Search USGS⌕ Search

Geology topics

Research about Alabama

Source-linked reports with geographic coverage including Alabama.

At least 163 records · Page 9Linked to original sources

Composition of biotite phenocrysts in Ordovician tephras casts doubt on the proposed trans-Atlantic correlation of the Millbrig K-bentonite (United States) and the Kinnekulle K-bentonite (Sweden)

Biotite phenocryst compositions in three thick, widespread Ordovician K-bentonites, the Deicke and Millbrig from Big Ridge, Alabama, and the Kinnekulle from Mossen, Västergötland, Sweden, fall into three distinct groups, and so the proposed intercontinental correlation of the Millbrig and the Kinnekulle is suspect. Because the biotites are nearly pristine compositionally, electron microprobe analyses provide a precise geochemical fingerprint of each bed. Millbrig and Kinnekulle biotites contain more FeO* and MnO and less MgO and TiO 2 than do Deicke biotites. Millbrig biotites contain more MgO and less TiO 2 than Kinnekulle biotites, and Kinnekulle biotites contain appreciably more Al 2 O 3 than either Deicke or Millbrig biotites. Each of these tephras was unmistakably the product of a gigantic explosive volcanic eruption, but the differences in phenocryst chemistry point to derivation from three compositionally different magma batches.

Alabama↗

Water resources data, Alabama, water year 1994

The Water Resources Division of the U.S. Geological Survey, in cooperation with State and Federal agencies, obtains a large amount of data pertaining to the water resources of Alabama each water year. These data, accumulated during many water years, constitute a valuable data base for developing ar improved understanding of the water resources of the State. To make these data readily available to interested parties outside the Geological Survey, the data are published annually in this report series entitled "Water Resources Data - Alabama."

Alabama↗

Water withdrawals in the Black Warrior-Tombigbee basin in Alabama, 1985-87

Public-supply, industrial, and power generation water withdrawals were inventoried for the Black Warrior-Tombigbee basin in Alabama for 1987. A water source capacity analysis was done for each facility to assess the risk of the future water demand exceeding the capacity of the current source. Approximately 96 percent of all water withdrawn in the study area was surface water. Surface water accounted for 88 percent of withdrawals by public suppliers and 99 percent of withdrawals by self- supplied industries.

Alabama↗

Hydrogeology and ground-water quality in the Black Belt area of west-central Alabama, and estimated water use for aquaculture, 1990

Commercial production of catfish in west-central Alabama began about 1970, and by 1991 catfish ponds covered about 16,000 acres in the Black Belt area of the State. The rapid increase in catfish farming or aquaculture and the associated demand for ground water led the U.S. Geological Survey in cooperation with other Federal and State agencies in 1990 to initiate a study to better define the ground-water resources in the Black Belt area. The major aquifers in the study area are sand and gravel beds in the Eutaw, Gordo, and Coker Formations. Recharge to these aquifers occurs primarily in areas where those formations crop out. The average recharge to the major aquifers in the study area, as estimated from baseflow analysis of streams in the outcrop area, is 11.4 inches per year. Water from the major aquifers in the study area generally is of good quality and suitable for most uses. Water from the Eutaw aquifer, however, contains chloride in concentrations greater than 500 milligrams per liter in central Greene County and in downdip areas in Marengo and Wilcox Counties and is not suitable for public water supply. Some ground water with elevated chloride concentrations is used for catfish farming in these areas, however. The total estimated water use for aquaculture in the study area in 1990 was 21.83 million gallons per day, 16.08 million gallons per day from ground-water sources, and 5.75 million gallons per day from surface water sources. About 13.54 million gallons per day of water was used for filling catfish ponds and an additional 8.29 million gallons per day was used to replace evaporation losses.

Alabama↗

Evaluation of the mussel fishery in Wheeler Reservoir, Tennessee River

We evaluated the freshwater mussel fishery on Wheeler Reservoir, a 27,155-hectare mainstream impoundment of the Tennessee River in Alabama. During July 1991 through June 1992, we used a roving creel survey to conduct 285 interviews over 57 weekdays and 12 weekend days. Total harvest during the 12-month survey period was estimated to be 570 metric tons, and included 15 mussel species. The most frequently harvested species were the washboard Megalonaias nervosa. Ohio pigtoe Pleurobema cordatum, and butterfly Ellipsaria lineolata. Harvest peaked in June at 290,414 mussels. Among collection techniques, total estimated effort was highest for divers (71,160 musseler-hours). The total estimated value of the 12-month mussel harvest (in terms of money paid to harvesters) from Wheeler Reservoir was US$2,119,921.

Alabama↗

Stratigraphy of the Mississippi-Alabama shelf and the Mobile River incised-valley system

The Mobile River incised-valley system located in the northern Gulf of Mexico occupies an area from southern Alabama through Mobile Bay to the outer Mississippi-Alabama continental shelf. During the Wisconsinan regression, this incised-valley system was fluvially eroded and extended across the exposed shelf to a shelf-margin delta complex. The last postglacial transgression drowned the entrenched alluvial valleys and reworked the alluvial fill and estuarine deposits to form shoals on the middle shelf. As the postglacial transgression slowed. Mobile Bay was formed. Mobile Bay is a large estuarine system protected by barrier islands. This paper documents the late Quaternary history of the Mobile River incised valley and fill. Mobile Bay is a large (> 1000 km 2 ) microtidal estuary in southern Alabama that receives drainage through the Mobile River system. The Mobile River catchment is the fourth largest in the United States and terminates at the bayhead delta of Mobile Bay. The bay is a classic example of a wave-dominated, drowned, fluvial incised valley. During the middle-late Wisconsinan, glacial maximum, relative sea level was approximately 120 m lower than present. The Mobile River incised valley was a conduit for drainage from the catchment to the shelf margin. The sediment carried by the fluvial system during this lowstand passed through the Mobile River incised valley, across the exposed shelf and was deposited on the shelf margin as deltaic lobes. Rapid sea-level rise forced coastal-plain shorelines landward across the present mid-continental shelf. Transgression of the estuary mouth left a series of estuary-mouth-bar deposits that were reworked and overlie alluvial fill. These sand-rich deposits were submerged by the continuing transgression and reworked to form shoals As the Holocene sea-level rise slowed, the Mobile River incised valley became an estuarine depocenter. In the present alluvial valley, lowstand deposits are overlain by estuarine sediments deposited during the initial flooding of the valley and subsequent formation of Mobile Bay. During the present highstand, longshore sediment transport formed a spit across much of the bay mouth, creating a restricted estuary into which a bayhead delta has prograded. Late Holocene deposits in Mobile Bay consists predominantly or lagoonal sediments with bayhead-delta deposits encroaching into the northern end of the bay. The Holocene incised-valley fill (estuarine facies) underlying Mobile Buy fit well into the conceptual facies model of a microtidal wave-dominated estuary. The model does not fit as well, however, with the rapidly transgressed shelf portion of the incised valley. The down dip section does not contain a clearly identifiable (from seismic profiles) estuarine facies; the valley fill is primarily fluvial and is overlain by marine shoals. In the Mobile River incised valley, the distal portion of the valley was rapidly drowned, allowing the thin estuarine facies to be reworked. The proximal portion was drowned more slowly, leaving the estuarine facies intact. Thus, the single incised valley contains two very different types of fill.

Alabama↗

Water resources data, Alabama, water year 1993

The Water Resources Division of the U.S. Geological Survey, in cooperation with State and Federal agencies, obtains a large amount of data pertaining to the water resources of Alabama each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the State. To make these data readily available to interested parties outside the Geological Survey, the data are published annually in this report series entitled "Water Resources Data - Alabama."

Alabama↗

Wind and tidal forcing of a buoyant plume, Mobile Bay, Alabama

AVHRR satellite imagery and in situ observations were combined to study the motion of a buoyant plume at the mouth of Mobile Bay, Alabama. The plume extended up to 30 km from shore, with a thickness of about 1 m. The inner plume, which was 3-8 m thick, moved between the Bay and inner shelf in response to tidal forcing. The tidal prism could be identified through the movement of plume waters between satellite images. The plume responded rapidly to alongshore wind, with sections of the plume moving at speeds of more than 70 cm s-1, about 11% of the wind speed. The plume moved predominantly in the direction of the wind with a weak Ekman drift. The enhanced speed of the plume relative to normal surface drift is probably due to the strong stratification in the plume, which limits the transfer of momentum into the underlying ambient waters.

Alabama↗

Observations of currents and density structure across a buoyant plume front

Observations of the Mobile Bay, Alabama, plume during a flood event in April 1991 reveal significant differences in the current field on either side of a front associated with the buoyant plume. During a strong southeasterly wind, turbid, low salinity water from Mobile Bay was pushed through an opening in the west side of the ebb-tidal delta and moved parallel to the coast. A stable front developed between the low salinity water of the buoyant plume (11‰) and the high salinity coastal water (>23‰) that was being forced landward by the prevailing winds. Despite the shallow water depth of 6 m, measurements of currents, temperature, and salinity show large shears and density gradients in both the vertical and the horizontal directions. At a station outside of the buoyant plume, currents at 0.5 m and 1.5 m below the surface were in the same direction as the wind. Inside the plume, however, currents at 0.5 m below the surface were parallel to the coast, 45°, off the direction of the wind and the magnitude was 45% larger than the magnitude of the surface currents outside the plume. Beneath the level of the plume, the currents were identical to the wind-driven currents in the ambient water south of the front. Our observations suggest that the wind-driven surface currents of the ambient water converged with the buoyant plume at the front and were subducted beneath the plume. The motion of the ambient coastal surface water was in the direction of the local wind stress, however, the motion of the plume had no northerly component of motion. The plume also did not show any flow toward the front, suggesting a balance between the northerly component of wind stress and the southerly component of buoyant spreading. In addition, the motion of the plume did not appear to affect the motion of the underlying ambient water, suggesting a lack of mixing between the two waters.

Alabama↗

Water resources data, Alabama, water year 1992

The Water Resources Division of the U.S. Geological Survey, in cooperation with State and Federal agencies, obtains a large amount of data pertaining to the water resources of Alabama each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the State. To make these data readily available to interested parties outside the Geological Survey, the data are published annually in this report series entitled "Water Resources Data - Alabama."

Alabama↗

Water resources data, Alabama, water year 1991

The Water Resources Division of the U.S. Geological Survey, in cooperation with State and Federal agencies, obtains a large amount of data pertaining to the water resources of Alabama each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the State. To make these data readily available to interested parties outside the Geological Survey, the data are published annually in this report series entitled "Water Resources Data - Alabama."

Alabama↗

The status of the Red Hills salamander Phaeognathus hubrichti, Alabama, USA, 1976–1988

A total of 144 sites in the Red Hills Physiographic Province in south-central Alabama, USA, were surveyed in 1988 for burrows of the Red Hills salamander Phaeognathus hubrichti . Of 92 sites surveyed in 1976, no change occurred in the habitat at 54 sites, conditions improved at 19 sites and deteriorated at 18 sites following selective or clear cutting. An additional 14 of 52 sites not surveyed in 1976 were adversely affected by logging. Burrows were most often found on high ( x ̄ = 17 m "> x̄= 17 m ), steep ( x ̄ = 50° "> x̄= 50° ), uncut slopes containing a high soil moisture content ( x ̄ = 57% "> x̄= 57% ) and full tree canopy. Slope angle and soil pH did not affect burrow abundance. Burrow openings averaged 10·9 mm high × 15·3 mm wide. Burrow angle was negatively correlated with burrow width and slope angle but low r 2 values indicate that little of the variation was explained by these variables. Burrows were most often found on the upper two-thirds of slopes; burrows on slopes affected by cutting were found in the middle of the slope where they were less prone to disturbance and desiccation. Although most timber companies claim to no longer cut steep slopes in order to protect salamanders, detrimental forestry practices are still occuring. In some instances, Red Hills salamanders survive selective and clear cutting, but the persistence and viability of affected populations remain unknown. Suggestions are made to reduce impacts from forestry operations. Acquisition of 25 sites containing viable salamander populations and retention as a threatened species under United States federal law are recommended.

Alabama↗

Water resources data, Alabama, water year 1990

The Water Resources Division of the U.S. Geological Survey, in cooperation with State and Federal agencies, obtains a large amount of data pertaining to the water resources of Alabama each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the State. To make these data readily available to interested parties outside the Geological Survey, the data are published annually in this report series entitled "Water Resources Data - Alabama."

Alabama↗

Temporal variability of remotely sensed suspended sediment and sea surface temperature patterns in Mobile Bay, Alabama

Distribution patterns of suspended sediments and sea surface temperatures in, Mobile Bay were derived from algorithms using digital data from the visible, near infrared, and infrared channels of the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-TIROS-N satellite. Closely spaced AVHRR scenes for January 20, 24, and 29, 1982, were compared with available environmental information taken during the same period. A complex interaction between river discharge, winds, and astronomical tides controlled the distribution patterns of suspended sediments. These same variables, coupled with air temperatures, also governed the distribution patterns of sea surface temperatures.

Alabama↗

Water resources data, Alabama, water year 1989

The Water Resources Division of the U.S. Geological Survey, in cooperation with State and Federal agencies, obtains a large amount of data pertaining to the water resources of Alabama each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the State. To make these data readily available to interested parties outside the Geological Survey, the data are published annually in this report series entitled "Water Resources Data - Alabama."

Alabama↗