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DOCUMENTATION_FORMAT: MIXTURE
SAMPLE_ID: CU01-4A
MIXTURE_TYPE: Intimate
MIXTURE: Hydrated Volcanic Glass + other phases
FORMULA: Not Available
FORMULA_HTML: Not Available
COLLECTION_LOCALITY: 6 km north of Western Center, Cuprite, Nevada, USA
ORIGINAL_DONOR: Gregg Swayze
COLLECTION_LATITUDE: N37 37.42' # degrees and decimal minutes (N or S)
COLLECTION_LONGITUDE: W117 13.92' # degrees and decimal minutes (W or E)
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 in an exposure of Tertiary volcanic tuff exposed north of the dirt road that transects the Goldfield Hills about 6 km north of the western center at Cuprite, NV.
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
Anorthite (major), sanidine (major), quartz (major), cristobalite or opal (minor), nontronite (minor), muscovite (trace), volcanic glass recognized as probably causing an "amorphous hump" in the diffractogram.
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 similar to those of opal and cristobalite. In particular is the small shoulder at 1.4675 microns on the long wavelength side of the 1st OH stretch overtone at 1.4153 microns. This shoulder appears in samples bearing cristobalite or opal. There is also a broad Si-OH combination band at 2.2145 microns that is a bit narrower than in opal or chalcedony (e.g. compare with CU00-15E and CU91-6A). The Si-OH combination band is partially overlapped on the long wavelength side by a nontronite absorption at 2.2926 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history of the Cuprite Mining District, southwestern Nevada: an integrated geological and geophysical approach: unpublished Ph.D. Dissertation, University of Colorado at Boulder, 399p.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: 1c2_3_4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns