Shallow Temperature Measurements at Juncalito, a Geothermal Prospect, Central Andes, Chile
Abstract
For many decades, shallow temperature measurements have been used as a key geothermal exploration tool. Subsurface temperature measurements at a depth of 1-meter is an efficient method for mapping thermal anomalies at a high level of detail. These thermal anomalies can be associated with interesting geothermal features. However, variations in near-surface temperatures can be caused by a number of non-geothermal factors, including changes in air temperature, soil moisture, near-surface groundwater flow and thermal inertia. The effects of these variables were qualitatively characterized during this survey. The study area corresponds to a Pleistocene-Holocene NW-SE volcanic chain with a series of volcanic complexes, strato-volcanoes, dome-complexes and lava and ignimbrite fields, in the Chilean Altiplano of the Central Andes. In this work, the results of 25 days of shallow temperature measurements are presented. First, thirty-three temperature loggers were installed in an area of aproximately 25 km^2 for a period of eight days. The purpose of this survey was to identify patterns of near-surface lateral flow of thermal signatures associated with known hot springs. The results of these survey showed relevant thermal anomalies not only associated with the hot springs but also in other sites without hydrothermal discharge. A second survey of one-hundred temperature measurements was developed for seventeen field work days. The temperature measurements were obtained in an area of aproximately 37 km^2. In this survey, thermal anomalies identified in the first survey were mapped at a higher level of detail. These results are complemented with Magnetotelluric and geochemical data, delineating potentially zones of upflow and outflow of a geothermal prospect.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFMNS23A1562L
- Keywords:
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- 0999 EXPLORATION GEOPHYSICS / General or miscellaneous;
- 3255 MATHEMATICAL GEOPHYSICS / Spectral analysis;
- 8424 VOLCANOLOGY / Hydrothermal systems