Geophysical survey. Part 1.
Posted by Ed Fleming on Wednesday, June 23
The geophysical survey took place June 1 - 16. A lot of rain and a temporary equipment failure made the survey go a couple days longer than expected. As I said in a previous post, we used three methods to test the geophysics of the site: electrical resistivity, magnetometry, and ground penetrating radar. The first step, however, was to set up a grid across the site. A grid of 20 x 20 meter squares was established. Stakes were put in at 20 meter intervals along an east to west baseline that runs through center of the site. Additional lines of stakes were placed along transects to the north and to the south until the entire 1.5 acre area of the site was within the grid. All geophysical data is associated with individual grid squares, and Don can then put the data into the correct spatial contexts. We will know where on the site anomalies show up. And we will then be able to place our excavation units approximately over the anomalies we choose to test. We will also map our excavation according to the grid coordinates. We will eventually associate our grid to US Monument 52, a point of known elevation just to the west of the project area that has real-world geographic coordinates. The grid that was established in 1954 for the previous SMM excavation is also associated with this monument, which is just to the west of the project area. The 0 South, 0 West point for that grid is located 297.6 feet to the north and 626.2 feet to the east of monument 52.
Preliminary results and observations during data collection suggest that there are some very likely subsurface cultural features showing up in the data. Don will be showing us the final results tomorrow. We will develop our excavation strategy based on those results.
