Geology topics

Research about Lawrence County, South Dakota

Source-linked reports with geographic coverage including Lawrence County, South Dakota.

4 recordsLinked to original sources

USGS2007

Characterization of ground-water flow and water quality for the Madison and Minnelusa aquifers in northern Lawrence County, South Dakota

The Madison and Minnelusa aquifers are used extensively for water supplies for the city of Spearfish and other users in northern Lawrence County, South Dakota. Ground water in the Madison and Minnelusa aquifers in the study area generally flows north from outcrop areas where recharge from sinking streams and infiltration of precipitation occurs. Ground water that moves northward and eastward around the Black Hills enters the study area from the west and results in hydraulic heads that are several hundred feet higher on the western side of the study area than on the eastern side. The estimated average recharge rate of 38 cubic feet per second (ft3/s) on outcrops of the Madison Limestone and Minnelusa Formation is less than the total estimated average spring discharge rate of 51 ft3/s in the northwestern part of the study area. Sixteen pounds of fluorescein dye were injected into Spearfish Creek on March 25, 2003, when streamflow was 6.6 ft3/s. The dye was detected in water samples from four wells completed in the Madison aquifer ranging from 2.6 to 4.5 miles north of the injection site. First arrival times ranged from 5 to 169 days, and ground-water velocities ranged from about 0.1 to 0.5 mile per day. Sixty-four pounds of Rhodamine WT was injected into Spearfish Creek at the same location on May 9, 2003, when streamflow was 5.6 ft3/s. Rhodamine WT dye concentrations measured in samples from the same four wells were about an order of magnitude less than measured fluorescein concentrations. Oxygen- and deuterium-isotope values for samples from Cox Lake and McNenny Pond springs indicated a probable component of spring discharge that originates from outcrops of the Madison Limestone and Minnelusa Formation on the Limestone Plateau south of the study area. Oxygen- and deuterium-isotope values for samples from Mirror Lake spring indicated possible contributions from overlying aquifers and local recharge. Oxygen- and deuterium-isotope values for the combined springflow contributing to Crow Creek in the northwestern part of the study area indicated that the primary source of water is the Madison and Minnelusa aquifers. Oxygen- and deuterium-isotope values for Old Hatchery and Higgins Gulch springs, located north of Spearfish, indicated a source water originating from the outcrops of the Madison Limestone and Minnelusa Formation within the study area. Concentrations of three chlorofluorocarbons (CFC-11, CFC-12, and CFC-113) were used to characterize ground-water residence times in the study area. For the four wells where dye was detected, CFC-11 apparent ages ranged from 12 to 26 years, indicating that the wells contained months-old water mixed with years- to decades-old water. Logarithmic regression analysis of the CFC-11 apparent ages for water from 10 wells and distance to a possible conduit trending north through the area where dye was detected, yielded an r2 value of 0.71. Straight-line regression analysis of the CFC-11 apparent ages for the six wells closest to the possible conduit had an r2 value of 0.96. Two wells located relatively close to the outcrop areas had no or very low tritium values indicating relatively long residence times and diffuse ground-water flow. The tritium value of 7.2 TU in water from well COL where dye was detected, indicated that the water probably is a bimodal mixture, with a substantial portion that is older than 50 years. Water from well ELL, where dye was detected, had a tritium value of 19.7 TU and a CFC apparent age of 15 years, indicating that the sample from this well probably is a unimodal mixture with very little water older than 50 years. Comparison of the CFC apparent age for three spring sites (Cox Lake, 26 years; McNenny Pond, 26 years; Mirror Lake, 13 years) also indicated that Mirror Lake spring probably has a component of local recharge from formations that overlie the Minnelusa Formation. In the Madison aquifer, specific conductance ranges from 18 to 945 microsiemens per cen

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USGS2006

Quantification of mass loading to Strawberry Creek near the Gilt Edge mine, Lawrence County, South Dakota, June 2003

Although remedial actions have taken place at the Gilt Edge mine in the Black Hills of South Dakota, questions remain about a possible hydrologic connection along shear zones between some of the pit lakes at the mine site and Strawberry Creek. Spatially detailed chemical sampling of stream and inflow sites occurred during low-flow conditions in June 2003 as part of a mass-loading study by the U.S. Geological Survey to investigate the possible connection of shear zones to the stream. Stream discharge was calculated by tracer dilution; discharge increased by 25.3 liters per second along the study reach, with 9.73 liters per second coming from three tributaries and the remaining increase coming from small springs and dispersed, subsurface inflow. Chemical differences among inflow samples were distinguished by cluster analysis and indicated that inflows ranged from those unaffected by interaction with mine wastes to those that could have been affected by drainage from pit lakes. Mass loading to the stream from several inflows resulted in distinct chemical changes in stream water along the study reach. Mass loading of the mine-related metals, including cadmium, copper, nickel, and zinc, principally occurred from the discharge from the Gilt Edge mine, and those metals were substantially attenuated downstream. Secondary loadings of metals occurred in the vicinity of the Oro Fino shaft and from two more inflows about 200 m downstream from there. These are both locations where shear zones intersect the stream and may indicate loading associatedwith these zones. Loading downstream from the Oro Fino shaft had a unique chemical character, high in base-metal concentrations, that could indicate an association with water in the pit lakes. The loading from these downstream sources, however, is small in comparison to that from the initial mine discharge and does not appear to have a substantial impact on Strawberry Creek.

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USGS2000

Water-quality characteristics for selected streams in Lawrence County, South Dakota, 1988-92

During the 1980’s, significant economic development and population growth began to occur in Lawrence County in the northern part of the Black Hills of western South Dakota. Rising gold prices and heap-leach extraction methods allowed the economic recovery of marginal gold ore deposits, resulting in development of several large-scale, open-pit gold mines in Lawrence County. There was increasing local concern regarding potential impacts on the hydrologic system, especially relating to the quantity and quality of water in the numerous streams and springs of Lawrence County. In order to characterize the water quality of selected streams within Lawrence County, samples were collected from 1988 through 1992 at different times of the year and under variable hydrologic conditions. During the time of this study, the Black Hills area was experiencing a drought; thus, most samples were collected during low-flow conditions. Streamflow and water-quality characteristics in Lawrence County are affected by both geologic conditions and precipitation patterns. Most streams that cross outcrops of the Madison Limestone and Minnelusa Formation lose all or large part of their streamflow to aquifer recharge. Streams that are predominantly spring fed have relatively stable streamflow, varying slightly with dry and wet precipitation cycles. Most streams in Lawrence County generally have calcium magnesium bicarbonate type waters. The sites from the mineralized area of central Lawrence County vary slightly from other streams in Lawrence County by having higher concentrations of sodium, less bicarbonate, and more sulfate. False Bottom Creek near Central City has more sulfate than bicarbonate. Nitrogen, phosphorous, and cyanide concentrations were at or near the laboratory reporting limits for most sites and did not exceed any of the water-quality standards. Nitrite plus nitrate concentrations at Annie Creek near Lead, Whitetail Creek at Lead, Squaw Creek near Spearfish, and Spearfish Creek below Robison Gulch were somewhat higher than at other sites. Mining activity, agricultural activity, and domestic development are possible sources of nitrogen to the streams. Increased mining activities were identified as the probable cause of increased nitrogen concentrations in Annie Creek. In the mineralized area of the northern Black Hills, detectable concentrations of trace elements are common in stream water, occasionally exceeding beneficial-use and aquatic-life criteria. In addition, many basins have been disturbed by both historical and recent mining operations and cleanup activities. The maximum dissolved arsenic concentration at Annie Creek near Lead (48 micrograms per liter) approached the current arsenic drinking-water standard. Concentrations at or greater than 5 micrograms per liter were found in samples from Annie Creek near Lead, Spearfish Creek above Spearfish, Whitetail Creek at Lead, and False Bottom Creek near Spearfish. Bear Butte Creek near Deadwood had one sample with a dissolved copper concentration that exceeded acute and chronic aquatic-life criteria. Bear Butte Creek near Deadwood had several manganese concentrations that exceeded the secondary maximum contaminant level of 50 micrograms per liter. Bed-sediment and water-quality data from selected sites in small drainage basins were used to determine if factors such as pH, arsenic concentrations in bed sediments, and calcite saturation control dissolved arsenic concentrations. Arsenic solubility is controlled by adsorption, mainly on ferrihydrite. In addition, adsorption/desorption of arsenic is controlled by the pH of the stream, with high arsenic concentrations appearing only at higher pH conditions (above 8). There are significant arsenic sources available to almost all the small streams of the northern Black Hills mining area, but arsenic is less mobile in streams that are not influenced to the higher pH values by calcite. Streams where arsenic is more mobile have lower iron concentrations in their bed sediments, and they have relatively high concentrations of calcite Additional water-quality data have been collected as part of other studies or monitoring programs by the South Dakota Department of Environment and Natural Resources, U.S. Environmental Protection Agency, U.S. Forest Service, and the U.S. Geological Survey. Summaries of selected data from these other sources are included as additional information.

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USGS1953

An occurrence of autunite, Lawrence County, South Dakota

In July 1952 an occurrence of autunite was found in the northern part of the Black Hills, South Dakota, during a reconnaissance for radioactive deposits. The autunite occurs as fracture coatings and disseminations in siltstone of the Deadwood formation of Cambrian age and is concentrated mainly in the lower 2 feet of the siltstone at the contact with an intrusive rhyolite porphyry; the radioactive zone is exposed in two old workings, which are 90 feet apart. An 18-inch vertical channel sample of the autanite-bearing siltstene contained 0. 048 percent uranium. The gangue minerals are fluorite and limonite. The uranium is believed to have been introduced into the siltstone by solutions of magmatic origin that migrated along the lower contact of the siltstone after or during emplacement of the porphyry'

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