Earth and Planetary Sciences ETDs

Publication Date

10-15-1981

Abstract

To help assess the applicability of shallow electrical resistivity measurements in New Mexico, two diverse areas in northwestern New Mexico were chosen as electrical resistivity survey sites: Volcano Cliffs and Warm Springs.

Volcano Cliffs, 15 km northwest of Albuquerque, is an area of Pleistocene volcanic activity which manifested itself in cinder cones and basalt flows. At Volcano Cliffs five different electrode configurations were employed to test the horizontality and derive the thicknesses and resistivities of the three geoelectric units present. All electrode configurations yielded reliable results. The ambiguities presented by the principle of equivalence were successfully treated. The first geoelectric unit, comprising aeolian sediments, alluvium and basalt boulders, was found to have a resistivity ranging from 35 to 110 ohm-m. The second geoelectric unit, a basalt flow, was found to have a resistivity of 2850 ohm-m. The third geoelectric unit, the Upper Buff Formation, has resistivities ranging from 90 to 160 ohm-m. The thicknesses obtained by the electrical method differ somewhat from those of well logs. The difference is attributed to real differences (different locations) and to the graded geoelectric boundary between the first two units.

At Warm Springs, approximately 22 km northwest of San Ysidro, an artesian well brings water with a temperature of 41 ° Cat the point of discharge to the surface and produces a thermal anomaly in the surrounding alluvium. A temperature probe survey was made in conjunction with shallow resistivity surveys. The temperature survey defined a zone of saturation within 2.5 m of the well. In this highly conductive environment, the Schlumberger array was found to be unreliable due to the limited sensitivity of the equipment used. The Wenner results agree with the probe survey in defining the zone of saturation and the distance at which the temperature effect of the well is negligible. A method of estimating the formation factor and the depth of exploration was tried but found unreliable, due to scatter in the data. The scatter was attributed to the geometrical problem of having the straight survey line cross the nearly circular temperature contours and the non-static water conditions of the area near the well. A porosity estimate of 40 percent was obtained from Archie's Law, but the error associated with this estimate is large.

Degree Name

Earth and Planetary Sciences

Level of Degree

Masters

Department Name

Department of Earth and Planetary Sciences

First Committee Member (Chair)

George Roger Jiracek

Second Committee Member

Frederick Trauger

Third Committee Member

Sherman Alexander Wengerd

Language

English

Document Type

Thesis

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