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Compilation of data on the uranium and equivalent uranium content of samples analyzed by U.S. Geological Survey during a program of sampling mine, mill, and smelter products

In 1942 the Geological Survey began to collect, in response to a request made by the War Production Board, samples of mine, mill, and smelter products. About 1,400 such samples were collected and analyzed spectrographically for about 20 elements that were of strategic importance, in order to determine whether any of the products analyzed might be possible sources of some of the needed elements. When attention was directed to radioactive elements in 1943, most of the samples were scanned for radioactivity. Part of the work was done on behalf of the Division of Raw Materials of the Atomic Energy Commission. The sources, mine mill, smelter, or prospect, from which these samples were collected, the kind of material sampled, i.e. ores, concentrates, middlings, tailings, flue dusts, and so forth, and the radioactivity of the samples are listed in this report. Samples of the materials collected in the course of the Geological Survey’s investigations for uranium are excluded, but about 500 such samples were analyzed spectrographically for some or all of the same 20 elements sought in the samples that are the subject of this report. Most of the samples were tested only for their radioactivity, but a few were analyzed chemically for uranium. The radioactivity of many of the samples tested in the early screening was determined only qualitatively. Several samples were tested at one time, and if the count obtained did not exceed a predetermined minimum above background, the samples were not tested individually. If the count was more than this minimum, the samples were tested individually to identify the radioactive sample or samples and to obtain a quantitative value for the radioactivity. In general, the rough screening served as a basis for separating samples in which the radioactivity amount to less than 0.003 percent equivalent uranium from those in which it exceeded that amount. Some aspects of various phases of the investigation of radioactivity in these samples have been reported in various other reports, as follows.

Trace Elements Investigations↗

Water-quality changes and organic-carbon characterization during recharge with recycled water at a research basin in Montebello Forebay, Los Angeles County, California, 1991-1996

During the early 1990s, the U.S. Geological Survey (USGS) investigated water-quality changes that occur in treated municipal wastewater (recycled water) at a small research basin constructed in the Montebello Forebay of the Central Ground-Water Basin in south-central Los Angeles County. The instrumented research basin is located on a 1/2-acre site at the upgradient end of the San Gabriel River Coastal Spreading Grounds where recharge has been augmented using recycled water since 1961. The facility was used to measure attenuation in selected constituents as recycled water delivered to the basin percolates downward and moves laterally beneath the basin. Attenuation in aqueous concentration was found to range from 20 to 60 percent for total dissolved nitrogen and was about one-third for dissolved organic carbon (DOC). Isotopic data confirmed permanent loss of nitrogen by denitrification. Detailed investigations showed that there were no large differences in the loss of various components of the DOC at the structural or compound level, although surfactants and their metabolites were abundant and did persist in the subsurface. The DOC of wastewater origin was found to have a lower trihalomethane (THM) formation potential upon chlorination than does organic matter of natural origin from most surface-water sources. The organization of this report into 12 topical chapters, and the report's relation to additional USGS publications from this study, is noted in a preface.

Water-Resources Investigations Report↗

Atmospheric deposition: Sample handling, storage, and analytical procedures for chemical characterization of event-based samples in North Dakota

The North Dakota atmospheric-deposition network uses HASL-type collectors to sample wet and dry deposition on an event basis for analysis of 8 principal mineral, 3 nutrient, and 15 trace constituents. Comparison of the compositions of wet deposition collected in adjacent collectors sampled on weekly and event bases indicates that weekly sampling leads to significant contamination of wet deposition samples with dry deposition. Elevation of the collectors 10 feet above ground surface may decrease wind-blown soil contamination significantly. This manual presents a summary of the research procedures adopted by the North Dakota District of the U.S. Geological Survey to investigate the consequences of increased fossil-fuel combustion on the quality of atmospheric deposition. The manual has been tested by field operatives for 3 years and shown to be an effective field guide and management tool.

North Dakota↗

Occurrence and distribution of nitrate and herbicides in the Iowa River alluvial aquifer, Iowa: May 1984 to November 1985

From May 1984 to November 1985, the U.S. Geological Survey, in cooperation with the University of Iowa Hygienic Laboratory and the Iowa Department of Natural Resources, Geological Survey Bureau, investigated nitrate and herbicides in the Iowa River alluvial aquifer. The occurrence and distribution of nitrate and selected herbicides were determined in the Iowa River alluvial aquifer, a sand and gravel aquifer beneath agricultural land along the Iowa River in Iowa County, Iowa. Test drilling and water-quality sampling of the aquifer indicated that the areal distribution of nitrate in the aquifer is variable. Nitrate (as nitrogen) concentrations range from less than 0.10 to 79 milligrams per liter. Although nitrate distribution is variable, extensive aquifer contamination by nitrate is not apparent. Median nitrate concentrations were 5.9 milligrams per liter for municipal wells and 7.2 milligrams per liter for area streams, but were less than 2.0 milligrams per liter for test wells and domestic wells. Atrazine, cyanazine, metribuzin, alachlor, metolachlor, and trifluralin were detected in ground-water samples. Maximum concentration of atrazine in ground-water samples was 2.4 micrograms per liter; maximum concentration of metribuzin was 8.1 micrograms per liter. Area streams also contained herbicides in concentrations generally larger than concentrations in ground water. At a municipal well adjacent to a stream, similar seasonal concentrations of atrazine were detected for both ground- and surface-water samples. Surface water sometimes may be a source of nitrate and herbicides to adjacent ground water. Detailed sampling of vertical profiles using well nests indicated that the distribution of nitrate and selected herbicides is not vertically homogeneous. Generally, larger nitrate concentrations were detected at shallow depths in the aquifer; at greater depths, the nitrate concentrations were near the detection limit. Herbicides were detected in a pattern similar to that determined for nitrate. The true areal distribution of nitrate may be masked by inconsistent depths of sampling or incomplete vertical sampling. Variations in nitrate concentrations with depth possibly are because local aquifer flow is predominantly horizontal and may limit significant vertical dispersion of nitrate and herbicides, and because nitrate may not act conservatively in ground water and may be removed from the system by denitrification. For nested wells, the seasonal variations of nitrate and herbicides were greater at the shallower sampling depths for domestic and test wells. Seasonal variations of nitrate and herbicides illustrate that these constituents move quickly from surface application to shallow underlying aquifers. These constituents can be detected in ground water soon after chemical applications, usually within 6 weeks.

Iowa↗

The computer program estimate trend (ESTREND), a system for the detection of trends in water-quality data

Computerized statistical and graphical procedures were developed for use in U.S. Geological Survey (USGS) investigations of trend in stream water-quality data. These procedures, identified as EStimate TREND (ESTREND), are described in this paper to assist USGS investigators involved in multiple-station studies of water-quality trends. Additional discussion focuses on certain statistical and operational decisions required in multiple-station analysis of trends. The statistical methods used in ESTREND overcome common statistical problems encountered by conventional statistical trend techniques in the analysis of water-quality data. The problems include data that are non-normal and seasonally varying and water-quality records with missing values, 'less-than' (censored) values, and outliers, all of which adversely affect the performance of conventional statistical techniques. Parametric and nonparametric statistical trend tests are used in ESTREND. A nonparametric method, the Seasonal Kendall test, is used for data that have few less-than values or data that have been censored at only one reporting limit. A parametric test for trend involving a maximum likelihood estimation method is used for data that have been censored at multiple reporting limits. The Seasonal Kendall test for uncensored data allows for the removal of flow variability in water-quality data which improves the performance of the statistical trend tests. Menu-driven procedures in ESTREND allow the user to easily retrieve water-quality data, analyze data for trend, and view tabular and graphical results of analyses.

Water-Resources Investigations Report↗

Hydrogeology and steady-state simulation of ground-water flow in the San Juan Basin, New Mexico, Colorado, Arizona, and Utah

As part of a multidisciplinary regional aquifer-system analysis, a three-dimensional steady-state ground-water-flow model was constructed for the San Juan Basin in parts of New Mexico, Colorado, Arizona, and Utah. The model simulated ground- water flow in 12 hydrostratigraphic units representing all of the major sources of ground water from aquifers of Jurassic and younger age. Ten map reports in the U.S. Geological Survey Hydrologic Investigations Atlas 720 series were prepared in conjunction with this investigation. The units that were described in the atlases were the San Jose, Nacimiento, and Animas Formations; Ojo Alamo Sandstone; Kirtland Shale and Fruitland Formation; Pictured Cliffs Sandstone; Cliff House Sandstone; Menefee Formation; Point Lookout Sandstone; Gallup Sandstone; Dakota Sandstone; and Morrison Formation. Additional descriptions of the alluvial and landslide deposits, Chuska and Crevasse Canyon Sandstones, Lewis and Mancos Shales, Wanakah Formation, and Entrada Sandstone are included in this report. Much of the information in the HA-720 series was generated from digital computer data bases that were directly usable by the computer for compilation of input data for the model. In essence, the major components of the ground-water- flow model were described and documented in the series of hydrologic atlases. The primary finding resulting from the ground-water-flow simulation was that boundary conditions and internal geometry of the aquifers are the major controls of steady-state ground-water flow and hydraulic heads in the San Juan Basin. Another significant finding was that the computed steady-state ground- water flux is a very minor component (about 1 percent) of the total water budget of the basin.

Water-Resources Investigations Report↗

Hydrogeology of northwestern Nassau and northeastern Queens Counties, Long Island, New York

A detailed investigation of the geology and ground-water occurrence in northwestern Nassau and northeastern Queens Counties, N.Y., has been completed by the U.S. Geological Survey, in cooperation with the Nassau County Department of Public Works and the New York State Water Resources Commission. The area, about 63 square miles, includes the peninsulas of Great Neck and Manhasset Neck and the western part of Nassau County as far south as Garden City. Unconsolidated sediments of Pleistocene and Cretaceous aged 200 to 800 feet thick, constitute the ground-water reservoir of the area. The reservoir includes three discrete aquifers, not all found in the same locality, which transect geologic boundaries. The shallow unconfined aquifer consists of those permeable Pleistocene and Cretaceous deposits that lie within the upper part of the zone of saturation, which extends from slightly below sea level to more than 110 feet above sea level. It is an abundant source of water in much of the area, particularly in the southern part, where the aquifer consists of coarse sand and gravel in a glacial-outwash plain. The intermediate or principal aquifer consists largely of that part of the Magothy(?) formation that occurs from about 50 feet below sea level downward to the top of the clay member of the Raritan formation. Locally, however, the aquifer includes Pleistocene deposits which blanket the Magothy(?) formation or lie in channels cut into it. Although the principal aquifer has limited extent to the north, it is the chief source of water in most of the area, except the peninsulas. The lower or deep confined aquifer is found beneath the entire project area, and consists of the Lloyd sand member of the Raritan formation and the hydraulically contiguous Jameco gravel. The lower limit of the aquifer is the bedrock surface; its upper limit is defined by the overlying clay member of the Raritan formation and the Gardiners clay, the latter abutting against the clay member on the north or, in some valleys and embankments, lying directly upon the clay member. Thus, hydraulic continuity exists between the Lloyd sand member of the Raritan formation (Cretaceous) and the Jameco gravel (Pleistocene) in the northern part of Manhasset and Great Necks. The two contiguous clay bodies overlying the aquifer, the clay member of the Raritan formation and the Gardiners clay, form an effective confining bed which probably extends beyond the shore lines of the project area. The deep confined aquifer is particularly important on Manhasset and Great Necks where locally it is the only source of water available for large public-supply or industrial needs. In general, ground-water supplies in sufficient quantity and of excellent quality can be obtained from the three aquifers underlying northwestern Nassau and northeastern Queens Counties, N.Y. Ground-water withdrawals for public supply have increased with population growth and expanded use from an average of about 10 millions of gallons per day in 1940 to 30 mgd in 1957. In addition, about 10 mgd are pumped for various industrial, institutional and private uses. Much of the water pumped by industry is returned to the ground by diffusion wells and recharge basins. However, an increasing amount of water is lost from the ground-water reservoir due to the expanding network of server systems discharging directly to the sea. In the Manhasset Neck and Great Neck areas, ground-water resources are approaching full development in terms of the total available supply, if such development has not been reached already (1959). The chief limiting factor to further expansion lies in the geometry of the aquifers and the reduced thickness of permeable saturated sediments. In the northern part of both peninsulas, the ground-water reservoir is only about 200 to 400 feet thick, and, locally, as much as 75 percent of the strata in the reservoir consists of rather impermeable silt and clay of the Raritan formation or the Gardiners clay. I

Water Supply Paper↗

Ground-water conditions and storage in the Central Sevier Valley, Utah

The central Sevier Valley, in the central part of Utah, extends from the town of Kingston to the Yuba Dam and from the Tushar and Valley Mountains and the Pavant Range to the Sevier, Fishlake, Wasatch, and Gunnison Plateaus. A geologic and hydrologic investigation of the valley was made to determine the relation between surface water and ground water and to determine if ground water can be used for irrigation supplies without affecting existing water uses. During the investigation, data were collected for about 700 wells and 26 springs. Monthly water-level measurements were made at 93 observation wells, and automatic recording gages were maintained at 6 additional wells. Chemical analyses were made of water collected from 68 wells and springs. Test holes were drilled at 21 sites to determine the thickness and hydrologic properties of the waterbearing materials. Consumption of ground water by vegetation was estimated on the basis of area and applied rates of evapotranspiration.

Utah↗

New evidence on the hydrothermal system in Long Valley caldera, California, from wells, fluid sampling, electrical geophysics, and age determinations of hot-spring deposits

Data collected since 1985 from test drilling, fluid sampling, and geologic and geophysical investigations provide a clearer definition of the hydrothermal system in Long Valley caldera than was previously available. This information confirms the existence of high-temperature (> 200??C) reservoirs within the volcanic fill in parts of the west moat. These reservoirs contain fluids which are chemically similar to thermal fluids encountered in the central and eastern parts of the caldera. The roots of the present-day hydrothermal system (the source reservoir, principal zones of upflow, and the magmatic heat source) most likely occur within metamorphic basement rocks beneath the western part of the caldera. Geothermometer-temperature estimates for the source reservoir range from 214 to 248??C. Zones of upflow of hot water could exist beneath the plateau of moat rhyolite located west of the resurgent dome or beneath Mammoth Mountain. Lateral flow of thermal water away from such upflow zones through reservoirs in the Bishop Tuff and early rhyolite accounts for temperature reversals encountered in most existing wells. Dating of hot-spring deposits from active and inactive thermal areas confirms previous interpretations of the evolution of hydrothermal activity that suggest two periods of extensive hot-spring discharge, one peaking about 300 ka and another extending from about 40 ka to the present. The onset of hydrothermal activity around 40 ka coincides with the initiation of rhyolitic volcanism along the Mono-Inyo Craters volcanic chain that extends beneath the caldera's west moat. ?? 1991.

Journal of Volcanology and Geothermal Research↗

Observation of suspended sediments in Mobile Bay, Alabama from satellite

As part of a comprehensive geologic study of coastal Alabama and Mississippi, the U.S. Geological Survey is investigating coastal sediment transport in Mobile Bay and the adjacent shelf. Satellite imagery from the NOAA AVHRR is being used to provide data on the variability of spatial patterns in the near-surface suspended sediment concentration. This imagery is processed using atmospheric corrections to remove haze and Rayleigh radiance in order to obtain water reflectances; the reflectances are than converted to approximate sediment concentrations using standard relationships between water reflectance and in situ sediment concentrations. A series of images from early 1990 shows rapid changes in sediment concentrations in response to high river flow of the Alabama-Tombigbee river system. During these times, suspended sediment tends to flow out Mobile Bay without mixing into the eastern lobe of the Bay (Bon Secour Bay). The sediment concentration field also appears to be disturbed by the main ship channel. The sediment plume extends more than 60 km offshore after the peak flow event. One wind event in December 1989 was identified as increasing sediment concentration in the Bay. It is not believed that such an event has been previously observed from satellite.

Conference Paper↗

Exploration drilling and reservoir model of the Platanares geothermal system, Honduras, Central America

Results of drilling, logging, and testing of three exploration core holes, combined with results of geologic and hydrogeochemical investigations, have been used to present a reservoir model of the Platanares geothermal system, Honduras. Geothermal fluids circulate at depths ??? 1.5 km in a region of active tectonism devoid of Quaternary volcanism. Large, artesian water entries of 160 to 165??C geothermal fluid in two core holes at 625 to 644 m and 460 to 635 m depth have maximum flow rates of roughly 355 and 560 l/min, respectively, which are equivalent to power outputs of about 3.1 and 5.1 MW(thermal). Dilute, alkali-chloride reservoir fluids (TDS ??? 1200 mg/kg) are produced from fractured Miocene andesite and Cretaceous to Eocene redbeds that are hydrothermally altered. Fracture permeabillity in producing horizons is locally greater than 1500 and bulk porosity is ??? 6%. A simple, fracture-dominated, volume-impedance model assuming turbulent flow indicates that the calculated reservoir storage capacity of each flowing hole is approximately 9.7 ?? 106 l/(kg cm-2), Tritium data indicate a mean residence time of 450 yr for water in the reservoir. Multiplying the natural fluid discharge rate by the mean residence time gives an estimated water volume of the Platanares system of ??? 0.78 km3. Downward continuation of a 139??C/km "conductive" gradient at a depth of 400 m in a third core hole implies that the depth to a 225??C source reservoir (predicted from chemical geothermometers) is at least 1.5 km. Uranium-thorium disequilibrium ages on calcite veins at the surface and in the core holes indicate that the present Platanares hydrothermal system has been active for the last 0.25 m.y. ?? 1991.

Journal of Volcanology and Geothermal Research↗

Geomorphological and geotechnical issues affecting the seismic slope stability of the Duwamish River Delta, Port of Seattle, Washington

Young Holocene deposits of the Duwamish River valley underlie a highly developed transportation-industrial corridor, extending from the City of Kent to the Elliott Bay-Harbor Island marine terminal facilities. The deposits have been shaped by relative sea-level rise, but also by episodic volcanism and seismicity. A geologic and geotechnical investigation of these river-mouth deposits indicates high initial liquefaction susceptibility during earthquakes, and possibly the potential for unlimited-strain disintegrative flow failure of the delta front.

Technical Council on Lifeline Earthquake Engineeri↗

Applications of optical sensors for high-frequency water-quality monitoring and research

The recent commercial availability of in-situ optical sensors, together with new techniques for data collection and analysis, provides the opportunity to monitor a wide range of water-quality constituents over time scales during which environmental conditions actually change. Traditional approaches for data collection (daily to monthly discrete samples) are often limited by high sample collection, processing, and analytical costs, difficult site access, and logistical challenges, particularly for long-term sampling at a large number of sites. Optical sensors that continuously measure constituents in the environment by absorbance or fluorescence properties (Figure 1) have had a long history of use in oceanography for measuring highly resolved concentrations and fluxes of organic matter, nutrients, and algal material. However, much of the work using commercially-available optical sensors in rivers and streams has taken place in only the last few years. Figure 1. [NOT SHOWN] Optical sensor technology is now sufficiently developed to warrant broader application for research and monitoring in coastal and freshwater systems, and the United States Geological Survey (a U.S. science agency) is now using these sensors in a variety of research and monitoring programs to better understand water quality in-situ and in real-time. Examples are numerous and range from the applications of nitrate sensors for calculating loads to estuaries susceptible to hypoxia (Pellerin et al., 2014) to the use of fluorometers to estimate methymercury fluxes (Bergamaschi et al., 2011) and disinfection byproduct formation (Carpenter et al., 2013). Transmitting these data in real-time provides information that can be used for early trend detection, help identify monitoring gaps critical for water management, and provide science-based decision support across a range of issues related to water quality, freshwater ecosystems, and human health. Despite the value of these sensors, collecting data that meet high-quality standards requires investment in and adherence to tested and established methods and protocols for sensor operation and data management (Pellerin et al., 2013). For example, optical sensor measurements can be strongly influenced by a variety of matrix effects, including water temperature, inner filtering from highly colored water, and scattering of light by suspended particles (Downing et al., 2012). Characterizing and correcting sensors for these effects – as well as the continued development of common methodologies and protocols for sensor use – will be critical to ensuring comparable measurements across sites and over time. In addition, collaborative efforts such as the Nutrient Sensor Challenge (www.nutrients-challenge.org) will continue to accelerate the development, production and use of affordable, reliable and accurate sensors for a range of environments. REFERENCES Bergamaschi .B.A., Fleck J.A., Downing B.D., Boss E., Pellerin B.A., Ganju N.K., Schoellhamer D.H., Byington A.A., Heim W.A., Stephenson M., Fujii R. (2011), Methyl mercury dynamics in a tidal wetland quantified using in situ optical measurements. Limnology and Oceanography, 56(4): 1355-1371. Carpenter K.D., Kraus T.E.C., Goldman J.H., Saraceno J., Downing B.D., Bergamaschi B.A., McGhee G., Triplett T. (2013), Sources and Characteristics of Organic Matter in the Clackamas River, Oregon, Related to the Formation of Disinfection By-products in Treated Drinking Water: U.S. Geological Survey Scientific Investigations Report 2013–5001, 78 p. Downing .B.D., Pellerin B.A., Bergamaschi B.A., Saraceno J., Kraus T.E.K. (2012), Seeing the light: The effects of particles, temperature and inner filtering on in situ CDOM fluorescence in rivers and streams. Limnology and Oceanography: Methods, 10: 767-775. Pellerin B.A., Bergamaschi B.A., Downing B.D., Saraceno J., Garrett J.D., Olsen L.D. (2013), Optical Techniques for the Determination of Nitrate in En

Conference Paper↗

Report from the Ice and Climate Evolution Science Analysis group (ICE-SAG)

This document is the final report of the Ice and Climate Evolution Science Analysis Group (ICESAG) that was formed by the Mars Exploration Program Analysis Group (MEPAG) as part of its preparations for the upcoming NASA Planetary Science Decadal Survey for 2023 through 2032 (see §1). Through telecons, one face-to-face meeting, and discussions with experts in relevant topics, ICE-SAG has identified high-priority science questions and key measurements that are needed to address them as well as the 2018 MEPAG Goals and the 2013-2022 NASA Planetary Science Decadal Survey goals [V&V, 2011] pertaining to ice1 and climate. Obtaining these measurements would yield dramatic improvements in our understanding of the climate history of Mars, which is critical to investigations of Martian geologic history and habitability and will also inform the potential of buried water ices as in situ resources for future human missions. In many ways, the Martian climate system serves as a laboratory for a broader understanding of planetary climate systems including the Earth’s, which is substantially more complex due to a denser atmosphere, a more active planetary interior, and interactions with oceans and abundant life, while operating under much more subtle orbital forcing. Thus, advancements in Martian climate science will have far-reaching impacts that extend to studies of the Earth and other planetary bodies.

Report↗

Appendix C: Interim report on subtask focused on resampling historic Kennedy/ITD plots for RP-284

In October 2019, an Idaho Transportation Department (ITD) Cooperative Transportation Research Program award was made to Boise State University in partnership with the U.S. Geological Survey to investigate the use of weed-suppressive bacteria (Pseudomonas fluorescens strain ACK55) with preemergent herbicides (imazapic and indaziflam) to reduce exotic annual grasses (cheatgrass, medusahead) on ITD right-of-ways. The work includes a subtask in which ITD right-of-ways treated with ACK55 by Dr. Ann Kennedy 4-5 years previously (2017 report; ITD-RP-258) were resampled in summer 2020, focusing only on ACK55 and not the herbicides (which are tested separately and will be reported on in the future). The 2020 sampling protocol was similar but more intensive than the ITD-RP-258. There were no differences in annual grasses on areas sprayed with ACK55 and nearby untreated areas.

Idaho↗

Ground water in Oklahoma

One of the first requisites for the intelligent planning of utilization and control of water and for the administration of laws relating to its use is data on the quantity, quality, and mode of occurrence of the available supplies. The collection, evaluation and interpretation, and publication of such data are among the primary functions of the U. S. Geological Survey, Since 1895 the Congress has made appropriations to the Survey for investigation of the water resources of the Nation. In 1929 the Congress adopted the policy of dollar-for-dollar cooperation with the States and local governmental agencies in water resources investigations of the U. S. Geological Survey, In 1937 a program of ground-water investigations was started in cooperation with the Oklahoma Geological Survey, and in 1949 this program was expanded to include cooperation with the Oklahoma Planning and Resources Board, In 1957 the State Legislature created the Oklahoma Water Resources Board as the principal State water agency and it became the principal local cooperator.

Oklahoma↗

Antimony deposits of Quetta-Pishin District, Quetta Division, Pakistan

Vein-type deposits of antimony ore, consisting of stibnite and quartz, are found in the hanging wall of faults cutting slate of probable Miocene age 15 miles northeast of Qila Abdullah in the Quetta-Pishin District. The ore is associated with zones of oxidized slate. Although the known deposits are small, the oxidized zones are found over several square miles, and the prospects for additional ore are encouraging. Deposits of stibnite and oxidized rock are also found in the Qila Viala area, about 25 miles east of the Qila Abdullah deposits. Geologic relationships in the two areas are similar and suggest that deposition of stibnite and quartz, accompanied by alteration of the host rocks, has taken place on a regional scale. This greatly increases the area to be investigated as well as the possibility that deposits of economic value can be found. A program for further geological investigations is recommended.

Quetta-Pishin District, Quetta Division↗

Land subsidence, groundwater levels, and geology in the Coachella Valley, California, 1993-2010

Land subsidence associated with groundwater-level declines has been investigated by the U.S. Geological Survey in the Coachella Valley, California, since 1996. Groundwater has been a major source of agricultural, municipal, and domestic supply in the valley since the early 1920s. Pumping of groundwater resulted in water-level declines as much as 15 meters (50 feet) through the late 1940s. In 1949, the importation of Colorado River water to the southern Coachella Valley began, resulting in a reduction in groundwater pumping and a recovery of water levels during the 1950s through the 1970s. Since the late 1970s, demand for water in the valley has exceeded deliveries of imported surface water, resulting in increased pumping and associated groundwater-level declines and, consequently, an increase in the potential for land subsidence caused by aquifer-system compaction. Global Positioning System (GPS) surveying and Interferometric Synthetic Aperture Radar (InSAR) methods were used to determine the location, extent, and magnitude of the vertical land-surface changes in the southern Coachella Valley during 1993–2010. The GPS measurements taken at 11 geodetic monuments in 1996 and in 2010 in the southern Coachella Valley indicated that the elevation of the land surface changed –136 to –23 millimeters (mm) ±54 mm (–0.45 to –0.08 feet (ft) ±0.18 ft) during the 14-year period. Changes at 6 of the 11 monuments exceeded the maximum expected uncertainty of ±54 mm (±0.18 ft) at the 95-percent confidence level, indicating that subsidence occurred at these monuments between June 1996 and August 2010. GPS measurements taken at 17 geodetic monuments in 2005 and 2010 indicated that the elevation of the land surface changed –256 to +16 mm ±28 mm (–0.84 to +0.05 ft ±0.09 ft) during the 5-year period. Changes at 5 of the 17 monuments exceeded the maximum expected uncertainty of ±28 mm (±0.09 ft) at the 95-percent confidence level, indicating that subsidence occurred at these monuments between August 2005 and August 2010. At each of these five monuments, subsidence rates were about the same between 2005 and 2010 as between 2000 and 2005. InSAR measurements taken between June 27, 1995, and September 19, 2010, indicated that the land surface subsided from about 220 to 600 mm (0.72 to 1.97 ft) in three areas of the Coachella Valley: near Palm Desert, Indian Wells, and La Quinta. In Palm Desert, the average subsidence rates increased from about 39 millimeters per year (mm/yr), or 0.13 foot per year (ft/yr), during 1995–2000 to about 45 mm/yr (0.15 ft/yr) during 2003–10. In Indian Wells, average subsidence rates for two subsidence maxima were fairly steady at about 34 and 26 mm/yr (0.11 and 0.09 ft/yr) during both periods; for the third maxima, average subsidence rates increased from about 14 to 19 mm/yr (0.05 to 0.06 ft/yr) from the first to the second period. In La Quinta, average subsidence rates for five selected locations ranged from about 17 to 37 mm/yr (0.06 to 0.12 ft/yr) during 1995–2000; three of the locations had similar rates during 2003–mid-2009, while the other two locations had increased subsidence rates. Decreased subsidence rates were calculated throughout the La Quinta subsidence area during mid-2009–10, however, and uplift was observed during 2010 near the southern extent of this area. Water-level measurements taken at wells near the subsiding monuments and in the three subsiding areas shown by InSAR generally indicated that the water levels fluctuated seasonally and declined annually from the early 1990s, or earlier, to 2010; some water levels in 2010 were at the lowest levels in their recorded histories. An exception to annually declining water levels in and near subsiding areas was observed beginning in mid-2009 in the La Quinta subsidence area, where recovering water levels coincided with increased recharge operations at the Thomas E. Levy Recharge Facility; decreased pumpage also could cause groundwater levels to recover. Subsidence concomitant with declining water levels and land-surface uplift concomitant with recovering water levels indicate that aquifer-system compaction could be causing subsidence. If the stresses imposed by the historically lowest water levels exceeded the preconsolidation stress, the aquifer-system compaction and associated land subsidence could be permanent.

California↗