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: Halloysite + others CU91-242D DESCRIPT

DOCUMENTATION_FORMAT: MIXTURE

SAMPLE_ID: CU91-242D

MIXTURE_TYPE: Intimate

MIXTURE: Halloysite CU91-242D + other mineral phases

FORMULA: Al2Si2O5(OH)4

FORMULA_HTML: Al₂Si₂O₅(OH)₄

COLLECTION_LOCALITY: Eastern Alteration Center, Cuprite, Nevada, USA

ORIGINAL_DONOR: Gregg Swayze

COLLECTION_LATITUDE: N37 32.07' # degrees and decimal minutes (N or S)

COLLECTION_LONGITUDE: W117 13.18' # 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 is from the southwestern portion of the western alteration center at Cuprite, NV. The sample is from altered lower Cambrian Harkless Phyllite hydrothermally altered about 7.5 Ma.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Based on glycolation halloysite was found. Also present are quartz, mica, alunite, and possibly dickite.

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 halloysite with a band at 2.2 microns with a weak shorter wavelength shoulder. The presence of trace amounts of alunite are indicated by the weak band at 1.477 microns.

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history of the Cuprite Mining District, southwestern Nevada: an integrated geological and geophysical approach: unpublished Ph.D. Dissertation, University of Colorado at Boulder, 399p.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