"INDUCED POLARIZATION DATA AT ... - University of Utah

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CHU generator unit. To reduce electrode noise, copper sulfate pots were used as potential electrodes for the 300m dipoles. The current transmitted ranged from 4 to 14 amps. Complex resistivity measurements were taken at eight frequencies from 32Hz down to 1/256Hz. Measurements are presented as magnitude of apparent resistivity (Q-m) , and phase (mr), with the convention that phase lags are positive. A complete set of data collected over Lines 1 and 2 is given by Chu et al, 1979. Representative data are presented here. Figures 6a,6b show apparent resistivity pseudosections from Line 2 at (a) 32Hz, and (b) 1/64Hz. Apparent resistivities in Figure 6b range from about 300Q-m near the Mineral Mountains on the east to less than 10Q-m in the alluvium filled Milford Valley on the west. The apparent resistivity contours of Figure 6b were established at approximately 1Hz and remained unchanged down to 1/256Hz, the lowest frequency measured. Figures 7a-7c show the phase pseudosections from Line 2 at (a) 32Hz, (b) 1Hz, and (c) 1/64Hz. Maximum phase measurements decrease from about 1000mr for large n spacings at 32Hz (Figure 7a), to between 20 and 30mr at 1/64Hz (Figure 7c). The dashed contours in the left corner of Figure 7c outline a region where erratic negative phases (not plotted) were obtained during a period of strong telluric activity. Telluric noise increased sharply with decreasing frequency. The percentage errors in the phase measurements below 1/64Hz were larger than those of the apparent resistivity measurements since, as frequency decreased, the phase of the complex resistivity measurement became
FIGS. 6a,6b. Apparent resistivity (n-m) pseudosections for (a) 32 Hz and (b) 1/64 Hz, on Line 2. Schematic at top of Figure 5a shows dipole-dipole datum plotted as a function of distance between current (Tx) and potential (Rx) electrode pairs; n is integer multiple of dipole length a; value plotted at intersection of 45 degree lines (dashed) from centers of current and potential dipoles. CHU
Page 1 and 2: GL04031 "INDUCED POLARIZATION DATA
Page 3 and 4: INTRODUCTION CHU The purpose of thi
Page 5: FIG. 2' Location map of Roosevelt H
Page 8: Data Acquisition LABORATORY RESEARC
Page 11 and 12: TABLE 1. Parameter values of effect
Page 13: FIGS. 2a-2f. Laboratory data arrang
Page 16 and 17: and (e). Both samples have comparat
Page 18 and 19: PI = background (rock) resistivity,
Page 20: FIG. 3. A schematic explanation of
Page 24 and 25: CHU the pyrite contents are about t
Page 26 and 27: - E q - r t- > C/) lJJ 0:: - lJJ -"
Page 28: FIG. 9. 20 resistivity model (botto
Page 31: FIG. 10. Fault pattern in survey ar
Page 34 and 35: -500 -400 -300 -200 !o- -100 E ....
Page 37: FIG. 12. Pseudosections resulting f
Page 40 and 41: SUMMARY AND CONCLUSIONS CHU The lab
Page 42 and 43: esponse of this hot-water dominated
Page 44: REFERENCES CHU Ballantyne, G. H., 1
Page 51: FIGS. la-le. Phase (mr) field data
Page 54: FIG. 8. 20 model (bottom) for Line

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