Sample Description USGS Spectral Library Version 7

USGS Spectral Library Version 7 Sample Description

Kokaly, R.F., Clark, R.N., Swayze, G.A., Livo, K.E., Hoefen, T.M., Pearson, N.C., Wise, R.A., Benzel, W.M., Lowers, H.A., Driscoll, R.L., and Klein, A.J., 2017, USGS Spectral Library Version 7: U.S. Geological Survey Data Series 1035, 61 p., https://doi.org/10.3133/ds1035
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TITLE: K-Alunite CU91-217G1 High Temp? DESCRIPT

DOCUMENTATION_FORMAT: MIXTURE

SAMPLE_ID: CU91-217G1

MIXTURE_TYPE: Intimate

MIXTURE: K-alunite + other mineral phases

FORMULA: KAl3(SO4)2(OH)6

FORMULA_HTML: KAl₃(SO₄)₂(OH)₆

COLLECTION_LOCALITY: Alunite Hill, Western Alter. Center, Cuprite, Nevada, USA

ORIGINAL_DONOR: Gregg Swayze

COLLECTION_LATITUDE: N37 31.45' # degrees and decimal minutes (N or S)

COLLECTION_LONGITUDE: W117 12.72' # degrees and decimal minutes (W or E) P> DATUM: NAD27 # coordinate datum

CURRENT_SAMPLE_LOCATION: U.S.G.S. Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: U.S.G.S. Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

This sample was collected next to a fault along which hydrothermal fluids may have emerged near the center of alunite hill in the southwestern portion of the relict hydrothermal center at Cuprite, NV. The sample may have been part of the lower Cambrian Harkless Phyllite or a Tertiary rhyolitic tuff which was altered by the hydrothermal fluids about 7.5 Ma.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

K-alunite and quartz.

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: XRF # XRF, EPMA, ICP(Trace), WChem

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

None

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

None

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

The spectrum has absorptions characteristic of alunite. The intense absorption features may indicate that the alunite formed at relatively high temperatures if the sample is deficient in Al.

See: Swayze, G.A., 1997, The hydrothermal and structural history of the Cuprite Mining District, southwestern Nevada: an integrated geological and geophysical approach: unpublished Ph.D. Dissertation, University of Colorado at Boulder, 399p.

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1b2_3_4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns