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No description available.

The Vazante Northern Extension is a continuation of the structurally controlled, hypogene nonsulfide zinc deposit from the Vazante Mine, Minas Gerais, Brazil. The deposit is hosted in Neoproterozoic carbonates of the Serra do Poço Verde Formation located in the Brasília Fold Belt along the western margin of the São Francisco Craton. The Northern Extension deposit is hosted within a shear zone that strikes 200 to 225 and dips 30º-70º NW and is associated with substantial folding that occurred in the same deformation (D2) event and later transcurrent faulting. The shear zone is composed of a tectonic-hydrothermal breccia that can be subdivided into four types: Type 1 Breccia– distally located from the willemite (Zn2SiO4) ore, weakly brecciated dolostone with some Fe-carbonate alteration; Type 2 Breccia–Strong Fe-carbonate alteration, intense brecciation; Type 3 Breccia–hematite replacement breccia, usually proximal to the Type 4 Breccia; Type 4 Breccia–willemite ore breccia, containing three generations of hypogene willemite (Zn2SiO4) as well as hematite (Fe2O3), and franklinite (ZnFe2O4). In the southern part of the deposit, late sulfide-rich veinlets are observed cutting the hypogene zinc silicate mineralization, and contain galena, sphalerite, native silver, covellite, and stromeyerite (Cu1-xAg1-xS). Geochemical studies conducted on the tectonic-hydrothermal breccia showed a strong regional signature enriched in Ag, Cd, Pb, and Zn. The presence of willemite as opposed to sphalerite and the ubiquity of hematite suggest that the zinc silicate mineralization has formed from the mixing between a low sulfur, acid, oxidizing metalliferous basinal brine similar to the fluids found in MVT deposits with a cooler, more oxidizing, meteoric fluid. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2012-02-29 16:45:36.41

Thesis (Professional Degree)--University of Missouri, School of Mines and Metallurgy, 1910. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed June 18, 2009)

Thesis (Ph. D.)--University of Canterbury, 2010. / Typescript (photocopy). "February 2010." Includes bibliographical references (p. 168-181). Also available via the World Wide Web.

Thesis (Ph. D.)--University of Alabama at Birmingham, 2009. / Title from PDF title page (viewed Feb. 3, 2010). Additional advisors: Renato Camata, Derrick Dean, Chris M. Lawson, Andrei Stanishevsky, Sergey Vyazovkin. Includes bibliographical references (p. 133-140).

published_or_final_version / abstract / Physics / Doctoral / Doctor of Philosophy

published_or_final_version / Physics / Master / Master of Philosophy

The separation of oxidation-reduction reactions into individual half-cells with a resulting "mixed potential" is well known as a dissolution mechanism for metals; however, the mechanism by which non-conducting crystals lose ions to the solution has been studied only slightly.

In making this study it is important to search for ways to enhance and, if possible, make detection of MMO signals simpler in order that this technique for obtaining FS measurements may be extended to other materials. This attempt to improve measurement techniques has resulted in a significant discovery: the eddy-current techniques described in detail in a later section which should allow MMO to be observed and sensitively measured in many additional solids. The second major thrust of the study has been to use the newly discovered eddy-current technique in obtaining the first indisputable observation of MMO in zinc.