RESISTIVITY´S VALUES IN BOYACÁ, COLOMBIA A SPECIAL HYDROGEOLOGICAL PHENOMENON: FAR FROM RHETORIC, CLOSER TO REALITY

Recently, an undergraduate thesis along several folded Cretaceous and Tertiary rocks in Turmequé, Boyacá, showed an extraordinary higher resistivity values of groundwater from drilling well-constructed at the Apple syncline (Sinclinal Manzano in Spanish) where the goal was the Hard Sandstone (Arenisca Dura in Spanish) the upper Cretaceous age. The scientific curiosity from authors about higher values of resistivity had promoted this article. The main purpose is to plan a future master research with more hydrogeological details because this type of topics look good for academic interest. The hypothesis based on the question: What does higher resistivity value mean in some areas of Boyacá such as Turmeque?

The authors have implemented a simple method based on literature review, chemical analysis, geo-electric on the area, and hydrogeological correlations. Also, measuring water`s resistivity in some wells drilled for a government`s agency for groundwater supply to rural communities.

The measure consists in find the amount of ohm/meters of the water through the time for each half-minute during five minutes recording how the range of groundwater resistivity was present. At the beginning of the measure, the water at surface had a range outside of the equipment’s range. The resistivity is possible to measure some seconds later when the water was in a recipient. Finally, with water in the same recipient, the value of resistivity is low.

The result was the same founded in the Tunja Syncline where the spectacular high resistivity value is about chemical composition of young and fresh water more than related to rocks composition. The values of resistivity during geo-electrical investigations were more than 2,000 ohm/m. it is an amazing value that the authors would like to check more during a near future academic master program.