Search USGS⌕ Search

SEARCH · Search USGS

Results for “River Basin Bulletin”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

263 records · Page 15Linked to original sources
USGS2017

Groundwater flow model for the Little Plover River basin in Wisconsin’s Central Sands

The Little Plover River is a groundwater-fed stream in the sand plains region of central Wisconsin. In this region, sandy sediment deposited during or soon after the last glaciation forms an important unconfined sand and gravel aquifer. This aquifer supplies water for numerous high-capacity irrigation, municipal, and industrial wells that support a thriving agricultural industry. In recent years the addition of many new wells, combined with observed diminished flows in the Little Plover and other nearby rivers, has raised concerns about the impacts of the wells on groundwater levels and on water levels and flows in nearby lakes, streams, and wetlands. Diverse stakeholder groups, including well operators, Growers, environmentalists, local land owners, and regulatory and government officials have sought a better understanding of the local groundwater-surface water system and have a shared desire to balance the water needs of the he liagricultural, industrial, and urban users with the maintenance and protection of groundwater-dependent natural resources. To help address these issues, the Wisconsin Department of Natural Resources requested that the Wisconsin Geological and Natural History Survey and U.S. Geological Survey cooperatively develop a groundwater flow model that could be used to demonstrate the relationships among groundwater, surface water, and well withdrawals and also be a tool for testing and evaluating alternative water management strategies for the central sands region. Because of an abundance of previous studies, data availability, local interest, and existing regulatory constraints the model focuses on the Little Plover River watershed, but the modeling methodology developed during this study can apply to much of the larger central sands of Wisconsin. The Little Plover River groundwater flow model simulates three-dimensional groundwater movement in and around the Little Plover River basin under steady-state and transient conditions. This model explicitly includes all high-capacity wells in the model domain and simulates seasonal variations in recharge and well pumping. The model represents the Little Plover River, and other significant streams and drainage ditches in the model domain, as fully connected to the groundwater system, computes stream base flow resulting from groundwater discharge, and routes the flow along the stream channel. A separate soil-water-balance (SWB) model was used to develop groundwater recharge arrays as input for the groundwater flow model. The SWB model uses topography, soils, land use, and climatic data to estimate recharge as deep drainage from the soil zone. The SWB model explicitly includes recharge originating as irrigation water, and computes irrigation using techniques similar to those used by local irrigation operators. The groundwater flow model uses the U.S. Geological Survey’s MODFLOW modeling code which is freely available, widely accepted, and commonly used by the groundwater community. The groundwater flow model and the SWB model use identical high-resolution numerical grids having model cells 100 feet on a side, with physical properties assigned to each grid cell. This grid allows accurate geographic placement of wells, streams, and other model features. The 3-dimensional grid has three layers; layers 1 and 2 represent the sand and gravel aquifer and layer 3 represents the underlying sandstone. The distribution of material properties in the model (hydraulic conductivity, aquifer thickness, etc.) comes from previous published geologic studies of the region, updated by calibration to recent streamflow and groundwater level data. The SWB model operates on a daily time step. The groundwater flow model was calibrated to monthly stress periods with time steps ranging from 1 to 16 days. More detailed time discretization is possible. The groundwater model was calibrated to water-level and streamflow data collected during 2013 and 2014 by adjusting model parameters (primarily hydraulic conductivity, storage, and recharge) until the model produced a conditionally optimal fit between field observations and model output, subject to consistency with previously published geologic studies. Calibration was performed under both steady and transient conditions, and used a sophisticated parameter-estimation procedure (PEST) for the calibration process and to identify important model parameters. For the Little Plover River, the two most important parameters are the global recharge multiplier and the hydraulic conductivity of the stream bed. The calibrated model produces water-level and mass-balance results that are consistent with field observations and previous studies of the area. The completed model is a powerful tool for testing and demonstrating alternative water-management scenarios. Example model applications described in this report include simulating how the cumulative impacts of pumping and land-use change have affected average baseflow in the Little Plover River. Depletion-potential mapping represents a method for predicting which wells and well locations have the greatest impact on nearby surface-water resources. The completed model is publicly available, along with a companion user’s guide to assist with its operation, at http://wgnhs.org/littleplover- river-groundwater-model.

Wisconsin↗
USGS2001

Petroleum geology and resources of the North Caspian Basin, Kazakhstan and Russia

The North Caspian basin is a petroleum-rich but lightly explored basin located in Kazakhstan and Russia. It occupies the shallow northern portion of the Caspian Sea and a large plain to the north of the sea between the Volga and Ural Rivers and farther east to the Mugodzhary Highland, which is the southern continuation of the Ural foldbelt. The basin is bounded by the Paleozoic carbonate platform of the Volga-Ural province to the north and west and by the Ural, South Emba, and Karpinsky Hercynian foldbelts to the east and south. The basin was originated by pre-Late Devonian rifting and subsequent spreading that opened the oceanic crust, but the precise time of these tectonic events is not known. The sedimentary succession of the basin is more than 20 km thick in the central areas. The drilled Upper Devonian to Tertiary part of this succession includes a prominent thick Kungurian (uppermost Lower Permian) salt formation that separates strata into the subsalt and suprasalt sequences and played an important role in the formation of oil and gas fields. Shallow-shelf carbonate formations that contain various reefs and alternate with clastic wedges compose the subsalt sequence on the 1 basin margins. Basinward, these rocks grade into deep-water anoxic black shales and turbidites. The Kungurian salt formation is strongly deformed into domes and intervening depressions. The most active halokinesis occurred during Late Permian?Triassic time, but growth of salt domes continued later and some of them are exposed on the present-day surface. The suprasalt sequence is mostly composed of clastic rocks that are several kilometers thick in depressions between salt domes. A single total petroleum system is defined in the North Caspian basin. Discovered reserves are about 19.7 billion barrels of oil and natural gas liquids and 157 trillion cubic feet of gas. Much of the reserves are concentrated in the supergiant Tengiz, Karachaganak, and Astrakhan fields. A recent new oil discovery on the Kashagan structure offshore in the Caspian Sea is probably also of the supergiant status. Major oil and gas reserves are located in carbonate reservoirs in reefs and structural traps of the subsalt sequence. Substantially smaller reserves are located in numerous fields in the suprasalt sequence. These suprasalt fields are largely in shallow Jurassic and Cretaceous clastic reservoirs in salt dome-related traps. Petroleum source rocks are poorly identified by geochemical methods. However, geologic data indicate that the principal source rocks are Upper Devonian to Lower Permian deep-water black-shale facies stratigraphically correlative to shallow-shelf carbonate platforms on the basin margins. The main stage of hydrocarbon generation was probably in Late Permian and Triassic time, during deposition of thick orogenic clastics. Generated hydrocarbons migrated laterally into adjacent subsalt reservoirs and vertically, through depressions between Kungurian salt domes where the salt is thin or absent, into suprasalt clastic reservoirs. Six assessment units have been identified in the North Caspian basin. Four of them include Paleozoic subsalt rocks of the basin margins, and a fifth unit, which encompasses the entire total petroleum system area, includes the suprasalt sequence. All five of these assessment units are underexplored and have significant potential for new discoveries. Most undiscovered petroleum resources are expected in Paleozoic subsalt carbonate rocks. The assessment unit in subsalt rocks with the greatest undiscovered potential occupies the south basin margin. Petroleum potential of suprasalt rocks is lower; however, discoveries of many small to medium size fields are expected. The sixth identified assessment unit embraces subsalt rocks of the central basin areas. The top of subsalt rocks in these areas occurs at depths ranging from 7 to 10 kilometers and has not been reached by wells. Undiscovered resources of this unit did not rec

Bulletin↗
USGS1996

Uranium provinces of North America — Their definition, distribution, and models

Uranium resources in North America are principally in unconformity-related, quartz-pebble conglomerate, sandstone, volcanic, and phosphorite types of uranium deposits. Most are concentrated in separate, well-defined metallogenic provinces. Proterozoic quartz-pebble conglomerate and unconformity-related deposits are, respectively, in the Blind River–Elliot Lake (BRELUP) and the Athabasca Basin (ABUP) Uranium Provinces in Canada. Sandstone uranium deposits are of two principal subtypes, tabular and roll-front. Tabular sandstone uranium deposits are mainly in upper Paleozoic and Mesozoic rocks in the Colorado Plateau Uranium Province (CPUP). Roll-front sandstone uranium deposits are in Tertiary rocks of the Rocky Mountain and Intermontane Basins Uranium Province (RMIBUP), and in a narrow belt of Tertiary rocks that form the Gulf Coastal Uranium Province (GCUP) in south Texas and adjacent Mexico. Volcanic uranium deposits are concentrated in the Basin and Range Uranium Province (BRUP) stretching from the McDermitt caldera at the Oregon-Nevada border through the Marysvale district of Utah and Date Creek Basin in Arizona and south into the Sierra de Peña Blanca District, Chihuahua, Mexico. Uraniferous phosphorite occurs in Tertiary sediments in Florida, Georgia, and North and South Carolina and in the Lower Permian Phosphoria Formation in Idaho and adjacent States, but only in Florida has economic recovery been successful. The Florida Phosphorite Uranium Province (FPUP) has yielded large quantities of uranium as a byproduct of the production of phosphoric acid fertilizer. Economically recoverable quantities of copper, gold, molybdenum, nickel, silver, thorium, and vanadium occur with the uranium deposits in some provinces. Many major epochs of uranium mineralization occurred in North America. In the BRELUP, uranium minerals were concentrated in placers during the Early Proterozoic (2,500–2,250 Ma). In the ABUP, the unconformity-related deposits were most likely formed initially by hot saline formational water related to diagenesis (»1,400 to 1,330 Ma) and later reconcentrated by hydrothermal events at »1,280–»1,000, »575, and »225 Ma. Subsequently in North America, only minor uranium mineralization occurred until after continental collision in Permian time (255 Ma). Three principal epochs of uranium mineralization occurred in the CPUP: (1) » 210–200 Ma, shortly after Late Triassic sedimentation; (2) »155–150 Ma, in Late Jurassic time; and (3) » 135 Ma, after sedimentation of the Upper Jurassic Morrison Formation. The most likely source of the uranium was silicic volcaniclastics for the three epochs derived from a volcanic island arc at the west edge of the North American continent. Uranium mineralization occurred during Eocene, Miocene, and Pliocene times in the RMIBUP, GCUP, and BRUP. Volcanic activity took place near the west edge of the continent during and shortly after sedimentation of the host rocks in these three provinces. Some volcanic centers in the Sierra de Peña Blanca district within the BRUP may have provided uranium-rich ash to host rocks in the GCUP. Most of the uranium provinces in North America appear to have a common theme of close associations to volcanic activity related to the development of the western margin of the North American plate. The south and west margin of the Canadian Shield formed the leading edge of the progress of uranium source development and mineralization from the Proterozoic to the present. The development of favorable hosts and sources of uranium is related to various tectonic elements developed over time. Periods of major uranium mineralization in North America were Early Proterozoic, Middle Proterozoic, Late Triassic–Early Jurassic, Early Cretaceous, Oligocene, and Miocene. Tertiary mineralization was the most pervasive, covering most of Western and Southern North America.

Bulletin↗
USGS1993

Aspects of three-dimensional strain at the margin of the extensional orogen, Virgin River depression area, Nevada, Utah, and Arizona

The Virgin River depression and surrounding mountains are Neogene features that are partly contiguous with the little-strained rocks of the structural transition to the Colorado Plateau province. This contiguity makes the area ideally suited for evaluating the sense, magnitude, and kinematics of Neogene deformation. Analysis along the strain boundary shows that, compared to the adjacent little-strained area, large-magnitude vertical deformation (both uplift and depression, locally exceeding 10 km) greatly exceeds extensional deformation and that significant amounts of lateral displacement approximately parallel the province boundary. Extensional kinematics, the directions of lateral displacements, and the position and orientation of uplifts and one major depression are such that isostatic rebound following tectonic denudation is an unlikely direct cause of the strong vertical structural relief adjacent to the strain boundary. Instead, the observed structures are first-order features defining a three-dimensional strain field produced by approximately east-west extension, vertical structural attenuation, and extension-normal shortening. All major structural elements of the strain-boundary strain field are also found in the adjacent Basin and Range. Especially evident is a discontinuous and inhomogeneous distribution of vertical structural relief resulting from uplift and tilting of the footwalls on convex-upward normal faults, combined with formation of extension-parallel folds. Deformation resulted in a bewilderingly complex mixture of coeval folds, normal faults, strike-slip faults, and, in some areas, reverse faults, thrust faults, and thrust faults reactivated as extensional detachment faults. These complexly mixed structures exhibit a tectonically important aspect of scale independence, ranging from micro- structures to mountain-range scale. Many intensely extended domains appear to reflect a process of surface-relief minimization above uplifted and tilted blocks. Some intensely extended zones are depth-limited by relatively undeformed rocks above, and intact tilted blocks below, and are best viewed as subhorizontal zones of accommodation for the uplift and tilt of subjacent blocks. Whether or not the intense deformation extends to the surface, its depth distribution commonly reflects lithologic or paleostructural controls. Whatever the cause for the concentration of extensional strain, many gently dipping zones are more accurately viewed as local features recording small to moderate extension-parallel translations than a regionally interconnected detachment faults recording enormous extension-parallel translations. Although the total Neogene strain field in the Nevada-Utah-Arizona tricorner area has unique aspects, other parts of the Basin and Range contain generally similar structures that presumably formed from similar processes. These processes include lateral mass transfer, probably by viscoelastic flow, of the material needed to inflate areas of strong uplift and to translate blocks laterally by tectonic rafting. Directions of mass transfer vary but are commonly both parallel and normal to the direction of extension or parallel to the boundaries of extended areas. Much of the strong vertical structural relief probably reflects boundary-condition or localized perturbations (in the form of restraints or releases) of the lateral flow system. These conclusions are consistent with modern concepts of the flexural strength and rheological stratification of the crust in regions undergoing extension.

Geological Society of America Bulletin↗
USGS1961

Geology and mineral deposits of the Carlile quadrangle, Crook County, Wyoming

The Carlile quadrangle-is along the northwestern flank of the Black Hills uplift in Crook County, Wyo. The area-is primarily one of canyons and divides that are a result of downcutting by the Belle Fourche River and its tributaries through an alternating succession of sandstone, siltstone, and mudstone or shale beds. The present topography is also influenced by the regional structure, as reflected by the beds that dip gently westward and by the local structural features such as anticlines, domes, synclines, basins, and terraces, which are superimposed upon the regional setting. Rocks exposed include shale and thin limestone and sandstone beds belonging to the Redwater shale member of the Sundance formation and to the Morrison formation, both of Late Jurassic age; sandstone, siltstone, and mudstone of the Lakota and Fall River formations of Early Cretaceous age; and shale and sandstone of the Skull Creek shale, Newcastle sandstone, and Mowry shale, also of Early Cretaceous age. In the southwestern part of the quadrangle rocks of the Upper Cretaceous series are exposed. These include the Belle Fourche shale, Greenhorn formation, and Carlile shale. Gravel terraces, landslide debris, and stream alluvium comprise the surficial deposits. The Lakota and Fall River formations, which make up the Iriyan Kara group, contain uranium deposits locally in the northern Black Hills. These formations were informally subdivided in order to show clearly the vertical and lateral distribution of the sandstone, siltstone, and mudstone facies within them. The Lakota was subdivided into a sandstone unit and an overlying mudstone unit; the Fall River was subdivided, in ascending order, into a siltstone unit, a mudstone unit, a sandstone unit, and an upper unit. The lithologic character of the Lakota changes abruptly locally, and the units are quite inconsistent with respect to composition, thickness, and extent. This is in contrast to a notable consistency in the lithologic character and thickness among all the Fall River units, with the exception of the upper unit. Petrographic studies on selected samples of units from both formations show differences in composition between Lakota and Fall River rocks. The Carlile quadrangle lies immediately east of the monocline that marks the outer limit of the Black Hills uplift, and the rocks in this area have a regional dip of less than 2° outward from the center of the uplift. Superimposed upon the regional uplift are many subordinate structural features anticlines, synclines, domes, basins, and terraces which locally modify the regional features. The most pronounced of these subordinate structural features are the doubly-plunging Pine Ridge, Oil Butte, and Dakota Divide anticlines, and the Eggie Creek syncline. Stress throughout the area was relieved almost entirely through folding; only a few small nearly vertical normal faults were found within the quadrangle. Uranium has been mined from the Carlile deposit, owned by the Homestake Mining Co. The ore minerals, carnotite and tyuyamnuite occur in a sandstone lens that is enclosed within relatively impermeable clayey beds in the mudstone unit of the Lakota formation. The ore also includes unidentified black vanadium minerals and possibly coffinite. Uranium minerals are more abundant in and adjacent to thicker carbonaceous and silty seams in the sandstone lens. A mixture of fine-grained calcium carbonate and calcium sulfate fills the interstices between detrital quartz grains in mineralized sandstone. Selenium and arsenic are more abundant in samples that are high in uranium. Drilling on Thorn Divide about 1 mile west of the Carlile mine has roughly outlined concentrations of a sooty black uranium mineral associated with pyrite In two stratigraphic intervals of the Lakota formation. One is in the same sandstone lens that contains the ore at the Carlile mine; the other is in conglomeratic sandstone near the base of the Lakota. These deposits are relatively deep, and no mining has been attempted. The mineralogy of the Carlile deposits and the lithologic features of the sandstone host rock suggest that uranium and vanadium were transported in the high-valent state by carbonate or sulfate solutions, were extracted from solution by organic material, and were reduced to low-valent states to form an original assemblage of oxides and silicates. These primary minerals were oxidized in place, and the present carnotite-tyuyamunite assemblage was formed. In general, radioactivity analyses correspond fairly closely with chemical analyses of uranium, thus it is believed that only minor solution and migration of uranium has occurred since the present suite of oxidized minerals was formed. The factors responsible for ore localization are not clear, but probably a combination of three lithologic and structural elements contributed to provide a favorable environment for precipitating uranium from aqueous solutions: abundant carbonaceous material or pyrite in a thin, permeable sandstone enclosed within relatively thick impermeable clays; local structural basins; and a regional structural setting involving a broad syncline between two anticlines. The structural features controlled the regional flow of ground water and the lithologic features controlled the local rate of flow and provided the proper chemical environment for uranium deposition. Bentonite has been mined from an opencut in the Mowry shale in the southwest part of the quadrangle. A bentonite bed in the Newcastle sandstone also seems to be of minable thickness and quality. Exploration for petroleum has been unsuccessful within the quadrangle; however, some wells that yielded oil were recently drilled on small anticlines to the west and southeast. It is possible that similar structural features in the Carlile area, that were previously overlooked, may be equally productive.

Wyoming↗
USGS2000

Composition and depositional environment of concretionary strata of early Cenomanian (early Late Cretaceous) age, Johnson County, Wyoming

Unusual, concretion-bearing mudrocks of early Late Cretaceous age, which were deposited in an early Cenomanian epeiric sea, have been recognized at outcrops in eastern Wyoming and in adjoining areas of Montana, South Dakota, Nebraska, and Colorado. In Johnson County, Wyo., on the western flank of the Powder River Basin, these strata are in the lower part of the Belle Fourche Member of the Frontier Formation. At a core hole in south-central Johnson County, they are informally named Unit 2. These strata are about 34 m (110 ft) thick and consist mainly of medium- to dark-gray, noncalcareous, silty shale and clayey or sandy siltstone; and light-gray to grayish-red bentonite. The shale and siltstone are either bioturbated or interlaminated; the laminae are discontinuous, parallel, and even or wavy. Several ichnogenera of deposit feeders are common in the unit but filter feeders are sparse. The unit also contains marine and continental palynomorphs and, near the top, a few arenaceous foraminifers. No invertebrate macrofossils have been found in these rocks. Unit 2 conformably overlies lower Cenomanian shale in the lowermost Belle Fourche Member, informally named Unit 3, and is conformably overlain by lower and middle Cenomanian shale, siltstone, and sandstone within the member, which are informally named Unit 1. The mineral and chemical composition of the three Cenomanian units is comparable and similar to that of shale and siltstone in the Upper Cretaceous Pierre Shale, except that these units contain more SiO2 and less CaO, carbonate carbon, and manganese. Silica is generally more abundant and CaO is generally less abundant in river water than in seawater. The composition of Unit 2 contrasts significantly with that of the underlying and overlying units. Unit 2 contains no pyrite and dolomite and much less sulfur than Units 1 and 3. Sulfate is generally less abundant in river water than in seawater. Unit 2 also includes sideritic and calcitic concretions, whereas Units 1 and 3 contain neither concretions nor siderite and only sparse calcite. Carbon-sulfur-iron chemistry for the concretions suggests that sulfate availability was the limiting factor in pyrite formation and sulfide incorporation in Unit 2. Isotopic compositions of the carbon and oxygen in siderite and calcite from several concretions are variable and suggest cementation during early diagenesis in a variety of microenvironments. The isotopic composition of these carbonate minerals differs from that of Upper Cretaceous marine limestones. When considered in conjunction with the proportions of sulfur, organic carbon, and iron in Unit 2, major-element and micropaleontological data suggest that the composition of the original pore waters and of overlying waters in the late early Cenomanian sea was brackish to fresh. The mudrocks of Units 3 and 2, and a lower part of Unit 1, accumulated on a shelf at low to moderate rates of sedimentation in association with variable but generally weak current action. In Unit 2 and laterally equivalent rocks of the region, the sideritic and calcitic concretions probably indicate the extent of a body of brackish to fresh and oxygen-deficient water. Rates of precipitation in this region during the mid-Cretaceous could have been unusually high and the precipitation probably was seasonal. The organic matter in Unit 2 is humic-rich and would have been derived from continental environments. If the epeiric sea was brackish to fresh in the region of eastern Wyoming and contiguous areas, meteoric runoff from the adjoining lowlands must have been periodically large and the seaway north of the region probably was constricted. Seasonal changes in salinity might have been accompanied by changes in water temperature and oxygen content. The lower part of the Frontier Formation (Units 3, 2, and 1) in Wyoming records an intermittently and easterly prograding shoreline during late early and early middle Cenomanian time. Laterally equivalent strata in Nebraska

Bulletin↗
USGS1944

Manganese Deposits in the Artillery Mountains Region, Mohave County, Arizona

The manganese deposits of the Artillery Mountains region lie within an area of about 25 square miles between the Artillery and Rawhide Mountains, on the west side of the Bill Williams River in west-central Arizona. The richest croppings are on the northeast side of this area, among the foothills of the Artillery Mountains. They are 6 to 10 miles from Alamo. The nearest shipping points are Congress, about 50 miles to the east, and Aguila, about 50 miles to the southeast. The principal manganese deposits are part of a sequence of alluvial fan and playa material, probably of early Pliocene age, which were laid down in a fault basin. They are overlain by later Pliocene (?) basalt flows and sediments and by Quaternary basalt and alluvium. The Pliocene (?) rocks are folded into a shallow composite S1ncline ttat occupies the valley between the Artillery and Rawhide Mountains, and the folded rocks along either side of the valley, together with the overlying Quaternary basalt, are broken by faults that have produced a group of horsts, grabens, and step-fault blocks. The manganiferous beds, lie at two zones, 750 to 1,000 feet apart stratigraphically, each of which is locally as much as 300 to 400 feet thick. The main, or upper, zone contains three kinds of ore - sandstone ore, clay ore, and 'hard' ore. The sandstone and clay ores differ from the associated barren sandstone and clay, with which they are interlayered and into which they grade, primarily in containing a variable proportion of amorphous manganese oxides, besides iron oxides and clayey material such as are present in the barren beds. The 'hard' ore is sandstone that has been impregnated with opal and calcite and in which the original amorphous manganese oxides have been largely converted to psilomelane and manganite. The average manganese content of the sandstone and clay ores is between 3 and 4 percent and that of the 'hard' ore is between 6 and 7 percent. The ore contains an average of 3 percent of iron, 0.08 percent of phosphorus, 1.1 percent of barium, and minute quantities of copper, lead, and zinc. Although the manganese content of the sandstone and clay ore may change abruptly from bed to bed, the content within any individual bed changes gradually, and for any large volume of ore both the nanganese and iron content are remarkably uniform. Explorations to June 1941 consisted chiefly of 49 holes diamond-drilled in the upper zone on the Artillery Mountains side of the area. The district is estimated to contain an assured minimum of 200,000,000 tons of material having an average manganese content of 3 to 4 percent. About 20,000,000 tons of this total contains 5 percent or more of manganese, and 2,000,000 to 3,000,000 tons contains 10 percent or more. To what extent these deposits can be utilized is a metallurgical and economic problem. Although the clay and sandstone ores, as well as the 'hard' ore, are present in large tonnages, the 'hard' ore is the only kind that combines minable tonnage with promising grade. About 15,000,000 tons of 'hard' ore is present; about 500,000 tons of this contains 15 percent or more of manganese and averages 17 percent, and somewhat over 2,000,000 tons contains 10 percent or more and averages nearly 13 percent. Except for closer drilling to determine such things as the tonnage, grade, spacing, and form of the richer shoots with greater accuracy before beginning to mine them, further explorations are not recommended, for any new ore found is likely to be similar, both in grade and kind, to that already discovered.

Arizona↗
USGS1961

Tertiary geology and oil-shale resources of the Piceance Creek basin between the Colorado and White Rivers, northwestern Colorado

The area of the Piceance Creek basin between the Colorado and White Rivers includes approximately 1,600 square miles and is characterized by an extensive plateau that rises 1,000 to more than 4,000 feet above the surrounding lowlands. Relief is greatest in Naval Oil-Shale Reserves Nos. 1 and 3 near the south margin of the area, where the spectacular Roan Cliffs tower above the valley of the Colorado River. The oldest rocks exposed in the mapped area are sandstone, shale, and coal beds of the Mesaverde group of Late Cretaceous age, which crop out along the east margin of the area. Overlying the Mesaverde is an unnamed sequence of dark-colored sandstone and shale, Paleocene in age. The Ohio Creek conglomerate, composed of black and red chert and quartzite pebbles in a white sandstone matrix, is probably the basal unit in the Paleocene sequence. The Wasatch formation of early Eocene age overlies the Paleocene sedimentary rocks. It is composed of brightly colored shale, lenticular beds of sandstone, and a few thin beds of fresh-water limestone. The Kasatch formation interfingers with and is overlain by the Green River formation of middle Eocene age. The Green River formation has been divided into the Douglas Creek, Garden Gulch, Anvil Points, Parachute Creek, and Evacuation Creek members. The basal and uppermost members, the Douglas Creek and Evacuation Creek, respectively, are predominantly sandy units. The two middle members, the Garden Gulch and Parachute Creek, are composed principally of finer clastic rocks. The Anvil Points member is present only on the southeast, east, and northeast margins of the area. It is a nearshore facies composed principally of sandstone and is the equivalent of the Douglas Creek, Garden Gulch, and the lower part of the Parachute Creek members. All of the richer exposed oil-shale beds are found in the Parachute Creek member, which is divided into two oil-shale zones by a series of low-grade oilshale beds. The upper oil-shale zone has several key beds and zones which can be traced throughout most of the mapped area. One of these, the Mahogany ledge or zone, is a group of very rich oil-shale beds at the base of the upper oil-shale zone. Drilling for oil and gas in the northeastern part of the area has revealed rich oil-shale zones in the Garden Gulch member also. Local unconformities within and at the base of the Evacuation Creek member are exposed at several places along Piceance Creek and at one place near the mouth of Yellow Creek; otherwise, the rock sequence is conformable. The mapped area is the major part of a large syncline, modified by numerous smaller structural features. Fractures, probably associated genetically with the minor structural features, are present in the central part of the area. These fractures are high-angle normal faults with small displacement. They occur in pairs with the intervening block downdropped. Two sets of joints are prominent, one trending northwest and the other northeast. The joint systems control the drainage pattern in the south-central part of the area. More than 20,000 feet of sedimentary rocks underlies the area. Many of the formations yield oil or gas in northwestern Colorado, northeastern Utah, and southwestern Wyoming. The Piceance Creek gas field, in which gas occurs in the Douglas Creek member of the Green River formation, is the largest oil or gas field discovered thus far within the area. About 7,000 million barrels of oil is contained in oil shale that yields an average of 45 gallons per ton from a continuous sequence 5 or more feet thick in the Mahogany zone. Oil shale in the Mahogany zone and adjacent beds that yields an average of 30 gallons of oil per ton from a continuous sequence 15 or more feet thick contains about 91,000 million barrels of oil. Similar shale in deeper zones in the northern part of the area, for which detailed estimates have not been prepared, are now known to contain at least an additional 72,000 million barrels of oil. Oil shale in a sequence 15 or more feet thick that yields an average of 25 gallons of oil per ton contains about 154,000 million barrels of oil in the Mahogany zone and adjacent beds; such shale in deeper zones in the northern part of the area probably contains at least an additional 157,000 million barrels of oil, although detailed estimates were not made. Oil shale in a sequence greater than 15 feet thick that yields an average of 15 gallons of oil per ton contains more than 900,000 million barrels of oil. These estimates of the oil content of the deposit do not take into account any loss in mining or processing of the shale.

Colorado↗
USGS1960

Geology and fluorspar deposits, Northgate district, Colorado

The fluorspar deposits in the Northgate district, Jackson County, Colo., are among the largest in Western United States. The mines were operated intermittently during the 1920's and again during World War II, but production during these early periods of operation was not large. Mining was begun on a larger scale in 1951, and the district has assumed a prominent position among the fluorspar producers in the United States. Within the Northgate district, Precambrian metamorphic and igneous rocks crop out largely in the Medicine Bow Mountains, and later sedimentary rocks underlie North Park and fill old stream valleys in the mountains. The metamorphic rocks constitute a gneiss complex that formed under progressively changing conditions of regional metamorphism. They consist principally of hornblende-plagioclase gneiss (hornblende gneiss), quartz monzonite gneiss, pegmatite, biotite-garnet-quartz-plagioclase gneiss (biotite-garnet gneiss), hornblende-biotite-quartz-plagioclase gneiss (hornblende-biotite gneiss) and mylonite gneiss. The igneous rocks comprise some local fine-grained dacite porphyry dikes near the west margin of the district, and a quartz monzonitic stock and associated dikes in the central and eastern parts of the district. The sedimentary rocks in the district range in age from Permian to Recent. Folded Permian and Mesozoic rocks underlie the basin of North Park, and consist in sequence from oldest to youngest, of Satanka(?) shale (0-50 feet of brick-red shale) and Forelle(?) limestone (8-15 feet of pink to light-gray laminated limestone) of Permian age, Chugwater formation of Permian and Triassic age (690 feet of red silty shale and sandstone), Sundance formation of Late Jurassic age (145 feet of sandstone containing some shale and limestone), Morrison formation of Late Jurassic age (445 feet of variegated shale and minor sandstone and limestone), Dakota group as used by Lee (1927), now considered to be of Early Cretaceous age in this area (200-320 feet of pebbly sandstone, sandstone, and shale), Ben ton shale of Early and Late Cretaceous age (665 feet of dark-gray thin-bedded shale), Niobrara formation of Late Cretaceous age (865 feet of yellow to gray limy siltstone and shale), and Pierre shale of Late Cretaceous age (more than 60 feet of dark-gray fissile shale). Unconformities separate the Chugwater and Sundance formations, and the Morrison formation and the Dakota group. Nonmarine strata of the White River formation of Oligocene age and the North Park formation of Miocene and Pliocene (?) age fill Tertiary valleys cut in the Precambrian rocks of the mountain areas, and Quaternary terrace gravel, alluvium, and dune sand mantle much of the floor of North Park. The main outlines of the modern Rocky Mountains formed during the Laramide orogeny in late Mesozoic and early Tertiary time. Most of the Laramide structures that can be recognized in the Northgate district involve the sedimentary rocks underlying North Park which are folded into northwest-trending anticlines and synclines. The folds are open and in most the beds dip 60° or less. Yet many anticlines are cut by reverse faults of widely different trends and directions of offset. Transverse faults offset some of the folds, and the character of folding commonly is markedly different on opposing sides of these faults. The North Park basin is cut off on the north by the east-trending Independence Mountain fault, a north-dipping reverse fault along which hard Precambrian rocks have been thrust up across the trend of the earlier Laramide structures. The North Park basin is still a major structure where it is interrupted by the Independence Mountain fault, and the original basin must have extended much farther north. Disrupted gradients at the base of pre-White River valleys suggest that the Northgate district and adjacent areas may have been deformed in middle Tertiary time, but the evidence is not conclusive. A more definite period of deformation took place in Pliocene time following deposition of the North Park formation. North Park strata in south-central North Park were folded into a northwest-trending syncline, and the central part of the Northgate district probably was warped up along a north- or northwestward-trending axis. Four north- to northwestward-trending faults cut the Precambrian rocks and White River formation on Pinkham Mountain and the area to the southeast. Similar faults 2½ and 15 miles west of the Northgate district cut rocks of the North Park formation, and all probably formed during the Pliocene period of deformation. The known commercial fluorspar deposits are localized along the two larger faults of the Northgate district, and they have been studied in detail. The White River formation in early Oligocene time covered a hilly terrain drained by southward-flowing streams. By late Miocene, the northward-flowing streams had cut to about the same levels reached by the pre-White River streams and had partly exhumed and modified the older terrain. During late Miocene and early Pliocene (?) time, the Northgate area was buried beneath the clays, sands, and gravels of the North Park formation. Subsequent erosion removed the higher part of the North Park formation, cut a surface of low relief across the exhumed Precambrian rocks, and removed all topographic evidence of the Pliocene period of deformation. The present courses of the major streams were superimposed across the buried terrains during this period of erosion. Rejuvenation during middle Pleistocene caused all major streams to become incised in sharp canyons. Copper minerals occur in small concentrations in some of the pegmatite masses in the gneiss complex. The copper-rich masses rarely exceed a few feet in diameter and constitute only a small part of the associated pegmatite body. Vermiculite is exposed in prospect pits and mine workings along the west margin of the Northgate district. All the venniculite that was seen is associated with small masses of horablendite, massive chlorite, or serpentinite where these masses are near or are cut by pegmatite bodies. Some of the deposits may be potential producers of commercial-grade vermiculite, but most are small and erratic in shape or grade. Fluorspar is the main mineral commodity that has been produced from the Northgate district. It was deposited during two distinct periods of mineralization, but only the younger deposits have been productive. Small bodies of silicified breccia containing minor coarsely crystalline fluorite occur along the Independence Mountain fault, and in a few places along other Laramide faults. The fluorspar is an integral part of the fault breccia and apparently was deposited while the enclosing fault was still active. The largest deposits of fluorspar in the Northgate district occur along the late Tertiary (?) faults on Pinkham Mountain. The fluorspar consists typically of botryoidal layers that formed as successive encrustations along open fractures, or as finely granular aggregates replacing and cementing fault gouge and White River formation. Many incompletely filled cavities, called water courses, still exist. Fluorite is the principal vein material; fragments of country rock constitute the chief impurity although finely granular quartz or chalcedony is common locally. Soft powdery manganese oxide coats many fractures and in places is associated with a fine white clay. Fluorspar was deposited in or adjacent to open spaces along the late Tertiary (?) faults. Fractures in hard granitic rocks tended to remain open after faulting and were the favored sites for fluorspar deposition; fractures in the less competent hornblende and hornblende-biotite gneiss and schist generally were tight and little fluorspar was deposited. The White River rocks, although soft, were permeable and were widely impregnated or replaced by fluorspar. Both of the main vein zones are along faults that have predominant rightlateral strike-slip displacement. As they theoretically should be, the vein zones are narrower and contain less fluorspar where the containing fault is deflected to the left than where the fault is deflected to the right and the fractures remained open. The crustified, vuggy structure of the fluorspar and the common association with chalcedony or finely granular quartz suggest deposition in a very shallow environment, but no direct evidence bearing on the depth at which the fluorspar formed was seen. Fluorspar was deposited throughout a vertical range of 600 feet or more on each of the main vein zones, and for a vertical range of 1,050 feet for the district as a whole. None of the deposits had been bottomed at the time this report was prepared. Exploration at depth beneath known ore bodies is favorable for developing large tonnages of fluorspar. The best possibilities for finding new ore bodies near the surface are along the northwestern and southeastern parts of the Fluorine-Camp Creek vein zone where large bodies of granitic rocks are intersected by the fault. These areas are generally mantled by a thick overburden, and have been inadequately tested so far.

Colorado↗
USGS1972

Water resources inventory of Connecticut Part 6: Upper Housatonic River basin

The upper Housatonic River basin report area has an abundant supply of water of generally good quality, which is derived from precipitation on the area and streams entering the area. Annual precipitation has averaged about 46 inches over a 30-year period. Of this, approximately 22 inches of water is returned to the atmosphere each year by evaporation and transpiration; the remainder flows overland to streams or percolates downward to the water table and ultimately flows out of the report area in the Housatonic River or in smaller streams tributary to the Hudson River. During the autumn and winter precipitation normally is sufficient to cause a substantial increase in the amount of water stored in surface reservoirs and in aquifers, whereas in the summer, losses through evaporation and transpiration result in sharply reduced streamflow and lowered ground-water levels. Mean monthly storage of water in November is 2.8 inches more than it is in June. The amount of water that flows into, through, and out of the report area represents the total amount potentially available for use ignoring reuse. For the 30-year period 1931 through 1960, the annual runoff from precipitation has averaged 24 inches (294 billion gallons). During the same period, inflows from Massachusetts and New York have averaged 220 and 64 billion gallons per year, respectively. A total average annual runoff of 578 billion gallons is therefore available. Although runoff indicates the total amount of water potentially available, it is rarely feasible to use all of it. On the other hand, with increased development, some water may be reused several times. The water availability may be tapped as it flows through the area or is temporarily stored in streams, lakes, and aquifers. The amounts that can be developed differ from place to place and time to time, depending on the amount of precipitation, on the size of drainage area, on the thickness, transmissivity, and areal extent of aquifers, and on the variations in chemical and physical quality of water. Differences in precipitation cause differences in the amount of streamflow whereas differences in the proportion of stratified drift affect its timing. Water can be obtained from wells almost anywhere in the area, but the amount obtainable at any particular point depends on the type and water-bearing properties of the aquifers tapped. Stratified-drift aquifers are the only ones generally capable of yielding more than 100 gpm (gallons per minute) to individual wells. Drilled, screened wells tapping this unit yield from 17 to 1,400 gpm, with a median yield of 200 gpm. Till and bedrock are widespread but generally provide only small supplies of water. Till is tapped in a few places by dug wells, which can yield small supplies of only a few hundred gallons per day throughout all or most of the year. Bedrock is the chief aquifer for privately owned domestic and rural supplies; it is tapped by drilled wells, about 90 percent of which will supply at least 2 gpm. Only 1 of 10 bedrock wells, however, will supply more than 30 gpm. The amount of ground water potentially available in the report area depends upon the thickness and hydraulic properties of aquifers, the amount of salvageable natural discharge of ground water, and the quantity of water available by induced infiltration from streams and lakes. From data on transmissivity, thickness, recharge, well performance, and streamflow, preliminary estimates of ground-water availability can be made for most stratified-drift aquifers in the report area. Long-term yields estimated for eight areas of stratified drift especially favorable for development of large ground-water supplies ranged from 0.6 to 5 mgd (million gallons per day). Detailed site studies are needed to verity these estimates and to determine optimum yields, drawdowns, and spacing of individual wells before major ground-water development is undertaken in these or other areas. The chemical quality of water in the report area is generally good; carbonate-bedrock units exert considerable local influence on water quality. Samples of naturally occurring surface water collected at 24 sites during low flow averaged 90 mg/l (milligrams per liter) dissolved solids and 60 mg/l hardness. Water from wells is generally more highly mineralized than naturally occurring water from streams. About 37 percent of the wells sampled yielded water with more than 200 mg/l dissolved solids and 50 percent yielded water with more than 120 mg/l hardness. These concentrations reflect the high degree of mineralization of ground water in carbonate bedrock and unconsolidated deposits derived from this bedrock. The larger streams, which transport varying amounts of industrial and domestic effluents, averaged about 150 mg/l dissolved solids and 90 mg/l hardness. Iron and manganese concentrations in both ground water and surface water at some places exceed recommended limits for domestic and industrial use. Most wells in the report area yield water with little or no iron or manganese. In certain localities however, the probability is high of encountering water with excessive concentrations of these constituents. Schists, especially the unit in the northwestern corner of the basin, are the likely sources of water with excessive iron and manganese. Iron concentrations in naturally occurring stream water exceed 0.3 mg/l under low-flow conditions at 29 percent of the sites sampled. These excessive concentrations result from discharge of iron-bearing water from aquifers or from swamps where iron is released from decaying vegetation. Water temperature in the larger streams ranges from 0°C (degrees Celsius) to about 28°C. Ground water between 30 feet and 200 feet below the land surface has a relatively constant temperature, usually between 8°C and 11°C. The quantity of suspended sediment transported by streams under natural conditions is negligible. Even in streams affected by man, turbidity is rarely a problem. The total amount of water used in the report area for all purposes during 1967 was about 6,360 million gallons, or 140 gpd per person. Public supplies furnished the domestic needs of nearly half the population of the area. All of the 14 public supplies sampled provided water that meets the drinking water standards of the U.S. Public Health Service.

Connecticut↗
USGS1968

Water resources inventory of Connecticut Part 3: lower Thames and southeastern coastal river basins

The lower Thames and southeastern coastal river basins have a relatively abundant supply of water of generally good quality which is derived from streams entering the area and precipitation that has fallen on the area. Annual precipitation has ranged from about 32 inches to 65 inches and has averaged about 48 inches over a 30-year period. Approximately 22 inches of water are returned to the atmosphere each year by evaporation and transpiration; the remainder of the annual precipitation either flows overland to streams or percolates downward to the water table and ultimately flows out of the report area through estuaries and coastal streams or as underflow through the deposits beneath. During the autumn and winter months precipitation normally is sufficient to cause a substantial increase in the amount of water stored underground and in surface reservoirs within the report area, whereas in the summer most of the precipitation is lost through evaporation and transpiration, resulting in sharply reduced stream-flow and lowered ground-water levels. The mean monthly storage of water on an average is about 3.8 inches higher in November than it is in June. The amount of water that flows through and out of the report area represents the total amount of water potentially available for use by man. For the 30-year period 1931 through 1960, the annual runoff from the report area has averaged nearly 26 inches (200 billion gallons), from the entire Thames River basin above Norwich about 24 inches (530 billion gallons), and from the Pawcatuck River basin about 26 inches (130 billion gallons). A total average annual runoff of 860 billion gallons is therefore available. Although runoff indicates the total amount of water potentially available, it is usually not economically feasible for man to use all of it. On the other hand, with increased development, it is possible that some water will be reused several times. The water available may be tapped as it flows through the area or is temporarily stored in streams, lakes, and aquifers. The amounts that can be developed vary from place to place and time to time, depending on the amount of precipitation, on the size of drainage area, on the thickness, permeability, and areal extent of aquifers, and on the variations in chemical and physical quality of the water. Differences in streamflow from point to point are due primarily to differences in the proportion of stratified drift in the drainage basin above each point, which affect the timing of streamflow, and to differences in precipitation, which affect the amount of streamflow. Ground water can be obtained from wells almost anywhere in the area, but the amount obtainable at any particular point depends upon the type and water-bearing properties of the aquifers. For practical purposes, the earth materials in the report area comprise three aquifers--stratified drift, bedrock, and till. Stratified drift is the only aquifer generally capable of yielding more than 100 gpm (gallons per minute) to individual wells. It covers about 20 percent of the area and occurs chiefly in lowlands where it overlies till and bedrock. The coefficient of permeability of the coarse-grained unit of stratified drift averages about 1,500 gbd (gallons per day) per sq ft. Drilled, screened wells tapping this unit are known to yield from 4 to 88o gpm and average 146 gpm. Dug wells in coarse-grained stratified drift supply about 2 gpm per foot of drawdown over a period of a few hours. Fine-grained stratified drift has an average coefficient of permeability of about 300 gpd per sq ft and can usually yield supplies sufficient for household use to dug wells. Bedrock and till are widespread in extent but generally provide only small water supplies. Bedrock is tapped chiefly by drilled wells, about 90 percent of which will supply at least 3 gpm. Very few, however, will supply more than 50 gpm. Till is tapped in a few places by dug wells which can yield small supplies of only a few hundred gpd throughout all or most of the year. The coefficient of permeability of till ranges from about 0.2 gpd per sq ft to 120 gpd per sq ft. The amount of ground water potentially available in the report area depends upon the amount of ground-water outflow, the amount of ground water in storage, and the quantity of water available by induced infiltration from streams and lakes. From data on permeability, saturated thickness, recharge, yield from aquifer storage, well performance, and streamflow, preliminary estimates of ground-water availability can be made for any point in the report area. Long-term yields estimated for 18 areas of stratified drift especially favorable for development of large ground-water supplies ranged from 1.3 to 66 mgd. Detailed site studies to determine optimum yields, drawdowns, and spacing of individual wells are needed before major ground-water development is undertaken in these or other areas. The chemical quality of water in the report area is generally good to excellent. Samples of naturally occurring surface water collected at 24 sites contained less than 151 ppm (parts per million) of dissolved solids and less than 63 ppm of hardness. Water from wells is more highly mineralized than naturally occurring water from streams. Even so only 12 percent of the wells sampled yielded water with more than 200 ppm of dissolved solids and only 8 percent yielded water with more than 120 ppm of hardness. Even in major streams, which are used to transport industrial waste, hardness rarely exceeds 60 ppm and the dissolved mineral content is generally less than 200 ppm. At a few places in the town of Montville however, waters may contain dissolved mineral concentrations of 2,000 to 4,000 ppm. Iron and manganese in both ground water and surface water are the only constituents whose concentrations commonly exceed recommended limits for domestic and industrial use. Most wells in the report area yield clear water with little or no iron or manganese, but distributed among them are wells yielding ground water that contains enough of these dissolved constituents to be troublesome for most uses. Iron concentrations in naturally occurring stream water exceed 0.3 ppm under low-flow conditions at 33 percent of the sites sampled. Large concentrations of iron in stream water result from discharge of iron-bearing water from aquifers or from swamps where it is released largely from decaying vegetation. Ground water more than 30 feet below the land surface has a relatively constant temperature, usually between 48°F and 52°F. Water temperature in very shallow wells may fluctuate from about 38°F in February or March to about 55°F in late summer. Water temperature in the larger streams fluctuates much more widely, ranging from 32°F at least for brief periods in winter, to about 85°F occasionally during summer. The quality of suspended sediment transported by streams in the area is negligible. Turbidity in streams is generally not a problem although amounts large enough to be troublesome may occur locally at times. The total amount of water used in the report area for all purposes during 1964 was about 118,260 million gallons, of which 105,600 million gallons was estuarine water used for cooling by industry. The average per capita water use, excluding estuarine, temporary summer residence, and institutional water was equivalent to 186 gpd. Public water systems supplied the domestic needs of nearly tw0-thirds the population of the report area. All of the 19 systems, which were sampled, provided water of better quality than the U.S. Public Health Service suggests for drinking water standards.

Connecticut↗