Micrometer-thin rims of hydrothermally altered zircon preserve significant geological information regarding the timing and nature of fluid infiltration. The research presented in this thesis details an investigation of the isotopic and geochemical composition zircon rims from deformed Archean meta-sedimentary rocks proximal to the world class Musselwhite gold deposit. A continuous ablation Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) U-Pb technique is proposed in conjunction with Secondary Ion Mass Spectrometry (SIMS) U-Pb and LA-ICP-MS REE depth profile methods. These techniques are capable of identifying and analyzing isotopic and chemical modification of zircon rims that are <5 μm thick by ablating directly into the surface of unpolished crystals. The age of analyzed rims is >100 m.y younger than crystal interiors and corresponds to periods of regional magmatism and hydrothermal activity. The measured thickness of rims is variable across single grains and between grain suites suggesting that they do not form as a uniform mantle around the crystal interior. Instead the interacting fluids exploit pre-existing structural weaknesses caused by sedimentary transport and the α-decay of uranium. A novel LA-ICP-MS single element grain 2-dimension mapping technique for unpolished zircon demonstrates preferential element mobility along fractures and in isolated patches. Pressure-temperature experiments were conducted on a zircon reference material under lower greenschist facies conditions to better understand the low temperature incorporation of REEs into the zircon structure. LA-ICP-MS element mapping of unpolished grains reveals that zircon are chemically modified under these conditions, as characterized by an increase in Ce and Y concentration (up to an order of magnitude enrichment) in CePO4-bearing and YPO4-bearing experiments, respectively, when compared with the concentrations of unaltered primary grains. The integration of these micro-analytical techniques on unpolished zircon can provide insight into the timing of low- to moderate-temperature history of supracrustal rocks which would remain otherwise undefined.

archives@tulane.edu / This dissertation combines laboratory experiments with analysis of field samples and geochemical modeling to examine rare earth elements (REEs) geochemistry. The Mississippi River estuary, Louisiana and the Pettaquamscutt River estuary, Rhode Island provided ideal study sites to investigate the effects of salinity and redox gradients, respectively, on the cycling of the REEs in natural environments. Similar to the REE behavior in major estuaries such as the Amazon estuary, the REEs in the Mississippi River undergo salt-induced coagulation removal during mixing with the saline Gulf of Mexico seawater. However, unlike the Amazon estuary in which dissolved REE removal of up to 90% has been reported, only ca. 50% removal is observed in the Mississippi River estuary. The closed-system batch reaction experiment which followed showed that interactions with the Mississippi River particulate material substantially alter the dissolved REE concentrations of the Gulf of Mexico seawater. Combined effects of dissolution of the labile phases on the riverine particles and secondary mineral precipitation of likely REE phosphate phases result in a 24 ± 12 folds (mean ± 1σ) net increase in the REE concentrations of the seawater. Less than 1% of the REE contents in the operationally defined “exchangeable” phase of the sediments was mobilized at the maximum REE concentrations in the reacted seawater. The behavior of the REEs in the Pettaquamscutt River estuary is coupled with the cycling of Fe and Mn oxides/oxyhydroxides in the oxic surface waters and across the chemocline. Reaction path modeling suggests that the REE content of the oxic surface waters depicts a combined effect of mixing of 3 water masses and surface complexation with hydrous manganese oxides to achieve the cerium depleted pattern that characterizes the entire water column. / 1 / Segun Adebayo

There are lots of important applications for lanthanides (Ln) because of their unique properties. The properties are closely linked to the environment of the crystal field. Thus, two kind of crystals Cs2NaLn(NO2)6 with high Th point-group symmetry and LnPO4 with monoclinic symmetry were chosen to study quantum cutting and Stokes shift. Quantum cutting is a kind of down-conversion energy transfer in which one excitation ultraviolet photon is transformed into multiple near infrared photons. This phenomenon has been studied in Cs2NaY0.96Yb0.04(NO2)6. The emission from Yb3+ can be excited via the NO2- antenna. The electronic transition of NO2- is situated at more than twice the energy of the Yb3+. At room temperature, one photon absorbed at 470 nm in the triplet state produced no more than one photon emitted. Some degree of quantum cutting was observed at 298 K under 420 nm excitation into the singlet state and at 25 K using excitation into singlet and triplet state. The quantum efficiency was about 10% at 25 K. In Chapter 3, Stokes shift which is the energy shift between the peak maxima in absorption and emission was studied. Stokes shift is related to the flexibility of the lattice and the coordination environment. Cs2NaCe(NO2)6 with 12-coordinated Ce3+ situated at a site of Th symmetry demonstrated the largest Ce-O Stokes shift of 8715 cm−1. The 4f1 ground state and 5d1 potential surfaces have displaced so much along the configuration coordinate that overlap takes place above the 5d1 minimum, leading to thermal quenching of emission at 53 K. A comparison of Stokes shifts with other Ce-O systems with different coordination number demonstrated larger Stokes shifts for Ce3+ ions with higher coordination number. Systematic research about the energy transfer (ET) and energy migration phenomenon is still scarce, although they exist extensively among lanthanide ions. The energy migration in highly doped materials has been stated as very fast or slow, but no experimental proof was reported. In Chapter 4, the ET between Tb3+ and Eu3+ was investigated experimentally and compared with available theoretical models in the regime of high Tb3+ concentrations in 30 nm LaPO4 nanoparticles at room temperature. The ET efficiency approached 100% even for lightly Eu3+-doped materials. The use of pulsed laser excitation and switched-off continuous wave laser diode excitation demonstrated that the energy migration between Tb3+ ions, situated on La3+ sites with a 4 Å separation was not fast. The quenching of Tb3+ emission in singly doped LaPO4 only reduced the luminescence lifetime by about 50% in heavily doped samples. Various theoretical models have been applied to simulate the luminescence decays of Tb3+ and Eu3+-doped LaPO4 samples of various concentrations. The transfer mechanism has been identified as forced electric dipole at each ion. The control of energy transfer rate and efficiency is also an important issue. There are many chemical and geometrical factors that affect energy transfer, including the spectra overlap, the dipole orientation and the distance between the donor and acceptor. The local field of the emission center is another factor that affect the energy transfer by changing the photonic environment. In Chapter 5, the local field effect on the energy transfer between Tb3+ and Eu3+ doped in LaPO4 dispersed in different solvents and solids with a wide range of refractive indexes was studied. The effects of local field (reflected by refractive index) on the ET efficiency and ET rates were clarified that the ET efficiency would decrease with increasing refractive index, while ET rates were independent of the refractive index

Scale 1 inch = 6 leagues. Library of Congress facsimile No. 1a, which is based on the sixth out of ten issues (known as "states"). The original map was published in 1612, and the revisions comprising the sixth state are from 1624. The map includes ca. 200 names including Native American tribes, and is considered the first authoritative map of Virginia. / https://dc.etsu.edu/rare-maps/1122/thumbnail.jpg

Indicates locations of seventy one historic properties in east Tennessee. Drawn by Penelope Lane in 1984. Scale 1 in = 250000 ft. / https://dc.etsu.edu/rare-maps/1128/thumbnail.jpg

Hand drawn map indicating general locations associated with 28 authors. Includes a ahart below the map lists 60 authors with a representative publication for each. Copyright 1965, Whitehaven High School, Tommy D. Harris. No Scale Provided. / https://dc.etsu.edu/rare-maps/1129/thumbnail.jpg

Includes four hand drawn maps: a complete map of Tennessee, indicating dates and locations for 26 treaties with Native Americans from the 18th and 19th centuries, traced from W.R. Garrett and A.V. Goodpasture, History of Tennessee, Its People and Its Institutions (Nashville, 1900), pages 128-129; and a tripartite map of east, middle, and west Tennessee (traced from 1968 issue by AAA) indicating state lines, county lines, and locations of county seats. Drawn May 1968 by Katherine W. Ewing, Nashville. Copyright Katherine W. Ewing, 1973. / https://dc.etsu.edu/rare-maps/1131/thumbnail.jpg

Hand drawn and hand colored map tracing portions of a map in J.G.M. Ramsey, Annals of Tennessee (1853), with excerpts from John Donelson's log of the voyage to Cumberland Country. Indicates eleven points along the route, with respective dates and brief descriptions of highlights of the journey. Drawn July 1968 by Katherine W. Ewing, Nashville, Tennessee. Copyright 1972, Katherine W. Ewing. No scale provided. / https://dc.etsu.edu/rare-maps/1132/thumbnail.jpg

Indicates 414 events or locations of historic significance, and includes a legend summarizing their significance. For the Netherland Inn Association. Cartographer: H.T. Spoden. Illustrator: Bob Hensley. Copyright 1969 by H.T. and M.C. Spoden. Scale 1 in = 0.6 miles. / https://dc.etsu.edu/rare-maps/1134/thumbnail.jpg

Indicates state lines, county lines, and county seats. Eight original shires, established 1634, tinted yellow. Independent cities (not administered by a county government), with dates of incorporation as cities, tinted blue, with the exception of Hampton and Newport News which cover areas of Original Shires, Warwich (River) and Elizabeth City couties, now extinct. County origins taken from charts and county abstracts in first edition of "A Hornbook of Virginia History" (1949, Division of History of the Virginia Department of Conservation and Development, Richmond); the recent consolidation of areas to form new cities taken from 1965 edition of the Hornbook (publ. by the State Library, Richmond, under direction of Randolph W. Church, Virginia State Librarian). Drawn May 1968 by Katherine W. Ewing, Nashville, Tennessee. No scale provided. / https://dc.etsu.edu/rare-maps/1135/thumbnail.jpg