Natural zeolites of New Zealand : occurrence, properties, use

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Baines, Alun (Alun Bernard)

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Recently there has been an increase in i:Qterest in zeolite minerals, mainly through commercial mining operations in the North Island and the research carried out by NIW A reporting on the potential of these deposits. Zeolites made a name in New fealand with the classical description of zeolite facies metamorphism (Coombs, 1951) based on the Taringatura Hills, in Southland. · Zeolite localities are numerous in New Zealand mainly in basic volcanic rocks and some outstanding specimens have been found and recorded. Specimens from some South Island localities have been collected and are described. Because of their small size, unless some means of magnification is provided, the specimens are not fully appreciated. Zeolites have been collected and examined by Optical techniques, Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Electron Probe Microanalyzer and X-ray Fluorescence (XRF) to determine their identity, morphology, and chemical composition. The chemistry of natural zeolites is complex; the capability of the zeolite to exchange cations and water at very low temperatures makes it difficult to the determine their composition. Electron microprobe analysis is made difficult with the ease that water is "boiled off' by th~ electron beam. Element mapping has provided an aid, and illustrates the chemical distribution of sodium and calcium cations in the crystal structure. The Scanning Electron Microscopy has been valuable in illustrating the process of twinning and epitaxal growth relations between different zeolites. A X-ray Diffraction database of New Zealand zeolites is being compiled for reference. The two commercial operations in the North Island have been visited to determine the geological environment in which these zeolites formed and to analyse the samples from these deposits. The work is ongoing. With the extent of Tertiary basaltic rocks and geothermal deposits in·the North Island provides great opportunities to find new deposits and hopefully more new zeolite specimens. ~

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vi, 77 leaves : ill. (some col.), maps ; 30 cm.

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2001Baines

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http://download.otagogeology.org.nz/temp/Abstracts/2001Baines.pdf

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Baines, Alun (Alun Bernard), “Natural zeolites of New Zealand : occurrence, properties, use ,” Otago Geology Theses, accessed May 22, 2024, https://theses.otagogeology.org.nz/items/show/376.

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