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At least 415 records · Page 23Linked to original sources
USGS2023

A model of transmissivity and hydraulic conductivity from electrical resistivity distribution derived from airborne electromagnetic surveys of the Mississippi River Valley Alluvial Aquifer, Midwest USA

Groundwater-flow models require the spatial distribution of the hydraulic conductivity parameter. One approach to defining this spatial distribution in groundwater-flow model grids is to map the electrical resistivity distribution by airborne electromagnetic (AEM) survey and establish a petrophysical relation between mean resistivity calculated as a nonlinear function of the resistivity layering and thicknesses of the layers and aquifer transmissivity compiled from historical aquifer tests completed within the AEM survey area. The petrophysical relation is used to transform AEM resistivity to transmissivity and to hydraulic conductivity over areas where the saturated thickness of the aquifer is known. The US Geological Survey applied this approach to a gain better understanding of the aquifer properties of the Mississippi River Valley alluvial aquifer. Alluvial-aquifer transmissivity data, compiled from 160 historical aquifer tests in the Mississippi Alluvial Plain (MAP), were correlated to mean resistivity calculated from 16,816 line-kilometers (km) of inverted resistivity soundings produced from a frequency-domain AEM survey of 95,000 km 2 of the MAP. Correlated data were used to define petrophysical relations between transmissivity and mean resistivity by omitting from the correlations the aquifer-test and AEM sounding data that were separated by distances greater than 1 km and manually calibrating the relation coefficients to slug-test data. The petrophysical relation yielding the minimum residual error between simulated and slug-test data was applied to 2,364 line-km of AEM soundings in the 1,000-km 2 Shellmound (Mississippi) study area to calculate hydraulic property distributions of the alluvial aquifer for use in future groundwater-flow models.

Mississippi River Valley Alluvial Aquifer↗
USGS1985

Mineralization of breccia pipes in northern Arizona

The Paleozoic sedimentary rocks on the Colorado Plateau of northern Arizona are host to hundreds ofbreccia pipes. The uranium and copper deposits in these breccia pipes transgress formation boundaries from the Mississippian Redwall Limestone to the Triassic Chinle Formation. They are not classic breccia pipes in that there is no volcanic rock associated with them in time or space. They are the result of solution-collapse within the Redwall Limestone and stoping of the overlying strata. The karst development in the Redwall Limestone began in the Mississippian and apparently either continued to the Triassic or was at least once again active during that time. The mineralization apparently occurred shortly thereafter, sometime during the Mesozoic. Mining activity in breccia pipes of the Grand Canyon region began during the nineteenth century and continues today with the operation of the Hack I, II, and III mines, although the exploited commodity has changed from Cu to U. Although small in size, these pipes contain samples with up to 55 percent U 3 O 8 and can yield ore averaging between 0.30 and 0.60 percent U 3 O 8 .Mineralization at the surface commonly occurs within nodules and concretions associated with pyrite and goethite and along fractures, while the primary ore of the unoxidized zones is commonly within a comminuted sandstone matrix surrounding breccia fragments of overlying formations. The ore mineral is uraninite, although associated with it are sphalerite, galena, chalcopyrite, tennantite, millerite, siegenite, and/molybdenite. Some of the surface nodules are encrusted with malachite and are exceptionally enriched in Ag. Pyrite is abundant, and the organic carbon content of some rocks is high enough to suggest that it, along with the pyrite, may be a reductant for uranium. In contrast, it is possible, if uranium were transported as a bicarbonate or carbonate complex, that only a conduit of brecciated rock was necessary to release CO 2 , thus disrupting the equilibrium and allowing uraninite to precipitate. An extensive suite of elements is significantly enriched in the mineralized rock: Ag, As, Ba, Cd, Co, Cr, Cs, Cu, Hg, Mo, Ni, Pb, Sb, Se, Sr, U, V, Zn, and the rare earth elements. Of these, Cu, Pb, Zn, Ag, and particularly As appear to be the best geochemical indicators of mineralized pipes. At present the origin of the mineralizing fluids is not known. The lack of extensive silification within the breccia, along with the 80 degrees to 173 degrees C fluid inclusion-filling temperatures on sphalerite, dolomite, quartz, and calcite, suggests relatively low-temperature mineralizing fluids, although heated in excess of what would be expected from the normal geothermal gradient on the Colorado Plateau. With the exception of the U-mineralized rock, the mineral assemblage and geochemistry is similar to Mississippi Valley-type deposits.

Economic Geology↗
USGS1916

The Pliocene Citronelle Formation of the Gulf Coastal Plain. The flora of the Citronelle Formation

In the spring of 1910 the writer, working under the direction of T. Wayland Vaughan, geologist in charge of Coastal Plain investigations, undertook a study of the later Tertiary formations of the Gulf Coastal Plain. According to the plans outlined before the work was begun, the beds that had formerly been grouped under the names Lafayette formation and Grand Gulf formation were to be studied with a view to their possible separation into more satisfactory stratigraphic units that might be correlated with other formations which, on the basis of their fossils, had been assigned to their proper positions in the geologic time scale. The original plan included a study of the post-Vicksburgian Tertiary deposits from western Florida to Mississippi River and correlations with formations previously recognized in Florida, southern Alabama, and Louisiana. This plan was subsequently modified to extend the investigation as far west as Sabine River. The field work was interrupted and the office work was delayed by calls for geologic work in other areas, so that the preparation of the reports could not be begun until the spring of 1914.

Alabama, Florida, Georgia, Louisiana, Mississippi↗
USGS2012

Offshore sand-shoal development and evolution of Petit Bois Pass, Mississippi-Alabama Barrier Islands, Mississippi, USA

Assessment of recently collected geophysical and sediment-core data identifies an extensive shoal field located off Dauphin and Petit Bois Islands. The shoals are the product of Pleistocene fluvial deposition and Holocene marine-transgressive processes, and their position and orientation oblique to the modern shoreline has been stable over the past century. The underlying stratigraphy has also influenced the evolution of the barrier platform and inlets. Buried distributary channels bisect the platform, creating erosion hotspots that breach during intense and repeated storms. Inlet growth inhibits littoral transport, and over time, reduces the down-drift sand supply. These relations demonstrate the role of the antecedent geologic framework on morphologic evolution. This study is part of the USGS Northern Gulf of Mexico Ecosystem Change and Hazard Susceptibility Project and the USACE Mississippi Coastal Improvements Program. These projects produced a wealth of information regarding coastal geology, geomorphology, and physical resources; some of the initial results are presented here.

Alabama;Mississippi↗
USGS1994

Recent applications of acoustic Doppler current profilers

A Broadband acoustic Doppler current profiler (BB-ADCP) is a new instrument being used by the U.S. Geological Survey (USGS) to measure stream discharge and velocities, and bathymetry. During the 1993 Mississippi River flood, more than 160 high-flow BB-ADCP measurements were made by the USGS at eight locations between Quincy and Cairo, Ill., from July 19 to August 20, 1993. A maximum discharge of 31,400 m3/s was measured at St. Louis, Mo., on August 2, 1993. A BB-ADCP also has been used to measure leakage through three control structures near Chicago, Ill. These measurements are unusual in that the average velocity for the measured section was as low as 0.03 m/s. BB-ADCP's are also used in support of studies of scour at bridges. During the recent Mississippi River flood, BB-ADCP's were used to measure water velocities and bathymetry upstream from, next to, and downstream from bridge piers at several bridges over the Mississippi River. Bathymetry data were collected by merging location data from Global Positioning System (GPS) receivers, laser tracking systems, and depths measured by the BB-ADCP. These techniques for collecting bathymetry data were used for documenting the channel formation downstream from the Miller City levee break and scour near two bridges on the Mississippi River.

Conference Paper↗
USGS1981

Seismic stratigraphic characteristics of upper Louisiana continental slope: an area east of Green Canyon

A high-resolution seismic reflection survey was conducted in a small area of the upper Louisiana Continental Slope known as Green Canyon Area. This area includes tracts 427, 428, 471, 472, 515, and 516, that will be offered for sale in March 1982 as part of Lease Sale 67. The sea floor of this region is, slightly hummocky and is underlain by salt diapirs that are mantled by early Tertiary shale. Most of the shale is overlain by younger Tertiary and Quaternary deposits, although locally some of the shale protrudes the sea floor. Because of proximity to older Mississippi River sources, the sediments are thick. The sediment cover shows an abundance of geologic phenomena such as horsts, grabens, growth faults, normal faults, and consolidation faults, zones with distinct and indistinct parallel reflections, semi-transparent zones, distorted zones, and angular unconformities. The major feature of this region is a N-S linear zone of uplifted and intruded sedimentary deposits formed due to diapiric intrusion. Small scale graben development over the crest of the structure can be attributed to extension and collapse. Large scale undulations of reflections well off the flanks of the uplifted structure suggest sediment creep and slumping. Dipping of parallel reflections show block faulting and tilting. Air gun (5 and 40 cubic inch) records reveal at least five major sequences that show masked onlap and slumping in their lower parts grading into more distinct parallel reflections in their upper parts. Such sequences can be related to local uplift and sea level changes. Minisparker records of this area show similar sequences but on a smaller scale. The distinct parallel reflections often onlap the diapir flanks. The highly reflective parts of these sequences may represent turbidite-type deposition, possibly at times of lower sea level. The acoustically more transparent parts of each sequence may represent deposits containing primarily hemipelagic and pelagic sediment. A complex ridge system is present along the west side of the area and distinct parallel reflections onlap onto this structure primarily from the east. Much of this deposition may be ascribed to sedimentation within a submarine canyon whose position is controlled by this ridge.

Louisiana Continental Slope↗
USGS2012

Seismic velocity model of the central United States (Version 1): Description and simulation of the 18 April 2008 Mt. Carmel, Illinois, Earthquake

We have developed a new three‐dimensional seismic velocity model of the central United States (CUSVM) that includes the New Madrid Seismic Zone (NMSZ) and covers parts of Arkansas, Mississippi, Alabama, Illinois, Missouri, Kentucky, and Tennessee. The model represents a compilation of decades of crustal research consisting of seismic, aeromagnetic, and gravity profiles; geologic mapping; geophysical and geological borehole logs; and inversions of the regional seismic properties. The density, P ‐ and S ‐wave velocities are synthesized in a stand‐alone spatial database that can be queried to generate the required input for numerical seismic‐wave propagation simulations. We test and calibrate the CUSVM by simulating ground motions of the 18 April 2008 M w 5.4 Mt. Carmel, Illinois, earthquake and comparing the results with observed records within the model area. The selected stations in the comparisons reflect different geological site conditions and cover distances ranging from 10 to 430 km from the epicenter. The results, based on a qualitative and quantitative goodness‐of‐fit (GOF) characterization, indicate that both within and outside the Mississippi Embayment the CUSVM reasonably reproduces: (1) the body and surface‐wave arrival times and (2) the observed regional variations in ground‐motion amplitude, cumulative energy, duration, and frequency content up to a frequency of 1.0 Hz. In addition, we discuss the probable structural causes for the ground‐motion patterns in the central United States that we observed in the recorded motions of the 18 April Mt. Carmel earthquake.

Illinois↗
USGS2004

Watersheds for U.S Geological Survey National Stream Quality Accounting Network (NASQAN) sampling sites 1996-2000

A digital representation of the watersheds of 43 sites on large river systems sampled by the National Stream Quality Accounting Network (NASQAN) of the U. S. Geological Survey (USGS) in 2000 was created primarily from 1:250,000 hydrologic units(HUCs) in the United States. Watershed information from Canada and Mexico was incorporated to complete the areas draining to the sampling sites from outside the United States. The sampled rivers are in one of four major river systems: the Mississippi, the Colorado, the Rio Grande, or the Columbia.

Report↗
USGS2013

Nitrate in the Mississippi River and its tributaries, 1980-2010: an update

Nitrate concentration and flux were estimated from 1980 through 2010 at eight sites in the Mississippi River Basin as part of the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey (USGS). These estimates extend the results from a previous investigation that provided nitrate estimates from 1980 through 2008 at the same sites. From 1980 through 2010, annual flow-normalized (FN) nitrate concentration and flux in the Iowa and Illinois Rivers decreased by 11 to 15 percent. These two rivers had the highest FN nitrate concentration in 1980 (5.3 milligrams per liter [mg/L] and 3.9 mg/L, respectively) of any of the study sites. Nitrate increased in the Missouri River (79 and 45 percent increase in FN concentration and flux, respectively), and at the four sites on the Mississippi River (17 to 70 percent increase in FN concentration and 8 to 55 percent increase in FN flux) from 1980 through 2010. Nitrate in the Ohio River was generally stable during this time. Historically, nitrate was high and changed little in the Iowa and Illinois Rivers; however, nitrate concentrations began to decrease around 2000, and this decrease continued through 2010. Also during this time, near-flat nitrate trends in lower sections of the Mississippi River began increasing, likely reflecting the acceleration of already increasing nitrate trends in the upper Mississippi and Missouri Rivers, in addition to increases in inputs from other tributaries in the lower part of the Mississippi River Basin. Spring trends (April through June) generally parallel annual trends at all sites from 1980 through 2010, except in the Iowa River where decreasing nitrate during the spring was not observed. In general, most sites had increases in nitrate concentration at low streamflows, which suggests increases in legacy nitrate from groundwater or point source contributions. In aggregate, the decreases in nitrate concentrations from the Iowa and Illinois Rivers, which largely occurred during high flows, appear to be overshadowed by increasing nitrate concentrations across much of the Mississippi River Basin.

Gulf Of Mexico;Illinois River;Iowa River;Mississip↗
USGS2023

Estimating streambed hydraulic conductivity for selected streams in the Mississippi Alluvial Plain using continuous resistivity profiling methods—Delta region

Introduction The Mississippi Alluvial Plain is one of the most important agricultural regions in the United States, and crop productivity relies on groundwater irrigation from an aquifer system whose full capacity is unknown. Groundwater withdrawals from the Mississippi River Valley alluvial aquifer have resulted in substantial groundwater-level declines and reductions in base flow in streams within the Mississippi Alluvial Plain. These effects are limiting well production and threatening future water availability in the region. A comprehensive assessment of water availability in the Mississippi Alluvial Plain is critically important for making well-informed management decisions about sustainability, establishing best practices for water use, and predicting changes to water levels in the Mississippi Alluvial Plain over the next 50–100 years. The first step in the new regional modeling effort was to run the existing Mississippi Embayment Regional Aquifer Study (MERAS) model and perform data-worth and uncertainty analyses to prioritize data collection efforts to improve model forecasts. Parameter estimation indicated that streambed conductance was one of the variables that the model was most sensitive to, but little data were available to constrain those general estimates. From this characterization of the existing data, a map of the streams that the MERAS model was most sensitive to was created by the U.S. Geological Survey to guide the collection of 862 kilometers of waterborne resistivity surveys within the Delta region of Mississippi to characterize streambed lithology. This technique characterizes the streambed itself and the 15–30 meters below the streambed that control the exchange of water between the stream and the alluvial aquifer. These data can be used to map changes in the lithology of the streambed and identify areas of potential groundwater/surface-water exchange. Additionally, electrical and nuclear well logs from the study area were compared to facilitate the development of a petrophysical relation between the waterborne resistivity data and hydraulic conductivity. Resistivity values may then be used as a cost-effective way to approximate aquifer hydraulic conductivity distributions for use in regional groundwater models.

Arkansas, Louisiana, Mississippi↗
USGS1977

The Winona-Tallahatta Aquifer in Mississippi

This aquifer atlas describing the Winona-Tallahatta aquifer is the seventh in a series prepared in cooperation with the Mississippi Board of Water Commissioners. The atlas summarizes the large amount of unpublished data available in the files of the U.S. Geological Survey and it describes the extent, character, and present utilization of the aquifer and its potential for additional development. The Winona-Tallahatta aquifer, which contains freshwater having less than 1,000 mg/liter of dissolved solids in about 25 percent of the State occurs in northwestern and central Mississippi. The water-bearing zones extend into Tennessee and become part of the Memphis aquifer. In Arkansas and Louisiana the aquifer is in the Cane River Formation. The Tallahatta Formation which is the basal unit of the Claiborne Group includes, in ascending order, the Meridian Sand, Basic City Shale, and Neshoba Sand Members. The Winona-Tallahatta aquifer is the source of water for only a few large water users, but is the source of water for hundreds of small-yield domestic and stock wells less than 200 feet deep. Total water use in the State in 1977 from the Winona-Tallahatta is estimated to be about 3 mdg. (Woodard-USGS)

Mississippi↗
USGS1988

Subsurface geology of Paleozoic, Mesozoic, and Cenozoic units in southeast Missouri

The U.S. Geological Survey is conducting a regional water-resources investigation of the Gulf Costal Plain, which includes all of the Mississippi Alluvial Plain of southeastern Missouri, locally known as the southeast lowlands. The purpose of the regional study is to describe and evaluate the major aquifer systems in sediments of Tertiary and younger age in parts of 10 states (Grubb, 1984). In the southeast lowlands of Missouri, the sub-surface stratigraphy and structural configuration of geologic units need to be described in detail to define the major aquifer syustems in the area. The purpose of this report is to describe the subsurface geologic framework for Paleozoic, Mesozoic, and Cenozoic units in the southeast lowlands of Missouri and to correlate these units to those in adjecent States using geophysical and geologic methods (index map). Geophysical logs of wells were used to determine which units are aquifers or confining beds. The drilling of the U.S. Geological Survey test well 1-X in New Madrid County, Missouri, and the subsequent interpretation of geohydrologic data from the well have provided valuable information used in the preparation of this report.

Missouri↗
USGS1994

U.S. Geological Survey yearbook, fiscal year 1993: At work across the Nation

The need for earth science has never been more paramount. The devastating flooding of the Mississippi River this past year, strikingly portrayed on the cover and discussed in detail in this report (p. 37-42), was a sobering reminder of nature's elemental power. As a Nation, we face many environmental and economic challenges, such as natural hazards, that can be addressed effectively only through science. Water quality, resource assessments, climate change, and toxic wastes are all critical issues that can best be dealt with when approached from a sound scientific base. The goal of the U.S. Geological Survey is to provide hydrologic, geologic, and topographic information and understanding that contribute to the wise management of the Nation's natural resources and that promote the health, safety, and well-being of all Americans. FY1993 has proven to be a particularly challenging one for the USGS. We entered into a time of transition from the long-term leadership of Director Dallas Peck and Associate Director Doyle Frederick to the appointment of a new director. We thank Dallas and Doyle for their many years of service and for their support during the transition.

Yearbook↗
USGS2018

Using mercury injection pressure analyses to estimate sealing capacity of the Tuscaloosa marine shale in Mississippi, USA: Implications for carbon dioxide sequestration

This work used mercury injection capillary pressure (MICP) analyses of the Tuscaloosa Group in Mississippi, including the Tuscaloosa marine shale (TMS), to assess their efficacy and sealing capacity for geologic carbon dioxide (CO 2 ) sequestration. Tuscaloosa Group porosity and permeability from MICP were evaluated to calculate CO 2 column height retention. TMS and Lower Tuscaloosa shale samples have, respectively, Swanson permeability values less than 0.003 md and 0.00245 md; porosity from 3.86% to 9.86% and 1.34% to 7.96%; median pore throat sizes from 0.00342 to 0.0111 μm and 0.00311 to 0.017 μm; and pore radii from 0.0130 to 0.152 μm and 0.0132 to 0.149 μm. Mercury entry pressures for the TMS and Lower Tuscaloosa range from 4.9 to 57.1 MPa and 5.0 to 56.3 MPa, respectively. Calculated CO 2 column heights that the TMS sample set can retain in the reservoir range from 23 to 255 m when the TMS is near 100% water saturation. Potential top seal leakage is more likely to be influenced by the numerous well penetrations through the confining system of the TMS rather than capillary failure. Results of this study demonstrate desirable sealing capacity of the TMS for geologic CO 2 sequestration in reservoir sandstones of the Lower Tuscaloosa and could provide an analogue to other potential CO 2 sequestration top seals.

Louisiana, Mississippi↗
USGS1996

Loess studies in central United States: Evolution of concepts

Few words in the realm of earth science have caused more debate than "loess". It is a common term that was first used as a name of a silt deposit before it was defined in a scientific sense. Because this "loose" deposit is easily distinguished from other more coherent deposits, it was recognized as a matter of practical concern and later became the object of much scientific scrutiny. Loess was first recognized along the Rhine Valley in Germany in the 1830s and was first noted in the United States in 1846 along the lower Mississippi River where it later became the center of attention. The use of the name eventually spread around the world, but its use has not been consistently applied. Over the years some interpretations and stratigraphic correlations have been validated, but others have been hotly contested on conceptual grounds and semantic issues. The concept of loess evolved into a complex issue as loess and loess-like deposits were discovered in different parts of the US. The evolution of concepts in the central US developed in four indefinite stages: the eras of (1) discovery and development of hypotheses, (2) conditional acceptance of the eolian origin of loess, (3) "bandwagon" popularity of loess research, and (4) analytical inquiry on the nature of loess. Toward the end of the first era around 1900, the popular opinion on the meaning of the term loess shifted from a lithological sense of loose silt to a lithogenetic sense of eolian silt. However, the dual use of the term fostered a lingering skepticism during the second era that ended in 1944 with an explosion of interest that lasted for more than a decade. In 1944, R.J. Russell proposed and H.N. Fisk defended a new non-eolian, property-based, concept of loess. The eolian advocates reacted with surprise and enthusiasm. Each side used constrained arguments to show their view of the problem, but did not examine the fundamental problem, which was not in the proofs of their hypothesis, but in the definition of the term. Between 1944 and about 1950, the debates about loess reached a maximum level of complexity. The main semantic problem was submersed in peripheral arguments about physical properties and genetic interpretations. The scholarly treatment of the subject by Fisk and Russell stimulated quality responses from a diversity of earth scientists interested in academic and applied studies, particularly geo-history, pedology, soil mechanics and stratigraphy. The long-lasting popularity of loess studies during the bandwagon era lasted to about 1970. By that time, the analytical and technical interests had attracted the mainstream into the fourth era with a focus beyond the old arguments. Although Fisk and Russell found themselves defending an unpopular theory, they stimulated a scientific interest in the late Quaternary history of the Mississippi Valley that may never be exceeded.

Engineering Geology↗