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At least 1,765 records · Page 98Linked to original sources
USGS1980

Hydrology and geochemistry of thermal ground water in southwestern Idaho and north-central Nevada

In southwestern Idaho and north-central Nevada, thermal groundwater occurs under artesian conditions in igneous or sedimentary rocks of Tertiary age. Temperatures of the groundwater range from 30 degrees to more than 80 degrees Celsius. Thermal waters are a sodium carbonate or bicarbonate type; nonthermal waters are a calcium bicarbonate. Chemical geothermometers indicate maximum reservoir temperatures near 100 degrees Celsius. Stable-isotope data indicate recharge to the system occurred when climate averaged 3 degrees to 5 degrees Celsius colder than at present; such conditions existed during Holocene glacial advances 3,000 and more than 8,000 years ago. Residence time calculated on the basis of reservoir volume and thermal-water discharge is 3,400 to 6,800 years. Considering estimates of heat flux in and heat discharged by conduction and convection, about 25.0 cubic feet per second, or about 18,000 acre-feet per year, of 50 degrees Celsius water is required to transport excess heat from the system advectively in groundwater. The conceptual model is one where water has circulated thousands, even tens of thousands, of years. Within model constraints, reservoir thermal energy for this geothermal system is 130x10 to the 18th power calories. (USGS)

Open-File Report↗
USGS1980

Ground-water resources investigation in the Amran Valley, Yeman Arab Republic

A program of hydrologic studies and exploratory drilling was conducted intermittently between 1974 and 1978 to evaluate the water-bearing properties of the unconsolidated alluvial sediments and associated rocks in the semi-arid Amran Valley basin, an 800-square-kilometer area in north-central Yemen Arab Republic. Inventory data from 395 wells were compiled, observation well and rain-gage networks were established and 16 standard complete chemical analyses were made for samples from selected wells. The water resources of the area were overexploited. The chemical quality of the water is generally good. Four aquifer tests were run to determine transmissivity and storage characteristics. The pumping tests show that groundwater occurs under semi-confined leaky-aquifer conditions in the valley fill. Wells drilled in the alluvial fill of the south-central part of the valley have the highest yields. Wells penetrating the limestone and volcanic rocks generally have little or no yield except in fracture zones. Basalt flows occur interbedded with the wadi alluvium at several depths. Cropping out rocks in the Amran Valley range in age from late Jurassic to Holocene. (USGS)

Open-File Report↗
USGS1980

Quaternary stratigraphic sections with radiocarbon dates, Chandler Lake Quadrangle, Alaska

Twenty-eight organic samples from 17 localities in the Anaktuvuk, Tulunga, and Itkillik Valleys and at Shainin Lake range in age from more than 40,000 to about 1000 14C yr B.P. These dates, combined with fossil identifications and measured stratigraphic sections, provide significant insights into the history of glaciation, climatic change, and related events of late Quaternary time in the north-central Brooks Range. Two dates from Tulunga Valley show that peat-forming intervals during the middle Wisconsin and during an earlier period were terminated by episodes of loess accretion that probably correspond to glaciations in the Brooks Range. The Anayaknaurak Bluff exposure in Anaktuvuk Valley contains a weathered till of the Banded Mountain (Itkillik I) glaciation overlain by unweathered outwash gravel of Antler Valley (Itkillik II) age. Radiocarbon dates from finer alluvium above the outwash indicate that a subsequent glacial readvance north of the range front occurred shortly after 13,000 yr B.P. This event was synchronous with a major glacial readvance that culminated between about 12,900 and 12,700 yr B.P. farther east in the Atigun and Sagavanirktok Valleys. Additional dates from Anaktuvuk Valley show that glacier ice had retreated from the Antler Valley end-moraine complex by 10,600 yr B.P. The elongate basin that formed behind the moraine dam was being filled by alluvium at this time, and filling continued as late as 6200 yr B.P. near the range front. A possible climatic reversal during this interval is suggested by dates from Anaktuvuk Valley and from Toolik Valley farther east, which show peat formation between about 9500 and 8200 yr B.P. followed by solifluction and fan-building. Soil test pits and other excavations near Anaktuvuk Pass show that the pass was deglaciated some time prior to 7250 yr B.P., and was suitable for human habitation by at least 6500 yr B.P. Dated buried peat suggests a change to more severe frost climate sometime after about 4750 yr B.P. Other dates from the Chandler Lake quadrangle bear mainly on formation of low (generally 2.5 to 6 m) river terraces during intervals of renewed glaciation at valley heads during the late Holocene. Neoglaciation in the north-central Brooks Range evidently began about 3500 yr B.P., or at least was perceptible by this time as increased loess influx to sites north of the range front. Stream alluviation was in progress 2800-2700 yr B.P. at sites near Anaktuvuk Pass, and continued until sometime after 2000 yr B.P. Final phases of alluviation began about 1200 and 450 yr B.P. Independent dating of cirque-glacier advances by lichenometry supports the alluvial chronology and suggests that alluviation was controlled largely by increased sediment yield to streams during times of cirque-glacier expansion and increased rock-glacier activity.

Alaska↗
USGS1980

Quaternary stratigraphic sections with radiocarbon dates, Wiseman Quadrangle, Alaska

The Wiseman quadrangle contains a rich stratigraphic record of alluvial, glacial, and periglacial events of the late Quaternary in the south-central Brooks Range. The numerous bluffs along the Koyukuk River and its tributaries expose drift sheets of the late Pleistocene Itkillik I glacial phase (table 1), and outwash and other proglacial deposits of the succeeding Itkillik II phase. During Itkillik I time, glaciers flowed south through virtually all of the valleys of the south-central Brooks Range to terminate in piedmont lobes within the Koyukuk lowland (Hamilton, 1978, 1979a). Outwash covered the Koyukuk Valley floor beyond the ice limits. Glaciers of Itkillik II age were more restricted; the largest reached positions near the south margin of the range, but many mountain valleys of the Wiseman quadrangle remained unglaciated. Lower alluvial terraces of Holocene age record alternating episodes of aggradation and soil development. Some of these events were controlled locally by mass movements and perhaps by faulting, but others may be related to regional climatic reversals and to fluctuations of cirque glaciers at valley heads.

Alaska↗
USGS1981

Preliminary hydrologic evaluation of the North Horn Mountain coal-resource area, Utah

North Horn Mountain is part of a deeply dissected plateau in central Utah which is characterized by deep, narrow, steep-walled canyons with local relief of more than 1,000 feet. Geologic units exposed in the North Horn Mountain area range in age from Late Cretaceous to Holocene and contain two mineable seams of Cretaceous coal. The area is in the drainage basin of the San Rafael River, in the Colorado River Basin. Runoff from the mountain is ephemeral. This runoff to the San Rafael River is by way of Cottonwood and Perron Creeks and represents less than 10 percent of their average annual runoff. Probable peak discharges (100-year flood) for the ephemeral streams draining North Horn Mountain are estimated to range from 200 to 380 cubic feet per second. The chemical quality of surface water in the area is good. The water is generally of a calcium magnesium bicarbonate type with average dissolved solids less than 500 milligrams per liter. Annual sediment yield in most of the area ranges from 0.1 to 0.2 acre-foot per square mile but locally is as high as 1.0 acre-foot per square mile. Most of the sediment is eroded during cloudbursts. Most of the ground water above the coal on North Horn Mountain probably is in perched aquifers. These aquifers support the flow of small seeps and springs. In some areas, the regional water table appears to extend upward into the coal. The principal source of recharge is precipitation that probably moves to aquifers along faults, joints, or fractures. This movement is apparently quite rapid. The dissolved-solids concentrations of ground water in the North Horn Mountain area range from less than 500 to about 1,000 milligrams per liter. Coal mining on North Horn Mountain should have minor "effects on the quantity and quality of surface water. The maximum predicted decrease in the annual flow of Ferron and Cottonwood Creeks is less than U percent. The sediment loads of affected streams could be significantly increased if construction were to take place during the summer cloudburst season. Subsidence, which usually follows underground coal mining, could create rock fractures through which a perched aquifer might be drained, thus depleting the flow of seeps or springs fed by that aquifer. It is considered unlikely that the mining will adversely affect the chemical quality of the ground water.

Utah↗
USGS1981

Infaunal and neoichnological characteristics of the South Texas Outer Continental Shelf

The zonation of macrobenthic infauna on the South Texas Outer Continental Shelf is related to water depth and sediment facies. Five zones can be defined by species distribution and density, diversity, equitability, and biogenic sedimentary structures. The numbers of species and individuals per unit area correlate locally with substrate characteristics (particularly sand-to-mud ratios). Sandier substrates have more species and individuals than muddier ones. In the study area, sand-to-mud ratios generally decrease as water depth increases. Consequently, the numbers of species and individuals decrease away from land. Diversity (H") is higher in sandier substrates than in muddier substrates. Overall diversity decreases in a seaward direction. Equitability increases as sand-to-mud ratios decrease and thus tends to increase as water depth increases. Biogenic sedimentary structures on the South Texas Outer Continental Shelf result from the interaction of biologic and geologic processes. The zonation of the structures is useful in overall environmental interpretations of Holocene events and processes. The zonation can be defined in terms of diversity, density, and distribution. Zonation of biogenic sedimentary structures parallel macrobenthic infaunal zonation. Substrates with diverse and dense biogenic sedimentary structures are associated with diverse, dense macrobenthic infaunal assemblages. The distribution of biogenic sedimentary structures is similar to the distribution of sediment types. Diversity and density of biogenic sedimentary structures decrease away from land. Locally, individual biogenic sedimentary structures become more obvious and distinct in finer sediments and deeper water.

Texas↗
USGS1981

Seismic-reflection and sidescan-sonar data collected on the Potomac River, Maryland and Virginia, during May 1979

The U.S. Geological Survey collected 2,170 line kilometers of single-channel seismic-reflection profiles and sidescan sonar records on the Potomac River during R/V NEECHO cruise NE-3-79 in May 1979. The purposes of the survey were to define: (1) areas of sediment accumulation and erosion; (2) the thickness of Holocene sediments; (3) the internal structure of the near-surface sediments; (4) the types of bottom topography; and (5) the general geologic framework of the tidal river and estuary. The survey utilized a variety of acoustic systems. Bottom data were obtained by using a Raytheon _ 1 / model DE-719 fathometer (200 kHz) and an EDO Western model 606 sidescan-sonar system (100 kHz). Subbottom data were collected with a 7-kHz Raytheon model PTR-106 system and a small airgun system (170-645 Hz band pass; l in 3 chamber). An EDO Western sidescan fish (model 604-150) coupled with a 2.5-kHz seismic-reflection system also was used during the longitudinal run up the river. The totals for the ,various kinds of data collected were 481 line kilometers each of fathometer, sidescan sonar, 7-kHz, and airgun records, and 246 line kilometers of 2.5-kHz records. Positional control for all tracklines was provided by frequent radar fixes, by dead reckoning, and by sightings on buoys, landmarks, and other navigational aids. The quality of the acoustic records varied with location in the river. Good fathometer and sidescan-sonar records were collected along all tracklines. However, because of the nature of the sediments within some sections of the river, the degree of subbottom penetration in many places was limited. In general, the subbottom penetration and resolution were poor in the upper and middle reaches of the river, whereas the subbottom records from the lower reach usually were quite good. The original records may be examined at the U.S. Geological Survey, Woods Hole, MA 02543. Microfilm copies of the data are available for purchase from the National Geophysical and Solar-Terrestrial Data Center (NGSDC), Boulder, CO 80303.

Maryl;Virginia↗
USGS1981

Single-channel seismic-reflection profiles and sidescan-sonar records collected by the R/V Neecho, cruise NE 79-06, on the inner shelf east of Cape Cod, Massachusetts

Cruise NE 79-06 of the R/V NEECHO was conducted by the U.S. Geological Survey during September 27-0ctober 3, 1979, in the nearshore zone (3-30 m water depth) seaward of Coast Guard Beach and the northern part of Orleans Beach, east of Cape Cod, Massachusetts. The purpose of the study was to map the types and extent of nearshore bed forms and to define the late Pleistocene and Holocene history of the area. The equipment used on this cruise consisted of an EG&G Uniboom, Raytheon echo sounder, and Edo Western sidescan-sonar system. The Uniboom data were mostly filtered to 400-4000 Hz and were recorded at a 1/4-s sweep rate. The 60-kHz echo-sounding data were recorded on a 6-in strip chart on which the depth was calibrated in feet. The sidescan sonar had an operating frequency of 100 kHz and was set to scan 50 m or 100 m to each side of the towed fish. All three data types were collected along 153 km of trackline. Navigation during the survey was by Loran-C and Motorola miniranger systems. Two shore stations were set up for the miniranger system and fixes were collected at either 1- or 2-min intervals. This system malfunctioned during parts of the survey, and during these times navigation was by Loran-C using a Northstar system. The original records can be seen and studied at the U.S. Geological Survey Data Library at Woods Hole, MA 02543. Microfilm copies of the subbottom, echo-sounding, and sidescan-sonar records can be purchased only from the National Geophysical and Solar-Terrestrial Data Center, NOAA/EDIS/NGSDC, Code D621, 325 Broadway, Boulder, CO 80303, (303-497-6338).

Open-File Report↗
USGS1981

Geology and potential hazards of the continental slope between Lindenkohl and South Toms Canyons, offshore mid-Atlantic United States

Because sediment instability, or slumping, has been identified as a potential hazard to petroleum development of the east-coast Continental Slope, the U.S. Geological Survey, in cooperation with the U.S. Bureau of Land Management, began a detailed study of a segment of the Continental Slope between Lindenkohl and South Toms Canyons off New Jersey. This 40-km x 35-km area was chosen for study because it lies within the area of high interest for petroleum development (Lease sales 49 and 59), and because it includes several wells which provide stratigraphic control. This report discusses the results of geologic mapping, using seismic-reflection data acquired in 1978 and 1979. Some initial results from more recently acquired data are included. The Continental Slope in the study area has a complex surface with ridges, canyons, and valleys. Three slump or slide features were observed in the heads and on the walls of canyons and valleys, and two slides were identified on an intercanyon area. The identified slumps or slides are found in Quaternary sediments and total about 1.3 percent of the Continental Slope area mapped. The slope is generally mantled by less than 2 m of Holocene sediments. Pleistocene sediment (primarily silty clay) is about 450 m thick at the top of the slope and thins to nearly zero or is absent on much of the mid and lower slope, where sediments of Miocene to Eocene age are exposed. Ridges on the midslope (water depths of 800-1,500 m) and parts of the lowr slope (1,500-2,150 m) result primarily from Pleistocene and older deposition. The intervening valleys show evidence of erosion along the deepest parts of their courses. Mid-range sidescan-sonar data show evidence that processes of bottom-current erosion and downcanyon transport of material may be active in the present day. However, major features of the sea floor appear to be unchanged since late-Pleistocene time.

Lindenkohl and South Toms Canyons↗
USGS1982

Probabilistic estimates of maximum acceleration and velocity in rock in the contiguous United States

Maximum horizontal accelerations and velocities caused by earthquakes are mapped for exposure times of 10, 50 and 250 years at the 90-percent probability level of nonexceedance for the contiguous United States. In many areas these new maps differ significantly from the 1976 probabilistic acceleration map by Algermlssen and Perkins because of the increase in detail, resulting from greater emphasis on the geologic basis for seismic source zones. This new emphasis is possible because of extensive data recently acquired on Holocene and Quaternary faulting in the western United States and new interpretations of geologic structures controlling the seismicity pattern in the central and eastern United States.

Open-File Report↗
USGS1982

Hydrology of the Floridan Aquifer in Northwest Volusia County, Florida

Northwest Volusia County, in east-central Florida, is a 262-square-mile area including the southern part of the Crescent City Ridge and the northern tip of the DeLand Ridge. The hydrogeologic units in the area include the Floridan aquifer, which is made up of parts of the Lake City Limestone, the Avon Park Limestone, and the Ocala Limestone, all of Eocene age; the confining bed, which is composed of clays of Miocene or Pliocene age; and the surficial aquifer, which is made up of Pleistocene and Holocene sands. Ornamental fern growing is a $12 million per year industry in northwest Volusia County. Fern culture requires a large amount of good-quality water for irrigation, and more significantly, a large water withdrawal rate for freeze protection during winter months. The source of most water used is the Floridan aquifer. The large irrigation withdrawals, especially in winter months when spray irrigation is used for freeze protection of ferns, introduce problems such as the potential for saltwater intrusion, the temporary loss of water in domestic wells caused by large potentiometric drawdown, and increased sinkhole activity. The water budget of the surficial layer consists of 55 inches per year rainfall, 39 inches per year evapotranspiration, 13 inches per year runoff, and a net downward leakage of 3 inches per year. Average ground-water irrigational withdrawal is 8.1 million gallons per day, while the peak withdrawal rate is 300 million gallons per day during freeze-protection pumpage. The average irrigation well depth exceeds 300 feet. Transmissivities of the Floridan aquifer range from 4,500 to 160,000 feet squared per day. Highest transmissivities are in the DeLeon Springs area and the lowest are in the east Pierson area. Storage coefficients range from 0.0003 to 0.0013. The water budget of the Floridan aquifer under present conditions of withdrawal consists of 108 cubic feet per second recharge, 2 cubic feet per second horizontal ground-water inflow, 34 cubic feet per second direct discharge, 40 cubic feet per second upward leakage, 22 cubic feet per second horizontal outflow, and 14 cubic feet per second pumpage. The Floridan aquifer contains good-quality water in most of the study area, but also contains brackish water underneath the stressed zones and in the upper zones along the western and southern limits of the area. The altitude of the fresh- saltwater interface varies in the area from 1,500 to 300 feet below sea level. Areal drawdowns in the fern-growing areas of Pierson are 5 feet during growth irrigation periods and 20 to 30 feet during freeze-protection withdrawals. The drawdown in the Pierson area at the end of one intense period of pumpage exceeded 30 feet over a 4.4-square-mile area. A significant amount of the withdrawn water was replaced by leakage during the pumping period. Drawdowns in some pumping wells in northeast Pierson exceed 90 feet during freeze-protection withdrawals. No long-term residual drawdown has occurred. The predominant effect of pumpage on the water budget of the Floridan aquifer has been an increase in recharge. Sinkhole activity has been increased by the temporary increase in load on the aquifer's skeletal structure during intense lowering of the potentiometric surface. There is no evidence of saltwater intrusion, but a monitoring network for future early detection is suggested.

Open-File Report↗
USGS1982

Reconnaissance geology of the Manjamah Quadrangle, sheet 18/41 A, Kingdom of Saudi Arabia

The Manjamah quadrangle (sheet 18/41 A) lies between lat 18?30' and 19?00' N. and long 41?00' and 41?30' E. and encompasses an area of 2,932 km2, of which about half is land and the remainder covered by the Red Sea. The geologic formations exposed in the quadrangle comprise Precambrian layered and intrusive rocks,. Tertiary layered rocks and gabbro dikes, and. Quaternary basaltic lavas, pyroclastic rocks, and surficial deposits. The Precambrian rocks are layered metasedimentary and metavolcanic rocks that have been assigned to the Baish and Bahah groups. These rocks are cut by Precambrian biotite quartz monzonite and by Miocene gabbro dikes that were intruded during the initial stages of the opening of the Red Sea rift. Tuffaceous siltstone of the Baid formation was also deposited during the Miocene, followed in the Pliocene by the polymict conglomerate of the Bathan formation. The Quaternary rocks include basalt that was extruded during a continuation of the opening of the Red Sea rift, after uplift of the escarpment parallel with the Red Sea but before the Holocene erosional cycle. The greater part of the land area of the quadrangle is covered by Quaternary coastal, pediment, and alluvial deposits of various kinds associated with the deltaic mouths of Wadi Hall and Wadi Yiba and their tributaries and with the development of fringing reefs and islands. The area also contains extensive Quaternary eolian deposits. The economic potential of the quadrangle lies essentially in the agricultural value .of its flood-plain deposits, which are frequently refreshed during flooding with the products of weathering and erosion of the Precambrian rocks in the valleys of Wadi Hal i and Wadi Yiba; coral reefs could possibly provide raw material for use in a cement industry, if any such industry were ever required in this area.

Open-File Report↗
USGS1982

Reconnaissance geology of the Jabal Hashahish Quadrangle, sheet 17/41 B, Kingdom of Saudi Arabia

The Jabal Hashahish quadrangle (sheet 17/41 B) lies between lat 17?30' and 18?00' N. and long 41?30' and 42?00' E. and encompasses an area of 2,950 km2, of which only about 600 km2 is land; the remainder is covered by the Red Sea. The geologic formations exposed in the quadrangle include Precambrian layered and intrusive rocks, Tertiary gabbro dikes, Quaternary basaltic lavas and pyroclastic rocks, and Quaternary surficial deposits. The Precambrian rocks include layered sedimentary and volcanic rocks that have been assigned to the Baish, Bahah, and Ablah groups. These rocks have been folded, metamorphosed, and invaded by intrusions. They are cut by Miocene gabbro dikes that were intruded during the initial stages of the opening of the Red Sea rift. The Quaternary rocks also include basalt that was extruded during a continuation of that opening, after the uplift that formed the escarpment that parallels the eastern shore of the Red Sea, but before the Holocene erosional cycle. Coastal, pediment, and alluvial, and eolian deposits of various kinds are also of Quaternary age. The economic potential of the quadrangle lies essentially in the agricultural value of its flood-plain deposits, though these are not so widely used as those in Wadi Hali and Wadi Yiba, which are located in the Manjamah quadrangle. The coral reefs possibly could provide raw materials for use in a cement industry, if any such industry were ever required in this area.

Open-File Report↗
USGS1982

High-resolution seismic-reflection profiles and sidescan-sonar records collected on Block Island Sound by U.S. Geological Survey, R/V ASTERIAS, cruise AST 81-2

Cruise AST 81-2 was conducted aboard the R/V ASTERIAS during September 10-18, 1981, in Block Island Sound by the U.S. Geological Survey. It was funded in part by the Connecticut Geological and Natural History Survey. The purpose of the study was to define and map the geology and shallow structure, to determine the geologic framework and late Tertiary to Holocene history, and to identify and map any potential geologic hazards of Block Island Sound. The survey was conducted using an EG&G Uniboom seismic system and an EDO Western sidescan-sonar system. Seismic signals were band-passed between 400 and 4,000 Hz and were recorded at a quarter-second sweep rate. Sidescan sonographs were collected at a 100-m scan range to each side of the ship track. In all, 702 km of seismic-reflection profiles and 402 km of sidescan-sonar records were collected. Navigation was by Loran-C, and the ship position was recorded at 5-minute intervals. Seismic-reflection profiling is continuous and good in quality. Sidescan-sonar records are varied in quality; coverage was intermittent and eventu­ally terminated owing to difficulties with the recorder. Original records can be seen and studied at the U.S. Geological Survey Data Library at Woods Hole, MA 02543. Microfilm copies of the seismic-reflection pro­files and the sidescan sonographs can be purchased only from the National Geo­physical and Solar-Terrestrial Data Center, NOAA/EDIS/NGSDC, Code D621, 325 Broad­way, Boulder, CO 80303 (telephone 303-497-6338).

Open-File Report↗
USGS1982

Reconnaissance geology of the Jabal Shaqran Quadrangle, sheet 17/44 B, Kingdom of Saudi Arabia

The Jabal Shaqran quadrangle lies in the southeastern Asir province, mostly within the westernmost part of the Rub al Khali desert, and is largely covered by Quaternary deposits. Proterozoic crystalline rocks are exposed as inselbergs or rock pediment surfaces along the western border of the quadrangle. The crystalline basement is metavolcanic rock intruded by plutonic to hypabyssal rocks consisting of diorite and gabbro, biotite tonalite gneiss, biotite-hornblende monzogranite, biotite-sodic amphibole granite, and syenogranite to quartz syenite, listed in the inferred order of emplacement. Rhyolite-dacite fels, associated with andesitic to basaltic metavolcanic flow rocks and minor amphibolite, is interpreted to have resulted from metasomatic alteration of the flow rocks during emplacement of granitic plutons. The Wajid Sandstone, of Cambrian to Ordovician age, is largely a coarse-grained quartz arenite with pebbly phases; common crossbedds indicate north-northwest to north-northeast directions of sand transport. Beds are cemented by iron oxide, carbonate, and minor quartz. The Wajid Sandstone is exposed only in the northwestern and northern parts of the quadrangle. Quaternary deposits record a climate that became increasingly more arid. They include Holocene and Pleistocene(?) alluvial and fluvial deposits of sand, gravel, and silt, minor carbonate crusts, and eolian sand and silt. Gravel terraces and gravel plains less than 10 m above the present major wadi channels are widespread and commonly are overlain by marly silt along the wadis. Between major wadis, which discharge into the Rub al Khali basin, gravel-topped surfaces are partly covered by a complex of low, sinuous, discontinuous, generally northwest trending transverse sand dunes. Normal to this trend, higher and more extensive linear dunes and dune complexes, including seif (irq) dunes as high as 50 m, have encroached southwestward. The transverse and linear dunes may represent two stages of advance separated by a pluvial cycle. Studies of aerial photographs indicate that the dunes have not changed appreciably in shape or size between 1951 and 1959, although some seif dunes have advanced their leading edges 15 to 25 m. No potentially economic mineral resources other than sand and gravel were found.

Open-File Report↗
USGS1982

Potential effects of surface coal mining on the hydrology of the Cook Creek area, Ashland coal field, southeastern Montana

The Cook Creek area of the Ashland coal field contains large reserves of Federally owned coal that have been identified for potential lease sale. A hydrologic study has been conducted in the potential lease area to describe existing hydrologic systems and to assess potential impacts of surface coal mining on local water resources. Hydrogeologic data collected from wells, springs, and drill holes indicate that shallow aquifers exist within the Tongue River Member of the Fort Union Formation (Paleocene age) and within valley alluvium (Pleistocene and Holocene age). Shallow aquifers within the Tonge River Member include coal beds, clinker, and lenses of sandstone and siltstone. The Knobloch coal bed, a principal shallow aquifer used for livestock watering in the area, averages about 55 feet in thickness and is completely saturated throughout most of its extent. Coarse alluvial deposits are the most productive aquifers and are a major source of stock water in the Cook Creek basin. Surface-water resources are limited to the upstream reach part of Cook Creek, which flows intermittently. The downstream reach part of Cook Creek, plus all other small drainages that originate in the study area, are ephemeral. Mining of the Knoblock and Sawyer coal beds would remove two alluvial springs, one bedrock spring, and two wells, which are all used for watering of livestock. The potentiometric surface within the Knobloch coal aquifer and the alluvial aquifer in the downstream part of the Cook Creek basin would be lowered during mining. Lowered water levels in these aquifers might substantially affect water levels in five wells outside the mine boundary. After mining, the alluvial aquifer downgradient from the mine area might show a long-term degradation in water quality as a result of leaching of soluble salts from overburden materials used to backfill mine pits. Although mining would alter the existing hydrologic systems and remove several springs and shallow wells, alternative ground-water supplies are available that could be developed to replace those lost by mining. (USGS)

Open-File Report↗
USGS1982

Water resources of Rockland Basin, southeastern Idaho

Rockland basin comprises about 320 sq mi of the Snake River drainage in southeastern Idaho. Mountain ranges bordering the basin are composed predominantly of limestone and are complexly faulted. Major aquifers include Holocene alluvium, Quaternary-Tertiary volcanic rocks, and Tertiary sedimentary rocks. Groundwater occurs under water table conditions except where it is locally confined. Groundwater discharges to springs in the Deep Creek Mountains and maintains perennial streamflow. Near the mouth of Rock Creek, groundwater movement is northward toward the Snake River. Underflow is estimated to be 51,000 acre-ft/yr. Total water yield available to Rockland basin is estimated to be 5.0 in. (85,000 acre-ft) of the estimated 17.3 in. of annual precipitation. Evapotranspiration ranges from 9.9 to 17 in./yr, depending, in part, on altitude of the land surface. An estimated 12,000 acre-ft of surface water and 3,500 acre-ft of groundwater are used annually for irrigation. Less than 100 acre-ft of water is used for public supply, domestic, and stock supplies. East Fork Rock Creek supplies the most surface water for irrigation of agricultural lands. At the present (1980) state of groundwater development in Rockland basin, streams and aquifers are hydraulically connected. Pumping of groundwater in increased quantities from wells near streams will affect groundwater movement and may diminish streamflow. There are no long-term regional water table declines at present. Continued water level monitoring of selected wells may aid in documenting effects of future management practices on the groundwater system.

idaho↗
USGS1982

Geohydrology of principal aquifers in the Republican River basin, Kansas

Principal aquifers in the Republican River basin in Kansas are unconsolidated alluvial deposits. One such aquifer is formed by the Ogallala Formation of Miocene age which covers most of the western part of the area. Because saturated thickness of the aquifer decrease northeastward, maximum yields to irrigation wells decrease in that direction from 2,000 to 500 gallons per minute. The Grand Island Formation of Pleistocene age occurs in an ancestral channel of the Republican River in northeast Jewell and northwest Republic counties. The maximum yield to wells from this aquifer was estimated to be 2,000 gallons per minute. Quaternary alluvium of Pleistocene and Holocene age occurs in most major stream valleys. The aquifer in the Republican River valley yields as much as 2,000 gallons per minute to irrigation wells. Water levels in the Ogallala Formation commonly declined from 5 to 40 feet during 1950-77 as a result of irrigation withdrawals. Recharge from irrigation by stream diversions have raised water levels as much as 25 feet in the Grand Island Formation and as much as 15 feet in the Quaternary alluvium of the Prairie Dog Creek valley. (USGS)

Open-File Report↗