List of Figures in Text ......................................... 4
List of Tables in Text ......................................... 12
List of Tables in Appendix ..................................... 13
Acknowledgements ............................................... 14
Abbreviations .................................................. 15
Abstract ....................................................... 16
1. State of Knowledge .......................................... 17
1.1. Geography .............................................. 17
1.2. Previous Scientific Works on the French Gulch-
Deadwood District ...................................... 17
1.3. Regional Geology ....................................... 18
1.4. Stratigraphy of the French Gulch-Deadwood District
(Redding Subterrane) ................................... 22
1.5. Structural Geology of the French Gulch-Deadwood
District ............................................... 26
1.6. Ore Mineralization of the French Gulch-Deadwood
District ............................................... 26
1.7. Mines and Historical Gold Production ................... 31
2. Fieldwork ................................................... 34
2.1. Introduction ........................................... 34
2.2. Sampling ............................................... 34
2.3. Description of the Mapped Units ........................ 35
2.3.1. Bragdon formation ............................... 35
2.3.2. Copley greenstone ............................... 36
2.3.3. Birdseye porphyry ............................... 36
2.3.4. Aplite .......................................... 37
2.3.5. Quartz porphyry ................................. 38
2.4. Dumps .................................................. 39
2.5. Description of Gold-Bearing Polymetallic Sulfide
Quartz Veins ........................................... 39
2.5.1. Introduction .................................... 39
2.5.2. 2156 vein ....................................... 41
2.5.3. Dean vein and Washington vein ................... 43
2.5.4. Lucky 7 vein .................................... 45
2.5.5. Klaus vein ...................................... 47
2.6. Structural Geology ..................................... 48
2.7. Microscopy ............................................. 52
2.7.1. Method .......................................... 52
2.7.2. Birdseye porphyry ............................... 52
2.7.3. Quartz porphyry ................................. 55
2.7.4. Aplite .......................................... 55
2.7.5. Copley greenstone ............................... 58
2.7.6. Dean/Washington vein and 2156 vein .............. 58
2.7.7. Lucky 7 vein and Klaus vein ..................... 62
2.7.8. Mineralized dump samples ........................ 66
2.8. Geological Interpretation and Discussion ............... 67
2.8.1. Temporal and spatial development of the mapped
rocks and veins ................................. 67
2.8.2. Temporal and spatial distribution of ore and
gangue minerals ................................. 69
2.8.3. Alteration ...................................... 74
3. Analytical Investigations and Discussion .................... 75
3.1. Whole-Rock and Ore Geochemistry ........................ 75
3.1.1. Geochemistry of quartz veins and mineralized
wall rock ....................................... 75
3.1.2. Geochemistry of wall rocks ...................... 82
3.2. Investigations with Scanning Electron Microscope ....... 90
3.2.1. Method .......................................... 90
3.2.2. Results ......................................... 91
3.3. Investigations with Electron Microprobe ............... 104
3.3.1. Method ......................................... 104
3.3.2. Results ........................................ 105
3.4. Discussion of Analyses ................................ 110
3.4.1. Whole-rock geochemistry of quartz veins and
mineralized wall rock .......................... 110
3.4.2. Whole-rock geochemistry of wall rock ........... 113
3.4.3. Scanning electron microscope data .............. 117
3.4.4. Electron microprobe data ....................... 120
3.5. Examples with Similarities to the French Gulch
Deposit ............................................... 121
3.5.1. Mother Lode (Sierra Nevada, California, USA) ... 122
3.5.2. Quartz Hill (Klamath Mountains, California,
USA) ........................................... 126
3.5.3. Gold mining districts in the vicinity of
French Gulch ................................... 127
3.5.4. Jundee Nimary (Yandal Belt, West Australia) .... 130
3.6. Comparison and Discussion ............................. 133
3.6.1. Comparison with similar deposits ............... 133
3.6.2. Differences between the gold-bearing quartz
veins .......................................... 137
3.6.3. Age of the gold-bearing quartz veins ........... 138
3.6.4. Maximal erosion of the deposit ................. 139
3.6.5. Role of the Birdseye porphyry dikes ............ 139
3.6.6. Deposit type ................................... 140
3.6.7. Evidences on the dike/sill formation ........... 141
3.6.8. Models of ore formation ........................ 141
3.6.9. Deposit potential .............................. 144
3.7. Future Work ........................................... 144
3.8. Conclusions ........................................... 145
3.9. References ............................................ 146
4. Appendix ................................................... 153
Appendix 1 Mine Plot of the French Gulch Mine, Shasta
County, California, USA ........................ 153
Appendix 2 Face Maps ...................................... 155
Appendix 3 Production and Geology of Historical Gold
Mines .......................................... 159
Appendix 4 Sample List and Sample Description ............. 164
Appendix 5 Dip Values of Au-Quartz Veins and Aplite
Dikes/Sills .................................... 307
Appendix 6 Bulk Geochemistry Data ......................... 308
Appendix 7 Scanning Electron Microscope Data .............. 316
Appendix 8 Electron Microprobe Data ....................... 348
Appendix 9 Fabric of Igneous Wall Rocks ................... 350
Appendix 10 SEM Pictures ................................... 357
Appendix 11 Geological Map of the French Gulch
Mine, Shasta County, California, USA
(1: 1,400) ........................ CD in book cover
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