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(For further information on spectroscopy, see:
http://speclab.cr.usgs.gov)
TITLE: MedHi Al-muscovite +others CU91-252D DESCRIPT
DOCUMENTATION_FORMAT: MIXTURE
SAMPLE_ID: CU91-252D
MIXTURE_TYPE: Intimate
MIXTURE: MedHi Al-muscovite + quartz + clinochlore + goethite
FORMULA: KAl2(Si3Al)O10(OH,F)2 + SiO2 + (Mg,Fe2+)5Al(Si3Al)O10(OH)8 + alpha-FeO(OH)
FORMULA_HTML: KAl2(Si3Al)O10(OH,F)2 + SiO2 + (Mg,Fe2+)5Al(Si3Al)O10(OH)8 + alpha-FeO(OH)
COLLECTION_LOCALITY: Western Alteration Center, Cuprite, Nevada, USA
ORIGINAL_DONOR: Gregg Swayze
COLLECTION_LATITUDE: N37 31.75' # degrees and decimal minutes (N or S)
COLLECTION_LONGITUDE: W117 13.77' # 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 200 meters west of the southwestern end of the western alteration center at Cuprite, NV. The sample is from lower Cambrian Harkless Phyllite.
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
Quartz (major), muscovite (mostly 2M1 with a trace of 1M polytypes), clinochlore (trace). Absence of XRD detection of goethite may be due to its presence as a thin coating or its fine grained crystal size. Jarosite may not be abundant enough to be detected by XRD.
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 characteristic of a number of minerals. In the electronic region (0.35 - 1.35 microns) absorptions resembling those of goethite are spectrally dominant. The goethite absorptions are superimposed on those of clinochlore. The first OH overtone band of muscovite is located at 1.4101 microns while the Al-OH combination band is located at 2.1998 microns. A weak absorption at 2.257 microns may indicate the presence of jarosite, perhaps under the goethite coating.
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history of the Cuprite Mining District, southwestern Nevada: an integrated geological and geophysical approach: unpublished Ph.D. Dissertation, University of Colorado at Boulder, 399p.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 8805 | 0.2-3.0µm | 200 | g.s.= |
| LIB_SPECTRA: | splib06a r 26143 | g.s.= |