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USGS Spectral Library Version 7 Sample Description

Kokaly, R.F., Clark, R.N., Swayze, G.A., Livo, K.E., Hoefen, T.M., Pearson, N.C., Wise, R.A., Benzel, W.M., Lowers, H.A., Driscoll, R.L., and Klein, A.J., 2017, USGS Spectral Library Version 7: U.S. Geological Survey Data Series 1035, 61 p., https://doi.org/10.3133/ds1035
For more information on the library, see: local link web link

TITLE: Olivine GDS71 Fo91 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: GDS71.a, GDS71.b

MINERAL_TYPE: Nesosilicate

MINERAL: Olivine

FORMULA: Mg2SiO4-Fe2SiO4

FORMULA_HTML: Mg2Si4-Fe2SiO4 Fo91

COLLECTION_LOCALITY: Twin Sisters Peak, Washington

ORIGINAL_DONOR: Trude V.V. King

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Samples were wet-sieved into grain size fractions and hand-picked prior to spectral measurements. This sample was derived from a dunite.

King, T.V.V. and W.I. Ridley, 1987, Relation of the Spectroscopic Reflectance of Olivine to Mineral Chemistry and Some Remote Sensing Implications. J. Geophys. Res., 11,457-11,469.

Grain size fractions are indicated by the extension after the sample number:
.a = 60-104µm
.b = less than 60µm

IMAGE_OF_SAMPLE:
Photo of sample

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV - 30 mA, 7.3-9.5 keV
File: oliv71.mdi (smear on quartz plate)
References: PDF2 #34-0189, 31-0795
Found: Forsterite

Comments: Sharp peaks show good resolution of the alpha1-alpha2 components. The pattern is very similar to that of HS-285.4B, including the shoulders. PDF2 34-0189 (synthetic endmember forsterite) is an excellent match for GDS-71, much better than 31-0795 (ferroan forsterite). The shoulders could be caused by slight Fe-Mg zoning.

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: EPMA # XRF, EPMA, ICP(Trace), WChem

COMPOSITION
KEYWORD		 Oxide
ASCII		 Amount Weight
Percent, %		 Oxide
html
COMPOSITION: SiO2 40.06 wt% SiO2
COMPOSITION: TiO2 0.14 wt% TiO2
COMPOSITION: Cr2O3 0.06 wt% Cr2O3
COMPOSITION: FeO 7.93 wt% FeO
COMPOSITION: NiO 0.28 wt% NiO
COMPOSITION: MnO 0.12 wt% MnO
COMPOSITION: MgO 50.70 wt% MgO
COMPOSITION: CaO 0.06 wt% CaO
COMPOSITION: Total 99.94 wt%

COMPOSITION_TRACE:

COMPOSITION_DISCUSSION:

This is a USGS microprobe standard analysis of Twin Sister Peak, Washington, dunite.

King, T.V.V. and W.I. Ridley, 1987, Relation of the Spectroscopic Reflectance of Olivine to Mineral Chemistry and Some Remote Sensing Implications. J. Geophys. Res., 11,457-11,469.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

This is a pure mineral separate. There are weak 2.3-µm alteration features, The rest of the spectrum rates an a.

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1b2c3b4_ # GDS71.a # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1b2c3b4u # GDS71.b # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns