Prospection in Depth 2007 participants tested the hypothesis generated by the investigation of Anomaly 1. The radar survey of Grid 7, especially slices 1-3 (ground surface to ca. 40 cm below), showed promise. [Figure Anomaly 2-1, Figure Anomaly 2-2, Figure Anomaly 2-3] A strong radar signature linked with the brick path identified and excavated the season before. Furthermore, it was larger than the path’s signature, as one might expect for a hearth. The gradiometer results, however, were puzzling, as they showed no significant magnetic signatures at all. [Figure Anomaly 2-4]
The preponderance of evidence suggested we might find a fireplace base or hearth grid-east of our G block excavations the year before. But the hypothesis did not stand. Excavation of another 1×1 m unit (GX13), flanked by five shovel tests at 1m intervals, failed to produce ash, charcoal, significant quantities of brick or fired clay, or any other sign of a chimney or structure. [Figure Anomaly 2-5, Figure Anomaly 2-6] For instance, excavators dug to a depth 35 cm below the ground surface and recovered 203 artifacts, most of which are tiny brick fragments (n=177, or 150.5 g), but the latter would fit in two hands and the quantity is typical of all excavation units in the vicinity of the brick feature [refer to table below].
|Artifacts Recovered from Unit GX13|
|wire nail||1||—||Type 11/12|
|UID ferrous metal||6||—||fragment|
To shed further light on the causes of the anomaly, researchers took core samples from three places on the floor of the excavation unit using a 1” diameter bore probe. The probe drew cores down to a depth of 88 cm below ground surface, and revealed only continuous, homogenous matrices of yellowish red silt loam. This is the same matrix as the sterile sediment exposed at the base of Unit G5.
Three additional 1x1m units near or adjacent to the G block to the grid-west also were unproductive. [Figure Anomaly 2-5, Figure Anomaly 2-6] In short, the thin scatter of brick sits in isolation in the field. The researchers currently interpret the feature as a scatter of brick used to fill in ruts in the road in the rainy season. The bricks were probably associated with a Coincoin period structure, hence the associated domestic debris, but whoever filled in the ruts scooped up the bricks from elsewhere on site and dumped them in the field.
Relative to geophysics, a series of primary questions emerges from the findings:
- Why was the source of the strong radar signal in Grid 7 not brick, as expected?
- Why did the adjacent Grid 6 produce a similar radar signal that equated to brick, when it did not do the same in a location only 2 m away?
- What was the real cause of the strongly reflected radar signal recorded in Grid 7?
- Prospection in Depth participants noted specifically where they encountered standing water in Grid 7, and there was none in the vicinity of the strong radar return. Could the sediment have retained moisture at a higher rate than surrounding sediments, causing the anomaly?
Funding for the research project from 2002-2007 was generously provided by the U.K. Arts and Humanities Research Council, the British Academy, the U.S. National Endowment for the Humanities, the Cane River National Heritage Area, the National Park Service’s Delta Initiative, and the Institute of Archaeology at University College London.