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Ground-Water Circulation in the Meade Thrust Allochthon Evaluated by Radiocarbon Techniques

Published online by Cambridge University Press:  18 July 2016

A B Muller
Affiliation:
Sandia National Laboratories, Albuquerque, New Mexico
A L Mayo
Affiliation:
University of Colorado, Colorado Springs, Colorado
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Abstract

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The Meade thrust, in southeastern Idaho, is a major element of the Western Overthrust Belt. The allochthon is of geo-economic importance both as a potential hydrothermal area and as the principal mining area within the Western Phosphate Field. To assist in the development of these two resources, an understanding of the regional ground-water circulation was sought. Geologic and hydrologic data from boreholes in this area are virtually nonexistent. Waterwell development in the area has not occurred because of the abundance of springs and only a few hydrocarbon exploration boreholes have been drilled. Thus, the problem lends itself to evaluation by isotope hydrologic and geochemical methods. Ten springs from within the thrust block and around its periphery were sampled for major ions, 2H/18O, and 14C/13C analysis. Data from these analyses and from field geologic evidence have identified two distinct flow regimes within the Meade thrust allochthon. Shallow flow systems lie above the impermeable Phosphoria Formation, usually within a few hundred meters of the surface. Most of the spring waters from this system are recent and cool. In all cases, they have mean subsurface residence times of less than a few hundred years. The deeper flow systems which lie below the Phosphoria formation are hydraulically isolated from the shallow system. Warm waters from these springs have 14C contents suggesting mean ground-water residence times on the order of 15,000 years. Although these waters could have circulated to as deep as 1900m, 2H/18O results show that high temperatures were never reached. There is no evidence to suggest that water from beneath the Meade thrust has contributed to the circulation in the allochthon.

Type
II. Hydrology
Copyright
Copyright © The American Journal of Science 

References

Armstrong, FC, 1969, Geologic map of the Soda Springs quadrangle, southeastern Idaho: US Geol Survey Misc Geol Inv Map I-557.Google Scholar
Craig, H, 1961, Isotopic variations in meteoric waters: Science, v 133, p 17021703.Google Scholar
Cressman, ER, 1964, Geology of the Georgetown Canyon-Snowdrift Mountain area, southeastern Idaho: US Geol Survey Bull 1153, 105 P.Google Scholar
Cressman, ER and Gulbrandsen, RA, 1955, Geology of the Dry Valley quadrangle, Idaho: US Geol Survey Bull 1015-I 18 P.Google Scholar
Fontes, JC and Gamier, JM, 1979, Determination of initial 14C activity of the total dissolved carbon: A review of the existing models and a new approach: Water Resources Research, v 15, no. 2, p 399413.Google Scholar
IAEA, 1981, Sampling of water for 14C analysis, Isotope Hydrology Lab, Vienna, IAEA.Google Scholar
Ingerson, E and Pearson, FJ Jr, 1964, Estimation of age and rate of motion in ground-water by the carbon-14 method, in : Tokyo Maruzen p 263283.Google Scholar
Mabey, DR and Oriel, SS, 1970, Gravity and magnetic anomalies in the Soda Springs region, southeastern Idaho: US Geol Survey Prof Paper 646-E, 15 P.Google Scholar
Mansfield, GR, 1927, Geography, geology, and mineral resources of part of southeastern Idaho, with description of carboniferous and Triassic fossils, by GH Girty: US Geol Survev Prof Paper 152, 453 P.Google Scholar
Mitchell, JC, 1976, Geothermal investigations in Idaho Pt 6 Geochemistry and geologic setting of the thermal and mineral waters of the Blackfoot Reservoir area, Caribou County, Idaho: Idaho Dept Water Resources, Water Info Bull No. 30 47 P.Google Scholar
Pearson, FJ Jr, and Hanshaw, BB, 1970, Sources of dissolved carbonate species in ground water and their effects on carbon-14 dating, in : Vienna, IAEA, p 271285.Google Scholar
Ralston, DR, Omj, M, Robinette, MJ, and Edwards, TK, 1977, Solutions of water resource problems associated with open-pit mining in the phosphate area of southeastern Idaho: Completion rept, Ground water study contract no. 50–897, US Dept Agric, Forest Service, 125 P.Google Scholar
Royse, F Jr, Warner, MA, and Reese, DC, 1975, Thrust belt structural geometry and related stratigraphic problems Wyoming-Idaho-Northern Utah, in : Denver, Colorado, Rocky Mountain Assoc Geol, p 4154.Google Scholar