Carolyn Dillian

Introduction: Perspectives on Trade and Exchange

Today, in America, we are surrounded by objects from distant places: toys from China, cars from Japan, shoes from Mexico, wine from Argentina, and myriad goods from around the world. Workers in Naivasha, Kenya, harvest roses in the afternoon, and by the next morning they are for sale in the flower shops of London. High-speed, economical transportation links producers and consumers in an international marketplace; the average home in the western world contains goods transported by trains, container ships, and cargo jets. In the prehistoric and historic past, when transport was slower and costlier, the exchange networks that linked distant peoples were complex and productive. Nonlocal goods were transported, traded, and exchanged through a variety of means, over short and long distances, and it was often the case that the social dynamics that were part of this process were as meaningful as the objects themselves. Archaeological tools for identifying foreign objects, such as provenance studies, stylistic analyses, and economic documentary sources reveal nonlocal materials in prehistoric and historic assemblages. Yet trade and exchange encompass more than mere production and consumption. Exchange was a mechanism for introducing the exotic into daily life. Foreign objects were integrated into everyday practice long before the advent of a global economy.

Interaction and Exchange Across the Transition to Pastoralism, Lake Turkana, Kenya

Artifacts from the Galana Boi Formation in Kenya present a rare view of the dynamics of ancient lifestyles. Archeological materials include evidence of hunter-gatherer and fishing economies, and the beginnings of the earliest pastoralism in Kenya. Through the use of X-ray fluorescence analysis for sourcing of obsidian artifacts, we present theories of social networks, mobility, and exchange that may ultimately shed light on the nature of pastoralism’s introduction to East Africa.

Long-Distance Exchange of Obsidian in the mid-Atlantic United States

Continuing research into the possibility of super-long-distance exchange of obsidian materials has revealed additional archaeological specimens bolstering theories of exchange across the North American continent. A collection of obsidian artifacts from East Coast archaeological sites has been analyzed using X-ray fluorescence to reveal West Coast geologic provenance. Increasing numbers of specimens with well-documented archaeological provenience suggest that super-long-distance exchange existed prehistorically. Though transport existed on a continental scale, we argue the mechanism for exchange happened on a personal scale through hand-to-hand and person-to-person interaction.

Heat treatment of Pennsylvania jasper

Heat treatment of silicate toolstone was performed prehistorically, which we assume was to improve characteristics desired in flintknapping, such as increased brittleness and more predictable and controlled conchoidal fracture. However, despite research into heat treatment spanning 50 years, the mechanisms by which stone was improved, and the reasons why people did it, remain unclear. In this study, experiments were designed to test two potential outcomes of heat treatment for Pennsylvania jasper. First, does heating reduce the disruptive effect of macroscopic impurities and flaws on controlled flaking? Second, does heating increase the stone’s brittleness as suggested by Crabtree and Butler in 1964? Such physical alterations would improve the quality of lithic material but may not always occur in high quality stone. The results of these experiments are used to hypothesize the expected heat treatment outcomes sought after by prehistoric flintknappers.

Blue Vivianite in Prehistoric Clay

Experiments have demonstrated that vivianite, when processed using heat, produces a vivid blue pigment that could have been used as body paint, yet this vivid blue pigment could have been utilized in other ways as well. Archaeologically, vivianite has been documented as a component of clay pottery, but this vivianite was part of the clay matrix, not applied to the surface of the vessel. Experiments designed to assess the utility of vivianite as a blue colorant to a prehistoric ceramic matrix are outlined here. Clay pellets were painted with a vivianite slip and alternately had vivianite added to the clay prior to drying. Contrary to expected results, this vivianite, when mixed with clay or applied to the surface, does not yield a vivid blue color with heating. As a result, we must assume that vivianite may have merely been an accidental inclusion in the clay matrix as documented archaeologically, perhaps as a naturally occurring component of the original clay source or tempering material.