Geology topics
Research about Idaho
Source-linked reports with geographic coverage including Idaho.
Mineral resource potential maps of the Jerry Peak, Jerry Peak West, and Boulder Creek Wilderness Study Areas, Custer County, Idaho
The U.S. Geological Survey and the U.S. Bureau of Mines made a geological and mineral survey of the Jerry Peak, Jerry Peak West, and Boulder Creek Wilderness Study Areas, Custer County, Idaho, from 1980 through 1983. The area is underlain chiefly by lavas and pyroclastic rocks of the Eocene Challis Volcanics. Paleozoic sedimentary rocks are exposed along the east border of the Jerry Peak Wilderness Study Area and in two small areas farther west in the Jerry Peak and Jerry Peak West Wilderness Study Areas. All the rocks locally are intricately faulted. No veins or pervasive hydrothermal alteration are associated with these faults.
Map showing geochemistry of stream sediments in the Jerry Peak Wilderness Study Area, Custer County, Idaho
The Jerry Peak Wilderness Study Area is about 25 mi south of Challis in Custer County, central Idaho (fig. 1). The study area contains 46,150 acres of land administered by the by the Bureau of Land Management and 1 sq mi owned by the State of Idaho, a total of 46,790 acres. Most of the study area is readily accessible by roads along tributaries of the East Fork Salmon River, especially Road Creek, Herd Creek, and Lake Creek. The southeastern part of the area can be reached from Road Creek by the road down Peck's Canyon and by roads from Thousand Springs Valley, southeast of the study area. Several access roads to past logging operations extend up Sage Creek and its tributaries in the southeast part of the study area. Access to points within the northern part of the area is facilitated by jeep trails that connect with Road Creek and lake Creek and by improved road that extends northward from Herd Lake. The study area is moderately rugged, with local relief approaching 2,000 ft. Jerry (10,010 ft), the highest point within the area, is a low knoll on a north-trending linear ridge (fig. 1). The ridge has not been glaciated, despite its relatively high altitude. Most of the area is thinly covered by grass and low shrubs; trees, for the most part, are restricted to valley bottoms or to local, small groves on hillslopes.
Maps showing selected geology and phosphate resources of the Stewart Flat quadrangle, Caribou County, Idaho
This report summarizes information on the thickness, grade, lateral continuity, phosphate resources, and ownership of phosplate-bearing units in the Meade Peak Phosphatic Shale Member of the Phosphoria Formation in the Stewart Flat quadrangle. This report is one of a series of quadrangle reports prepared by the Idaho Bureau of Mines and Geology under U.S. Geological Survey cost sharing contract # 14-08-0001-17925 to calculate phosphate resources in southeastern Idaho (fig. 1).
Maps showing selected geology and phosphate resources of the Sage Valley quadrangle, Caribou County, Idaho
This report summarizes information on the thickness, grade, lateral continuity, phosphate resources, and ownership of phosphate-bearing units in the Meade Peak Phosphatic Shale Member of the Phosphoria Formation in the Sage Valley quadrangle. This report is one of a series of quadrangle reports prepared by the Idaho Bureau of Mines and Geology under U.S. Geological Survey costsharing contract #1408-0001-17925 to calculate phosphate resources in southeastern Idaho (fig. 1).
Maps showing selected geology and phosphate resources of the Diamond Flat quadrangle, Caribou County, Idaho
This report summarizes information on the thickness, grade, lateral continuity, phosphate resources, and ownership of phosphate-bearing units in the Meade Peak Phosphatic Shale Member of the Phosphoria Formation in the Diamond Flat quadrangle. This report is one of a series of quadrangle reports prepared by the Idaho Bureau of Mines and Geology under U.S. Geological Survey cost-sharing contract #14-08-0001-17925 to calculate phosphate resources in southeastern Idaho (fig. 1).
Maps showing selected geology and phosphate resources of the Henry quadrangle, Caribou County, Idaho
No abstract available.
Maps showing selected geology and phosphate resources of the Fossil Canyon quadrangle, Bear Lake and Caribou Counties, Idaho
This report summarizes information on the thickness, grade, lateral continuity, phosphate resources, and ownership of phosphate-bearing units in the Meade Peak Phosphatic Shale Member of the Phosphoria Formation in the Fossil Canyon quadrangle. This report is one of a series of quadrangle reports prepared by the Idaho Bureau of Mines and Geology under U.S. Geological Survey cost-sharing contract #14-08-0001-17925 to calculate phosphate resources in southeastern Idaho (fig. 1).
Hydrologic conditions at the Idaho National Engineering Laboratory, Idaho; 1979-1981 update
No abstract available.
Application of a parameter-estimation technique to modeling the regional aquifer underlying the eastern Snake River Plain, Idaho
A nonlinear, least-squares regression technique for the estimation of ground-water flow model parameters was applied to the regional aquifer underlying the eastern Snake River Plain, Idaho. The computer program simulates two-dimensional, steady-state ground-water flow. Hydrologic data for the 1980 water year were used to calculate recharge rates, boundary fluxes, and spring discharges. Groundwater use was estimated from irrigated land maps and crop consumptive-use figures. These estimates of ground-water withdrawal, recharge rates, and boundary flux, along with leakance, were used as known values in the model calibration of transmissivity. Leakance values were adjusted between regression solutions by comparing model-calculated to measured spring discharges. In other simulations, recharge and leakance also were calibrated as prior information regression parameters, which limits the variation of these parameters using a normalized standard error of estimate. Results from a best-fit model indicate a wide areal range in transmissivity from about 0.05 to 44 feet squared per second and in leakance from about 2.2 x 10 -9 to 6.0 x 10 -8 feet per second per foot. Along with parameter values, model statistics also were calculated, including the coefficient of correlation between computed and observed head (0.996), standard error of the estimates of head (40 feet), and parameter coefficients of variation (about 10-40 per-cent). Additional boundary flux was added in some areas during calibration to achieve proper fit to ground-water flow directions. Model fit improved significantly when areas that violated model assumptions were removed. Model fit also improved when y-direction (northwest-southeast) transmissivity values were larger than x-direction (northeast-southwest) transmissivity values. The model was most sensitive to changes in recharge, and in some areas, to changes in transmissivity, particularly near the spring discharge area from Milner to King Hill.
Water resources data, Idaho water year 1983
Water resources data for the 1983 water year for Idaho consist of records of stage, discharge, and water quality of streams; stage, contents, and water quality of lakes and reservoirs; and water levels and water quality of ground water. This report contains discharge records for 170 gaging stations; stage only records for 2 gaging stations; stage only for 8 lakes and reservoirs; contents only for 17 lakes and reservoirs; water quality for 21 gaging stations and 37 wells: and water levels for 433 observation wells. Additional water data were collected at various sites, not involved in the systematic data collection program, and are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Idaho, adjacent States, and Canada.
Maps showing distribution of dissolved solids and dominant chemical type in ground water, Basin and Range Province, Idaho
This map report is one of a series of geologic and hydrologic maps of States in the Basin and Range Province. These map reports contain information on ground-water hydrology, ground-water quality, surface distribution of selected rock types, data on tectonic conditions, areal geophysical data, Pleistocene lakes and marshes and natural resources. This information is the basis tor a summary report that characterizes the Basin and Range Province. The geologic and hydrologic characterization will be used to evaluate the Province for prospective regions for further study relative to isolation of high-level radioactive waste. (Bedinger, Sargent and Reed, 1984).
Ground-water-level trends in Idaho, 1971-82
Water-level trends, net water-level changes, and major causes governing these water-level fluctuations are presented for 366 wells in the Idaho statewide observation-well network. Water-level trends were determined for 293 wells. Downward trends in 176 of these wells ranged from less than 1 foot per year to a maximum of 7 feet per year; upward trends in 90 wells ranged from less than 1 foot per year to a maximum of 6 feet per year. Trends were level (no change) in 27 wells. Net water-level changes were determined for 361 wells. Net declines in 269 of these wells ranged from less than 1 foot to a maximum of 52.65 feet; net rises in 92 wells ranged from less than 1 foot to a maximum of 25.12 feet. Significant net water-level declines and downward trends were most apparent in or near areas designated as critical ground-water areas by the Idaho Department of Water Resources. (USGS)
Hydrologic, demographic, and land-use data for the Snake River Plain, southeastern Idaho
No abstract available.
Evaluation of hydrologic processes affecting soil movement in the Hagerman fauna area, Hagerman, Idaho
The Hagerman fauna area on the western slope of the Snake River canyon in south-central Idaho is one of the most important locations of upper Pliocene fossils in the world. The fossil beds are distributed vertically through a 500-foot stratigraphic section of the Glenns Ferry Formation. Accelerated soil movement caused by surface-water runoff from irrigated farmlands on the plateau above the canyon and discharge from springs and seeps along the slope of the canyon is eroding the fossil beds. Source of the springs and seeps is a perched aquifer, which is probably recharged by seepage losses from two irrigation canals that head near the canyon rim. Annual canal losses are about 1,900 acre-feet. Annual discharge from springs and seeps is about 420 acre-feet. Corrective measures that could be taken to stabilize the soil movement and preserve the fauna area include: (1) Lining or treating the canals, (2) eliminating the practice of flushing irrigation systems, (3) constructing road berms and cross dips, and (4) establishing an uncultivated strip of land between irrigated farmlands and the canyon rim. (USGS)
Water-table contours, directions of ground-water movement, and measurements of inflow to American Falls Reservoir, southeastern Idaho, April 1984
In 1978 the U.S. Geological Survey began a 5-year study of the High Plains regional aquifer system to provide hydrologic information for evaluating the effects of long-term development of the aquifer and to develop a capability for predicting aquifer response to alternative changes in ground-water management. By use of a digital model, this report presents a quantitative description of the High Plains aquifer in Oklahoma. The High Plains aquifer consists predominantly of the Tertiary Ogallala Formation and overlying Quaternary alluvium and terrace deposits which are hydraulically connected to the High Plains aquifer. Much of the aquifer is underlain by formations of Permian through Cretaceous age, which generally have very small hydraulic conductivities. In some areas parts of underlying Triassic, Jurassic, or Cretaceous rocks are hydraulically connected with the aquifer. The High Plains aquifer is a water-table aquifer in which water moves generally to the east-southeast. Before the beginning of extensive irrigation of the 1960's, the aquifer was essentially in dynamic equilibrium with recharge from precipitation balanced by natural discharge from the aquifer. Ground-water discharge appeared in streams leaving the area or was returned to the atmosphere through evapotranspiration. Accurate records of irrigation pumpage are not available from the High Plains. In order to estimate irrigation pumpage, published records of crop distribution were used and a consumptive use was assigned to each principal irrigated crop. This method gave an estimated irrigation demand. Pumpage was taken as a percentage of the total irrigation demand. Irrigation has decreased ground-water discharge from the High Plains aquifer. Ground-water discharge was estimated as approximately 118 cubic feet per second in 1980. A finite-difference digital model was used to simulate flow in the High Plains aquifer. The recharge was adjusted so that 1980 ground-water discharge was 118 cubic feet per second, the estimated ground-water discharge for 1980. Recharge in the eastern half of the modeled area was 0.45 inch per year; one-half this value was used in the western half of the modeled area. Hydraulic conductivity was divided into three zones: 19.3 feet per day in the eastern zone; 16.2 feet per day in the central zone; and 8.28 feet per day in the western zone. A specific yield of 14.7 percent was used in the model. Using all these parameters, the model was calibrated so that the mean difference between predevelopment modeled and measured head was -0.044 foot. Following the calibration procedure, the model was used to predict the volumes of water in storage and distribution of saturated thickness in 1993 and 2020 using the 1980 pumping rates. The calculated quantity of water in storage in the aquifer in 1941 (predevelopment) was approximately 135.2 million acre-feet; in 1980, approximately 121.9 million acre-feet; in 1993 approximately 112.7 million acre-feet; and in 2020, approximately 96.2 million acre-feet. The High Plains aquifer in Oklahoma will continue to be an important source of water past the year 2000. As withdrawals continue from the aquifer at the present rate, the water table will continue to decline and when the water table drops below the streambed in any part of the area, ground-water discharge to streams will cease in that area. Based on the calculated volumes of water in storage, the volume of water remaining in storage as compared to the predevelopment volume is as follows: 90 percent in 1980, 83 percent in 1993, and 71 percent in 2020.