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(For further information on spectroscopy, see:
http://speclab.cr.usgs.gov)
TITLE: Desert_Varnish GDS78A DESCRIPT
DOCUMENTATION_FORMAT: MIXTURE
SAMPLE_ID: GDS78A
MIXTURE_TYPE: Coating # Areal, Intimate, Coating, or Molecular
MIXTURE: Desert_Varnish
FORMULA: Na4Mn14O27*9H20 + alpha-Fe2O3 + clays
FORMULA_HTML: Na4Mn14O27•9H2 + alpha -Fe2O3
COLLECTION_LOCALITY: Stoddard Wells, CA.
ORIGINAL_DONOR: George Rossman, California Inst. of Technology
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
"Desert varnish invariably consists of birnessite in intimate mixture with hematite and large amounts of clay minerals. The clays are generally of the illite-montmorillonite type with minor kaolinite, but in several samples this concentration ratio is reversed."
This sample is a coating on desert pavement rhyolite and quartz cobbles.
Potter, R.M. and G.R. Rossman, 1979, Mineralogy of manganese dendrites and coatings. American Mineralogist, v.64, pp 1219-1226.
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: # XRF, EM(WDS), ICP(Trace), WChem
| COMPOSITION KEYWORD |
Oxide ASCII |
Amount | Weight Percent, % |
Oxide html |
|---|---|---|---|---|
| COMPOSITION: | SiO2 | 34.35 | wt% | SiO2 |
| COMPOSITION: | TiO2 | 0.78 | wt% | TiO2 |
| COMPOSITION: | Al2O3 | 20.01 | wt% | Al2O3 |
| COMPOSITION: | FeO | 10.96 | wt% | FeO |
| COMPOSITION: | MnO | 22.63 | wt% | MnO |
| COMPOSITION: | MgO | 2.43 | wt% | MgO |
| COMPOSITION: | BaO | 1.22 | wt% | BaO |
| COMPOSITION: | CaO | 1.28 | wt% | CaO |
| COMPOSITION: | Na2O | 0.23 | wt% | Na2O |
| COMPOSITION: | K2O | 1.89 | wt% | K2O |
| COMPOSITION: | P2O5 | 1.10 | wt% | P2O5 |
| COMPOSITION: | Total | 96.88 | wt% | |
| COMPOSITION: | O=Cl,F,S | wt% | #correction for Cl, F, S | |
| COMPOSITION: | New Total | wt% |
COMPOSITION_TRACE: None
COMPOSITION_DISCUSSION:
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1a2_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: | splib04a r 1365 | 0.2-3.0µm | 200 | g.s.= |
| LIB_SPECTRA: | splib05a r 9102 | 0.2-3.0µm | 200 | g.s.= |
| LIB_SPECTRA: | splib06a r 26731 | g.s.= |