Pre-Historic Pottery of Guam
Pottery making skills came with first settlers
Guam has a history of pottery-making that is more than 3,000 years long. The first people to arrive in the Mariana Islands apparently had brought with them pottery-making skills; the broken remains of their pots, called sherds, have been found at archaeological sites dating back to circa 3500 BP (Before Present). While the earliest Guam pottery shares some characteristics with similarly aged pottery collections from the Philippines and Southeast Asia, its specific place of origin remains unknown. Traditional methods of manufacture continued until the widespread introduction of new manufacturing techniques and Western manufactured vessels during the eighteenth century.
Guam’s prehistoric period, spanning at least 3,000 years, witnessed significant changes in pottery styles and techniques of manufacture. Analysts on Guam describe these changes according to distinct types and specific attributes. These types and attributes are compared with radiocarbon dates taken from the same sites to develop a pottery chronology that encompasses the changes in manufacture over time.
Because the historic literature lacks descriptions of the traditional pottery making techniques and materials, archaeological research provides the basis for what is now known. Researchers generally agree that the pots were made from locally available clays and tempering materials, using paddle-and-anvil construction techniques (although there is some evidence of coiling), and that firings took place in above-ground bonfires for relatively short times at low temperatures.
Although archaeological excavations have uncovered only a few whole pots, they have provided mounds of sherds for partial reconstructions. Much is now known about a fairly wide range of vessel forms.
Marianas Redware and Marianas Plain
Two dominant pottery types are Marianas Redware and Marianas Plain. Marianas Redware dominates the earlier pottery, and Marianas Plain dominates the later pottery. While these two types are still commonly referred to, assigning individual sherds to such broad pottery types does not adequately acknowledge the subtle changes in various attributes (vessel form, rim thickness and shape, surface treatments, wall thickness, and temper inclusions) that occurred through time. As a consequence, most ceramic analyses focus upon definition and interpretation of these attributes.
Marianas Redware vessels consist of small, very thin-walled bowls and jars with a red-slipped or painted exterior finish. Small numbers of Marianas Redware exhibit intricate, lime-filled impressions. These designs are similar to those of an early pottery type from Melanesia and Polynesia, called Lapita. Over time, these designs changed from complex to simple patterns. The decorated pots disappeared about 1500 BP.
Shortly following 2500 BP, large, flat-bottomed pans with thick, vertical sidewalls begin to appear. Vessels with these attributes continue for nearly a thousand years (between about 1600 and 1500 BP). In some cases, mat impressions appear on the exterior surface of the pan’s flat base. The woven pattern of these impressions can be compared to the over-and-under weave used to make pandanus mats in the Caroline Islands (now the Federated States of Micronesia). Perhaps the impressions formed when the clay was placed on a woven mat to give it support during the vessel’s construction.
About 1600 BP, bowls with more rounded bases and thinner walls replace the pans. Other attributes – such as vessel thickness, rim form, and surface treatment – become less consistent. Gradually, perhaps around 1200 to 1000 BP, this vessel form appears to develop into the bowl and jar forms common to the late part of the ceramic sequence (Marianas Plain). These later vessels associated with the Latte Period (1200 – 500 BP) consist of large, thick walls with smooth, or roughened, exterior finishes, volcanic temper inclusions, thickened rims, and rounded or conical bases. Some sherds from this time period have grooves that suggest that some pots were equipped with cords, possibly to suspend them, to provide a better surface for gripping or pouring, or to secure a lid.
Clues to past
Beyond association with a particular time period, there is much that analysis of pottery can tell us about the lives of Guam’s prehistoric inhabitants. For example, the temper included in some sherds have been analyzed in order to gain information about the exchange of pottery vessels among different island communities in the Marianas archipelago. Other studies have identified charred remains on the interior surfaces of some sherds that can indicate the types of food that were prepared in these pots.
For further reading
Dickinson, W.R., B. M. Butler, D.R. Moore, and M. Swift. “Geologic Sources and Geographic Distribution of Sand Tempers in Prehistoric Potsherds from the Mariana Islands.” Geoarchaeology: An International Journal 16 (2001):827-54.
Hunter-Anderson, R.L., G.B. Thompson, and D.R. Moore. “Rice as a Prehistoric Valuable in the Mariana Islands, Micronesia.” Asian Perspectives 34 (1995) 69-89.
Moore, D.R. “Measuring Change in Marianas Pottery: The Sequence of Pottery Production at Tarague, Guam.” M.A. thesis, University of Guam, 1983.
Reinman, F.R. An Archaeological Survey and Preliminary Test Excavations on the Island of Guam, Mariana Islands, 1965-1966. Mangilao, GU: University of Guam Richard F. Taitano Micronesian Area Research Center, 1977.
Spoehr, A. Marianas Prehistory, Archaeological Survey and Excavations on Saipan, Tinian and Rota. Field Museum of Natural History Anthropological Series, Fieldiana: Anthropology 48. Chicago: Chicago Natural History Museum, 1957.