Geology Commons^™

Iron Concretions In The Cretaceous Dakota Formation, Anthony Kohtz, Richard Kettler, David Loope

UCARE Research Products

The Cretaceous Dakota Formation contains abundant iron oxide concretions. The precursors to the iron concretions are siderite (FeCO3) nodules that formed in a reducing floodplain environment. A variety of concretion morphologies formed when the precursor siderite nodules were dissolved by oxidizing groundwater in a paleoaquifer. Iron-oxidizing bacteria are able to oxidize aqueous Fe(II) to Fe(III) oxy-hydroxide at microaerophilic and neutrophilic conditions. This study investigated these concretions to determine if there was a microbial element in their formation and to characterize the concretion morphologies present in the Dakota. This is important for complete paleoenvironment interpretations and astrobiology pursuits.

Iron Mobility In Desert Sandstone Aquifers: The Possible Role Of Siderite, Lubna Al Azri, David Loope

UCARE Research Products

Jordanians and a large number of refugees are drinking radiumcontaminated water from a sandstone aquifer. The problem is that this water passed through sandstone of the Disi Formation only after carbon dioxide and methane had bleached the sandstone, dissolving the Iron-oxide coatings and liberating heavy metals and radionuclides . The Iron that once coated the grains migrated to form Iron bands in the lower Um Ishrin Formation.

The major practical significance of this study involves water quality. The movement of Iron sandstone aquifers can drastically change groundwater chemistry; understanding how and when this movement takes place will help in locating …

Using Kriging, Cokriging, And Gis To Visualize Fe And Mn In Groundwater, Crystal Johnson

Electronic Theses and Dissertations

For aesthetic, economic, and health-related reasons, allowable concentrations of iron (Fe) and manganese (Mn) found present in drinking water are 0.3 mg/L and 0.05 mg/L, respectively. Water samples taken from private drinking wells in the rural communities within Buncombe County, North Carolina contain amounts of these metals in concentrations higher than the suggested limits. This study focused on bedrock geology, elevation, saprolite thickness, and well depth to determine factors affecting Fe and Mn. Using ArcGIS 10.2, spatial trends in Fe and Mn concentrations ranges were visualized, and estimates of the metal concentrations were interpolated to unmonitored areas. Results from this …

Geophysical Signatures Of Disseminated Iron Minerals: A Proxy For Understanding Subsurface Biophysicochemical Processes, Gamal Z. Abdel Aal, Estella A. Atekwana, Andre Revil

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Previous studies have linked biogeophysical signatures to the presence of iron minerals resulting from distinct biophysicochemical processes. Utilizing geophysical methods as a proxy of such biophysicochemical processes requires an understanding of the geophysical signature of the different iron minerals. Laboratory experiments were conducted to investigate the complex conductivity and magnetic susceptibility signatures of five iron minerals disseminated in saturated porous media under variable iron mineral content and grain size. Both pyrite and magnetite show high quadrature and inphase conductivities compared to hematite, goethite, and siderite, whereas magnetite was the highly magnetic mineral dominating the magnetic susceptibility measurements. The quadrature conductivity …

High-Resolution Magnetic Susceptibility Measurements For Investigating Magnetic Mineral Formation During Microbial Mediated Iron Reduction, Estella A. Atekwana, Farag M. Mewafy, Gamal Z. Abdel Aal, D. Dale Werkema, Andre Revil, Lee D. Slater

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Disimilatory iron-reducing bacteria play an important role in the reduction of Fe(hydr)oxides and the production of secondary solid-iron mineral phases that can have magnetic properties. Magnetic susceptibility can therefore play an important role in identifying zones where microbial-mediated iron reduction is occurring. We investigated the magnetic susceptibility variations in a hydrocarbon-contaminated aquifer where methanogenesis and iron reduction are the main biogeochemical processes. Our objectives are to (1) determine the variability of magnetic susceptibility, (2) determine the hydrobiogeochemical controls on the magnetic susceptibility variability, and (3) evaluate the use of magnetic susceptibility as a viable technique for identifying zones where the …

Dissolution Rates Of Amorphous Al- And Fe-Phosphates And Their Relevance To Phosphate Mobility On Mars, Valerie Tu

UNLV Theses, Dissertations, Professional Papers, and Capstones

Phosphate is an essential element for life on Earth, and therefore if life exists or ever existed on Mars it may have required phosphate. Amorphous Al- and Fe-phosphates rapidly precipitate from acidic solutions and amorphous Al-phosphates likely control phosphate concentrations in some natural waters on Earth. Amorphous phases may be even more important on Mars than on Earth, and amorphous phosphates are therefore likely important in the phosphate cycle on Mars. Despite this importance, however, few dissolution rates exist for amorphous Al- and Fe- phosphates. In this study, dissolution rates of amorphous Al- and Fe-phosphates were measured in flow-through reactors …

Distributions Of Particulate Heme B In The Atlantic And Southern Oceans- Implications For Electron Transport In Phytoplankton, Martha Gledhill, Eric P. Achterberg, David J. Honey, Maria C. Nielsdottir, Micha J.A. Rijkenberg

OES Faculty Publications

Concentrations of heme b, the iron-containing component of b-type hemoproteins, ranged from b concentrations were enhanced in the photic zone and decreased with depth. Heme b concentrations correlated positively with chlorophyll a (chl a) in the TNA (r=0.41, pb did not correlate with chl a in the IB or SS. In the IB and SS, stations with high-chlorophyll and low-nutrient (Fe and/or Si) concentrations exhibited low heme bconcentrations relative to particulate organic carbon (< 0.1 μmolmol^-1, and high chl a:heme b ratios (> 500). High chl a:heme b ratios resulted from relative decreases in …

Magnetic Susceptibility As A Proxy For Investigating Microbially Mediated Iron Reduction, Farag M. Mewafy, Estella A. Atekwana, D. Dale Werkema, Lee D. Slater, Dimitrios Ntarlagiannis, Andre Revil, Magnus E. Skold, Geoffrey N. Delin

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

We investigated magnetic susceptibility (MS) variations in hydrocarbon contaminated sediments. Our objective was to determine if MS can be used as an intrinsic bioremediation indicator due to the activity of iron-reducing bacteria. A contaminated and an uncontaminated core were retrieved from a site contaminated with crude oil near Bemidji, Minnesota and subsampled for MS measurements. The contaminated core revealed enriched MS zones within the hydrocarbon smear zone, which is related to iron-reduction coupled to oxidation of hydrocarbon compounds and the vadose zone, which is coincident with a zone of methane depletion suggesting aerobic or anaerobic oxidation of methane is coupled …

The Microbial Community Structure In Petroleum-Contaminated Sediments Corresponds To Geophysical Signatures, Jonathan P. Allen, Estella A. Atekwana, Eliot A. Atekwana, Joseph W. Duris, D. Dale Werkema, Silvia Rossbach

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The interdependence between geoelectrical signatures at underground petroleum plumes and the structures of subsurface microbial communities was investigated. For sediments contaminated with light non-aqueous-phase liquids, anomalous high conductivity values have been observed. Vertical changes in the geoelectrical properties of the sediments were concomitant with significant changes in the microbial community structures as determined by the construction and evaluation of 16S rRNA gene libraries. DNA sequencing of clones from four 16S rRNA gene libraries from different depths of a contaminated field site and two libraries from an uncontaminated background site revealed spatial heterogeneity in the microbial community structures. Correspondence analysis showed …

Groundwater Quality In Kentucky: Iron, R. Stephen Fisher, Bart Davidson

Information Circular--KGS

Iron is one of the most abundant elements in rocks and soils, and one of the most common problems in groundwater supplies. Rainwater seeping through soils and bedrock dissolves iron and carries it to wells and springs. In deep groundwater systems that lack oxygen, iron occurs as dissolved ferrous ion and the water is clear. Under oxidizing conditions such as in shallow groundwater systems or where the water is exposed to air at a tap or faucet, however, iron converts to a ferric form when it combines with oxygen to form reddish-brown rust particles. In addition to natural sources, elevated …

Generalized Geologic Map For Land-Use Planning: Greenup County, Kentucky, Daniel I. Carey

Map and Chart--KGS

This map is not intended to be used for selecting individual sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions that affect the selection of sites for various purposes. The properties of thick soils may supercede those of the underlying bedrock and should be considered on a site-to-site basis. At any site, it is important to understand the characteristics of both the soils and the underlying rock.

The Efficacy Of Plant Residue Degradation Products On Phosphorus, Iron, Iodine, And Fluorine Bioavailability To Plants, Cheryl L. Mackowiak

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Plant and animal wastes degrade in soils to form relatively stable humified compounds, which form ion complexes that affect the bioavailability of elements in the soil solution. Hydroponic studies with wheat and rice were conducted to characterize the effect of humic acid (HA) on phosphorus (P), iron (Fe), fluorine (F), and iodine (I) bioavailability. Ferrihydrite [Fe(OH)₃] precipitation was greater on root surfaces without HA or synthetic chelates. Oxides such as ferrihydrite strongly adsorb P and provide exchange sites for metals. HA reduced this precipitate and increased P and Fe uptake.

Humic acid had no effect on F toxicity …

The Long-Term Viability Of A Zero-Valent Iron Permeable Reactive Barrier, Stuart Cowburn

Dissertations and Theses

Zero-valent iron permeable reactive barriers (PRB's) hold significant potential as a tool for groundwater remediation. Uncertainties remain, however, as to the effective lifetime of Fe⁰ barrier technology under full-scale operational conditions. Potential limits on barrier lifetime include reductions in permeability due to clogging by precipitates and oxidation of all Fe⁰ prior to the exhaustion of the contaminant source.

A 46 m long, 0.6 m wide, and 7.3 m deep Fe⁰ PRB was installed at the US Coast Guard Support Center, Elizabeth City, NC, in June 1996. The barrier was designed to remediate groundwater principally contaminated with Cr(VI) …

Physico-Chemical Principles Of Sixteenth Century Metallurgy, Robert E. Johnson

Bachelors Theses and Reports, 1928 - 1970

Following a review of sixteenth century metallurgical literature and a discussion of Gibbs free energy, this thesis discusses thermodynamic considerations of galena (PbS) reduction by iron from a lead assay of this period. The importance of fluxes in this assay is emphasized. The discussion covers both equilibrium and non-equilibrium conditions at 1100 degrees Celsius. Possible substitutes for iron are also covered.

Information from twenty-one small controlled lead assays is correlated with the thermodynamic discussion to determine the purpose of each constituent in the assay.

An Investigation Of The Sintering Of Iron-Wire Compacts, George L. Vivian

Bachelors Theses and Reports, 1928 - 1970

A study of the sintering of iron has been made by observing the rate of bonding of iron wires wound on iron spools. The specimens were sintered at a constant temperature of 850c in vacuum furnaces capable of producing pressures of 10-5 to 10-4 mm of mercury, and the growth of the bond between wires was observed as a function of time.

It has been concluded that the volume-diffusion mechanism is strongly operating in the sintering of iron at 850c, but in an evacuated system, the evaporation-condensation mechanism also contributes to the sintering process.

Investigation Of Inclusions In Armco Ingot Iron, Edwin J. Duncan

Bachelors Theses and Reports, 1928 - 1970

Various chemical and electrolytic separation methods were investigated in an attempt to separate the in­clusions in Armco ingot iron. Residues obtained were X-rayed for identification purposes. The microstruc­tures of this iron were studied with the object of de­termining the relative sizes, locations, and possible compositions of the inclusions.

Ferromagnetic Alloys In The System Cu-Mn-Zn, W. Michael Yim

Bachelors Theses and Reports, 1928 - 1970

The purpose of this investigation is to determine whether ferromagnetic alloys exist in the ternary sys­tem Cu-Mn-Zn analogous to the other Heusler alloys. The work in this thesis is a preliminary investi­gation on these alloys using a common metallographic re­search technique and augmented with X-ray methods.

Hot-Dip Aluminizing Of Low-Carbon Steels, Claude R. Barnes Jr.

Bachelors Theses and Reports, 1928 - 1970

In a relatively short period of sixty-five years, aluminum has grown to the rank of fifth in total weight of met­als produced in the world. Throughout its short life, aluminum has been found to have excellent corrosion-resistant properties; yet only in recent years has aluminum been under consideration as a corrosion-resistant coating for iron and steel.

The Electrodeposition Of Iron-Manganese Alloys, Kenneth H. Larson

Bachelors Theses and Reports, 1928 - 1970

Although the alteration of properties resulting from the alloying of metals in their usual commercial forms has been extensively investigated, the field of electrodeposition of alloys is believed generally not to have received the atten­tion that it merits.

The Corrosion Resistance Of Iron-Tin Compacts As Produced By Powder Metallurgy, Robert W. Gambill

Bachelors Theses and Reports, 1928 - 1970

The art of Powder Metallurgy deals with the preparation of metal powders and their utilization. As a more pertinent definition, the following has been suggest­ed: "Powder Metallurgy is the art of producing metal powders and shaped objects from individual, mixed, or alloyed metal powders, with or without the inclusion of non-metallic consti­tuents".

Hardness And Electrical Resistivity Of Copper-Iron Powder Metal Compacts, Fred A. Foyle Jr.

Bachelors Theses and Reports, 1928 - 1970

Although powder metallurgical methods have been used for years to fabricate tungsten and platinum, very little scientific data have been recorded until the beginning of this century. A large percentage of all commercial production at present is based upon past practice rather than upon scientific knowledge.

Electrolytic Deposition Of Iron, Irving M. Kenoffel

Bachelors Theses and Reports, 1928 - 1970

In this thesis the purpose was to obtain a good iron deposit from a relatively simple bath. The deposit was to be of good nature and low in Carbon content. Also included is a summary of the uses to which electrolytic iron can be put as well as a summary of work done by other researchers in depositing iron electrolytically.

Some Preliminary Investiagtions Of The Magnetic Permeabilities Of Alloys Of The Ferromagnetic Metals, John H. Gambill Jr.

Bachelors Theses and Reports, 1928 - 1970

The problem presented for this thesis was an investigation of the magnetic properties of the alloys produced by the methods of powder metallurgy. The question behind this was the correlation of the magnetic properties with the bonding properties and with the diffusion of the constituents.