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(For further information on spectrsocopy, see:
http://speclab.cr.usgs.gov)
TITLE: Biotite WS660 DESCRIPT
DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: WS660
MINERAL_TYPE: Phyllosilicate
MINERAL: Annite (Mica group)
FORMULA: K(Fe+2)3AlSi3O10(OH,F)2
FORMULA_HTML: KFe+23AlSi3O10(OH,F)2
COLLECTION_LOCALITY: Bancroft, Ontario, Canada
ORIGINAL_DONOR: Wards Scientific
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
The sample appears uniform dark green and the visible-NIR spectrum shows strong iron bands and a spectrum typical of pure biotite.
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
Triocathedral mica - major - probably a mixture of compositions. No other components.
Konnert, Judith and Marta Flohr, 1992, unpublished data, USGS Reston, VA.
40 kV - 30 mA, 7.3-9.5 keV
File: annit660.out, -.mdi (edge=random mount)
References: Huebner's reference patterns; JCPDS #42-1413, 33-1016
Found: trioctahedral mica, 3T or 1M polytype
Comment: Basal reflections are surprisingly weak, even considering
the use of a random mount. Some peak broadening or splitting
suggests compositional heterogeneity of zoning. The position of the
(060) is consistent with Fe/(Mg+Fe+Mn) = 0.25 +/- 0.05 (phlogopite), but
not annite or siderophyllite.
J.S. Huebner, J. Pickrell, T. Schaefer, written communication(USGS)
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: EM(WDS) # XRF, EM(WDS), ICP(Trace), WChem
| COMPOSITION KEYWORD |
Oxide ASCII |
Amount | Weight Percent, % |
Oxide html |
|---|---|---|---|---|
| COMPOSITION: | SiO2 | 39.526 | wt% | SiO2 |
| COMPOSITION: | TiO2 | 2.042 | wt% | TiO2 |
| COMPOSITION: | Al2O3 | 11.052 | wt% | Al2O3 |
| COMPOSITION: | FeO | 16.995 | wt% | FeO |
| COMPOSITION: | MnO | 0.693 | wt% | MnO |
| COMPOSITION: | MgO | 14.456 | wt% | MgO |
| COMPOSITION: | CaO | 0.008 | wt% | CaO |
| COMPOSITION: | Na2O | 0.607 | wt% | Na2O |
| COMPOSITION: | K2O | 9.668 | wt% | K2O |
| COMPOSITION: | Cl | 0.052 | wt% | Cl |
| COMPOSITION: | F | 3.181 | wt% | F |
| COMPOSITION: | Total | 98.281 | wt% | |
| COMPOSITION: | O=Cl,F,S | wt% | #correction for Cl, F, S | |
| COMPOSITION: | New Total | wt% |
COMPOSITION_TRACE: None
COMPOSITION_DISCUSSION:
None
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
Bimodal grain size distribution:
population 1 avg. grain size size = 300µm 80 vol%
population 2 avg. grain size size = 10µm 20 vol%
avg. grain size of populations = 270µm
Pure biotite with larger grains 80% coated by smaller grains. Micaceous flakes with avg. flake diameter = 20µm. Biaxial (-), larger 2V, slight pleochroism, single good basal cleavage. G. Swayze
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 435 | 0.2-3.0µm | 200 | g.s.= 270 µm |
| LIB_SPECTRA: | splib05a r 1358 | 0.2-3.0µm | 200 | g.s.= |
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