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USGS1996

Water resources of the Wind River Indian Reservation, Wyoming

Existing data were used in conjunction with onsite measurements to evaluate the water resources on the Wind River Indian Reservation, Wyoming. The reservation is located mainly in the Wind River drainage basin. Ground water is used for public- supply, domestic, agricultural, and industrial purposes, and potentially for irrigation. Deposits of Quaternary age provide water for domestic and public-supply uses. Median well yields from different types of Quaternary deposits ranged from 6 to 20 gallons per minute. The Wind River Formation of Tertiary age is a major source of water for domestic and public-supply uses; well yields ranged from 0.1 to 350 gallons per minute. For the Tensleep Sandstone and Madison Limestone of Paleozoic age, wells might yield as much as 1,000 gallons per minute. The dissolved-solids concentration of water from the Little Wind River and Popo Agie River flood-plain alluvium near mountains was generally less than 400 mg/L (milligrams per liter), but with increasing distance from mountains, the range was about 600 to about 750 mg/L. Dissolved-solids concentrations of water in the Wind River Formation ranged from 211 to 5,110 mg/L. Streams provide most water used for irrigation. Discharge records from streamflow-gaging stations indicate flow characteristics of streams on the reservation are extremely variable. Average annual runoff was 122 to 1,150 acre-feet per square mile on perennial streams with gaging stations. Near the mountains, most perennial streams had dissolved-solids concentrations less than 200 mg/L, and with increasing distance from the mountains, concentrations were about 400 to 600 mg/L.

Water-Resources Investigations Report↗

USGS1999

Geohydrology of monitoring wells drilled in Oasis Valley near Beatty, Nye County, Nevada, 1997

Twelve monitoring wells were installed in 1997 at seven sites in and near Oasis Valley, Nevada. The wells, ranging in depth from 65 to 642 feet, were installed to measure water levels and to collect water-quality samples. Well-construction data and geologic and geophysical logs are presented in this report. Seven geologic units were identified and described from samples collected during the drilling: (1) Ammonia Tanks Tuff; (2) Tuff of Cutoff Road; (3) tuffs, not formally named but informally referred to in this report as the 'tuff of Oasis Valley'; (4) lavas informally named the 'rhyolitic lavas of Colson Pond'; (5) Tertiary colluvial and alluvial gravelly deposits; (6) Tertiary and Quaternary colluvium; and (7) Quaternary alluvium. Water levels in the wells were measured in October 1997 and February 1998 and ranged from about 18 to 350 feet below land surface. Transmissive zones in one of the boreholes penetrating volcanic rock were identified using flowmeter data. Zones with the highest transmissivity are at depths of about 205 feet in the 'rhyolitic lavas of Colson Pond' and 340 feet within the 'tuff of Oasis Valley.'

Nevada↗

USGS1999

Ground-water quality in the eastern part of the Silurian-Devonian and upper Carbonate aquifers in the eastern Iowa basins, Iowa and Minnesota, 1996

Ground-water samples were collected from 33 domestic wells to assess the water quality of the eastern part of the Silurian-Devonian and Upper Carbonate aquifers in the Eastern Iowa Basins National Water-Quality Assessment Program study unit. Samples were collected during June and July 1996 and analyzed for major ions, nutrients, pesticides and pesticide metabolites, volatile organic compounds, tritium, radon222, and environmental isotopes. Calcium, magnesium, and bicarbonate were the dominant ions in most samples and were likely derived from the solution of carbonate minerals (calcite and dolomite) present in the aquifer materials. The dominance of sulfate in samples from several wells suggests the dissolution of evaporite minerals. Ammonia and orthophosphorus were the most commonly detected nutrients. Nitrate was detected in about half of the samples and exceeded the U.S. Environmental Protection Agency maximum contaminant level (10 milligrams per liter) in 6 percent of samples. Atrazine and metolachlor were the only pesticides detected and were present in 18 percent and 12 percent of samples, respectively. Alachlor ethanesulfonic acid and deethylatrazine were the most commonly detected pesticide metabolites and were present in 16 percent and 9 percent of samples, respectively. Radon-222 was detected in all samples, and 47 percent had concentrations in excess of the U.S. Environmental Protection Agency previously proposed maximum contaminant level (300 picocuries per liter). Radon-222 concentrations were significantly higher in samples from wells that produced recently recharged water. This relation suggests that uranium-bearing glacial deposits (Schumann, 1993) may be a source of radon-222 in the underlying aquifers. The presence of regional confining units and thick overlying Quaternary-age deposits have an effect on water quality in the Silurian-Devonian and Upper Carbonate aquifers in the study area. Tritium-based ground-water ages were significantly older, and dissolved-solids concentrations were significantly higher in relatively well protected areas (where the aquifers are overlain by a bedrock confining unit or more than 100 feet of Quaternary-age deposits). Ammonia concentrations were significantly higher in relatively well protected areas and in samples from wells that produced older water. Higher ammonia concentrations also were observed in ground water with dissolved-oxygen concentrations of 0.5 milligram per liter or less, allowing for the anaerobic reduction of nitrate to ammonia. Nitrate concentrations were significantly higher in relatively poorly protected areas (where the aquifers are not overlain by a bedrock confining unit or are overlain by less than 100 feet of Quaternaryage deposits) and in samples from wells that produced recently recharged water. Pesticide and metabolite concentrations were significantly higher in samples from wells that produced recently recharged water. Atrazine, metolachlor, and deethylatrazine were not detected in any samples from relatively well protected areas of the aquifers.

Iowa, Minnesota↗

USGS1999

Hydrogeology of the surficial aquifer in the vicinity of a former landfill, Naval Submarine Base Kings Bay, Camden County, Georgia

Neogene and Quaternary sediments constitute the surficial aquifer beneath the study area; in descending order from youngest to oldest these include-the Quaternary undifferentiated surficial sand and Satilla Formation; the Pliocene(?) Cypresshead Formation; and the middle Miocene Coosawhatchie Formation. Beneath the surficial aquifer, the upper Brunswick aquifer consists of part of the lower Miocene Marks Head Formation. The surficial aquifer is divided into three water-bearing zones on the basis of lithologic and geophysical properties of sediments, hydraulic-head differences between zones, and differences in ground-water chemistry. The shallowest zone-the water-table zone-consists of medium to fine sand and clayey sand and is present from land surface to a depth of about 77 feet. Below the water-table zone, the confined upper water-bearing zone consists of medium to very coarse sand and is present from a depth of about 110 to 132 feet. Beneath the upper water-bearing zone, the confined lower water-bearing zone consists of coarse sand and very fine gravel and is present from a depth of about 195 to 237 feet. Hydraulic separation is suggested by differences in water chemistry between the water-table zone and upper water-bearing zone. The sodium chloride type water in the water-table zone differs from the calcium bicarbonate type water in the upper water-bearing zone. Hydraulic separation also is indicated by hydraulic head differences of more than 6.5 feet between the water-table zone and the upper water-bearing zone. Continuous and synoptic water-level measurements in the water-table zone, from October 1995 to April 1997, indicate the presence of a water-table high beneath and adjacent to the former landfill-the surface of which varies about 5 feet with time because of recharge and discharge. Water-level data from clustered wells also suggest that restriction of vertical ground-water flow begins to occur at an altitude of about 5 to 10 feet below sea level (35 to 40 feet below land surface) in the water-table zone because of the increasing clay content of the Cypresshead Formation.

Georgia↗

USGS1959

Ground-water conditions and storage capacity in the San Joaquin Valley, California

The San Joaquin Valley includes roughly the southern two-thirds of the Great Central Valley of California. It is a broad structural trough surrounded by mountains. The northern part of the valley drains through the San Joaquin River northward to San Francisco Bay ; the southern part of the valley normally is a basin of interior drainage tributary to evaporation sumps in the trough of the valley, chiefly Tulare and Buena Vista Lake beds. In years of normal discharge most of the streamflow in the southern part of the valley not diverted for irrigation finds its way to Tulare and Buena Vista Lake beds. In the historic past, however, during years of heavy floods the low divide between Buena Vista and Tulare Lakes and the low divide between Tulare Lake and the San Joaquin River were overtopped and through-flowing drainage occurred over the full length of the valley. Because the Tulare Lake bed is the lowest point and also the largest sump, this whole basin of interior drainage is commonly referred to as the Tulare Lake drainage basin. Average annual precipitation ranges from more than 15 inches in the north- eastern part of the valley to less than 4 inches in the southwestern part. The precipitation decreases from north to south and from east to west across the valley. Streamflow, the critical quantity in the water supply, depends almost wholly on the amount and distribution of precipitation in the Sierra Nevada to the east. Much of this precipitation falls as snow, and the snowpack acts as a natural reservoir retaining much of the annual runoff until late spring and early summer. The mean seasonal runoff to the San Joaquin Valley is nearly 10 million acre- feet, of which about two-thirds is tributary to the San Joaquin River; the remaining third is tributary to Tulare Lake drainage basin. In 1952 about 8.5 million acre-feet of surface water was diverted for irrigation. Withdrawals of ground water for irrigation in 1952 approximated 7.5 million acre-feet. The surface of the San Joaquin Valley is not a featureless plain but is characterized by various types of physiography such as dissected uplands, low alluvial plains and fans, river flood plains and channels, and overflow lands and lake bottoms. The dissected uplands fringe the valley along its mountain borders. They are underlain by unconsolidated to semiconsolidated continental deposits of late Tertiary and early Quaternary age which have been moderately tilted and folded. The topography of these uplands ranges from deeply dissected hill land having a relief of several hundred feet to gently rolling land whose relief Is only a few feet. The low plains and fans border the dissected uplands along their valley- ward margins. They are generally fiat to gently undulating and featureless and are underlain by undeformed to slightly deformed alluvial deposits of Quaternary age. The river flood plains and channels lie along the San Joaquia and Kings Rivers in the axial part of the valley and along the major east-side streams. Where the rivers are incised below the general land surface, the flood plains are well defined; but in the axial trough of the valley, where the rivers are flanked by low-lying overflow lands, the flood-plain and channel deposits are confined to the stream channel and to the natural levees that slope away from the river. Overflow lands and lake bottoms include the historic beds of Tulare, Buena Vista, and Kern Lakes in the southern part of the valley, and the low-lying lands in the axial trough between the low alluvial plains and fans and the natural levees of the San Joaquin River and its major tributaries. They are level and featureless and are underlain by lake and swamp deposits of Recent age. The San Joaquin Valley is a great structural downwarp between the tilted block of the Sierra Nevada on the east and the complexly folded and faulted Coast Ranges on the we

Water Supply Paper↗

USGS1959

Geology and ground-water resources of the upper Lodgepole Creek drainage basin, Wyoming, with a section on chemical quality of the water

The principal sources of ground-water supply in the upper Lodgepole Creek drainage basin-the part of the basin west of the Wyoming-Nebraska State line-are the Brule formation of Oligocene age, the Arikaree formation of Miocene age, the Ogallala formation of Pliocene age, and the unconsolidated deposits of Quaternary age. The Brule formation is a moderately hard siltstone that generally is not a good aquifer. However, where it is fractured or where the upper part consists of pebbles of reworked siltstone, it will yield large quantities of water to wells. Many wells in the Pine Bluffs lowland, at the east end of the area, derive water from the Brule. The Arikaree formation, which consists of loosely to moderately cemented fine sand, will yield small quantities of water to wells but is not thick enough or permeable enough to supply sufficient water for irrigation. Only a few wells derive water from it. The Ogallala formation consists of lenticular beds of clay, silt, sand, and gravel which, in part, are cemented with calcium carbonate. Only the lower part of the formation is saturated. Nearly all the wells in the upland part of the area tap the Ogallala, but they supply water in amounts sufficient for domestic and stock use only. Two of the wells have a moderately large discharge, and other wells of comparable discharge probably could be drilled in those parts of the upland where the saturated part of the Ogallala is fairly thick. Most of the unconsolidated deposits of Quaternary age are very permeable and, where a sufficient thickness is saturated, will yield large quantities of water to wells. These deposits are a significant source of water supply in the southeastern part of the area. The Chadron formation of Oligocene age, which underlies the Brule formation, is a medium- to coarse-grained sandstone where it crops out in the Islay lowland. No wells tap the Chadron, but it probably would yield small quantities of water to wells. It lies at a relatively shallow depth beneath most of the Islay lowland, near the west end of the area, and at a depth of about 800 feet beneath the Pine Bluffs lowland. In the latter area it probably is finer grained and may not be permeable enough to yield water to wells. All the ground water in the area is derived from precipitation. It is estimated that about 5 percent of the precipitation infiltrates directly to the zone of saturation. The remainder either is evaporated immediately; is retained by the soil, later to be evaporated or transpired; or is discharged by overland flow to the surface drainage courses. Most of the water that reaches the surface drainage courses eventually sinks to the zone of saturation or is evaporated. The slope of the water table and the movement of ground water are generally eastward. The depth to water ranges from less than 10 feet in parts of the valley to about 300 feet in the upland areas. In much of the Pine Bluffs lowland, the depth to water is less than 50 feet. Ground water not pumped from wells within the area is discharged by evapotranspiration where the water table is close to the land surface, by outflow into streams, or by underflow eastward beneath the State line. The chemical quality of ground water from the principal sources is remarkably uniform, and the range in concentration of dissolved constituents is narrow. In general, the water is of the calcium bicarbonate type, is hard (hardness as CaC03 is as high as 246 ppm), and contains less than about 400 parts per million of dissolved solids, which is a moderate mineralization. Silica constitutes a large proportion of the dissolved solids. The water is suitable for irrigation and, except for iron in water from some wells that tap the Ogallala formation, meets the drinking water standards of the U.S. Public Health Service for chemical constituents. Because the water is siliceous, alkaline, and hard, it is unsuitable for many industrial uses unless treated.

Water Supply Paper↗

USGS1961

Geologic control of mineral composition of stream waters of the eastern slope of the Southern Coast Ranges, California

Chemical analyses of waters of streams that drain the semiarid eastern slope of the southern Coast Ranges in California demonstrate that differences in the anion composition, especially in the ratio of bicarbonate to sulfate, are related chiefly to the lithologic character of the rocks exposed in the tributary drainage area. Where more than hall the drainage area of a typical eastern-slope stream is underlain by clastic marine sedimentary rocks of Jurassic and Cretaceous age, bicarbonate generally predominates over sulfate; the ratio of bicarbonate to sullate, both expressed in equivalents per million, in samples of the streams at low-flow stage ranges from 0.8 to 6. Conversely, where more than hall the drainage area is underlain by marine and continental deposits of Tertiary age and continental deposits of Quaternary age, sulfate predominates over bicarbonate, and the ratio of bicarbonate to sulfate in samples taken during the low-flow stage ranges from 0.02 to 0.7. Organic siliceous marine shale of Tertiary age deposited in a reducing environment is probably the primary source of sullate in the region. Secondary deposits of sulfate minerals, chiefly gypsum, which are abundant in the continental deposits of late Tertiary and Quaternary age, also contribute sullate to the stream waters.

Water Supply Paper↗

USGS1969

Ground-water resources of the Wind River Indian Reservation, Wyoming

The area of this investigation is in the western part of the Wind River Basin and includes parts of the Absaroka, Washakie, Wind River, and Owl Creek Mountains. The purposes of the study were to determine the general hydrologic properties of the rocks in the area and the occurrence and quality c f the water in them. Structurally, the area is a downfolded basin surrounded by upfolded mountain ranges. Igneous and metamorphic rocks of Precambrian age are exposed in the mountains: folded sedimentary rocks representing all geologic periods, except the Silurian, crop out along the margins of the basin; and relatively flat-lying Tertiary rocks are at the surface in the central part of the basin. Surficial sand and gravel deposits of Quaternary age occur along streams and underlie numerous terraces throughout the basin. The potential yield and quality of water from most rocks in the area are poorly known, but estimates are possible, based on local well data and on data concerning similar rocks in nearby areas. Yields of more than 1,000 gpm are possible from the rocks comprising the Bighorn Dolomite (Ordovician), Darby Formation (Devonian), Madison Limestone (Mississippian), and Tensleep Sandstone (Pennsylvanian). Total dissolved solids in the water range from about 300 to 3,000 ppm. Yields of as much as several hundred gallons per minute are possible from the Nugget Sandstone (Jurassic? and Triassic?). Yields of 20 gpm or more are possible from the Crow Mountain Sandstone (Triassic) and Sundance Formation (Jurassic). Dissolved solids are generally high but are less than 1,000 ppm near outcrops in some locations. The Cloverly and Morrison (Cretaceous and Jurassic), Mesaverde (Cretaceous) and Lance(?) (Cretaceous) Formations may yield as much as several hundred gallons per minute, but most wells in Cretaceous rocks yield less than 20 gpm. Dissolved solids generally range from 1,000 to 5,000 ppm but may be higher. In some areas, water with less than 1,000 ppm dissolved solids may be available from the Cloverly and Morrison Formations. Tertiary rocks yield a few to several hundred gallons per minute and dissolved solids generally range from 1,000 to 5,000 ppm. Wells in the Wind River Formation (Eocene) yield about 1.-500 gpm of water having dissolved solids of about 200-5,000 ppm. Yields of a few to several hundred gallons per minute are available from alluvium (Quaternary). Dissolved solids range from about 200 to 5,000 ppm. Many parts of the Wind River Irrigation Project have become waterlogged. The relation of drainage problems to geology and the character and thickness of rocks in the irrigated areas are partly defined by sections drawn on the basis of test drilling. The drainage-problem areas are classified according to geologic similarities into five general groups: flood plains, terraces, underfit-stream valleys, slopes, and transitional areas. Drainage can be improved by open drains, buried drains, relief wells, and pumped wells or by pumping from sumps or drains. The methods that will be most successful depend on the local geologic and hydrologic conditions. In several areas, the most effective means of relieving the drainage problem would be to reduce the amount of infiltration of water by lining canals and ditches and by reducing irrigation water applications to the optimum. Water from underground storage in alluvium could supplement water from surface storage in some areas. A few thousand acre-feet of water per square mile are in storage in some of the alluvium. The use of both surface and underground storage would reduce the need for additional surface-storage facilities and also would alleviate drainage problems in the irrigated areas.

Water Supply Paper↗

USGS1964

Ground water in folded Cretaceous sandstone of the Bhachau area, Kutch, India, with reference to the Kandla Port water supply

This report is based on an investigation of the availability of ground-water supplies in the Bhachau area for the nearby Kandla Port and township development undertaken by the Government of India. This seaport lies on an estuary of the Gulf of Kutch in western India and in the eastern part of the State of Kutch. The fieldwork on the investigation was carried on from November 1952 through April 1953 with continuing hydrologic observations through 1954-55. The fieldwork included: geologic mapping and delimitation of the principal aquifers of the region; preparation of water-table maps; a detailed inventory of existing wells and springs; observations of significant water table fluctuations; preparation of isobicarb, isochlor and isosulf maps to show the areal distribution of ground-water salinity. The Bhachau area includes about 116 square miles in eastern Kutch and lies in a belt of semiarid low-latitude steppes. The mean annual rainfall is about 15 inches, most of which falls from late June to late September during the southwest monsoon. The area includes a central sandy upland ranging from about 100 to 250 feet above sea level ; a northern lowland of between about 50 to 125 feet altitude that slopes north to the Great Rann of Kutch; a belt of low buttes and discontinuous ridges ranging from about 200 to 275 feet above sea level; and southern lowland which slopes in a southerly to southeasterly direction from an altitude of about 125 feet to 25 feet or less near the Gulf of Kutch. The principal streams are Kageshwar Vokra and Kara Vokra which drain north to the Great Rann and Kotwala Vokra and Dalwala Vokra which drain south toward the Gulf of Kutch. The rocks of the Bhachau area include nonmarine and marine sediments of Mesozoic, Tertiary, and Quaternary age and volcanic rocks of late Mesozoic to early Tertiary age. The oldest rocks in the area are medium- to coarse-grained white to buff current-bedded friable sandstone with occasional partings of white silty shale of the Upper Bhuj series that has been assigned to the Early Cretaceous. The soft friable sandstone of the Upper Bhuj series constitutes the most productive ground-water reservoir in the Bhachau area. At present (1955) there are nine irrigated tracts for which water is obtained from dug wells less than 90 feet deep in the Upper Bhuj. These wells are worked by bullocks and 'motes' (leather bags) at withdrawal rates ranging from about 6,000 to 24,000imperial gallons per day; however, many existing individual wells if equipped with mechanical pumps are capable of yielding 100,000 gallons per day. The Deccan trap of Late Cretaceous to Eocene age occurs in a sequence of basaltic lava flows in the Bhachau area, but trap dikes, sills and plugs that are common in other parts of Kutch have not been observed in the area. Laterite of probable Eocene age is extensive at the top of the Deccan trap, and in places where the lava flows are thin the parent rock has been almost completely lateritized. The Deccan lava flows or the laterite, where the trap is absent, rest disconformably on the Upper Bhuj. No wells have been observed in the Deccan trap of the Bhachau area, but it is possible that locally small supplies of good water may be obtained from these rocks. The Tertiary sediments, which are assigned to the Manchhar series of Pliocene age, generally rest on the laterite or the Deccan trap ; but where both are absent, the Manchhar rests directly on the Upper Bhuj. The Manchhar series includes massive reddish-brown gypseous clay shales, laminated gray siltstones, some limestone, mottled sandstone, and laterite trap gravel. Only meager supplies of brackish water are obtained from wells in these sediments. Along the channels of Kotwala, Dalwala, Kageshwar, and Kara Vokras are narrow bands of unconsolidated coarse sand with fine gravel of Quaternary age. No wells were observed in these deposits, but it is possible that locally they may contain small supplies of bracki

Water Supply Paper↗

USGS1965

Water-supply potential from an asphalt-lined catchment near Holualoa Kona, Hawaii

The Jenkins-Whitesburg area includes approximately 250 square miles In Letcher and Pike Counties in the southeastern part of the Eastern Coal Field. In this area ground water is the principal source of water for nearly all rural families, most public supplies, several coal mines and coal processing plants, and one bottling plant. The major aquifers in the Jenkins-Whitesburg area are the Breathitt and Lee Formations of Pennsylvanian age. Other aquifers range in age from Devonian to Quaternary but are not important in this area because they occur at great depth or yield little or no water. The Breathitt Formation occurs throughout the area except along the crest and slopes of Pine Mountain and where it is covered by unconsolidated material of Quaternary age. The Breathitt Formation consists of shale, sandstone, and lesser amounts of coal and associated underclay. The yield of wells penetrating the Breathitt Formation ranges from less than 1 to 330 gallons per minute. Well yield is controlled by the type and depth of well, character of the aquifer, and topography of the well site. Generally, deep wells drilled in valleys of perennial streams offer the best potential for high yields. Although enough water for a minimum domestic supply (more than 100 gallons per day) may be obtained from shale, all high-yielding wells probably obtain water from vertical joints and from bedding planes which are best developed in sandstone. About 13 percent of the wells inventoried in the Breathitt Formation failed to supply enough water for a minimum domestic supply. Most of these are shallow dug wells or drilled wells on hillsides or hilltops. Abandoned coal mines are utilized as large infiltration galleries and furnish part of the water for several public supplies. The chemical quality of water from the Breathitt Formation varies considerably from place to place, but the water generally is acceptable for most domestic and industrial uses. Most water is a calcium magnesium bicarbonate or sodium bicarbonate type, and nearly all sampled water contained enough iron to stain cooking and laundry utensils. The water ranged from soft to very hard, and only one well in the Breathitt Formation produced salty water. The absence of salty water may be due to abundant fractures which are associated with the Pine Mountain fault and which have allowed fresh water to enter the formation. The Lee Formation underlies the Cumberland Mountain section and is exposed along the crest and southeast slope of Pine Mountain. The Lee Formation consists of massive sandstone and conglomerate with thin beds of shale and a few thin coal seams. Although the Lee Formation is tapped by only a few wells in this area, it is potentially an important aquifer. Wells penetrating the Lee Formation in the Cumberland Mountain section would probably yield water under artesian pressure. Unlike most water from the Lee Formation in other part.3 of eastern Kentucky, all water from the Lee Formation in the Jenkins-Whitesburg area is fresh. All water from the Lee Formation contained more than 0.3 parts per million of iron and ranged from soft to moderately hard.

Water Supply Paper↗

USGS1967

Geology and ground water of the Savannah River Plant and vicinity, South Carolina

The area described in this report covers approximately 2,600 square miles in west-central South Carolina and includes the site of the Savannah River Plant, a major production facility of the U.S. Atomic Energy Commission. The climate, surface drainage, and land forms of the study area are typical of the southern part of the Atlantic Coastal Plain. Precipitation is normally abundant and fairly evenly distributed throughout the year, and the mean annual temperature is moderately warm (64?F). The major streams that drain the area (the Savannah, Salkehatchie, and Edisto Rivers) have low gradients and flow in a southeasterly direction toward the Atlantic Ocean. Surface features of the area include narrow, flat-bottomed, steep-sided valleys and broad gently rolling interfluvial areas. Those parts of the Coastal Plain included within the report area can be subdivided into the Aiken Plateau, the Congaree Sandhills, and the Coastal Terraces. The area is underlain by a sequence of unconsolidated and partly consolidated sediments of Late Cretaceous, Tertiary, and Quaternary age. The unconsolidated sediments were deposited unconformably on a basement of igneous and metamorphic rocks of Precambrian and Paleozoic age and sedimentary rocks of Triassic age. The basement rocks are similar to the granite-diorite complex of the Charlotte Belt, the metamorphosed rocks of the Carolina Slate Belt, and the consolidated sediments of the Newark Group. The unconsolidated sediments strike about N. 60 ? E. and dip 6-20 feet per mile to the southeast. They form a wedge-shaped mass that increases in thickness toward the southeast to slightly more than 1,200 feet in the vicinity of Allendale, S.C., on the southeast or downdip side of the study area. The oldest or lowermost unconsolidated sedimentary unit, the Tuscaloosa Formation of Late Cretaceous age, is overlain in the subsurface by beds that are also probably Late Cretaceous in age and that herein are named the Ellenton Formation. The Upper Cretaceous deposits are, in turn, overlain by the, McBean Formation and the Congaree(?) Formation of middle Eocene age, the Barnwell Formation of late Eocene age, the Hawthorn Formation of early and middle Miocene age, and by fluvial and marine(?) terrace deposits of Pliocene(?), Pleistocene, and Recent age. In the mapped area, the Congaree(?) Formation includes undifferentiated rocks (mostly Congaree and Barnwell Formations and some Mcbean outliers). (See map explanation.) Structurally, the Upper Cretaceous sediments are overlapped to the northwest by Tertiary deposits. A preliminary geologic map of the general area is included in the report. The principal aquifer in the area is composed of the beds of medium to coarse sand and gravel contained in the Tuscaloosa and Ellenton Formations. Subordinate aquifers include deposits of sand and limestone of Tertiary and Quaternary age. The ground water in the principal aquifer occurs under water-table conditions in the outcrop area of the Tuscaloosa Formation in the northern and western parts of the study area, but it is under artesian pressure downdip in the southern and eastern parts of the study area. Contours drawn on the piezometric surface of the water in the principal aquifer indicate that water is recharged to the aquifer mainly by leakage through the overlying Tertiary formations. Likewise, the piezometric contours show that the outcrop area of the Tuscaloosa Formation functions chiefly as an area of discharge. Doubtless, water is also discharged from the aquifer by moving downdip to areas near the coast where the prevailing hydraulic gradient may favor the upward leakage of water through the upper confining beds. The hydraulic properties of the principal aquifer were determined by a series of pumping tests. The results indicate that the aquifer is highly productive and could supply 15 million gallons per day in the vicinity of the Savannah River Plant without exceeding the available drawdown.

South Carolina↗

USGS1984

Availability and quality of water from the Dakota aquifer, northwest Iowa

The Dakota aquifer in northwest Iowa consists of sandstones in the Dakota Formation. It underlies most of the study area and is the most extensive source of ground water in the area. Individual sandstone beds are from less than 10 to more than 150 feet thick. The cumulative thickness of sandstone is more than 200 feet throughout much of the area. The aquifer is confined by overlying Cretaceous limestone and shale, Quaternary glacial deposits and loess. The underlying confining material is shale of the Dakota Formation, undifferentiated Paleozoic age rocks, or Precambrian crystalline rock. Water flows through the aquifer from the northcentral part of the study area to the east, south and southwest. Recharge is dominantly by infiltration from the land surface through the confining materials. Discharge is to underlying Paleozoic aquifers and to the alluvium and glacial outwash deposits along the Missouri and Big Sioux Rivers in the southwest part of the area. Flow components toward bedrock valleys may reflect discharge to Quaternary sand and gravel deposits in these valleys. Pumping tests conducted in the study area indicate a narrow" range of hydraulic conductivities of the Dakota aquifer, from 37 to 50 feet per day. Consequently, an average hydraulic conductivity of 40 feet per day was used to estimate the potential yield to wells completed in the aquifer. Yields of more than 250 gallons per minute can be expected throughout much of the study area and more than 1,000 gallons per minute could be produced in some areas. The quality of water from the Dakota is a calcium, magnesium, sulfate type. It is generally suitable for irrigation purposes, based on comparisons of sodium adsorption ratios and electrical conductivities. In some areas the aquifer has water with high salinity hazard that may restrict its use to irrigation of only well-drained types of soil. The concentration of radium-226 and other radionuclides exceeds recommended limits at several sites. The quality of water pumped from the aquifer may be altered by induced leakage from the underlying aquifers in Paleozoic age rocks if withdrawals reverse the pattern of natural flow from the Dakota into the Paleozoic aquifers. Evidence for such a reversal exists in the area around the city of LeMars.

Iowa↗

USGS2014

Interpreting the paleozoogeography and sea level history of thermally anomalous marine terrace faunas: A case study from the the last interglacial complex of San Clemente Island, California

Marine invertebrate faunas with mixtures of extralimital southern and extralimital northern faunal elements, called thermally anomalous faunas, have been recognized for more than a century in the Quaternary marine terrace record of the Pacific Coast of North America. Although many mechanisms have been proposed to explain this phenomenon, no single explanation seems to be applicable to all localities where thermally anomalous faunas have been observed. Here, we describe one such thermally anomalous fossil fauna that was studied on the second emergent marine terrace at Eel Point on San Clemente Island. The Eel Point terrace complex is a composite feature, consisting of a narrow upper bench (terrace 2a) and a broader lower bench (terrace 2b). Terrace 2b, previously dated from ∼128 ka to ∼114 ka, was thought to date solely to marine isotope stage (MIS) 5.5, representing the peak of the last interglacial period. Nevertheless, the fauna contains an extralimital northern species and several northward-ranging species, as well as an extralimital southern species and several southward-ranging species. Similar faunas with thermally anomalous elements have also been reported from San Nicolas Island, Point Loma (San Diego County), and Cayucos (San Luis Obispo County), California. U-series dating of corals at those localities shows that the thermally anomalous faunas may be the result of mixing of fossils from both the ∼100-ka (cool-water) and the ∼120-ka (warm-water) sea level high stands. Submergence, erosion, and fossil mixing of the ∼120-ka terraces by the ∼100-ka high-sea stand may have been possible due to glacial isostatic adjustment (GIA) effects on North America, which could have resulted in a higher-than-present local sea level stand at ∼100 ka. The terrace elevation spacing on San Clemente Island is very similar to that on San Nicolas Island, and we hypothesize that a similar mixing took place on San Clemente Island. Existing fossil records from older terraces elsewhere in California also show thermally anomalous elements, indicating that the scenario presented here for the last interglacial complex may have applicability to much of the marine Quaternary record for the Pacific Coast.

California↗

USGS1999

The Puelche volcanic field: Extensive Pleistocene rhyolite lava flows in the Andes of central Chile

A remote volcanic field in the rugged headwaters of the Río Puelche and Río Invernada (35.8°S) constitutes the largest cluster of Quaternary rhyolite lava flows yet identified in the Andean Southern Volcanic Zone. The Puelche Volcanic Field belongs to an intra-arc belt of silicic magmatic centers that extends, at least, 140 km north-south and lies well east of the volcanic front but nonetheless considerably west of the intraplate extensional fields of basaltic and alkaline centers of pampean Argentina. The authors' mapping has distinguished one shallow intrusive mass of early Pleistocene biotite rhyodacite (70.5% SiO 2 ), 11 eruptive units of mid-Pleistocene high-K biotite-rhyolite lava (71.3-75.6% SiO 2 ), and 4 eruptive units of basaltic andesite (53.95-4.9% SiO 2 ), the conduits of which cut some of the rhyolites. Basal contacts of the rhyolite lava flows (and subjacent pyroclastic precursors) are generally scree covered, but glacial erosion has exposed internal flow structures and lithologic zonation superbly. Thicknesses of individual rhyolite lava flows range from 75 m to 400 m. Feeders for several units are well exposed. Cliff-draping unconformities and intracanyon relationships among the 11 rhyolite units show that the eruptive sequence spanned at least one glacial episode that accentuated the local relief. Lack of ice-contact features suggests, however, that all or most eruptions took place during non-glacial intervals probably between 400 ka and 100 ka. Post-eruptive glacial erosion reduced the rhyolites to several non-contiguous remnants that altogether cover 83 km 2 and represent a surviving volume of about 21 km 3 . Consideration of slopes, lava thicknesses, and paleotopography suggest that the original area and volume were each about three times greater. Phenocryst content of the rhyolites ranges from 1 to 12%, with plagioclase>>biotite>FeTi oxides in all units and amphibole conspicuous in the least silicic. The chemically varied basaltic andesites range from phenocryst-poor to phenocryst-rich, exhibiting large differences in proportions of clinopyroxene, olivine, plagioclase, and xenocrystic quartz. Compositional bimodality of the volcanic field is striking, there being no Quaternary eruptive units having SiO 2 contents between 55 and 70%. Major and trace element compositions of the mafic and silicic rocks are nonetheless typical of continental-margin arc suites, not of intracontinental suites. The lack of intermediate eruptive units and the differences between the mafic and rhyolitic lavas in Sr-isotope composition suggest that the rhyolites fractionated from a hybrid parent rather than continuously from basaltic magma. The rhyolites may contain larger contributions of upper-crustal partial melts than do silicic products of the volcanic-front centers 30 km to the west.

Revista Geologica de Chile↗

USGS1983

GEOLOGIC FRAMEWORK FOR GEOTHERMAL ENERGY IN THE CASCADE RANGE.

Quaternary volcanoes of the Cascade Range form a 1200-km-long belt from northern California to southwest British Columbia and lie above the subduction zone formed as the Juan de Fuca plate is consumed beneath North America. Volcanoes throughout this belt may have been active during Quaternary time, and many have erupted within Holocene time. Thermal springs are few and inconspicuous. Surface expression of hydrothermal systems possibly is masked by infiltration of abundant rainwater and snowmelt. Several geologic and geophysical features suggest that the Oregon and California parts of the Cascades are characterized by moderate east-west crustal extension, tectonic regime conducive to relatively widespread volcanism and to the formation of normal fault zones of potentially high permeability. Refs.

Conference Paper↗

USGS2003

The stream net as an indicator of cryptic systematic fracturing in Louisiana

The stream net in many parts of Louisiana includes straight reaches with preferred alignment in a few directions, with some examples spanning tens of kilometers. In places the reaches form classic rectangular drainage patterns. These characteristics are obvious on maps at a variety of scales, and are recognizable on some portion of nearly every 7.5-minute quadrangle in the state, excepting those quadrangles situated entirely within the Ho??ocene coastal marshes or the Holocene flood plains of the larger rivers. Such patterns of lineaments are reminiscent of patterns associated with systematic fracturing in other regions. In Louisiana, however, verification and measurement of fractures that may exist in the vicinity of rectilinear drainage anomalies is problematic because surface deposits are comparatively young and sparsely exposed, and tend, especially near waterways, to be heavily weathered and vegetated. An indirect approach to evaluating the potential influence on drainage by fracturing involves evaluating the frequency distribution of stream-course orientations based on its degree of similarity with that of the strikes of previously mapped or reported fractures (faults and/or joints). A rose diagram of orientation frequencies for the stream net of the entire state, created utilizing a publicly available line dataset processed into 100-m segments (N 290,000), shows a nonrandom distribution with three visually identifiable trends: the strongest, oriented essentially N-S; a subsidiary trend oriented N20??-30??W; and a weak trend oriented N80??-90??W. The entire population of orientations yields a mean direction of N17.5??W ?? 4.2?? with a probability of 95 percent. The strike frequencies of mapped faults show little correspondence with these trends. This suggests, if mapped faults are at least representative of actual faults, that insofar as apparent lineaments reflect structure and not the influence of a south-southeasterly regional drainage gradient, they predominantly reveal the influence of joints. These could reflect either a Quaternary stress regime, or propagation in young sediment of a structural pattern in underlying older strata. The data available at present do not compel either interpretation, though in south Louisiana at least, where reactivated early Tertiary growth faults have surface expression that in places is juxtaposed with differently oriented drainage lineaments, propagation of a preexisting pattern from depth appears plausible. Widespread systematic fracturing in this predominantly Quaternary coastal-plain setting could have important implications for groundwater flow and for other processes that depend substantially on permeability.

Southeastern Geology↗

USGS2011

The regional structural setting of the 2008 Wells earthquake and Town Creek Flat Basin: implications for the Wells earthquake fault and adjacent structures

The 2008 Wells earthquake occurred on a northeast-striking, southeast-dipping fault that is clearly delineated by the aftershock swarm to a depth of 10-12 km below sea level. However, Cenozoic rocks and structures around Wells primarily record east-west extension along north- to north-northeast-striking, west-dipping normal faults that formed during the middle Miocene. These faults are responsible for the strong eastward tilt of most basins and ranges in the area, including the Town Creek Flat basin (the location of the earthquake) and the adjacent Snake Mountains and western Windermere Hills. These older west-dipping faults are locally overprinted by a younger generation of east-dipping, high-angle normal faults that formed as early as the late Miocene and have remained active into the Quaternary. The most prominent of these east-dipping faults is the set of en-échelon, north-striking faults that bounds the east sides of the Ruby Mountains, East Humboldt Range, and Clover Hill (about 5 km southwest of Wells). The northeastern-most of these faults, the Clover Hill fault, projects northward along strike toward the Snake Mountains and the approximately located surface projection of the Wells earthquake fault as defined by aftershock locations. The Clover Hill fault also projects toward a previously unrecognized, east-facing Quaternary fault scarp and line of springs that appear to mark a significant east-dipping normal fault along the western edge of Town Creek Flat. Both western and eastern projections may be northern continuations of the Clover Hill fault. The Wells earthquake occurred along this east-dipping fault system. Two possible alternatives to rupture of a northern continuation of the Clover Hill fault are that the earthquake fault (1) is antithetic to an active west-dipping fault or (2) reactivated a Mesozoic thrust fault that dips east as a result of tilting by the west-dipping faults along the west side of the Snake Mountains. Both alternatives are precluded by the depths of the earthquake and aftershocks, about 8 km and as deep as 12 km, respectively. These depths are below where an antithetic fault would intersect any main fault, and a tilted, formerly shallow and sub-horizontal thrust fault would not extend to depths of more than about 5–6 km. The east-dipping, high-angle, earthquake fault cuts older west-dipping faults rather than reactivating them, highlighting a change in the structural style of Basin and Range extension in this region from closely-spaced, west-dipping faults that rotated significantly during slip and accommodated large-magnitude extension, to widely-spaced, high-angle faults that accommodate much less total strain over a long time span.

Nevada↗

USGS1973

Geology and water resources of the Wharton Tract and the Mullica River basin in southern New Jersey

The Wharton Tract is an area of 150 square miles located in the Mullica River basin in southern New Jersey's Pine Barrens region. The tract is a relatively flat, low-lying, generally sandy area containing shallowly incised streams. The larger streams are commonly bordered by swamps. The tract was purchased by the State primarily as a water-supply preserve, but also for conservation and recreational purposes. Mean streamflow at three continuous record gaging stations in the Wharton Tract is: Mullica River near Batsto (46.1-square mile drainage area), 6 mgd (million gallons per day); Batsto River at Batsto (70.5-square mile drainage area), 81 mgd; Oswego River at Harrisville (64.0-square mile drainage area), 55 mgd. Thus mean discharge from this 180.6-sq mi (square mile) area is 202 mgd or 1.12 mgd per sq mi. Principal aquifers in the Wharton Tract and Mullic River basin are in the Kirkwood Formation of middle Miocene age, Cohansey Sand of Miocene(?) and Pliocene(?) age, and in overlying hydraulically connected deposits of Quaternary age. The Kirkwood Formation is composed of sand, silt, and clay. Diverse lithologies represent deposition in different environments such as nearshore marine, barrier bar, lagoonal, estuarine, and tidal marsh. Hydraulic characteristics of the Kirkwood in the Mullica River basin are virtually unknown. Most Kirkwood aquifers in the basin are believed to be hydraulically connected with the overlying Cohansey Sand. The Cohansey Sand is dominantly a quartz sand containing minor amounts of pebbly sand, silty sand, and interbedded clay. Almost all of the Wharton Tract and most of the Mullica River basin lie within the sandier area of the Cohansey, which contains approximately 75 percent sand beds and 25 percent silt and clay beds. Data from test drilling show that the upper 100 feet of sediments in the Wharton Tract contain about 93 percent sand beds, 3.5 percent clay beds, and 3.5 percent silt beds. The Cohansey in the Tract ranges in thickness from less than 50 feet to about 180 feet; the average thickness is about 125 feet. The Cohansey Sand is believed to be, in overall aspect, a deltaic deposit. It contains materials that were deposited locally in nearshore-marine, fluvial, estuarine, lagoonal, and beach environments. The hydraulic conductivity of Cohansey aquifer material ranges from about 90 to 250 feet per day (660 to 1,885 gallons per day per square foot) in southern New Jersey. One aquifer test in the Wharton Tract gives an average value of 130 feet per day (1,000 gallons per day per square foot). The transmissivity of the Cohansey Sand aquifer through most of the Wharton Tract is typically between 10,000 and 20,000 square feet per day (75,000 and 150,000 gallons per day per foot). Deposits of Quaternary age form a discontinuous veneer lying unconformably above the Cohansey Sand. The most important hydrologic function of most of these deposits is to absorb precipitation and transmit the water to the underlying Cohansey Sand. Thicker deposits of estuarine sand and clay of the Cape May Formation fill a channel in the underlying Cohansey Sand along the lower reaches of the Mullica River. This channel deposit is 85 feet thick near Batsto. Ground water and surface water in the Mullica River basin are low in dissolved solids, generally less than 50 mg/1 (milligrams per liter). Iron concentrations are generally high, up to 49,000 micrograms per liter (49 mg/1) in ground water and up to 7,100 micrograms per liter (7.1 mg/1) in the streams. The water is acidic as indicated by typical pH values of from 4.5 to 6.5. Color of the surface water is commonly high, ranging from 3 - 150 platinum-cobalt units. After appropriate treatment these waters are acceptable for most uses. The Wharton Tract is well situated to support the growing water needs of nearby New Jersey communities. Maximum development of water can be achieved by conjunctive use of ground and surface water. During most of the year, some water would be withdrawn either directly from streams or from adjacent wells. During periods of low flow during summer or fall water would be pumped from wells farther from the stream~. From analysis of flow-duration curves it is estimated that 70 mgd of water could be developed with minimal effect upon low flows in the half of the tract above the gaging stations on the Mullica and Batsto Rivers. The quantity available in the entire tract is greater, possibly in the order of 150 mgd. With augmentation of streamflow by pumping from ground water, it is likely that considerably more water could be safely used on a perennial basis. A possibility exists for multiple use of the water resources of the Mullica River through construction of an inexpensive tide barrier at the Garden State Parkway. This would create a fresh water lake in a State forest, park, and recreational area, which would also provide a flexible and economical water supply for much of the Atlantic coastal resort development.

New Jersey↗