Marshall I. Weisler

Geochemical characteristics of West Molokai shield‐ and postshield‐stage lavas: Constraints on Hawaiian plume models

There are systematic geochemical differences between the < 2 Myr Hawaiian shields forming the subparallel spatial trends, known as Loa and Kea. These spatial and temporal geochemical changes provide insight into the spatial distribution of geochemical heterogeneities within the source of Hawaiian lavas, and the processes that create the Hawaiian plume. Lavas forming the similar to 1.9 Ma West Molokai volcano are important for evaluating alternative models proposed for the spatial distribution of geochemical heterogeneities because ( 1) the geochemical distinction between Loa and Kea trends may end at the Molokai Fracture Zone and ( 2) West Molokai is a Loa- trend volcano that has exposures of shield and postshield lavas. This geochemical study ( major and trace element abundances and isotopic ratios of Sr, Nd, Hf, and Pb) shows that the West Molokai shield includes lavas with Loa- and Kea- like geochemical characteristics; a mixed Loa- Kea source is required. In contrast, West Molokai postshield lavas are exclusively Kea- like. This change in source geochemistry can be explained by the observed change in strike of the Pacific plate near Molokai Island so that as West Molokai volcano moved away from a mixed Loa- Kea source it sampled only the Kea side of a bilaterally zoned plume.

High Precision U/Th Dating of First Polynesian Settlement

Previous studies document Nukuleka in the Kingdom of Tonga as a founder colony for first settlement of Polynesia by Lapita peoples. A limited number of radiocarbon dates are one line of evidence supporting this claim, but they cannot precisely establish when this event occurred, nor can they afford a detailed chronology for sequent occupation. High precision U/Th dates of Acropora coral files (abraders) from Nukuleka give unprecedented resolution, identifying the founder event by 2838±8 BP and documenting site development over the ensuing 250 years. The potential for dating error due to post depositional diagenetic alteration of ancient corals at Nukuleka also is addressed through sample preparation protocols and paired dates on spatially separated samples for individual specimens. Acropora coral files are widely distributed in Lapita sites across Oceania. U/Th dating of these artifacts provides unparalleled opportunities for greater precision and insight into the speed and timing of this final chapter in human settlement of the globe.

A multidisciplinary approach for dating human colonization of Pacific atolls

ABSTRACT The timing of reef platform emergence and the detailed chronology of reef island development provides a powerful backdrop for constraining the earliest period possible for prehistoric human colonization of low-lying atolls. Since Pacific atolls consist of biogenetic sediments, we dated foraminifera sands composed of well-preserved shallow-water species that are reliable indicators of facies formation. From transect excavations across the largest islet of Utrōk Atoll (11°13’N, 169°50’E) and Maloelap Atoll (8°47’N, 171°05’E), Marshall Islands, we selected nine foraminifera dating samples and five charcoal samples from prehistoric ovens in well-defined cultural layers and charcoal from buried A horizons. We document that: 1) the largest islets of Utrōk and Maloelap atolls expanded towards the lagoon shore at a rate of ∼70 m/kyr and ∼200m/kyr, respectively; 2) foraminifera sands immediately below buried A horizons in the islets “core” areas represents the timing of islet development at ∼2750 and ∼2400 cal BP, respectively; and 3) the oldest cultural dates (1850 and 1790 cal BP, ∼900–600 years younger than islet development) indicates that occupation much older than 2000 cal BP is unlikely, which is supported by sea level falling from its high stands to the present levels around 2000 cal BP for the northwestern Pacific.

Bayesian modeling and chronological precision for Polynesian settlement of Tonga

First settlement of Polynesia, and population expansion throughout the ancestral Polynesian homeland are foundation events for global history. A precise chronology is paramount to informed archaeological interpretation of these events and their consequences. Recently applied chronometric hygiene protocols excluding radiocarbon dates on wood charcoal without species identification all but eliminates this chronology as it has been built for the Kingdom of Tonga, the initial islands to be settled in Polynesia. In this paper we re-examine and redevelop this chronology through application of Bayesian models to the questioned suite of radiocarbon dates, but also incorporating short-lived wood charcoal dates from archived samples and high precision U/Th dates on coral artifacts. These models provide generation level precision allowing us to track population migration from first Lapita occupation on the island of Tongatapu through Tonga’s central and northern island groups. They further illustrate an exceptionally short duration for the initial colonizing Lapita phase and a somewhat abrupt transition to ancestral Polynesian society as it is currently defined.

The Mangarevan Sequence and Dating of the Geographic Expansion into Southeast Polynesia

A recently published archaeological sequence supported by information from six sites excavated in the Mangarevan group in 1959 is summarized in the context of additional data and current interpretations of the prehistory of southeastern Polynesia. The known part of the Mangareva sequence covers the period from ca. a.d. 1200 to the time of early nineteenth-century contact with Europeans, with its datingen hanced by four new radiocarbon age determinations plus four previous ones, all on samples collected in 1959. More recent information from archaeological investigations on nearby Pitcairn and Henderson islands, showing they formed part of a long-term interaction sphere with Mangareva, indicate that while the early part of the Mangareva sequence from ca. a.d. 800–1200 remains undocumented, buried cultural deposits for this interval probably exist within Rikitea village on the main island of Mangareva. An a.d. 700–800 settlement for the Mangareva group is consistent with a similar age and origin for the first inhabitants of Easter Island, as aspects of the thirteenthcentury assemblages from both places are comparable. A similar age is also supported by several dates for an initial colonization of Henderson Island in this period. Recent linguistic reworkingof the early subgroupingof Eastern Polynesian suggests Easter Island, Original Mangarevan, and probably the extinct Polynesian languages of Henderson and Pitcairn were the first in the region, placing the age of that subgroup around a.d. 700–800. A major secondary contact with Marquesan speakers who may have settled in Mangareva at a.d. 1100–1300, seems to have been the basis for changing it into a Marquesic language, of a form then taken to Rapa. The archaeology, biological relationships, and linguistic history of the region now provides a robust and consistent outline for the geographic expansion into Southeast Polynesia.

Analysis of Plant Microfossils in Archaeological Deposits from Two Remote Archipelagos: The Marshall Islands, Eastern Micronesia, and the Pitcairn Group, Southeast Polynesia

ABSTRACT Pollen and starch residue analyses were conducted on 24 sediment samples from archaeological sites on Maloelap and Ebon Atolls in the Marshall Islands, eastern Micronesia, and Henderson and Pitcairn Islands in the Pitcairn Group, Southeast Polynesia. The sampled islands, two of which are “mystery islands” (Henderson and Pitcairn), previously occupied and abandoned before European contact, comprise three types of Pacific islands: low coral atolls, raised atolls, and volcanic islands. Pollen, starch grains, calcium oxylate crystals, and xylem cells of introduced non-Colocasia Araceae (aroids) were identified in the Marshalls and Henderson (ca. 1,900 yr B.P. and 1,200 yr B.P. at the earliest, respectively). The data provide direct evidence of prehistoric horticulture in those islands and initial fossil pollen sequences from Pitcairn Island. Combined with previous studies, the data also indicate a horticultural system on Henderson comprising both field and tree crops, with seven different cultigens, including at least two species of the Araceae. Starch grains and xylem cells of Ipomoea sp., possibly introduced I. batatas, were identified in Pitcairn Island deposits dated to the last few centuries before European contact in 1790.

LATE HOLOCENE 14C MARINE RESERVOIR CORRECTIONS FOR HAWAI'I DERIVED FROM U-SERIES DATED ARCHAEOLOGICAL CORAL

The first application of U-series dating and accelerator mass spectrometry (AMS) assay of Polynesian archaeological Pocillopora spp. branch corals for deriving a precise local marine reservoir correction (ΔR) is described. Known-age corals were selected that spanned the entire culture-historical sequence for the Hawaiian Islands, thus eliminating the problem of not having known-age dated samples that cover the period of direct relevance to prehistorians; in this case, about AD 700–1800. Dating coral samples from windward and leeward coastlines of Moloka‘i Island, with different offshore conditions such as upwelling, currents, wind patterns, coastal topography, and straight or embayed shorelines, provides insights into possible variations of local conditions on the same island—something that has never been attempted. In this regard, there was no spatial variability in ΔR during the 17th century. We report a weighted average ΔR value for Moloka‘i Island of 52 ± 25 yr using 12 pair-dated dedicatory branch corals from religious archaeological sites and demonstrate that there is no significant temporal variability in ΔR between about AD 700 to 1800. In combination with 4 selected previously published ΔR values based on pre-bomb known-age marine shells, a revised ΔR of 66 ± 54 yr is established for the Hawaiian Islands. However, future research should examine the archipelago-wide spatial variability in ΔR with the analysis of additional dated archaeological coral samples

A New Eastern Limit of the Pacific Flying Fox, Pteropus tonganus (Chiroptera: Pteropodidae), in Prehistoric Polynesia: A Case of Possible Human Transport and Extirpation.

ABSTRACT Five bones, representing one adult of the Pacific Flying Fox, Pteropus tonganus, were recovered from an archaeological site on Rurutu (151°21′W, 22°27′S), Austral Islands, French Polynesia, making this the most eastern extension of the species. For the first time, flying fox bones from cultural deposits were directly dated by accelerator mass spectrometry, yielding an age of death between A.D. 1064 and 1155. Their stratigraphic position in an Archaic period archaeological site and the absence of bones in the late prehistoric to historic layers point to extirpation of the species. No flying fox bones were found in pre-human deposits and human transport of the species cannot be ruled out.

Kurturniaiwak (Badu) and the archaeology of villages in Torres Strait

Abstract Despite more than 30 years of archaeological research, not a single detailed site report has ever been published for a village site in Torres Strait. This paper presents the results of small-scale excavations at the 700 year old village of Kurturniaiwak on Badu island in mid-western Torres Strait. It represents the first in an ongoing series of systematic excavations of village sites in this part of Torres Strait. Initial results support conclusions of major socio-cultural change for the region as recently proposed by McNiven, and indicate that a major reconfiguration of settlement-subsistenceritual systems probably took place in western Torres Strait sometime between 600 and 800 years ago.

A quarried landscape in the Hawaiian Islands

Abstract Polynesian stone adze quarries anchor the system of tool production, distribution and consumption and are critical for examining changing social organization, symbolic values attributed to particular stone sources, economic intensification and ancient interaction. Although major adze quarries are known from most Polynesian archipelagos, a geologically informed archaeological survey was designed for discovering the variability in stone-tool-quality rock sources. Thirteen quarries and sources within the ∼20,000 hectare traditional land unit of Kaluako‘i (literally, the adze pit) on Moloka‘i, Hawaiian Islands, vary considerably in size, production output and settlement context, suggesting that individual adze quarries were accorded different roles across the social landscape. Some sixty-four radiocarbon age determinations and U-series dates from quarries and habitation sites with artefacts originating from quarries, document the temporal sequence of use beginning in the Late Expansion Period (ad 1400–1650), at least two centuries after settlement of the island. Further studies will report on adze technology and on-going geochemical sourcing analyses.