Pollen, Starch, and Biosilicate Analysis of Archaeological Deposits on Guam and Saipan, Mariana Islands, Northwest Pacific: Evidence for Chamorro Subsistence Crops and Marine Resources

Recent advances in the study of crop fossils have been made at sites across much of the Pacific by the application of a range of microfossil techniques, namely analysis of pollen, phytoliths, and starch. Compared with Melanesia and Polynesia, however, the application of this in Micronesia is limited. Here we report on microfossil analysis of Micronesian archaeological deposits from the Mariana Islands, from two sites on Guam: Tumon and Ipan, and another near Lake Susupe, Saipan. All three sites contained subsurface deposits, dated ca. 1300-300 BP. The phytolith and starch data indicate the use of several subsistence taxa, including Musa (banana), up to three Dioscorea (yam) species, and other possible subsistence taxa, starch grains of which can be difficult to differentiate. Radiolarian fragments from the inside surface of a potsherd reflect the use of marine resources. Because plants have differential production and preservation of pollen, phytoliths, and starch, the data illustrate the value of using combined analyses of these microparts. This method also shows the combination and geographic range of crops, and that Micronesian archaeological deposits potentially contain microfossil evidence for prehistoric subsistence plants and other resources as detailed as that shown for elsewhere in the Pacific.