Composition of fluid inclusions from the cave-in-rock bedded-replacement fluorite deposits in the Illinois-Kentucky district

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Composition of fluid inclusions from the cave-in-rock bedded-replacement fluorite deposits in the Illinois-Kentucky district

Please use this identifier to cite or link to this item: http://hdl.handle.net/10355/14347

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dc.contributor.advisor Appold, Martin Stephan en_US
dc.contributor.author Pelch, Michael A.
dc.date.accessioned 2012-05-23T17:20:22Z
dc.date.available 2012-05-23T17:20:22Z
dc.date.issued 2011
dc.date.submitted 2011 Summer en_US
dc.identifier.other PelchM-072111-T45
dc.identifier.uri http://hdl.handle.net/10355/14347
dc.description Title from PDF of title page (University of Missouri--Columbia, viewed on May 23, 2012). en_US
dc.description The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. en_US
dc.description Thesis advisor: Dr. Martin Appold en_US
dc.description Includes bibliographical references. en_US
dc.description Dissertations, Academic -- University of Missouri--Columbia -- Geological sciences. en_US
dc.description "July 2011" en_US
dc.description.abstract The stable mid-continent platform of North America hosts some of the greatest known concentrations of Mississippi Valley-type (MVT) mineralization in the world. Most of the mineralization occurs between two major physiographic regions, the Ozark Plateau and the Interior Low Plateau. The Illinois-Kentucky district is one of three principal MVT districts in the Interior Low Plateau and is distinct from other North American mid-continent MVT deposits in that its ore mineral assemblage is dominated by fluorite instead of sulfide minerals or barite. However, like these other MVT deposits, the Illinois- Kentucky deposits were probably precipitated from northward flowing sedimentary brines set in motion by topographic gradients created by the Alleghanian-Ouachita orogeny during the Late Paleozoic. The primary objective of the current study was to quantify the chemical composition of the mineralizing fluids through in situ fluid inclusion analysis using microthermometry, laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), and laser Raman spectroscopy in order to try to gain insights into the ore formation process. Results show that the fluids that formed the Illinois-Kentucky district are chemically distinct from the fluids that formed MVT deposits in the Ozark Plateau. These differences can be attributed to interaction of the mineralizing sedimentary brines with ultramafic, rift-related igneous rocks present in the Illinois-Kentucky district but not in any of the Ozark Plateau districts. Fluid inclusion homogenization temperature and salinity relationships suggest that MVT mineralization in the Illinois-Kentucky district was produced from a mixture of at least three brines, two of which had relatively high salinities and temperatures and the third of which was cooler and more dilute. Mixing among at least three fluids is supported by the elemental concentration data, which tend not to correlate with one another or with the microthermometry data, but rather plot as two-dimensional arrays. The compositions of the end member fluids could not be pinpointed from the available data, however it appears that at least one of the fluids had elevated concentrations of the ore metals, Pb, Zn, Cu, and Fe as high as on the order of 1000's of ppm. en_US
dc.format.extent vii, 52 pages en_US
dc.language.iso en_US en_US
dc.publisher University of Missouri--Columbia en_US
dc.relation.ispartof 2011 Freely available theses (MU) en_US
dc.subject fluid inclusion en_US
dc.subject Mississippi Valley type deposits en_US
dc.subject mineralization en_US
dc.subject fluorite en_US
dc.title Composition of fluid inclusions from the cave-in-rock bedded-replacement fluorite deposits in the Illinois-Kentucky district en_US
dc.type Thesis en_US
thesis.degree.discipline Geological Sciences en_US
thesis.degree.grantor University of Missouri--Columbia en_US
thesis.degree.name M.S. en_US
thesis.degree.level Masters en_US
dc.relation.ispartofcommunity University of Missouri-Columbia. Graduate School. Theses and Dissertations. Theses. 2011 Theses


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