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(For further information on spectroscopy, see:
http://speclab.cr.usgs.gov)
TITLE: Montmorillonite-Na + others CU93-52A DESCRIPT
DOCUMENTATION_FORMAT: MIXTURE
SAMPLE_ID: CU93-52A
MIXTURE_TYPE: Intimate
MIXTURE: Na-montmorillonite + others
FORMULA: (Na,Ca)0.33(Al,Mg)2Si4O10(OH)2*nH20
FORMULA_HTML: (Na,Ca)0.33(Al,Mg)2Si4O10(OH)2•nH20
COLLECTION_LOCALITY: Stonewall Playa, Cuprite, Nevada, USA
ORIGINAL_DONOR: Gregg Swayze
COLLECTION_LATITUDE: N37 31.85' # degrees and decimal minutes (N or S)
COLLECTION_LONGITUDE: W117 09.42' # 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 from the surface of the dry Stonewall Mud
playa 1 km east of the eastern alteration center at Cuprite, NV.
The original surface was preserved and spectrally measured in the
lab.
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
Quartz (major), anorthite (minor), albite (minor), calcite (minor),
orthoclase ( minor), muscovite (minor), montmorillonite (minor),
kaolinite (trace), magnesiohornblende (trace).
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 is relatively bright with an over all reflectance of about
52%. Spectral absorptions are weak with the strongest 1.917 microns due
to adsorbed or structural water in hydrated phases. The 1st OH overtone
is located at 1.4160 microns. There is a weak Fe-absorption at 0.9127
microns. The 6% band at 2.2094 microns is mostly due to montmorillonite
with contributions from muscovite. A weak calcite band may be indicated
by a 1.5% absorption at 2.347 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geological and geophysical approach: unpublished Ph.D. Dissertation,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 8657 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib06a r 25995 g.s.=