(For further information on spectroscopy, see:
TITLE: Nontronite + others CU00-13A DESCRIPT
MIXTURE: Nontronite + other mineral phases
COLLECTION_LOCALITY: 5 km north of western center, Cuprite, Nevada, USA
ORIGINAL_DONOR: Gregg Swayze
COLLECTION_LATITUDE: N37 35.87' # degrees and decimal minutes (N or S)
COLLECTION_LONGITUDE: W117 14.07' # 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
This sample was collected from a weathered outcrop of the Tertiary rhyolitic Spearhead member of the Stonewall Flats Tuff about 5 km north of the western center at Cuprite, NV. Rocks at this site bordering a small drainage were weathering in an exfoliation pattern.
Clay separate contains smectite (major), kaolinite (trace), and mica (trace). XRD was unable to identify specific mineralogy of the smectite.
COMPOSITIONAL_ANALYSIS_TYPE: XRF # XRF, EM(WDS), ICP(Trace), WChem
The spectrum has an absorption at 2.2907 microns characteristic of nontronite (e.g. Nontronite NG-1 has a similar band at 2.2883 microns). A weak absorption at 2.2408 microns may be from a ferrouginous smectite. A sharp narrow absorption at 0.4490 microns may be from nontronite but is at a slightly shorter wavelength than a similar band in Nontronite NG-1 (e.g. at 0.4600 microns). Alternatively this narrow band may be from an Fe-sulfide mineral.
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history of the Cuprite Mining District, southwestern Nevada: an integrated geological and geophysical approach: unpublished Ph.D. Dissertation, University of Colorado at Boulder, 399p.
SPECTRAL_PURITY: 1b2_3_4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
|LIB_SPECTRA:||splib05a r 8851||0.2-3.0µm||200||g.s.=|
|LIB_SPECTRA:||splib06a r 26189||g.s.=|