A Prelimnary Geophysical Investigation Involving Remote Sensing At The Archaeological Site Trinchera Cave, Co

Abstract

Geodetic, resistivity, magnetic and seismic surveys were carried out at the Trinchera cave archaeology site in southeastern Colorado. Information was gathered in order to locate and image the foundation walls of an ancient ‘jacal’ structure, found in the Simpson study of 1974 and covered due to subsequent excavations. Geodetic and Resisivity methods were the focus of this three-week investigation, but both magnetic and seismic methods were explored for experience in both the acquisition and interpretation of data. The Topcon GTS-302D total station wsa used to represent the topography of the site. A detailed topographic map was generated to both clarify the site dimensions for this study and share with anthropologists interested in further investigation. The Iris Instruments Syscal-Junior resistivity meter was used to map resistivity anomalies. The resistivity survey yielded an approximate location and depth of a moderately resistive anomaly at 1-2 m from the cave overhang, 2 m depth and 8- 11 m from the start of the acquisition line and NE-SW datum used in previous research. We believe this anomaly to be the foudation walls of the ancient 'jacal' structure. Magnetic and seismic data was also collected, but both surveys were inconclusive. The GEM GSM-19 Overhauser magnetometer produced questionable findings due to highly magnetic metal posts and pipes present at the site. Magnetic surveying should not be pursued further due to these disturbances and lack of magnetic signature emitted from sandstone. The Geometrics Geode 12-Channel seismograph yielded refraction seismology results clouded with human and instrumental error, but with additional testing can be used to support the overall interpretation of the study. Further excavation should be done both to test these findings and to more accurately understand the dimensions of the structure.