or section of an item. Most previous experimental work and discussion has involved flaking of isotropic, microcrystalline siliceous rocks such as chert. Yet, many other types of stone, such as sandstone, basalt, and andesite can be effectively flaked, and were so prehistorically and ethnohistorically. No matter if the desired implement was a sandstone metate or a chert biface, when large amounts of material had to be removed, flaking would have been the preferred method. As such, the most important distinction between these two implements is not their means of production, since both may have been flaked, but their use and social roles. While flaking can be used to efficiently rough-out a metate blank (see Geib 1986; Huckell 1986), it cannot be employed to finish it. Pecking is required to prepare a metate surface for use. As a reduction method, pecking removes substantially less material than flaking and does so by crushing and shattering rock grains or initiating a sequence of minute conchoidal fractures that serve to fracture away small portions. Pecking can be done with either pointed and sharp-edged precursors or those with rounded use surfaces. Pointed or sharp-edged implements focus the force application and, on granular rocks such as sandstone, serve to penetrate the stone, removing material and leaving a small depression. Rounded percussion stones do not penetrate the worked rock, so less material is removed. Both means of force application were probably used prehistorically since they complement each other-sharp pecking implements remove more material but leave a rather irregular surface, and rounded pecking stones remove less material but leave a regular surface, almost identical to that produced by coarse abrasion. Almost any stone can be reduced by pecking, including all flakable stone, even obsidian.2 Pecking can be used to produced finished use-ready surfaces of tools such as manos and metates. It cannot produce useful edges or points, although it is often an important intermediate step in their production, as with axes that were flaked to rough-out the form, pecked to refine the form, and finished by grinding. Abrasion is the third reduction technique. It works effectively on virtually all materials and can be used to produce both sharp edges and smooth surfaces. It usually proceeds from using coarse abrasives to fine, with the finest abrasives resulting in a polish. Care must be taken to differentiate between production and use-related abrasion. Grinding is the most costly stone reduction technique in terms of the amount of material removed for the time and energy expended. This production technique can increase the longevity and efficiency of certain tools and thus is often well worth the extra investment. For example a stone axe could have a bit finished by grinding versus one with a bit finished by flaking. Some items, such as ornaments, could not have been made except by abrasion. ANALYSIS METHODS AND DEFINITIONS Recovery Procedures Most of the stone artifacts were collected from excavated and screened proveniences. Mesh sizes included 1/4" for routine use at Basketmaker and Puebloan sites and 1/8" at Archaic sites. Sediment from many features at Basketmaker and Puebloan sites, including all structure floor fill and floors and samples of trash middens, were also screened with 1/8" mesh. To augment the sample of less common lithic tools, crews collected all tools/cores observed while removing sediment from unscreened proveniences such as erosional structure fill and shovel-stripped portions of middens. Such items were analyzed together with unbiased samples since they provide an essential addition to the sample size of certain artifact classes. The general field procedure was to bag all small flaked stone artifacts together (debitage and flaked facial tools) from any single provenience, although some temporal diagnostics (projectile points) or other interesting items were bagged separately. All grinding tools and larger stone artifacts such as hammerstones were usually bagged separately from the debitage and flaked facial tools so as to avoid artifact damage. Special mention must be made of sandstone debitage, derived principally from early 2 The pecking of obsidian and chert involves slowly fracturing away minute particles of stone by the intersection of numerous ringcracks initiated by the precursor; thus, it differs from the pecking of stones such as sandstone and basalt. V.5.5 |
