Introduction to reflectance spectroscopy and Spectral geology

Welcome to this presentation on an introduction to reflectance spectroscopy and spectral geology, two critical fields in the study of Earth's surface materials and their properties. Reflectance spectroscopy, a technique that measures the reflection of light or other electromagnetic radiation off a surface, provides vital information about the composition, texture, and structure of various materials. By analyzing the spectra—the unique patterns of light absorption and reflection—scientists can identify and quantify the minerals present in rocks, soils, and other geological formations.

Spectral geology leverages this technique to explore and understand the Earth's crust. Through the interpretation of spectral data, geologists can map mineral distributions, assess the quality of mineral deposits, and monitor environmental changes. The integration of reflectance spectroscopy into geological studies has revolutionized the field, offering a non-destructive, efficient, and highly accurate method for examining vast areas of the Earth's surface.

This presentation will delve into the principles of reflectance spectroscopy, exploring how different materials interact with light and how these interactions are captured and analyzed. We will discuss the instrumentation involved, including spectroradiometers and hyperspectral imaging systems, which collect data across a wide range of wavelengths. Additionally, we will explore the processing and interpretation of spectral data, including the use of software tools and algorithms to extract meaningful information.

Furthermore, we will highlight the applications of spectral geology in various domains such as mineral exploration, environmental monitoring, and planetary science. Through case studies and examples, we will demonstrate how spectral data is used to uncover hidden mineral resources, track changes in vegetation and soil composition, and even analyze the surface of other planets.

In essence, this presentation aims to provide a comprehensive overview of reflectance spectroscopy and spectral geology, shedding light on the powerful capabilities of these techniques in advancing our understanding of the Earth's surface and beyond. Whether you are a geologist, an environmental scientist, or simply someone with a keen interest in the natural world, this presentation will equip you with the knowledge to appreciate and leverage the insights gained from spectral analysis.

1. Introduction to
Reflectance Spectroscopy

3. GOLDFIELD, NV
ASD FIELDSPEC PRO

4. SPECTRAL GEOLOGY
EXPLORATION –PRECIOUS AND
BASE METALS
CORE LOGGING
METALLURGICAL
PETROLEUM -CORE LOGGING
MAPPING
LITHOLOGIES
REMOTE SENSING
INDUSTRIAL MINERALS
HYDROGEOLOGY
SOILS ENVIRONMENTAL
MONITORING

5. VIS NIR SWIR MIR

6. COMMNON ALTERATION MINERALS
•Micas:muscovite -paragonite, biotite
•Chlorites: variations in Fe-Mg
•Clays:
•illite, illite/smectite, kaolinite, dickite
•Sulfates:
•alunite, jarosite, gypsum, hydrous-sulfates
•Carbonates:
•e.g. calcite, dolomite, ankerite, siderite
•Tourmaline:
•e.g. schorl, elbaite

7. •Mineral Chemistry -SSS
•Mapping
Geology
Outcrops
Pit Benches
Alteration Zoning
•Core Logging
•Blast Hole Logging
•Ground Truth -Remote Sensing
•Metallurgical
•Grade Control
SPECIFIC APPLICATIONS

8. IN-SITU
ANALYSIS

9. PIMA at ~5000 m Pascua/Llama, Chile

10. IRON COATED SURFACES

11. VIRGINIA CITY, NV

12. HAND SAMPLE ANALYSIS
SOIL

13. KAOLINITE
CRYSTALLINITY
CRYSTALLINITY
APPLICATION

14. MINERAL CHEMISTRY
VIS REGION
SUBSTITUTION
IRON MINERALS

15. Fe2+
Fe3+
Ni
Cr
Mn
Mn
VISIBLE REGION SPECTRA
Fe2+ Fe3+ Cr
Ni Mn
chlorite
hematite
goethite
Cr-diopside
chrysoprase
rhodonite

16. CHEMICAL VARIABILITY
Mg --Fe
CHLORITES CARBONATES
ALUNITES
Ca Mg
Ca->K->Na->NH4

17. Alunite Group Minerals
K, Na, Ca and NH
4-bearing
Confirmed by SEM -EDS Analysis.
Mineral Chemistry -Alunite
SOURCE: PetraScience Consultants

18. CHLORITES
•CHEMICAL CHANGES PLOT
•VMS AUS EXAMPLE

19. Mg
Fe
CHLORITES

20. ASD#DepthKaolIllGoethHemChl/VChlSil Minerals
0001-2m 2204 763 kaolinite-poor goethite
00112-13m 2206x 2352 kaolinite, chlorite?
00221-22m 2205x 761 2354x hematite, kaolinite-poor, chlorite?
00331-32m 2205x 772 2353x kaolinite-poor, chlorite, sil, goethite
00441-42m 2205x 7852358minkaolinite-xln, FeOx, silica illite
00551-52m 2205 7952355x kaolinite, silica, FeOx
00661-62m 2205? 7992358x kaolinite-xln, FeOx
00771-72m 2205x 8092354x kaolinite, chlorite, silica, illite
00881-82m 2205x 8292352x chlorite, kaolinite silica illite
00991-92m 2205x 8282351tr kaolinite, chlorite, illite
010102-103m2205x 8132348? kaolinite, chlorite-2348- illite VMS DEPOSIT -AUSTRALIA

21. IRON MINERALS

22. USGS References
IRON OXIDES
Jarosite
Hematite
GoethiteBest (?) References USGS







Individual Average all ref CSM Average USGS
Hematite 862nm 866
Goethite 920 908
Jarosite 920 and 894 921 915

700nm J < H < G

900nm H < J < G


703
766
745
862
894
920
420

23. GOETHITE -HEMATITE
Hematite
Goethite

24. LOW
ALTITUDE
AVIRIS
JAROSITE
DRAGON MINE

25. LAKE CREEK, CO UNDEVELOPED PORPHYRY COPPER
IRON OXIDE SPECIES
pH 1-4
Colorado
Geological
Survey

26. RED MOUNTAIN EAST
SOURCE AREAS
RED MOUNTAIN WEST
SPRINGS
UNEXPLOITED
PORPHYRY SYSTEMS
ALTERATION
QSP, QS, PHYLLIC, ADVANCED
ARGILLIC
SULFIDE MINERALIZATION
Cu, Mo vein stockwork
GROUNDWATER

27. PYRITE SOURCE
SPRING
pH = 2.3-2.8
FERRIHYDRITE
GOETHITE
SCHWERTMANNITE
JAROSITE
pH = 3-6
pH = 4.5->
pH = +7
IRON MINERALS in
NATURAL ACID DRAINAGE
Peek-A-Boo Source
South Fork

28. Lepidocrocite
Ferrihydrite
Maghemite
Goethite
Hematite
Fe OXIDES
Schwertmannite
Jarosite
Copiapite
Coquimbite
Melanterite
SULFATES

29. LAKE CREEK
pH DISTRIBUTION LAKE CREEK WATERSHED
SOUTH FORK
PEEK A BOOpH Key
2.0-2.99
3.0-3.5
3.51-3.99
4.0 -4.5
4.51-4.99
5.0-5.5
5.51-5.99
6.0-6.5
6.51-6.99
7.0 - 7.5
7.51-7.99
SAYERS GULCH
SAYERS BOWL
STREAM
WR
E
R
NORTH FORK
~50
sites

30. GOETHITE,Lepidocrocite, Green Rust
MINERAL DISTRIBUTION
FERRIHYDRITES
chwertmannite
Jarosite
JAROSITE
Copiapite
Schwertmannite
MelanteritepH Key
2.0-2.99
3.0-3.5
3.51-3.99
4.0 -4.5
4.51-4.99
5.0-5.5
5.51-5.99
6.0-6.5
6.51-6.99
7.0 - 7.5
7.51-7.99
SCHWERTMANNITE
Ferrihydrite
Jarosite
GREEN RUST
Tschermigite
Jarosite
SCHWERTMANNITE
AlOH

31. pH vs IRON MINERAL SPECIES
LAKE CREEK
PEEK-A-BOO
SOUTH FORK
pH avg7
pH avg5-6
pH avg 4
pH avg2-3
GOETHITE, Amorphous
FERRIHYDRITE
JAROSITE
MAGHEMITE
pH data 09/02
Red
Mtn
80 SAMPLE SITES

32. LAA IMAGE GOETHITE
RULE IMAGE SAM <.05-0.25
GOETHITE
LC-9
Lc-9

33. SF-5
SBS-1
SF-9
SF-13
SF-7
SF-18
SF-14
SOUTH FORK –AVIRIS -VIS

34. 3.0
4.7SF
SBS
SBS

35. TC
CLASSIFICATION
1 METER

36. CANYON CREEK
IRON
PRECIPITATES

37. Canyon Creek -CASI Fe Image
Star Tailings Repository

38. APPLICATION MAPPING
ALTERATION
OUTCROP
LITHOLOGIC
PIT
BLAST HOLES

39. MINERAL MAPPING -in the Field
OutcropPit Walls Hand Samples

40. ALTERATION MAPPING
Source: OroCandente, Petrascience Consultants

41. PIT MAPPING
NEW
CALEDONIA
BINGHAM CANYON
TAMBO, CHILE

42. BLAST HOLE
ANALYSIS
Pit Walls

43. METALURGICAL

44. Core
Logging
CONSISTENCY

45. Core and RC Chip Logging3.7
20
40
60
80
100
120
140
160
180
200
220
240
260
280
EOH
Au (ppb), >350000 Vuggy quartz +/- dickite
Dickite +/- al, diaspore, kaol
Alunite +/- kaolinite, dickite
Kaolinite +/- montmorillonite, illite
Montmorillonite +/- illite, chlorite
Alteration
5000’ -5’ -8 hours

46. HIGH SULFIDATION SYSTEM DRILL HOLE :: GOLD vs MINERALOGY
DEPTH Wave Au KlDikAlkIllSmSilJarChALT Minerals
40 2206 0.005 x x 1Jarosite, trace gyp, illite?
68 2206 0.005 x x 1Illite + silica
74 2206 0.009tr x x 1Illite, silica tr gyp tr kaolinite
80 2206 0.024x x x 1Illite -> kaolinite, gyp, silica
81 2204 0.024 x x 1Illite, gypsum - - jarosite?
94 2210 0.007 x 1Illite
100a 2206 0.013 x x 1Illite, jarosite
117 2206 0.008 x 1Illite
124 2204 0.025 x x 1Illite jarosite
140 2212 0.005 x x 1Illite, jarosite, gypsum?
146 2192 0.011 x x 1Illite, silica
150 2164 0.011x 1Kaolinite
164 2166 0.099x 1Kaolinite, well x/n
170 2168 0.099x 1Kaolinite, MW
173 2180 1.473xxx 4Dickite, alunite, kaolinite
175 2180 1.473 xx 4Alunite + dickite
178 2170 1.473 x x 5Alunite + silica
181 2177 0.133 xx x 4Dickite and alunite silica
182 2181 0.133 xtr 3Dickite, trace alunite
183 2180 0.133 x 3Dickite
186 2166 0.035x 1Best kaolinite
196 2167 0.013x x 1Kaolinite + silica
204 2167 0.005x 1Kaolinite
214 2177 0.099xtr 1Kaolinite tr dickite
218 2166 0.099x x 1Kaolinite - poor illite
224 2166 0.016tr x 1Smectite + minor kaolinite
229 2167 0.016x 1Kaolinite
235 2164 0.196x 1Kaolinite - still wet
238 2164 0.196x 1Kaolinite
244 2164 0.007x 1Kaolinite CORE
and
RC CHIP
LOGGING
Goldfield Core
from Main District

47. RC CHIPS

48. CORING
THE
TAILINGS

49. APPLICATION
LITHOLOGIC MAPPING

50. Paris Basin –LITHOLOGIC MAPPING

51. Paragenesis Kaolinite/Smectite
Alkaline
Smectite
Wet
Kaolinite/smectite
Acid
Kaolinite
Acidic -Delta

52. Argilles Plastique
K/S clays
Paris Basin

53. CASE STUDIES PRECIOUS METALS
GOLD
GOLDFIELD,NV
SEDIMENT HOSTED GOLD
CARLIN TREND
COPPER
RAY MINE, AZ

54. GOLDFIELD
PIT BENCH MAPS
OUTCROP MAPS
CORE LOGGING

55. RED TOP PIT

56. RED TOP PIT
STRUCTURE
ROMARCO MINERALS
Illite
Kaolinite
Alunite
Dickite/Diasp
ore
Alunite
Kaolinite
Illite

57. N
RAY MINE, AZ
REMOTE SENSING GROUND TRUTH
ALTERATION MAPPING
ENVIRONMENTAL MONITORING

58. RAY MINE , ARIZONA
PORPHYRY COPPER
Muscovite
Illite
Biotite -Phlogopite
Chlorite
Amphiboles
Gypsum -Anhydrite
Carbonates
Kaolinite
Smectite
Jarosite
Alunite
Silica
Sulfates -Al -Fe -Cu
Groupo de Mexico/ASARCO

59. Oxide Ore
CHRYSOCOLLA
Grade Control

60. POTASSIC
ZONE

61. SFSI Images
MUSCOVITE and
ILLITE
Altered Muscovite
2µ
LEACH CAP

62. SULFATES
A
C
D
B
pH 1-2

63. COPPER
SULFATES
CHILE
DRAINAGE
FROM Cu
MINE

64. SEDIMENT
HOSTED

65. Carlin Mine, Carlin Trend, Nevada

66. ORIGINAL
CARLIN
MINE

67. Sediment-hosted Deposits:
ILLITE
NH4-ILLITE
KAOLINITE
DICKITE
CALCITE
DOLOMITE
JAROSITE
ALUNITE
SMECTITE
SILICA

68. DEE -X-Section 4, DEE Fault Zone
Dickite, Silica, NH4-Illite

69. Ground Truth
Remote Sensing
El Hueso
Chile

70. PATHFINDER MINERALS
GOLD alunite, dickite, pyrophyllite,
illite/muscovite, jarosite, ammonia,
carbonates?, hematite, goethite
PORPHYRY muscovite/illite, hematite, goethite,
jarosite, alunite, dickite, epidote,
chlorite
KIMBERLITES serpentines, saponite,chlorites,
olivine
VMS chlorite, muscovite/illite
SKARN chlorites, talc, serpentine, carbonates,
epidote, actinolite/tremolite
BASE METALS carbonates, ammonia minerals
IRON hematite, goethite

71. SFSI Image
Red= alunite;
green= buddingtonite;
blue= kaolinite
CUPRITE
Ground Truth Images
CUPRITE, NV

72. PIMA
DRAGON -ALUNITE
SFSI
PIMA
HAA

73. ROSE LAKE
Zn
RIVER
BEND
TAILINGS
AVIRIS

74. ROSE LAKE
AVIRIS SFSI
Pb
Zn
Pb = 1600-4800 PPM
Zn = 1800-4900 PPM

75. PIMA
Traverse A
JAROSITE -SPECTRA
VIS/NIR
Traverse A

76. HAA -MODTRAN
LAA -E.L.
JAROSITE

77. APPLICATIONS
KIMBERLITES
NH4
NI-LATERITES
SAPROLITES
REE
SKARN

78. APPLICATION
KIMBERLITE ANALYSIS

79. Mg-Minerals
as
Pathfinders
for
KIMBERLITES
Saponite, Serpentine, Olivine,
Nontronite, Calcite, Chlorites,

80. INFRARED ACTIVE EXPLORATION MINERALS
GARNETS
OLIVINE
DIOPSIDE
SERPENTINE
CALCITE
CHLORITE
AMPHIBOLE
APOPHYLLITE
SAPONITE
NONTRONITE

81. CANADA
KIMBERLITES
Core Analysis

82. Buffalo Hills
Alberta
MineralogySamples Plotted Relative to Depth and Mineralogy
Sample IDDepthSapSerCO3ApoGypChlMg
ASHK10 14.65
DDH 14-01 x??
ASHK11 14.65
DDH 19-03 x x
ASHK02 49.15
DDH 4A-02 M tr
ASHK13 58.4Sm ???
DDH 7C-01
ASHK07 59.13
DDH2-01 x ?x
ASHK08 63
DDH 4C-01 x
ASHK04 66.15
DDH 1B-02 x x
ASHK01 76.7
DDH 1A-01 x trx
ASHK 14 76.93
DDH 7B-01 x x
ASHK03 84.23
DDH 5A-02 x
ASHK12 84.93
DDH91-03 x ?
ASHK06 110.15
DD6-02 x
ASHK09 119
DDH 7A-01 x
ASHK05 140.65
DDH 4B-01 x x
SAPONITE
CALCITE
Mg-SILICATES
CHLORITE
SERPENTINE
ZONING WITH DEPTH

83. C-14K C-14E
Epidote Chlorite
Calcite
Serpentine Saponite
Saponite Serpentine
Apophyllite
Chlorite
Serpentine
Apophyllite
Serpentine
Serpentine
Serpentine -Matrix
Calcite
Matrix Serpentine
D
C-14I
CORE ANALYSIS C-14

84. ASTER
IMAGE
ARGYLE
MINE
Processed by
David Coulter

85. ARGYLE MINE, AUS
ASTER
PROCESSED BY: David Coulter
SERPENTINE
SWIR-2
SWIR-1
VISIBLE

86. NH
4FOR GOLD
•CUPRITE
•MERCUR
•TRES CRUCES -PERU
•MEXICO
•CARLIN TREND
•OTHER NEVADA LOCATIONS

87. CUPRITE, NEVADA
Hydrothermal Alteration
Buddingtonite
Area
LANDSAT

88. Theredisammonia
minerals,illiteisblue
yellowiskaolinite
MERCUR
DISSEMINATED GOLD
DEPOSIT

89. NI-LATERITES
Changes in VIS region
Absorption Features can be
used to track Nickel Content

91. Sample IDASD#NiMaghOlivGoethSerpHemSapCO3Paly
1001 x x
Ferricrete 2002 x x
3003 x x
hematite 4 004 x
5005 x
6, 7007 ? x Mj min
8008 ? x Mj min
saprolite 9009 Mj min
10010 Mj min
11011 Mj min
12012 Mj min
13013tr x x x
14014tr x x x
15015x min Mj
ore 16016x min Mj
17017x x Mj
18018x x Mj
19019x x Mj
20020x ? Mj
ore 1001X X X
2002X X X
3003X X X
4004X X X
veinlets 5006MIX X TR
6007X TR X
magnesite 7009 TR X X ?
Palygorskite 8010 TR x X
silicified 9012 X ? ? ?
10014 X ? X ?
peridotite 11 016 X X
12017 X X X
opal 13018X X X
garnierite 14020X X
15022X ? X TR
veins 16025X X X
peridotite 17026 X X ?
18027 X X
19028 X
20030 X X TR

92. file nameFeM ix G oeKaolSmecHemNonserpCO3Ni%MgFe% W ave 1 W ave 2 W ave 3 W ave 4
MMH3862
.001752865 trxx .18.5021.5 2203
.002750868 trxx .12.3032.8 2203
.003751878 trxx .09.4041.3 2204
.004760886xxxx .11.3038.6 2204
.005761898xxxx .13.2035.5 2204
.006754889tr xxsm .14.1031.2 2207 2292
.007753886trtrxxtr .12.0521.8 2207 2295
.008749884tr xxx .11.0524.2 2208 2244 2295
.009774907x tr x .12.0520.2 2209 2242 2293
.010775908x tr x .14.1027.0 2210 2243 2292
.011783923sm tr x .14.2026.9 2208 2242 2292
.012794965sm tr x .16.3028.2 2209 2244 2293
.013823960 sh x .34.2050.8 22122250 sh 2294
.014811966 x .36.6039.4 2247 2295
.015828906 ? sm ?.771.926.82209 sh2253 sh 2296
.016802895 ? sm ?1.081.928.22207 sh2251 sh 2295
.017783904 ? x 1.232.428.32208 sh2250 sh 2296
.018780899 x 1.142.824.8 2295
.019779925 x ?1.02.926.5 2252 sh 2294
.020787909 ? x ?2.14.019.0 sh2252 sh 2295 b
.021768948? ? xxx1.874.5916.0 sh2250 sh 2297 2320
.022785916 x 1.554.2413.4 2302 b 2319
.023784943 x? 1.164.1611.4 2295 b
.024781954 x? 1.13.9411.1 2295 B
.025776943 xx 1.035.1911.7 2300 b 2321
.026787930 xx 1.025.312.4 2299 2320
.027789914 trx?.7583.579.7 sh2294 sh 2323
.028802939 trx .7414.949.8 2248 sh sh 2323
.029784938 trx .8287.2810.7 sh 2321
.030789959 xx .68110.19.2 2298 2320
.031798952 trx .786.710.0 2299 sh 2322
.032815934 trx .847.011.8 2247 sh 2322
.033819913 trx .728.710.2 2243 sh2293 sh 2321
.034781931 ? xtr .577.89.12207 sh 2299 b
.035783 ? xtr .647.911.1 sh 2299 b
.036779 xtr .357.04.5 2300 b b
.037784 ?x?.338.43.9 2312 B2312 B
.038793 ?x?.349.34.1 23042316 b
.039796 ?x?.2212.11.9 23022315 b
.040780 ?x?.1810.50.5 23032320 B
.041782 ?x?.218.12.4 2303 b2318 b
.042779 ?x.178.80.4 2304 b b
.043782 ?x.237.82.9 2307 b2319b
.044783 xx.367.78.1 2304 b2323 b
.045796 ?xx.20117.5 2307 b 2318
.046792963 xx.2011.64.6 2304 b2318b
file nameFeM ix G oeKaolSmecHemNonserpCO3Ni%MgFe% W ave 1 W ave 2 W ave 3 W ave 4 KEY: FeMix= uncertain category that mixes an iron oxide and possibly
nickel. Goe= goethite -this is usually a mix of goethite and first hematite at
the top of the hole and then with nickel; Kaol= poorly crystalline kaolinite;
Smec= smectite; Hem= hematite; Ni= nickel as a probable constituent of
nontronite; Non= nontronite; Mag= magnesite; Serp= serpentine; Sil= silica

93. Saprolite
Cliffs
in
The
Australian
Outback
at
Sunset
December, 2001

94. GEORGIA -SAPROLITIC
WEATHERING PROFILE

95. REE
REE Carbonates
MOUNTAIN PASS, CA

96. MOUNTAIN PASS
NEODYNIUM
USGS REFERENCES
ASD FSP SPECTRA

98. MOUNTAIN PASS
REE MINE
LOW AND HIGH ALTITUDE
AVIRIS IMAGES
COURTESY OF:
Larry Rowan, USGS

106. SOILS

107. APPLICATION
ENVIRONMENTAL
MONITORING

108. Mine
Waste
Characterization
Trench logging with
Prototype PIMA
Leadville, CO

109. CANYON CREEK
DUMP
PURPLE = HIGH Pb
CYAN = MODERATE Pb
SFSI
IMAGE

110. MONITOR ACID PRODUCING MINERALS
AVIRIS Image
DRAGON-JAROSITE
JAROSITE

111. NATURAL ACID DRAINAGE SYSTEMS
IRON OXIDE SPECIES
pH 1 -4
COLORADO
GEOLOGICAL
SURVEY

112. Sampling a
large
segregated
dump
Cripple Creek

113. INTERNATIONAL
SMELTER
SITE

114. FAILING RE-MEDIATION
A
B
Iron Bull’s Eye
Sufates
Blue Tailings
Toxic Metals

115. Site AS-12: “Iron Bull's-Eye”
ALUNOGENJAROSITE KAOLINITE
pH 1-2 pH 3 pH 4-5

116. CASI
HYPERION
BAUER

117. SMELTER EMISSIONS MAPPING
Gypsum
Dolomite
CLAY
A
B
C

118. HOW MANY GEOLOGISTS DOES IT TAKE ……...
FIELD METHODS

119. Reflectance
measurement with the
ASD HH
Running the ASD
from the Vehicle
Battery

120. Sample collection at each
point along the grid.
Samples were put into plastic bags
and left at the collection points to
give a visual perspective of the
extent of the grid -notes were taken

121. Grid outlined
with the sample bags

122. ASD HH VIS/NIR
Field Spectrometer
JAROSITE

124. FSP with
SOLAR
ILLUMINATION
OPTION
SPOTTING SCOPE
CALIBRATION

125. EMPIRICAL
LINE
CALIBRATION

126. Occidental Lode
Alteration Map
Virginia City

127. Hyperspectral
SFSI Scanner
Red= illite
Green= Dickite
Blue = alunite
Data Processing By:
Homestake Mining Company

128. SFSI Images
REMOTE SENSING
Altered Muscovite
2µ
LEACH CAP
MUSCOVITE

129. SFSI Images
REMOTE SENSING
Altered Muscovite
2µ
LEACH CAP
MUSCOVITE