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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.
21

Published works, including book 'Structural Geology of Folded Rocks'

Whitten, E. H. Timothy January 1966 (has links)
No description available.
22

Facies and sequence stratigraphic analyses of the Upper Ordovician shales in northeast Indiana and northwest Ohio

Xu, Jingqi 27 September 2016 (has links)
<p> The Upper Ordovician Maquoketa Group equivalent strata in Indiana and Ohio were part of a westward-thinning shale-dominant succession. Large amounts of fine-grained siliciclastics were shed from the eastern highlands during the Taconic Orogeny. </p><p> The detailed lithofacies analysis of the Upper Ordovician shales has yielded recognition of a series of genetically related sequences in a seemingly homogenous succession. The lower succession is pyritic laminated/banded organic-rich mudstone that accumulated after the onset of a major flooding event. Cryptobioturbation, bottom current ripples, graded silt/clay couplets and well preserved benthic fossils indicate an oxygen-depleted dysoxic condition. In addition, layers enriched in phosphatic fossils, phosphate and pyritic grains appear to mark flooding surfaces and sediment starvation. The maximum organic-matter enrichment mainly occurred within black homogenized mudstone in the middle succession. Upsection, more extensive bioturbation and carbonate production are observed. The intermittent yet frequent wave and current activity, suggested by cross-lamination, wavy-lenticular stratification and hummocky cross stratification, indicate a shallower and proximal settings with enhanced sediment influx. </p><p> The deposition of the Upper Ordovician shales in the Maquoketa Group reflects a complex interplay between storms, sediment supply, and eustatic sea-level changes. Nonetheless, with distinct characteristics of lithofacies, wireline logs, and organic carbon isotope data, a high-resolution sequence stratigraphic framework of the Upper Ordovician shales can be compiled for the study area. The whole studied interval comprises an entire 3rd order sequence, wherein the lower part appears to be a transgressive systems tract and the remaining overlying strata represent a highstand systems tract. This project is an example how integration of sedimentological observations, geophysical data, petrographical and geochemical data enable a better understanding of the accumulation of this mudstone succession in a regional sequence stratigraphic context.</p>
23

SURFACE LITHOFACIES, BIOFACIES, AND DIATOM DIVERSITY PATTERNS AS MODELS FOR DELINEATION OF CLIMATIC CHANGE IN THE SOUTHEAST ATLANTIC OCEAN

Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 40-07, Section: B, page: 3055. / Thesis (Ph.D.)--The Florida State University, 1979.
24

MINERALOGY, GEOCHEMISTRY AND RADIOACTIVITY OF SOME EGYPTIAN PHOSPHORITE DEPOSITS

Unknown Date (has links)
Mineralogical, geochemical, and radiogeological studies of forty nine phosphorite samples from three main mining areas in Egypt, Abu Tartur (Western Desert), Sibaiya (Nile Valley), and Safaga (Red Sea) have been carried out and the results are incorporated in this dissertation. / X-ray diffraction studies of these Egyptian phosphorites show that carbonate-fluorapatite (francolite) is the major phosphorite mineral in these deposits, with partial substitution of Mg and Na for Ca, and (CO(,3)) for (PO(,4)). Other minerals identified using the x-ray diffraction and scanning electron microscope include calcite, dolomite, pyrite, quartz, gypsum, feldspars, micas and clay (smectite). Electron microprobe analysis of the apatite pellets was utilized for deducing the structural formula of the average phosphorites of Egypt. Francolites exhibit several systematic isomorphous substitutions including Na, Mg, Sr, and Cd for Ca; and SO(,4) and CO(,3) for PO(,4). These substitutions result in measurable variations in the unit cell dimensions. These variations in the chemical compositions and unit cell dimensions of the pelletal phosphorites in Egypt show some relation to their coloration. / The uranium content and U/P(,2)O(,5) ratio show low values in Abu Tartur phosphorite deposits relative to the Red Sea and Nile Valley deposits. Autoradiographic studies of the Egyptian phosphorites showed that the radioactivity is unequally distributed among its constituents. The opaque pellets are the most radioactive and the bone fragments are the least radioactive. / Geochemically, four distinct groups of minerals were identified in the Egyptian phosphorites according to the degree of correlation between the major apatite components and the trace elements. These mineral groups are apatite, clays, heavy minerals and leached group. The results showed that the phosphorites of Nile Valley are relatively rich in Co and Zn whereas the Red Sea phosphorites are relatively rich in Pb and U. The Western Desert phosphorites are much richer in Ti as compared to the other two areas. Relative to the world phosphorites, the Egyptian phosphorites are geochemically enriched in Co, Mn, and Ni and impoverished in Sr, Cr, U, Zn, Cu, Ti, and V. / Source: Dissertation Abstracts International, Volume: 42-10, Section: B, page: 3987. / Thesis (Ph.D.)--The Florida State University, 1981.
25

Miocene–Pliocene Calcareous Nannofossil Biostratigraphy of IODP Site U1457, Arabian Sea

Unknown Date (has links)
International Ocean Discovery Program (IODP) Expedition 355 drilled two sites (U1456 and U1457) in Laxmi Basin, located in the eastern Arabian Sea. The primary objective of Expedition 355 is to better understand the impact that the Indian (southwest) summer monsoon has on weathering and erosion of the Himalayas and how this in turn affects mountain building. Laxmi Basin is located within the Indus Fan, the second largest submarine fan in the world that has primarily been fed by the Indus River and its associated tributaries since the collision of India and Eurasia in the Paleogene. Thus, the drill sites are ideally situated to record changes in erosion from the Himalayas through time, which requires a robust chronostratigraphic framework. Analysis of 275 samples for calcareous nannofossil biostratigraphy from Hole U1457C has refined the age model that was produced onboard during Expedition 355. The section is assigned to nannofossil Zones NN11–17 (late Miocene to early Pleistocene). In conjunction with shipboard magnetostratigraphy and planktonic foraminifer biostratigraphy, the age model indicates variable sedimentation rates as well as the presence of an unconformity that spans at least 1.46 m.y. between ~5.5 and 4 Ma. Late Miocene sedimentation was variable at ~27 cm/k.y. before 7.42 Ma, but averaged ~2.4 cm/k.y. between 5.94 and 7.42 Ma. Sedimentation rates increased again from 5.94 to 5.59 Ma to ~20 cm/k.y., when deposition was interrupted for at least 1.46 m.y. until ~4 Ma. After the hiatus and through the Pliocene, sedimentation rates were lower at ~3.6 cm/k.y. until the early Pleistocene when sedimentation rates reached ~8.9 cm/k.y. before slowing to ~3.4 cm/k.y. through 2.39 Ma. Further work to incorporate additional biostratigraphic and paleomagnetic constraints, should produce a robust chronostratigraphic framework that is necessary to examine the evolution of the Himalayas as well as climate in the late Miocene through Pliocene. / A Thesis submitted to the Department of Earth, Ocean & Atmospheric Science in partial fulfillment of the requirements for the degree of Master of Science. / Fall Semester 2015. / November 12, 2015. / Arabian Sea, biostratigraphy, miocene, nannofossil, pliocene / Includes bibliographical references. / Sherwood W. Wise, Professor Directing Thesis; Denise K. Kulhanek, Committee Member; William C. Parker, Committee Member; Leroy Odom, Committee Member.
26

Paleozoic history of the Nantahala and Brasstown formations of the basal Murphy belt, southwesternmost North Carolina and northernmost Georgia

Unknown Date (has links)
The Murphy belt of Georgia and North Carolina is located in the western Blue Ridge of the southern Appalachians. The general structure is a first generation, northeast trending, isoclinal synclinorium, overturned to the northwest. Coaxial second generation folds and oblique third generation folds produce interference patterns. The siliciclastics rocks, which form the basal units in the Murphy belt (Nantahala and Brasstown Formations), are overlain stratigraphically by the Murphy Marble. These three formations make up the Hiwassee River Group. The Nantahala Formation was conformably deposited upon the Great Smoky Group of the Ocoee Supergroup, and the Mineral Bluff Group was unconformably deposited upon the Murphy Marble and underlying units. Subarkosic metasandstones of the Nantahala Formation are composed of recrystallized quartz, detrital feldspar, micas and tourmaline. Nantahala Formation metasiltstones consist of alternating laminations of light-colored, fine-grained subarkosic metasandstone and dark-colored, graphitic metasiltstone containing biotite, garnet, and pyrrhotite. The Brasstown Formation consists of interlayered, dark-colored metapelite, alternating with quartz-rich mica schist, and contains biotite, garnet, and locally staurolite porphyroblasts and detrital feldspar. / These rocks were polydeformed and were metamorphosed up to staurolite grade, but many primary structures are preserved. Planar-tabular cross bedding, asymmetric ripple marks, penecontemporaneous contortion, rip-up clasts, and conglomerate were identified. Progradational relative sea-level cycles as reflected in the Nantahala Formation are associated with the deposition of numerous metasandstone units. These stacked units coarsen upward from metasiltstone into metaconglomerate. Progradational facies were overlain by a transgressive facies represented by the Brasstown Formation, followed by a starved shelf environment during a highstand as represented by the Murphy Marble. / Although direct correlation is complicated by numerous faults, the Early Cambrian Chilhowee Group, overlain by the Shady Dolomite, in the western boundary of the Blue Ridge is probably correlative to the Hiwassee River Group. From Georgia the Hiwassee River Group thickens along strike to the northeast and may be an easterly extension of the Chilhowee Group depositional basin. The fluvial to shallow marine, transgressive Chilhowee Group units were deposited during the initial drift phase in the formation of the Iapetus Ocean on the Atlantic-type Laurentian margin. Hiwassee River Group rocks were probably distal facies equivalents of the Chilhowee Group and were deposited in a middle-shelf environment. / Source: Dissertation Abstracts International, Volume: 55-09, Section: B, page: 3778. / Major Professor: James F. Tull. / Thesis (Ph.D.)--The Florida State University, 1994.
27

THE NEOGENE STRATIGRAPHY OF THE CENTRAL FLORIDA PANHANDLE

Unknown Date (has links)
Two groups, ten formations, and one member are recognized and described from the Neogene strata of the central Florida panhandle. The Alum Bluff Group is redefined on the basis of lithology and includes the Chipola Formation, Oak Grove Sand, Shoal River Formation, Whites Creek Member of the Shoal River Formation, Choctawhatchee Formation, and Jackson Bluff Formation. Hawthorn deposits, including the Torreya Formation, are excluded from the Alum Bluff Group. The Coastal Group includes the Bruce Creek Limestone, St. Joe Limestone, and Intracoastal Limestone. The Citronelle Formation is not included in either group. / Portions of three structural features are present in the central Florida panhandle. The Gulf Coast Basin is restricted to the region west of the Choctawhatchee River, the Apalachicola Embayment extends east of the Chipola-Apalachicola River area, and the Chattahoochee Arch lies between. The stratigraphy is related to these structural features. The main mass of the Alum Bluff Group is restricted to the eastern margin of the Gulf Coast Basin and to the vicinity of the Chattahoochee Arch whereas the Hawthorn deposits are restricted to the Apalachicola Embayment area. / At least seven periods of deposition and at least seven periods of nondeposition are recognized. The periods of deposition include the following biostratigraphically equivalent formations: (1) undifferentiated Chickasawhayan deposits - "Suwannee" limestone - Chattahoochee Formation of late Oligocene, Chattian age; (2) Chipola Formation - Chipola-equivalent sands - Chipola-equivalent limestone of early Miocene, Burdigalian age; (3) Bruce Creek Limestone - Oak Grove Sand of middle Miocene, Langhian age; (4) Whites Creek Member - St. Joe Limestone of middle Miocene, late Langhian and early Serravallian age; (5) middle and upper Shoal River Formation - St. Joe Limestone of middle Miocene, Serravallian age; (6) Choctawhatchee Formation of late Miocene, Tortonian age; and (7) Intracoastal Limestone - Jackson Bluff Formation - phosphoritic sand unit of Pliocene, late Zanclian to Piacenzian age. There is evidence that an eighth, late Pleistocene period of deposition is present. / Source: Dissertation Abstracts International, Volume: 45-01, Section: B, page: 0101. / Thesis (Ph.D.)--The Florida State University, 1984.
28

AN INVESTIGATION OF THE GEOLOGY, HYDROGEOLOGY, AND HYDROCHEMISTRY OF THE LOWER SUWANNEE RIVER BASIN (FLORIDA)

Unknown Date (has links)
The purpose of this study was to conduct a unified comprehensive investigation of the hydrogeology of a basin located in a carbonate terrain. This study defines the geologic and hydrogeologic characteristics of the Lower Suwannee River Basin, Florida. This research is believed to be the first basin study that incorporates multivariate factor analysis and uranium disequilibrium methodology as an integral part of a carbonate basin study. / All of the area within the Lower Suwannee River Basin is underlain by limestones and dolomites; most of these deposits lie near the surface. Solution of the carbonates has resulted in the development of a karst plain. Examination of 222 sets of well cuttings, 67 sets of auger samples and six cores permitted the construction of geologic cross-sections that show the Ocala Group limestones and, to a lesser extent, the Suwannee Limestone as the major lithologic components of the Upper Floridan aquifer. / Utilizing R-mode factor analysis and correlation coefficient analyses, it was possible to distinguish water samples from wells completed into a surficial aquifer from those completed into the Floridan aquifer. Three water masses were delineated in the Upper Floridan aquifer utilizing the same analyses. / Analyses for uranium were performed on water samples from 62 wells, 32 springs, and 5 river sites. Factor analysis showed an inverse relationship between the U-238 concentration and the U-234/U-238 activity ratio; however, the uranium parameters were not associated with any of the other parameters measured. / The activity ratios for wells and springs ranged from .39 (+OR-) .02 to 2.57 (+OR-) .60. The uranium concentrations range from less than .02 ppb to 44.8 (+OR-) .11 ppb. Generally, high ratio-low concentration values are associated with areas of very low to moderate recharge to the Floridan aquifer, whereas the low ratio-high concentration values are usually associated with areas of high recharge. / The Lower Suwannee River is almost totally dependent on groundwater contributions for its flow. Both river hydrochemical data and the uranium disequilibrium results supported this conclusion. / Source: Dissertation Abstracts International, Volume: 44-09, Section: B, page: 2685. / Thesis (Ph.D.)--The Florida State University, 1983.
29

LEAD AND SULFUR ISOTOPE SYSTEMATICS IN SULFIDE DEPOSITS OF THE PIEDMONT AND BLUE RIDGE PROVINCES OF THE SOUTHERN APPALACHIANS

Unknown Date (has links)
Lead isotope ratios of galenas from stratabound massive sulfide deposits in upper Precambrian metasediments of the Blue Ridge (BR) geologic province are too radiogenic for their presumed synsedimentary, late Precambrian age. A positive correlation between lead and sulfur isotope ratios in galenas from Ducktown, Tennessee, is interpreted as an original characteristic of the ores, and indicates that the radiogenicity of the lead is not the result of metamorphic processes, but of derivation of lead from U/Pb-enriched elastic sediments. At Ducktown, however, lead and sulfur isotope ratios indicate a component derived from a mafic source, and suggest that rift basin faulting may have controlled mineralization. Lead isotope ratios in Mount Rogers Formation rhyolites and in BR Paleozoic plutons indicate different sources of lead than those contributing to lead in massive sulfide deposits. / Lead isotope ratios of galenas from Piedmont province polymetallic massive sulfide (PMS) deposits define a trend of decreasingly ensialic volcanism from northeast to southwest. A regression through the data has a slope that corresponds to a secondary isochron age of about 3.7 b.y. The line is proposed to represent mixing between variable amounts of upper crustal lead (decreasing to the southwest) with lead from a source depleted in U/Pb and Th/Pb ratios relative to upper crust. The depleted source has, however, experienced either continuous or episodic enrichment of uranium relative to lead. The occurrence of a similar trend in galenas from Kings Mountain belt ores is further evidence for such a source. Sulfur isotope ratios in PMS are consistent with derivation of sulfur from lower Paleozoic seawater sulfate. / Rocks and ores from the southern Appalachians have lead isotope patterns that suggest three distinct isotope provinces. Rocks and vein deposits of the Blue Ridge and Inner Piedmont appear to be dominated by lead derived from Grenville-age crust. Some rocks of the eastern Piedmont are characterized by lower ('207)Pb/('204)Pb and ('208)Pb/('204)Pb ratios than BR and Inner Piedmont rocks. PMS and the Kings Mountain belt have isotope ratios suggesting a mixed source with Grenville-age basement as one end menber and mantle or mantle-derived material as the other. / Source: Dissertation Abstracts International, Volume: 44-09, Section: B, page: 2688. / Thesis (Ph.D.)--The Florida State University, 1983.
30

THE LITHOSTRATIGRAPHY OF THE HAWTHORN GROUP (MIOCENE) OF FLORIDA (PHOSPHATE, PHOSPHOGENESIS, PHOSPHORITE, FLORIDA, GEORGIA)

Unknown Date (has links)
The Hawthorn Formation of previous investigators has been raised to group status in Georgia. The present investigation extends the formations recognized in southern Georgia into northern Florida with some modifications. The Hawthorn Group of southern Florida represents new lithostratigraphic nomenclature. / The Hawthorn Group in northern Florida consists of, in ascending order, the Penney Farms, the Marks Head and the Coosawhatchie formations. The Coosawhatchie Formation grades laterally and, in a limited area, vertically into the Statenville Formation. / Lithologically, the Hawthorn Group in northern Florida is made up of a basal carbonate with interbedded clastics (Penney Farms), a clastic-carbonate sequence (Marks Head), a predominantly clastic unit (Coosawhatchie) and a crossbedded, predominantly clastic unit (Statenville). Phosphate is present throughout these sediments. The ages range from early Miocene (Aquitanian) to Middle Miocene (Serravalian). / In southern Florida the group is comprised of two formations (in ascending order) the Arcadia and the Peace River. The Tampa Formation of former usuage is included as a lower member of the Arcadia Formation. Similarly, the Bone Valley Formation of former usuage is incorporated as a member in the Peace River Formation. / Lithologically the Arcadia Formation is composed of carbonate with varying amounts of clastics. Clastic sediments in the Arcadia are most prevalent in the Nocatee Member (basal Arcadia). The Peace River Formation is predominantly a clastic unit with some interbedded carbonates. Phosphorite gravel is most common in the Bone Valley Member. Sand sized phosphate is virtually ubiquitous in these sediments with the exception of the Tampa Member where it is often absent. The ages range from Early Miocene (Aquitanian) to Early Pliocene (Zanclian). / The Hawthorn Group in the eastern Florida panhandle is composed of the Torreya Formation and in a few areas a Middle (?) Miocene unnamed clastic unit. Lithologically, the Torreya consists of a carbonate rich basal section and a dominantly clastic upper unit. Phosphate is noticably less common in the panhandle Hawthorn Group sediments. / Source: Dissertation Abstracts International, Volume: 47-06, Section: B, page: 2350. / Thesis (Ph.D.)--The Florida State University, 1986.

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