Colin Renfrew, J. E. Dixon, and J. R. Cann devised a method for tracing ten-thousand-year-old Near Eastern trade routes by means of trace-element analysis of obsidian, marking a breakthrough in the archaeology of the Near East.
Scholars have long been intrigued by the rapid spread of Neolithic farming throughout southwestern Asia and the Mediterranean. The fact that isolated, widely scattered small villages made the transition from hunting and gathering to farming almost simultaneously suggested that these early communities had somehow been in contact. The problem, however, was to devise a way to trace the trade network and thereby confirm the existence of communication between the ten-thousand-year-old settlements.
In the early 1960’s, Colin Renfrew and his colleagues, J. R. Cann and J. E. Dixon, realized that a comparative study of artifacts from the centers of early agricultural development might hold the clue needed to reconstruct prehistoric trade networks. Previous comparative studies had attempted mostly to analyze techniques of manufacture or stylistic similarities: If two cultures used pottery decorated in identical ways, it suggested the two had been in contact. This type of interpretation was limited, however, for the two societies might have devised the same techniques independently. Renfrew, Dixon, and Cann suggested that the raw materials from which tools were manufactured might hold more promise as a diagnostic of contact. If the materials recovered from the archaeological deposit do not occur naturally in the region, they must have been obtained in trade from another population.
The first problem faced by the researchers was to choose what material to study. They decided on obsidian, the easily chipped volcanic glass used by early tool makers throughout the world. Obsidian artifacts are found all over the Mediterranean basin and southwest Asia, but obsidian source areas occur only in regions that have seen recent volcanic activity: Italy, the Aegean, Turkey, and Iran. The next question was how to trace the obsidian to its source area. Obsidian tools often appear in archaeological deposits hundreds of kilometers from the nearest source. Tracing the tools to particular source areas was difficult, for obsidians from a single volcanic deposit may differ greatly, while those from different deposits might seem outwardly quite similar. Microscopic examination revealed little because early tool makers had always favored obsidian of uniform structure, free of the inclusions that sometimes distinguish one source from another. Nor did chemical analysis offer much information, for obsidians are all essentially identical in gross chemical makeup.
In 1962, the researchers turned to the relatively new field of trace-element analysis. The theory behind trace-element analysis is that each rock or mineral source has a trace-element pattern distinct from any other—a sort of chemical fingerprint made up of elements that are present in minute amounts. No matter how many flows might be represented in a single source site—and regardless of their outward appearance—all would display essentially the same trace-element pattern because they all derived from the same volcanic source.
Renfrew, Dixon, and Cann decided to use a method known as optical spectrography,
Beginning with samples of well-known obsidian sources in the Mediterranean basin, the researchers set out to determine if the sources could be distinguished by their trace-element makeup. They found that the elements barium and zirconium showed the most noticeable concentration differences in the samples, and often the relative proportions of those two elements alone were sufficient to distinguish one obsidian source area from another. The team then decided to test their thesis with a study of the ancient obsidians from the island of Malta, south of Sicily.
Earlier archaeologists had speculated that the obsidian on Malta was shipped by Minoan traders from Mílos, an island 966 kilometers away. Trace-element analysis suggested, instead, that the Neolithic people on Malta had sailed to the small island of Pantelleria, 240 kilometers north, for their obsidian. Further tests revealed that the obsidians found by Sir Arthur Evans
Renfrew and his colleagues were able to distinguish six sources for obsidian in the Mediterranean during Neolithic times: Sardinia, west of Italy; Palmarola, Pantehleria, and Lipari in the central Mediterranean; and the islands of Giali and Mílos, in the Aegean. They concluded also that there were two distinct trade regions: the central Mediterranean and the Aegean. Within each region, obsidian was often shipped long distances from its origin point, and a single site might yield samples of obsidian from two or more source areas. There seemed, however, to be no trade between the two regions.
Dixon, Cann, and Renfrew next applied their method to a study of obsidians from the earliest settled communities in the “fertile crescent” of Egypt, Palestine, Anatolia, and Mesopotamia. There they found abundant obsidian materials in early Neolithic village sites, but few obsidian source areas. Their studies of the obsidian revealed eight different types, some of which could not be matched to the known source areas in ancient Armenia (eastern Anatolia), Cappadocia (central Anatolia), or Ethiopia. Careful detective work, based on a comparison of the composition of the samples in various regions, led to the discovery of some of the missing source areas and a clearer picture of the patterns of trade in operation at the beginning of the Agricultural Revolution.
The Near Eastern research, first published in 1964, showed that the entire region of the Fertile Crescent (including the island of Cyprus) was supplied with obsidian from two major source areas: the Armenian and the Cappadocian. Renfrew found that obsidian distribution was surprisingly regular—within 240 to 320 kilometers of a source area, 80 percent of the chipped stone tools found at early Neolithic village sites were made of obsidian. Outside that radius, the amount of obsidian present at a particular site depended on its distance from the “supply zone.” The drop-off of obsidian in this “contact zone” was a nearly perfect exponential function of distance: The farther from the supply zone, the fewer obsidian tools. Several sites in Palestine yielded obsidian artifacts from both source areas, a fact that the researchers suggest might have resulted from trade with two different groups: the nomads of the semiarid zone and the coastal farmers.
Renfrew, Dixon, and Cann concluded from their research that the regularity of obsidian distribution patterns in the early Neolithic settlements of the Mediterranean and Near East was the result of continuous, regular trade from as early as 8,000
Questions about the origins of agriculture have fascinated scholars for decades, for the transition from hunting and gathering to food production was a monumental change in humankind’s cultural adaptations. For the first time in 2 million years of prehistory, people were no longer forced to pursue wild food resources in endless, seasonal cycles of nomadic movement. They now controlled the animals and plants they needed for food. Food production was also the modification that made possible the later development of civilization, for the Neolithic farmer provided the economic base necessary to support the specializations and specialists of the Bronze Age world.
Trade was probably not an innovation of the Neolithic period. There is ample evidence of trade in obsidian, flint, amber, and other raw materials from upper Paleolithic times, and the Neolithic obsidian trade would have been a logical outgrowth of these early contacts. One must be careful, as Renfrew and his colleagues point out, not to read too much complexity into this early exchange or overestimate the amount of actual face-to-face contact that resulted from it. Nevertheless, where there was exchange of materials there might have been the potential for exchanging ideas as well, and therein lies the real importance of establishing the existence of trade routes in antiquity.
At the time Renfrew and his colleagues developed their method of obsidian tracing in the mid-1960’s, a major issue facing scholars doing Neolithic studies was the question of origins. Evidence of early farming had been uncovered in at least three centers within the greater Fertile Crescent area: Palestine, southern Anatolia, and the Zagros range of Mesopotamia. Much effort had been spent to determine which of these areas was the first farming community or if each had independently invented the process. Radiocarbon dating, unfortunately, was inexact enough to fuel a controversy, and scholars become involved in a rather heated argument of the issue.
The Renfrew, Dixon, and Cann research did not provide a definitive answer to the question of origins, but it did provide a mechanism to help trace the channels of communication in place at the time. As they pointed out, the Neolithic Revolution was not as abrupt a change as its name implied, but rather a gradual process that probably took several centuries or longer to mature fully. Given the existence of widespread trade (and therefore communication) among the cultures in the area, it would be difficult to conceive of such a series of changes taking place without some knowledge of those changes (if not the domesticated plants and animals themselves) making their way to others in the trade network.
Renfrew, Dixon, and Cann’s successful reconstruction of the Mediterranean obsidian trade gave rise to dozens of similar investigations in Europe, North America, Mexico, New Zealand, and Africa—virtually everywhere ancient peoples used obsidian for their tools. The increased knowledge of trade patterns resulting from this research has greatly enhanced an understanding of the development of prehistoric culture and the process of cultural change throughout the ancient world.
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Blashford-Snell, John, and Richard Snailham. Kota Mama: Retracing the Lost Trade Routes of Ancient South American Peoples. London: Headline, 2000. Story of the reconstruction of South American trade routes: Serves as a useful comparative case study to the work of Cann, Dixon, and Renfrew in the Middle East. Bibliographic references and index. -
Cann, J. R., J. E. Dixon, and Colin Renfrew. “Obsidian Analysis and the Obsidian Trade.” In Science in Archaeology, edited by Don Brothwell and Eric Higgs. Rev. ed. New York: Praeger, 1970. An article that deals specifically with the application of optical spectrography, the trace-element method used in the obsidian studies carried out by Renfrew and his colleagues. A somewhat technical but interesting discussion of how characterization studies can be used in the field of archaeological analysis. Includes graphs and illustrations. -
Cann, J. R., and Colin Renfrew. “The Characterization of Obsidian and Its Application to the Mediterranean Region.” Proceedings of the Prehistoric Society 30 (1964): 111-133. The landmark article that launched the researchers’ obsidian characterization and trade studies. Outlines the method of trace-element analysis and the technique of optical spectrography using test materials from the west Mediterranean. A classic study that showed the great potential of such studies for an understanding of cultural process. -
Costa, Paolo M. “South Arabian Coast and the Ancient Trade Routes in the Light of Recent Exploration and a Discussion of Written Sources.” In Studies on Arabia in Honour of Professor G. Rex Smith, edited by J. F. Healey and V. Porter. New York: Oxford University Press, 2002. Reviews both physical and documentary evidence of ancience Arabian trade routes available in the early twenty-first century. Bibliographic references and index. -
Dixon, J. E., J. R. Cann, and Colin Renfrew. “Obsidian and the Origins of Trade.” Scientific American 218 (March, 1968): 38-46. A general article that discusses obsidian characterization studies and the origins of trade in both the Mediterranean and the Near Eastern areas. A good summary article covering the first five years of their research. Written for an audience with less scientific background. Good illustrations. -
Renfrew, Colin. “Trade as Action at a Distance: Questions of Integration and Communication.” In Ancient Civilization and Trade, edited by Jeremy A. Sabloff and C. C. Lamberg-Karlovsky. Albuquerque: University of New Mexico Press, 1975. A theoretical study of the obsidian trade that applies system theory and locational analysis in the reconstruction of the formation of civilization. Useful for those interested in the application of model building in archaeological analysis. Good bibliography. -
Renfrew, Colin, J. E. Dixon, and J. R. Cann. “Further Analysis of Near Eastern Obsidians.” Proceedings of the Prehistoric Society 34 (1968): 319-331. A follow-up on the original study of Near Eastern obsidians. This article gives new information about the Anatolian sources and some revised results for the early Neolithic obsidian trade pattern. Useful illustrations and charts. -
_______. “Obsidian and Early Cultural Contact in the Near East.” Proceedings of the Prehistoric Society 32 (1966): 30-72. An extensive article on the obsidian trade in the Near East. Uses the same characterization methods as the original west Mediterranean study with similar, impressive results. Contains several charts and graphs. Excellent maps and bibliography. -
Vanished Civilizations. New York: Reader’s Digest, 2002. This general mass-market work on ancient civilizations includes a chapter devoted to their trade routes. Index.
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