Download Guidebook as .pdf (2.2 Mb) - Carolina Geological Society

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2008 annual meeting – Spruce Pine Mining District: Little Switzerland, North Carolina
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Warner, R., Meadows, J., Fleisher, C., Sojda, S., Crawford, B., Stone, P.A., Price, V., and Temples, T.,
2004, Petrography and uranium mineralogy of SC DHEC well core, Jenkins Bridge Road near
Simpsonville, South Carolina: Geological Society of America Abstracts with Programs, v. 36, p. 225.
Wilson, W.F. and McKenzie, B.J., 1985, Some mineral collecting sites in North Carolina: Rocks and
Minerals, v. 60, p. 84-93.
FIGURE CAPTIONS
Figure 1. Backscattered electron images of uraninites from Spruce Pine pegmatites. Scale is given by bars
below each image. A) Relatively homogeneous uraninite from Deake mine. B) Higher magnification
image showing small-scale heterogeneities in uraninite, Deer Park mine. Brighter areas have higher
uranium. C) Broad-scale banding in uraninite from Pink mine. Darker area (bottom) yielded lower
analysis totals and is more prone to damage from the electron beam. D) Compositional banding in
uraninite from Goog Rock mine. Darker area (lower right) is Ca-rich; brighter areas have higher uranium.
Figure 2. X-ray diffraction patterns of uraninite from Goog Rock mine (top) and Carolina Mineral Co. No.
20 mine (bottom). The scans show diffraction peaks with the background removed. Beneath are the peaks
located from the scans and, below that, matching uraninite peaks from a data file.
Figure 3. A) Backscattered electron image of inhomogeneous uraninite from Deake mine (bar gives
scale). B) X-ray map of Ca distribution in same field of view. Note that brighter areas are higher in Ca
(and also yield higher analysis totals).
Figure 4. Ternary plot of A-site cations in samarskite-group minerals. Subdivision into samarskite-(Y),
ishikawaite, and calciosamarskite is based on relative dominance of (Y+REE), (U+Th), and Ca,
respectively (Hanson and others, 1999). Open triangles, data from this study; filled star, samarskite-(Y)
analysis reported by Allen (1877); open star, calciosamarskite analysis reported in Hanson and others
(1999).
Figure 5. Backscattered electron images of uranium-bearing niobate-tantalate minerals in Spruce Pine
pegmatites. Scale is given by bars below each image. A) Sample from McKinney mine consisting of
intergrown uranoan microlite (brightest phase), samarskite-(Y) (intermediate brightness), and fergusonite
(dark phase). Note burn marks (from electron beam damage) in fergusonite (near center of image and
toward right side above uranoan microlite). B) Fergusonite (darker, inhomogeneous phase on left side of
grain) and plumbopyrochlore (bright, on right side of grain) from W. W. Wiseman mine. Tiny, very bright
material included in fergusonite and in plumbopyrochlore is uraninite. Separate grain at lower right is
samarskite-(Y).
Figure 6. Ternary plot of B-site cations in pyrochlore-group minerals. Fields for betafite, pyrochlore, and
microlite are based on Hogarth (1977) classification. Symbols: open triangles, uranoan microlite from this
study; filled triangle, plumbopyrochlore from this study; open star, uranoan pyrochlore from Mitchell
County (Allen, 1877; Frondel, 1958); plusses, betafite from Maw Bridge pegmatite, South Carolina
(Warner and Fleisher, 2004).
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