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TITLE: Na Alunite + Dickite MV99-6-26b

MATERIAL TYPE: MINERAL

SAMPLE ID: MV99-6-26b

MINERAL TYPE:  Intimate mixture

FORMULA: 

COLLECTION LOCALITY:  Yellow Jacket mine, Antelope Range, Sevier County, Utah

COLLECTION LOCALITY LAT/LONG:  38º 32’ 3.90” N, 112º 12’ 33.66” W

ORIGINAL DONOR:  Barnaby W. Rockwell

CURRENT SAMPLE LOCATION: USGS Denver, CO

ULTIMATE SAMPLE LOCATION: USGS Denver, CO

SAMPLE DESCRIPTION:

Highly argillized rock occurring along narrow fracture zone.

XRD ANALYSIS:

Major (>25%):  quartz
Minor (5%-25%):  natroalunite, dickite
Trace (<5%):  gypsum

COMPOSITIONAL ANALYSIS TYPE: EM(WDS) # XRF, EM(WDS), ICP(Trace), WChem

Compound/Element

Composition weight %

SiO2

TiO2

Al2O3

FeO

MnO

MgO

CaO

Na2O

K2O

Total

O=Cl,F,S

New Total

COMPOSITION DISCUSSION:

MICROSCOPIC EXAMINATION:

WAVELENGTH INTERVALS OF ABSORPTION FEATURES USED IN SPECTRAL ANALYSIS:

Absorption
Feature Number

Left continuum endpoint
(interval for averaging, in microns)

Right continuum endpoint
(interval for averaging, in microns)

1

2.060

2.090

2.230

2.260

2

1.455

1.470

1.528

1.558

3 (W)

2.258

2.288

2.348

2.378

SPECTRAL REGION USED FOR CURVE SHAPE COMPETITION:  1.4 - 2.5 µm, Tetracorder group 2

SPECTROSCOPIC DISCUSSION:

Since its addition to the spectral library used for Tetracorder analysis, this mineral mixture has been successfully identified and mapped at several locations, including:

1)      at the southern end of the western alteration center at Cuprite, Nevada,

2)      in the Goldfield Hills between Preble Mountain and the town of Goldfield, Nevada, and

3)      at the Big Star natroalunite mine, Antelope Range, Marysvale volcanic field, Sevier County, Utah.

USGS SPECTRAL LIBRARY LOCATION AND SPECTRAL RANGE:  sprlf01a r 364 0.35-2.50µm


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