Geology and mineral deposits of Jumbo Basin, southeastern Alaska.
Geological Survey professional paper 251
Geological Survey professional paper ;
Abstract -- Introduction -- Previous work -- Present work -- Acknowledgments -- Geography -- Location and accessibility -- Topography -- Climate, water supply, and vegetation -- History and production -- Geology -- Bedded rocks -- Limestone -- Calcareous schist -- Quartz-mica schist -- Greenstone schist -- Intrusive rocks -- Granodiorite and related rocks -- Structure -- Petrography and petrology -- Composition -- Igneous suite from the Jumbo basin and vicinity -- Monzonite, granodiorite, and quartz diorite -- Contaminated rocks -- Gabbroic rocks -- Distribution of rocks types within the stock -- Comparison of rocks of intrusive stock with rocks of the Coast Range batholith -- Igneous rocks in relation to ore deposits -- Dike rocks -- Distribution -- Varieties -- Age -- Structure -- Regional features -- Local features -- Folds -- Faults -- Contact metamorphism -- Distribution of the skarn rocks -- Marmorization -- Metamorphism in the vicinity of the Magnetite Cliff bodies -- General relations -- Exomorphism of the marble -- Localization of the metamorphic products -- Mineralogy, paragenesis, and textural relations -- Chemical changes -- Criteria for the distinction of metamorphic products -- Metamorphism of the schists -- Metamorphism of the dike rocks -- Metamorphism in the vicinity of the upper magnetite bodies -- Exomorphism of the marble -- Endomorphism of the intrusive rocks -- Metamorphism in the vicinity of the Jumbo mine -- Exomorphism of the marble -- Endomorphism of the intrusive rocks -- Metamorphism of the dike rocks -- Metamorphism of schists, northeast slope, Jumbo basin -- Contrasts between the skarn zones -- Genesis of contact-metamorphic deposits, Jumbo basin -- Existing views of contact metamorphism -- Time of contact metamorphism, Jumbo basin -- Source of contact-metamorphosing solutions -- State of contact-metamorposing solutions -- Reactions with carbonate rocks -- Channelways of the contact-metamorposing solutions -- Origin of sharp contacts -- Classification of the Jumbo basin contact-metamorphic deposits -- Mineral deposits of the Jumbo basin -- Magnetic survey -- Applicability -- Field methods -- Magnetic data and interpretation -- General features -- Anomalies in the vicinity of the Magnetite Cliff bodies -- Anomalies in the vicinity of the upper magnetite bodies -- The deposits -- Magnetite Cliff bodies and vicinity -- Geology -- Structure -- Ore deposits -- Reserves -- Tonnage -- Grade -- Upper magnetite bodies -- Geology -- Ore deposits -- Reserves -- Jumbo mine -- Mine workings -- Geology -- Structure -- Ore deposits -- Reserves -- Suggestions for prospecting -- Bibliography -- Index.
