Test Pit Excavations (March-April 1991)

This Volume begins with a brief description of a series of test pits, excavated by Mari Mari Kellum and I, in an attempt to gain a broad general picture of the local stratigraphy as well as look for evidence of deeply buried deposits. This work which had been long overdue was finally accomplished, thanks to the enormous generosity of Mari Mari who accepted the job despite the many limitations which are necessarily imposed by minimum funding. In the brief period of the three weeks that were allotted to this project it was hoped that enough vital information would be gathered, and while it was proposed that some of the materials recovered may be dated by radio carbon methods, it was unlikely that we could entirely depend on this possibility.

In as much as there are but few natural geological processes which could produce buried or layered deposits in Tubuai, it seemed likely that there would be but one relatively continuous occupation deposit. Not discounting however the more remote possibility that occasional tidal waves or river flooding may have sealed in certain older deposits.

If it happens that the bulk of the cultural remains are found to be confined within the first 30 centimeters, then one can assume that modern cultivation methods will have already destroyed most of the vital stratigraphic evidence. However if deposits could be discovered below a depth of 40 cm one might be able to recover information even from cultivated sites. One of our major objectives then would be to establish the depth of deposits as well as the nature and limits of cultivation damage.

Methods

Years of artifact collection and fossicking enabled a quick selection of important sites. TEAOA and HANATAI being also easily accessible, were the first chosen. A series of pits one meter square were undertaken in an attempt to show a good cross section of the site as well as cultivation damage. The pits were established by measuring from known reference points, stakes and strings laid out, and datum points established. Excavation proceeded with trowels and the material excavated was screened. Fine screens, were employed, the grades varying (2-4mm mesh). Arbitrary 10 cm layers were employed in the absence of clearly defined layers, while in other cases where distinct layers could be detected, these were excavated following their natural stratigraphy. The collected material from screening, such as shell and basalt flakes was bagged and marked by layer, while clearly defined artifacts such as tools were individually bagged and mapped. Photographs and cross sections were taken in most cases and drawings made of unique features, such as post holes or fire pits. Most test pits were excavated to sterile and beyond, to ensure that no hidden layers were present. In many cases the water table was reached and this became the natural limit to the excavation, however some features penetrated beyond this limit. Generally speaking, the water table was encountered 80 to 90 cm below the surface in most coastal sites, some worked basalt flakes were recovered from below the water table in test pit #1.

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