Thursday, July 9, 2009

Zeroing in?

Over the past week, the crew has made progress on several fronts, though we lost a full day and a half of work to the rainy weather on Monday and Tuesday. As noted in our last post, we were intrigued by several underground anomalies discovered using Ground Penetrating Radar (GPR) equipment last Thursday, and since these anomalies were very close to a shovel test with a good amount of mission-period Native American ceramics, we decided to conduct additional remote sensing over this area. Dr. Thompson returned this week and conducted two sets of tests in a 20 meter by 20 meter area, using not just GPR but also soil resistivity equipment within a carefully-arranged grid pattern (see photo to right, and video below). Once the data is processed, both these surveys should provide more detailed information about the soil characteristics below ground in the 20 x 20 m. block around the positive shovel test, including information about subsurface pits, layers, and larger objects (revealed using radar data) as well as the relative resistivity of the soil to electrical currents, based on factors such as moisture and organic content. Based on these results, we hope to "ground-truth" one or more anomalies in order to see what they are. With any luck, we may encounter soil disturbances associated with mission-village structures or activity areas, though many may turn out to be natural.
video
At the same time, one crew has been continuing to excavate shovel tests farther south along the river bluff in an area where the river begins to veer away from the high ground we have been focusing our search on, while other crews have continued to test in the area where we have been finding quite a bit of mission-period Native American ceramics. The total absence of any evidence of Native American occupation to the south is in stark contrast to our continued testing in the area of our previous discoveries, where we now have a total of 8 contiguous shovel tests with traces of what we believe is probably mission-era occupation. Just today we excavated one of the most productive shovel tests in this area, with more than a few potsherds bearing characteristics in common with that documented mid-18th-century Apalachee Indians in the area of Pensacola and Mobile Bays.

Since our positive shovel tests are all clustered along the edge of a patch of woods that we have not yet surveyed (and which lies directly between both concentrations of mission-period Native American pottery we have discovered), students have also spent much of this week clearing transects through the brush in order to lay in new shovel tests. This is slow and tedious work, and the combination of heat and poison ivy has been a challenge. Nevertheless, tomorrow we should be able to begin testing in this area, which may turn out to be just as productive as the field to the south.

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