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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.


Unknown Date (has links)
The complex, polyphase structural, metamorphic, and magmatic history of the Alabama Tin Belt has been studied in order to yield unique solutions to the petrogenetic evolution of this region. The structural setting of the study area is interrelated with the metamorphic and igneous processes and provides temporal relationships between kinematic phases of deformation and the thermochemical aspects of orogenesis. / The metamorphic history of the study area is quantitatively characterized through mineral equilibria. The Wedowee, Hatchet Creek, and Higgins Ferry Groups' metamorphic rocks of the study area have experienced kyanite-sillimanite facies series regional metamorphism during the Acadian orogeny. A Barrovian geothermal gradient is defined in P-T space which is abruptly terminated by isothermal decompression associated with migmatization and S-type, Rockford Granite intrusion. The composition of the prograde metamorphic fluid is dominantly a H(,2)O-CO(,2)-CH(,4)-H(,2)S fluid phase. / The kinematic response to the polymetamorphic history of the area and later Alleghenian faulting in the Northern Alabama Piedmont involves at least three phases of foliation and four episodes of folding. The study area is subdivided into five structural domains in order to analzye the structures in each domain stereographically. This yields important information on the temporal, genetic, and geometric relationships between foliations, folds, and various lineations in the study area. / Geochemical characterization of the Rockford Granite indicates that it is a peraluminous, trondhjemite-granite suite. The trondhjemites are interpreted to be produced via Na-metasomatism where a pervasive, infiltrating, (delta)('18)O- and Na-rich metamorphic fluid alters an original granite. The predominant mineral reaction associated with the metasomatism involved a one-to-one, Na for K replacement in the feldspar and mica phases. The relatively unaltered Rockford Granite's granite is interpreted to be the result of 40% partial melting of a metasedimentary source. Differentiation within the granites involved restite-melt separation processes and minor fractionation. The Elkahatchee Quartz Diorite in the study area is characterized as a granodiorite-tonalite batholith. / Source: Dissertation Abstracts International, Volume: 47-05, Section: B, page: 1900. / Thesis (Ph.D.)--The Florida State University, 1986.

Relationship between the Dadeville Complex and Opelika Group, Appalachian Inner Piedmont of Alabama and Georgia

Unknown Date (has links)
The southern Appalachian Inner Piedmont in east central Alabama and west Georgia consists of two tectonically separated Ordovician lithotectonic units: the structurally upper Dadeville Complex and the underlying Opelika Group. The Dadeville Complex, a large Taconic arc fragment, now occurs as a klippe composed of prominently metavolcanic and metaplutonic rocks that forms the core of the regional NW-plunging Tallassee synform. The structurally underlying Opelika Group, composed predominantly of metasedimentary rocks, is part of an Ordovician back-arc basin. The Dadeville Complex and Opelika Group are separated by a bounding Alleghanian thrust, the Stonewall Line. These two tectonic entities have been mapped in the Lanett S. 7.5’ quadrangle, located along the Chattahoochee River on the Alabama/Georgia border. All units generally strike northeast and dip northwest. In this area, the Dadeville Complex consists of the Ordovician Ropes Creek Amphibolite, whose protolith was mostly tholeiitic basalt, but also includes thin interlayers of dacitic meta-tuff and metasedimentary rocks. The Opelika Group consists of the Loachapoka Schist, a kyanite/sillimanite schist with interlayered quartzite/metaconglomerate and thin amphibolite. The Auburn Gneiss occurs structurally below the Loachapoka Schist and consists of interlayered biotite gneiss and migmatitic muscovite schist. Both of the latter units were intruded by the Farmville Granite, but this unit does not cross the Stonewall Line. The Stonewall Line is ~5-10-meter-wide fault zone, with units of the Ropes Creek Amphibolite thrust above thin lenses of Farmville Granite and the Loachapoka Schist. In the study area, units in both hanging and footwall are semi-concordant, but regional mapping shows that to the northwest, the basal thrust cuts up section several kilometers in the hanging wall, while remaining concordant to footwall units. This geometry indicates that the Stonewall Line’s thrust trajectory was that of a large hanging wall ramp (Dadeville Complex) on a footwall flat (Opelika Group), as the arc complex was emplaced to the northwest upon its companion back-arc basin. / A Thesis submitted to the Department of Earth, Ocean and Atmospheric Science in partial fulfillment of the requirements for the degree of Master of Science. / Summer Semester 2018. / June 29, 2018. / Dadeville Complex, Opelika Group / Includes bibliographical references. / James F. Tull, Professor Directing Thesis; Stephen A. Kish, Committee Member; Mainak Mookherjee, Committee Member.

Investigations of the Southern Appalachian Eastern Blue Ridge of East Central Alabama and West Central Georgia Using Structural, Geochemical, and Thermobarometric Analyses

Unknown Date (has links)
Recent work in the southern Appalachians has identified the remnants of a historically critical Ordovician back-arc basin that now resides in the Talladega belt, eastern Blue Ridge, and Inner Piedmont terranes of Alabama, Georgia and North Carolina. This basinal sequence is believed to have been formed in response to extensional accretionary orogenesis along the southeastern margin of Laurentia during the Taconic orogeny. In an attempt to better characterize the development and evolution of this basin, this study examines the Wedowee and Emuckfaw (New Georgia) Groups of the eastern Blue Ridge, which together comprise a majority of what remains of the basin’s stratigraphy. These units consist of thick sequences of pelitic and psammitic schists with minor metapsammites interbedded with mostly mafic metavolcanic rocks. Field observations and statistical analysis of structural attitude measurements conducted in the Bowdon West 7.5’ quadrangle (AL/GA) suggest the Wedowee-Emuckfaw contact is a polydeformed gradational stratigraphic boundary with no evidence of faulting as had been previously thought. Petrologic and thermobarometric analysis of Wedowee and Emuckfaw samples from east central Georgia and west central Alabama indicate peak regional metamorphic conditions reached middle amphibolite facies during the Neoacadian with evidence of greenschist-grade retrograde reequilibration during uplift. Geochemical analysis of mafic metavolcanic rocks from various locations throughout the Wedowee and Emuckfaw units in Alabama and Georgia display compositions indicative of tholeiitic metabasalts with distinct arc and MORB-like signatures. These geochemical characteristics support the model that these metabasalts were generated in a suprasubduction back-arc setting. / A Thesis submitted to the Department of Earth, Ocean, and Atmospheric Science in partial fulfillment of the requirements for the degree of Master of Science. / Spring Semester 2018. / January 31, 2018. / Appalachian, back-arc, Emuckfaw, Wedowee / Includes bibliographical references. / James F. Tull, Professor Directing Thesis; A. Leroy Odom, Committee Member; Stephen A. Kish, Committee Member.

A Geochemical Analysis of Rare Earth Elements Associated with Significant Sedimentary Phosphate Deposits of West-Central Florida

Unknown Date (has links)
Rare earth elements (REEs), yttrium and uranium are important industrial resources in many technology sectors; therefore, demand and production will likely continue to increase. Increased international market prices have led to new exploration for REE mineral resources in North America. It has been proposed that phosphorite deposits are a viable economic source of REE but the overall concentrations, depositional conditions, and ages are relatively unconstrained. Phosphorite is commonly associated with nutrient replete seawaters and sedimentary deposition, which is driven by upwelling, and/or continental delivery of bio-essential elements that are deposited on continental shelf regions. This project analyzed three sonic drill cores to better constrain, spatiotemporal REE concentrations of the Miocene-Pliocene aged samples from the Peace River Formation, which is associated with North America’s largest phosphate deposit. This project presents concentration data from a lateral (west-east) transect collected in central Florida that documented phosphatic sands, silts and clays. Newly obtained cores contained samples with well-rounded quartz sands, dolomitic silts, teeth, bones, and marine fossils commonly found in a near shore depositional environment. Sedimentary archives of the area are highly enriched in REEs, yielding concentrations nearing 200 ppm for some REEs. Our analysis confirms a previous study that phosphate grains, teeth, bones, and bulk sediment indicate REE are not associated with and/or sourcing from biogenic components, but rather associated with phosphate grains through secondary diagenetic processes. Together, a variety of factors could explain enrichment seen in Miocene phosphatic sediments including nutrient-rich runoff, oceanic upwelling, and sediment reworking. Although concentrations do not reach values as high as other mining sources, the relative ease of extraction from sedimentary deposits may make them a valuable source. A compilation of major global phosphate deposits through geologic history documents that a majority (based on tonnage phosphorite) of the burial are associated with climatic transitions from icehouse to greenhouse conditions. / A Thesis submitted to the Department of Earth, Ocean, and Atmospheric Science in partial fulfillment of the requirements for the degree of Master of Science. / Spring Semester 2018. / April 20, 2018. / geochemistry, geology, mining, phosphate, phosphorite, rare earth elements / Includes bibliographical references. / Jeremy D. Owens, Professor Directing Thesis; William C. Parker, Committee Member; Vincent J. Salters, Committee Member.


Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 30-05, Section: B, page: 2258. / Thesis (Educat.D.)--The Florida State University, 1969.


Unknown Date (has links)
Cores recently drilled along Florida's east coast by the Florida Bureau of Geology have yielded a record of the most complete Florida Hawthorn fossiliferous sediments heretofore available for biostratigraphic analysis. The record of Hawthorn deposition extends from the Early Miocene in sediments near the base of this formation in Nassau County to what appears to be Early Pliocene time in core sediments present in Indian River and St. Lucie counties. / A diversity of microfossil groups including diatoms, silicoflagellates, foraminifera and coccoliths were identified in the Hawthorn sediments. Diatoms, which represented the largest and most definitive number of species, were the primary group used to determine the biochronology and paleoenvironmental interpretations of this important phosphate-bearing formation. Three biostratigraphic zones of Middle Miocene to Late Middle Miocene age can be recognized in the Hawthorn sediments (Coscinodiscus plicatus, Coscinodiscus plicatus/Delphineis penelliptica, Delphineis penelliptica zones). The utilization of the diatom Rhaphoneis lancetulla as a substitution for Coscinodiscus plicatus in these zonal correlations was necessary to make the Florida Hawthorn zonation more adaptable to the observed fauna. / The occurrence of an upwelling diatom assemblage in Hawthorn sediments of four northern cores is believed to be the result of coastal upwelling and/or influx from a postulated offshore cool water current during Middle Miocene time. Alternatively, the absence of an upwelling fauna in the Pliocene sediments was significant and may be related to paleoceanographic changes such as closing of the Isthmus of Panama during the Early Pliocene and/or cessation of upwelling. In general, species diversity was less in the Pliocene sediments as compared to the Middle Miocene sediments. Fluctuations in productivity, as expressed in terms of species diversity and numbers of brackish water species in the Middle Miocene and Pliocene assemblages, are attributed in part to sea level changes on a shallow marine depositional environment. / Source: Dissertation Abstracts International, Volume: 43-06, Section: B, page: 1772. / Thesis (Ph.D.)--The Florida State University, 1982.


Unknown Date (has links)
The Towaliga-Goat Rock and Bartletts Ferry deformation zones are major tectonic boundaries of the southeastern Piedmont. The Towaliga zone separates the Pine Mountain Belt and the Inner Piedmont and the Goat Rock and Bartletts Ferry Zones separate the Pine Mountain and Uchee Belt. / The Uchee Belt is composed of granitic gneisses and amphibolites modified by at least five deformational phases, each represented by distinctive mesoscopic folding patterns. The earliest (F(,1)) is a poorly developed folding of obscure compositional layering (S(,0)). Later leucocratic banding (S(,1)) is folded by recumbent isoclines with subhorizontal axial plane cleavage (S(,2)). Intensification of S(,2) to the northwest produces the southeast dipping mylonitic foliation of the Goat Rock and Bartletts Ferry Zone. A third phase (F(,3)) produces overturned similar to concentric folds rotated about subhorizontal axes with northwest transport indicated by northwest vergence. Cross folding (F(,4)) is followed by displacement on the fault at the base of the Uchee Belt, which is interpreted as a thrust emplacing Uchee rocks over the south limb of the Pine Mountain antiform. Quartz fabrics are not rotated by F(,3) and are interpreted as syn- or post- F(,3) recrystallization and recovery fabrics. A pre- S(,2) major regional metamorphic event (M(,1)) to at least sillimanite grade is recognized followed by a weak post- F(,4) retrogressive event (M(,2)). / Only the north limb of the Pine Mountain antiform and a portion of the ancient core are exposed in the study area. The Pine Mountain rocks are overprinted by at least five deformational phases. The earliest phase (F(,1)) is characterized by isoclinal folding about subhorizontal axes of the original compositional layering (S(,0)) with southeast transport indicated by southeast vergence. Intensification of the axial plane cleavage (S(,1)) produces the northwest dipping Towaliga mylonitic foliation which is modified by continued isoclinal and assymetrical folding (F(,2)) about subhorizontal axes with southeast vergence. A third phase (F(,3)) involving the adjacent Inner Piedmont, Towaliga Zone and north limb of the Pine Mountain antiform, is characterized by right lateral transport. Isoclinal and monoclinal folding (F(,3)) with axes plunging northwest downdip and axial plane cleavage (S(,3)) coplanar to S(,1) exhibits dextral vergence. Broad folds and undulations (F(,4)) of S(,1) - S(,3) are tentatively correlated with F(,4) of the Uchee Belt. A regional metamorphic event to sillimanite grade (M(,1)) followed by a retrogressive event (M(,2)) is recognized. The Towaliga quartz fabrics are interpreted as syn- or post- F(,3) recrystallization and recovery overprinted by later deformation fabrics, possibly F(,4). / The movement picture outlined by mesoscopic structural patterns poses considerable difficulty for a "meganappe" model. The patterns can be accounted for by regional compressive folding accompanied by ductile drag folding and mylonitization on the limbs of a major anticlinal structure. / Source: Dissertation Abstracts International, Volume: 42-06, Section: B, page: 2272. / Thesis (Ph.D.)--The Florida State University, 1981.


Unknown Date (has links)
This work is an application of the scanning electron microscopy in the study of clays. / The total number of samples studied by scanning electron microscopy exceeded 160. The majority of these samples were collected from various stratigraphic horizons of the kaolin deposits of Georgia and South Carolina. A smaller part of the samples were collected from various localities in the U. S. and from several foreign countries. / For practical purposes, the investigation of the kaolin samples was divided into three parts. These include: (a) minerals that appear to be kaolinitized, or in the process of kaolinitization, such as mica and feldspars; (b) minerals which are inert with respect to kaolinitization, such as silica and quartz; and (c) the crystallomorphic characteristics of the kaolinite, which constitutes the predominent part of the samples. / The kaolinitization of feldspars produced small, randomly oriented kaolinite flakes, whereas the kaolinitization of micas produced large, vermicular books. Possibly, silica was mobilized as a result of the kaolinitization process. The formation of authigenic minerals such as zeolites and cristobalite, took place only where local conditions provided the necessary elements during epidagenesis. / The Cretaceous kaolins were found to have a consistent texture, whereas the Tertiary kaolins have a wide range of textural appearance. Both the crystal perfection of the kaolinite flakes and the crystallinity index are statistically higher for the Cretaceous samples than for the Tertiary samples, although the correlation of these two variables was found to be very poor. / Strong correlation of Ca ions and viscosity indicates the presence of montmorillonite which was found to occur in very small amounts in almost all of the samples. / The inverse relationship between the titanium mineral content to the smectite content is found to be a useful indicator of the extent of weathering of kaolin deposits. The occurrence of the kaolinite books is more common at the upper part of the kaolin beds. This suggests that kaolinitization of mica took place in situ by the reaction of the downward-migrating waters with mica. The occurrence of large vermicular books and angular, friable quartz grains indicates that the kaolins could not have been transported in their present composition. The data of this study indicates, in general, that the kaolinitization process has taken place during epidiagenesis and after deposition. / Source: Dissertation Abstracts International, Volume: 41-03, Section: B, page: 0866. / Thesis (Ph.D.)--The Florida State University, 1980.


Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 41-01, Section: B, page: 0107. / Thesis (Ph.D.)--The Florida State University, 1972.

Lateral distribution of detrital clay minerals in Lower Cretaceous sediment, western North Atlantic and its continental margin

Unknown Date (has links)
Fine grained sediment from Lower Cretaceous turbidites (DSDP Site 603) and their correlative deltaic deposits (Baltimore Canyon Trough) were compared mineralogically and texturally. The shelf sediment is coarser grained than deep sea sediment and both are poorly sorted. Deltaic sediment is dominated by illite and kaolinite while deep sea sediment is dominated by illite and smectite. Some kaolinite in deltaic units is authigenic and fills pore space, but at least part of it, particularly in fine-grained sediment, is detrital. Deltaic illite appears to be largely detrital in the SEM. In some deltaic samples where heavy minerals appear partly dissolved, authigenic corrensite fills pore space. / In deep-sea turbidites, smectite dominates the $<$0.5 micrometer fraction and illite is most abundant in coarser clay fractions. Smectite level is highest in clay-rich sand beds and in clay rip-up clasts, indicating it has been reworked from deep sea fan levee deposits. Illite levels increase uphole, indicating an increase from the Valanginian to the Albian. Smectite in potassium feldspar-rich samples exhibits delicate fibrous overgrowths interpreted as illite. / Previous studies of the clay mineral composition of Lower Cretaceous western North Atlantic sediment hypothesized extensive vertisols along the eastern North American margin to account for high smectite levels, but the results of this study indicate high levels may result from pericontinental fractionation as a result of differential clay mineral flocculation and settling velocities. The greater volume of shelfal sediment (several kilometers thick) compared to abyssal sediment (tens to two hundred meters) further indicates that smectite was probably not the dominant clay weathered from the Early Cretaceous eastern North America. From field and literature studies, Lower Cretaceous paleovertisols of the Salisbury Embayment comprise a minor component of paleosols. / Possible sources for pelagic smectite include Early Cretaceous volcanic ash derived from the New England-Quebec volcanic event, from andesitic volcanism in Mexico, and possibly more extensive exposure of syn-rift diabase and associated basalt. A high iron content of the smectite (over 7% Fe*) supports the latter source. / Source: Dissertation Abstracts International, Volume: 50-05, Section: B, page: 1814. / Major Professor: Sherwood Willing Wise, Jr. / Thesis (Ph.D.)--The Florida State University, 1989.

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