Geologic and topographic maps of Marble Canyon-Mine Canyon area, Sierra Diablo, Culberson County, Texas
No abstract available.
Texas↗
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Geology and ore deposits of the Uncompahgre (Ouray) Mining District, Southwestern Colorado
The Uncompahgre mining district, part of the Ouray mining district, includes an area of about 15 mi 2 on the northwestern flank of the San Juan Mountains in southwestern Colorado from which ores of gold, silver, copper, lead, and zinc have had a gross value of $14 to 15 million. Bedrock within the district ranges in age from Proterozoic to Cenozoic. At least three major uplifts of the ancestral San Juan Mountains occurred during the Proterozoic and at the close of the Paleozoic and Mesozoic, respectively. The last event, known as the Laramide orogeny, locally was accompanied by extensive intrusion of igneous rocks. The principal ore deposits of the district were associated with crosscutting and laccolithic intrusions of porphyritic granodiorite formed during the Laramide orogeny. The ores were deposited chiefly in Paleozoic and Mesozoic sedimentary strata. Ore deposits range from low-grade, contact-metamorphic through pyritic base-metal bodies containing silver and gold tellurides and native gold to silver-bearing lead-zinc deposits. Ore deposition was largely controlled by structural trends and axes of uplift established during Paleozoic deformation, and also in part by structural lines established during the Proterozoic. There are two main structural axes in the district: (1) a north-northwest-trending axis of uplift, called the Uncompahgre axis, and (2) an intrusive axis of northeastward trend. The two axes intersect near the center of eruptive activity and divide the district into four structural sectors. Sources of the ore-forming fluids lie along the northeast-trending intrusive zone and appear to be related genetically to the igneous rocks. Contact-metamorphic deposits and most of the pyritic gold-bearing deposits were found in the central parts of the district. The silver-lead-zinc deposits were found chiefly in the northern and southern sectors of the district. Ore deposition was controlled by nearness to the intrusive contacts, nearness to zones of shallow tensional fractures, and other factors. The largest and highest grade deposits were either mostly developed or nearly exhausted at the time of our studies; they occurred in a zone near the Uncompahgre axis.
Colorado↗
U.S. Geological Survey exploration program in the Trixie area, East Tintic mining district, Utah County, Utah
The Trixie area is in the south central part of the East Tintic mining district, Utah, and is believed to include the intersections of several mineralized pebble dike-fissure zones and a major, easterly trending fault. The fissure-fault intersections, which are considered to be favorable ore-locallizing structures, are concealed by lavas and tuffs several hundred feet thick that are strongly bleached and altered and which contain positive geochemical anomalies. During the summer months of 1954 and 1955 for the U. S. Geological Survey, under contract, 9 exploration holes were drilled in the Trixie area: 1) to investigate the relations of surface geochemical anomalies to possible concealed ore, 2) to determine the structure and stratigraphic units in the sedimentary rocks concealed beneath the lava, and 3) to further develop and refine geologic and geochemical techniques that may be useful in prospecting for concealed ore deposits in the East Tintic and other mining districts. This report briefly discusses the geology, hydrothermal alteration, and geochemical and geophysical anomalies in the Trixie area and presents the logs of the drill holes and tables of the copper, lead, zinc, and silver content, expressed in parts per million, of the drill cuttings and drill core.
Utah↗
Mine wastes and human health
Historical mining and mineral processing have been linked definitively to health problems resulting from occupational and environmental exposures to mine wastes. Modern mining and processing methods, when properly designed and implemented, prevent or greatly reduce potential environmental health impacts. However, particularly in developing countries, there are examples of health problems linked to recent mining. In other cases, recent mining has been blamed for health problems but no clear links have been found. The types and abundances of potential toxicants in mine wastes are predictably influenced by the geologic characteristics of the deposit being mined. Hence, Earth scientists can help understand, anticipate, and mitigate potential health issues associated with mining and mineral processing.
Elements↗
Geology of the Klamath Mountains
No abstract available.
California Division of Mines and Geology Bulletin↗
Geologic controls on the composition of natural waters and mine waters draining diverse mineral-deposit types
No abstract available.
Reviews in Economic Geology↗
Geology of the Klamath Mountains province
No abstract available.
California Division of Mines and Geology Bulletin↗
Geologic map of the Verdi Peak Quadrangle, Elko County, Nevada
A 1:24,000-scale, full-color geologic map of the Verdi Peak 7.5-minute quadrangle in Elko County, Nevada, with one cross section and descriptions of 19 rock units. Accompanying text describes the geology of the quadrangle.
Nevada↗
Geology and nickel mineralization of the Julian-Cuyamaca area, San Diego County, California
The Julian-Cuyamaca area is in the San Diego Mountains, one of the Peninsular Ranges of southern California. It lies in San Diego County, about 3 miles south of Julian, and approximately 60 miles northeast of San Diego. The area was mapped, and its nickel mineralization studied, from March to June, 1944; the work was part of the U. S. Geological Survey's program of strategic mineral investigations.
California↗
Reconnaissance map of the Cenozoic geology in the Carlin basin area, Elko and Eureka counties, Nevada
The middle Miocene Carlin sedimentary basin encompasses a large area between the Adobe Range to the east, the Piñon Range to the south, the southern Independence Mountains and Marys Mountain to the west, and Swales Mountain to the north. The town of Carlin is in the southern part of the basin. The geologic map includes detailed to more reconnaissance mapping of Cenozoic units in the main part of the basin, including different facies of the middle Miocene Humboldt Formation. The mapping was part of a broader study of the Miocene and younger paleogeographic evolution of the region. Earlier work obtained numerous 40 Ar/ 39 Ar and tephra correlation dates on sedimentary and volcanic units in the basin. The basin connected to the east into the Elko sedimentary basin and to the northwest and northeast into similar smaller basins between present-day mountain ranges. Early sediments, largely fluvial, began to accumulate in the lowlands between the surrounding ranges at about 16.5 Ma. The sediments were derived from Paleozoic sedimentary and middle Tertiary volcanic units in the nearby highlands, and flow patterns indicate a general southward flow towards present-day Pine Valley. The eruption of the Palisade Canyon–Marys Mountain rhyolite flows at the southwest end of the basin at 15.3 Ma blocked the southward flow, and a lake began to form in the basin. As the lake grew in extent, sedimentary units around the fringes of the lake included a mixture of inflowing fluvial sediments mixed with the pyroclastic-fall, ash-rich sediments deposited in the lake. The lake margin expanded, and stratigraphic sections record the progressive transition from fluvial to mixed fluvial and lacustrine, and finally to entirely lacustrine. The volcanic rock dam was breached at about 14.7 Ma, the lake drained, and fluvial sediments blanketed the entire basin for an unknown period of time after that. Sedimentation progressively buried existing highlands and bridged gaps between adjacent basins. For example, the Carlin and Elko basins connected across the southern Adobe Range. Normal faulting produced numerous, mostly north- to north-northeast-striking faults that cut the sedimentary units and surrounding highlands largely after sedimentation ceased. The largest fault formed in the eastern third of the basin and tilted all of the sedimentary units in the western two-thirds of the basin, as well as the eastern part of Marys Mountain, to the east. Some offset took place during sedimentation. Many other normal faults of smaller extent and offset cut the sedimentary units. The integration of streams draining the Elko and Carlin basins began after about 9.8 Ma. The streams, which together comprised the early stages of the Humboldt River, flowed regionally southwestward beyond the Carlin basin. As many as thirteen, downward-stepping strath terraces in the Carlin basin record the progressive downcutting into and removal of the middle Miocene sediments. Gravel deposits form a thin veneer on some of the higher terraces. Clasts in those gravel deposits, as well as the overall terrace pattern, indicate southward drainage towards the Humboldt River. The erosion gradually re-exposed the flanks of the surrounding highlands. A brief pause in downcutting allowed the formation of a small lake in the Hemphillian (late Miocene), represented by lacustrine units northwest of Carlin. The sedimentary rocks of the Carlin basin conceal a large segment of the world-class, late Eocene Carlin gold trend, which extends from the southern Independence Mountains south into the Piñon Range. Sedimentation largely buried the Gold Quarry and Mike gold deposits in the northwestern part of the basin. Later faulting and erosion re-exposed the Gold Quarry deposit, but the Mike deposit remains buried. The basin’s sedimentary units conceal potential Paleozoic host rocks, and the sedimentary facies and post-sedimentation faults shown on the map may help guide interpretations of geophysical and other exploration data in the Carlin basin. The current map publication was supported by the USGS National Cooperative Geologic Mapping Program under STATEMAP award number G19AC00383.
Nevada↗
Evaluation of Streamflow Gain-Loss Characteristics of Hubbard Creek, in the Vicinity of a Mine-Permit Area, Delta County, Colorado, 2007
In 2007, the U.S. Geological Survey, in cooperation with Bowie Mining Company, initiated a study to characterize the streamflow and streamflow gain-loss in a reach of Hubbard Creek in Delta County, Colorado, in the vicinity of a mine-permit area planned for future coal mining. Premining streamflow characteristics and streamflow gain-loss variation were determined so that pre- and postmining gain-loss characteristics could be compared. This report describes the methods used in this study and the results of two streamflow-measurement sets collected during low-flow conditions. Streamflow gain-loss measurements were collected using rhodamine WT and sodium bromide tracers at four sites spanning the mine-permit area on June 26-28, 2007. Streamflows were estimated and compared between four measurement sites within three stream subreaches of the study reach. Data from two streamflow-gaging stations on Hubbard Creek upstream and downstream from the mine-permit area were evaluated. Streamflows at the stations were continuous, and flow at the upstream station nearly always exceeded the streamflow at the downstream station. Furthermore, streamflow at both stations showed similar diurnal patterns with traveltime offsets. On June 26, streamflow from the gain-loss measurements was greater at site 1 (most upstream site) than at site 4 (most downstream site); on June 27, streamflow was greater at site 4 than at site 2; and on June 27, there was no difference in streamflow between sites 2 and 3. Data from streamflow-gaging stations 09132940 and 09132960 showed diurnal variations and overall decreasing streamflow over time. The data indicate a dynamic system, and streamflow can increase or decrease depending on hydrologic conditions. The streamflow within the study reach was greater than the streamflows at either the upstream or downstream stations. A second set of gain-loss measurements was collected at sites 2 and 4 on November 8-9, 2007. On November 8, streamflow was greater at site 4 than at site 2, and on the following day, November 9, streamflow was greater at site 2 than at site 4. Data collection on November 8 occurred while the streamflow was increasing due to contributions from stream ice melting throughout different parts of the basin. Data collection on November 9 occurred earlier in the day with less stream ice melting and more steady-state conditions, so the indication that streamflow decreased between sites 2 and 4 may be more accurate. Diurnal variations in streamflow are common at both the upper and the lower streamflow-gaging stations. The upper streamflow-gaging station shows a melt-freeze influence from tributaries to Hubbard Creek during the winter season. Downstream from the study reach, observed diurnal variation is likely due to evapotranspiration associated with dense flood-plain vegetation, which consumes water from the creek during the middle of the day. Varying diurnal patterns in streamflow, combined with possible variations in tributary inflows to Hubbard Creek in the study reach, probably account for the observed variations in streamflow at the tracer measurement sites. During both sampling periods in June and November 2007, conditions were less than ideal and not steady state. The June 27 sampling indicates that the streamflow was increasing between measurement sites 2 and 4, and the November 9 sampling indicates that the streamflow was decreasing between measurement sites 2 and 4. The data collected during the diurnal and day-to-day variations in streamflow indicated that the streamflow reach is dynamic and can be gaining, losing, or constant.
Scientific Investigations Report↗
Integrated investigations of environmental effects of historical mining in the Basin and Boulder Mining Districts, Boulder River watershed, Jefferson County, Montana
The Boulder River watershed is one of many watersheds in the western United States where historical mining has left a legacy of acid mine drainage and elevated concentrations of potentially toxic trace elements. Abandoned mine lands commonly are located on or affect Federal land. Cleaning up these Federal lands will require substantial investment of resources. As part of a cooperative effort with Federal land-management agencies, the U.S. Geological Survey implemented an Abandoned Mine Lands Initiative in 1997. The goal of the initiative was to use the watershed approach to develop a strategy for gathering and communicating the scientific information needed to formulate effective and cost-efficient remediation of affected lands in a watershed. The watershed approach is based on the premise that contaminated sites that have the most profound effect on water and ecosystem quality within an entire watershed should be identified, characterized, and ranked for remediation. The watershed approach provides an effective means to evaluate the overall status of affected resources and helps to focus remediation at sites where the most benefit will be gained in the watershed. Such a large-scale approach can result in the collection of extensive information on the geology and geochemistry of rocks and sediment, the hydrology and water chemistry of streams and ground water, and the diversity and health of aquatic and terrestrial organisms. During the assessment of the Boulder River watershed, we inventoried historical mines, defined geological conditions, assessed fish habitat, collected and chemically analyzed hundreds of water and sediment samples, conducted toxicity tests, analyzed fish tissue and indicators of physiological malfunction, examined invertebrates and biofilm, and defined hydrological regimes. Land- and resource-management agencies are faced with evaluating risks associated with thousands of potentially harmful mine sites, and this level of effort is not always feasible for every affected watershed. The detailed work described in this report can help Federal land-management agencies decide which characterization efforts would be most useful in characterization of other affected watersheds.
Montana↗
Franciscan and related rocks, and their significance in the geology of western California
No abstract available.
California Division of Mines and Geology Bulletin↗
Geology and ore deposits of the Whitepine area, Tomichi mining district, Gunnison County, Colorado
The Tomichi mining district is on the western slope of the Continental Divide near the southern end of the Sawatch Range in southeastern Gunnison County, Colorado. The most productive part of the Tomichi district was the Whitepine area. It is estimated that since the discovery of ore in 1879 the area has produced approximately $7,000,000, principally in lead and zinc, with lesser amounts of silver, copper, and gold. Geologically, the Whitepine area is a faulted syncline of Paleozoic rocks that was intruded by Tertiary igneous rocks. The oldest rock of the area is the Silver Plume granite of pre-Cambrian age. Deposited upon this successively were the Sawatch quartzite (Late Cambrian), Manitou dolomite (Early Ordovician), Harding quartzite (Middle Ordovician), Fremont dolomite (Lade Ordovician), Chaffee formation (Late Devonian), Leadville limestone (Late Mississippian), and Beldon shale (Late Pennsylvanian); a total thickness of about 1,450 feet. During the Laramide Revolution, the sedimentary rocks were folded into a broad northward-plunging syncline, faulted, and intruded by a series of igneous rocks. The igneous rocks, in order of relative age from oldest to youngest, are: a rhyolite stock, the Princeton quartz monzonite batholith, quartz monzonite or quartz latite porphyry dikes, and rhyolite or pitchstone porphyry dikes. The ore deposits of the Whitepine area may be classified into replacement deposits, vein deposits, and contact metamorphic deposits. The replacement deposits may be further subdivided into deposits along faults and bedded deposits. Of the types of deposits, the most productive have been the replacement deposits along faults. The major replacement deposits along faults are those of the Akron, Morning Star, and Victor mines. The ore deposits of these mines are in the foot wall of the Star faults in the Akron mine in the Manitou dolomite and in the Morning Star and Victor mines in the Leadville limestone. The chief bedded replacement deposits are those of the Erie, North Star, and Tenderfoot mines. In the Erie mine the ore deposits are in the Leadville limestone at, or just below, its contact with the Belden shale. In the North Star and Tenderfoot mines the ore bodies are in the Manitou dolomite along the crest of an anticline and the trough of a syncline, respectively. The vein deposits occur in the Silver Plume granite, Princeton quartz monzonite, and Paleozoic sedimentary rocks. The only vein of commercial importance was that of the Spar Copper mine, which is in the Silver Plume granite. Contact metamorphic minerals are found chiefly in the top of the Leadville limestone in the vicinity of the Erie mine, and in the limestone of the Belden shale. Magnetite is the only ore mineral and it was produced only from the Iron King mine. The replacement deposits consist, in general, of sphalerite, galena, pyrite, and chalcopyrite in a gangue of siliclfied limestone or dolomite, quartz, and calcite. The veins, for the most part, consist of pyrite and quartz with only minor amounts of galena, sphalerite, and chalcopyrite. In both types of deposits gold is believed to be associated with the pyrite and sphalerite and silver with the galena. Oxidized ore was the chief product of the early mining. This ore consists of calamine, cerussite, smithsonite, or anglesite, or a combination of these minerals, in a gangue of siliceous limestone or silicified limestone or dolomite. Oxidation did not extend, in most cases, for more than 150 feetbelow the surface. The ore deposits are believed to be genetically related to the Princeton quartz monzonite batholith. Ore-bearing solutions derived from the cooling of magma are believed to have migrated upwards along the pre-existing faults replacing favorable zones in the sedimentary rocks, or depositing quartz and ore minerals in open fissures in the igneous rocks.
Open-File Report↗
Surface-mining modeling for USGS coal assessments
The value of national coal deposits is determined for the Solid Fuel Energy Resources Assessment and Research Project through economic evaluations using hypothetical mining models. Deposits near the surface are evaluated with the U.S. Geological Survey (USGS) surface-mining model, which is patterned after the standard mining techniques and infrastructures of commercial mining projects. The USGS surface-mining model uses these commercial mining project techniques as guides to develop a quantitative measurement to distinguish between potential recoverable resources and reserves by comparing total project cost and market value.
Open-File Report↗
New geologic, ground magnetic, E-mode VLF, and radiometric surveys at Phillips Mine-Camp Smith uranium prospect, Westchester and Putnam Counties, New York
This report updates U.S. Geological Survey Open-File Report 77-780 by including new field data taken in July 1978. A revised geologic map is included, as are new geophysical data from an approximately 0.3-km by 0.5-km area just northeast of and adjoining the area surveyed earlier. The pattern which had been observed to the southwest of spatially coincident radiometric highs, magnetic highs, and resistivity lows deteriorates to the northeast: there the radiometric highs fall on magnetic lows and the correlation with resistivity lows disappears.
New York↗
Occurrences of copper minerals in Alaska
The following references give data, as of June 1, 1982, on localities where copper minerals have been found in Alaska. References are keyed by number to locations shown on the accompanying map. An asterisk (*) preceding a locality name indicates recorded production. In most instances the report(s) cited for each occurrence is a summary of data in older reports and was compiled since 1975. Most of the summary reports contain lists of the reports used in their compilation. Citations are in standard bibliographic format with the exception that each includes, in parentheses, an abbreviation for the report or map series and the number of the report or map. Abbreviations used are: AOF, State of Alaska Division of Geological and Geophysical Surveys Open-File Report; B, U.S. Geological Survey Bulletin; BMOF, U.S. Bureau of Mines Open-File Report; C, U.S. Geological Survey Circular; MF, U.S. Geological Survey Miscellaneous Field Studies Map; OF, U.S. Geological Survey Open-File Report; P, U.S. Geological Survey Professional Paper.
Alaska↗