U.S. Geological Survey home page


Clark et. al. 2003 USGS Open File Report 03-395
Spectral Library splib05a Sample Description

(For further information on spectrsocopy, see: http://speclab.cr.usgs.gov)

TITLE: Hydrated Volcanic Glass CU01-4A DESCRIPT

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history of the Cuprite Mining District, southwestern Nevada: an integrated geological and geophysical approach: unpublished Ph.D. Dissertation, University of Colorado at Boulder, 399p.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

LIB_SPECTRA_HED: where Wave Range Av_Rs_Pwr Comment
LIB_SPECTRA: splib05a r 8339 0.2-3.0µm 200 g.s.=


USA.gov logo  Take Pride in America button