14The timing and unprecedented speed of the Lapita migration from the western edge of Oceania 15 to western Polynesia in the Central Pacific have long been of interest to archaeologists. The 16eastern-most extent of that great human migration was the Samoan Archipelago in West 17Polynesia, although critical questions have remained about the timing and process of Samoan 18 colonization. To investigate those questions, we carried out a Bayesian analysis of 19 19 radiocarbon dates on charcoal and 8 uranium-thorium (U-Th) series coral dates from four 20 archaeological sites on Ofu Island in the eastern reaches of Samoa. The analysis indicates initial 21 settlement of Ofu at 2717-2663 cal BP (68.2%) by people using Plainware rather than the 22 diagnostic dentate-stamped Lapita pottery. This date range indicates that there is not a 23 significant chronological gap between Lapita and Plainware sites in Samoa, which holds 24 implications for modeling the settlement process in the Central Pacific. 25

The availability of lidar datasets has led to several advances in archaeology, notably in the process of site prospection. Some remote sensing practitioners have aimed to create automated feature extraction (AFE) techniques that increase the efficiency and efficacy of identification and analysis. While these advances have been successful, many archaeological professionals who might have an interest in lidar-derived products do not have the technical experience to modify or create AFE techniques for particular regions or environments. Additionally, some features are not appropriate for AFE. Instead, the most widely used technique is still likely to be visually based manual feature identification. Using authors of different experience levels, we seek to evaluate the use of manual techniques for feature identification and subsequent analysis by implementing a publicly available lidar-derived digital elevation model (DEM). We demonstrate that manual feature extraction (MFE) can be accurate when more than one researcher is involved in a sort of “checks and balances” process. We also show that the use of confidence ratings can be an important part of this process if those ratings have some systematic and clearly defined underpinning. Finally, we argue, using a case study from American Samoa, that manually identified features can be analytically important as part of larger landscape studies.

The 9th–15th century Angkorian state was Southeast Asia’s greatest premodern empire and Angkor Wat in the World Heritage site of Angkor is one of its largest religious monuments. Here we use excavation and chronometric data from three field seasons at Angkor Wat to understand the decline and reorganization of the Angkorian Empire, which was a more protracted and complex process than historians imagined. Excavation data and Bayesian modeling on a corpus of 16 radiocarbon dates in particular demand a revised chronology for the Angkor Wat landscape. It was initially in use from the 11th century CE with subsequent habitation until the 13th century CE. Following this period, there is a gap in our dates, which we hypothesize signifies a change in the use of the occupation mounds during this period. However, Angkor Wat was never completely abandoned, as the dates suggest that the mounds were in use again in the late 14th–early 15th centuries until the 17th or 18th centuries CE. This break in dates points toward a reorganization of Angkor Wat’s enclosure space, but not during the historically recorded 15th century collapse. Our excavation data are consistent with multiple lines of evidence demonstrating the region’s continued ideological importance and residential use, even after the collapse and shift southward of the polity’s capital. We argue that fine-grained chronological analysis is critical to building local historical sequences and illustrate how such granularity adds nuance to how we interpret the tempo of organizational change before, during, and after the decline of Angkor.

a b s t r a c tA long standing research approach in island Oceania is the examination of community and regional level patterning of archaeological remains. However, these efforts are impeded by heavy vegetation and rugged terrain, which limit the implementation and productivity of traditional archaeological methods. Aerial lidar data provide an opportunity to survey large archaeological landscapes effectively and efficiently in these environments. In this paper, we present the results of a lidar-based survey and analysis of community-level spatial patterning for at sites in the Manu'a Group of American Samoa. Using lidar data in conjunction with pedestrian survey results, we first established the suitability of lidar for identifying archaeological features, and then applied the technique to a previously unexamined landscape. We were able to record archaeological remains and analyse the data to discern spatial patterning in their distribution. The patterning of these remains is broadly comparable, though not identical, to that of three other settlement zones on Olosega and the adjacent island of Ofu, which previously were intensively surveyed. The differences in the characteristics and distribution of structural features within and between these four settlement zones may reflect differences in social status and ranking.

This study summarizes the impacts of geomorphological processes on human settlement strategies on the island of Ofu in the Samoan Archipelago from island colonization to permanent settlement in the interior uplands (c. 2700–900 b.p. ). Previous archaeological research on Ofu has documented a dynamic coastal landscape at one location, To’aga, on the southern coast. Using a new geoarchaeological data set, our study extends this assessment to a site on the western coast of the island. We conclude that although the sequence of coastal evolution is broadly consistent between the two areas there are also differences indicating that island-wide coastal evolution did not progress everywhere at the same rate. Using this data set, we record changes in human settlement patterns temporally correlated with coastal progradation—perhaps related to continued drawdown from the mid-Holocene sea-level highstand—and sediment aggradation. We suggest that coastal landscape change on Ofu may have been one factor in the expansion of the terrestrial component of the human subsistence base and the more intensive use of the interior uplands of the island. The timing of this settlement change was slightly earlier than elsewhere in the region, demonstrating the variability of human response to regional-scale environmental changes.