Chapter X: Copper, Lead and Zinc Minerals 197

COPPER ORES 197
Economic features 197
Geologic features 199
Copper deposits associated with igneous flows 200
Copper veins in igneous rocks 201
"Porphyry coppers" 203
Copper in limestone near igneous contacts 204
Copper deposits in schists 204
Sedimentary copper deposits 205
General comments 206

LEAD ORES 209
Economic features 209
Geologic features 211

ZINC ORES 213
Economic features 213
Geologic features 216

CHAPTER XI. GOLD, SILVER, AND PLATINUM MINERALS 221

GOLD ORES 221
Economic features 221
Geologic features 226

SILVER ORES 231
Economic features 231
Geologic features 234

PLATINUM ORES 237
Economic features 237
Geologic features 239