GENERAL LEG RESULTS FROM LEG 139 LEG SPECIFIC OBJECTIVES FOR LEG 169 SCIENTIFIC 139 169 OBJECTIVE SITES SITES
Large Scale Hydrology Reaction Zone 857C-D Pore-fluids match vent composition, 857D, Sample bore hole fluids after determined alteration mineralogy 858G unCORKing holes Active Upflow 858A-G Localized by basement high, nearly BH8, Determine relationship of active Zone isothermal, determined alteration ET1-5 fluid flow to alteration of mineralogy sulfide mounds Paleo Upflow 856A-B Distal hydrothermal alteration BH1-6 Establish controls on fluid flow Zone under Bent Hill massive sulfide Permeability 857D Packer measurements, CORK data 857 D Hole-to-hole hydrology experiment, Distribution 858G induced seismicity experiment, detailed packer experiment Temperature All Detailed temperature records All Detailed temperature records Structure sites sites Small Scale 858B, Lateral flow of hydrothermal fluids, DD1-4 Extent and composition of caprock, Hydrology C,D,F presence of caprock under vent field relation of lateral flow to active vents Sulfide Genesis Localization 858G Localized over basement high BH1-6, Determine if controlled by of Deposits ET1-5 basement high or faulting Size/Geometry 856C-G 95 m minimum thickness of BH1-6, Determine limits of mineralization of Deposits massive sulfide deposit ET1-5 and alteration Timing 856B Uplift of Bent Hill post dates BH1-6, Establish depositional history of sulfide deposition ET1-5 sulfide deposits Metal Zoning 856G-H Extensive recrystallization and BH1-3, Establish extent and geometry of metal remobilization BH8, ET1-5 mineral zoning Fluid 856 Bent Hill formed by high temperature BH8, Drilling of actively venting Composition 858 hydrothermal system distinct from ET-5 massive sulfides to determine presently active vents, Dead Dog not geochemical relationship to depositing massive sulfide deposits Hydrothermal 857 Hydrothermal metamorphism of BH1-6, Map extent and nature of high Alteration 858 sediment controls vent composition BH8, temperature, sulfide depositing ET1-5 hydrothermal system Source of 856C-G Bent Hill formed from dominantly BH1-6, Contrast Escanaba Trough, which Metals 858B basaltic metal source ET1-5 has a dominantly sedimentary metal source, with Bent Hill Tectonics and Structure Spreading 857C-D Basement is sill-sediment complex, 857D, Investigate mechanism of sill Mechanism in similar to initial rift sequences 858G, emplacement and sediment deformation, Sedimented Rifts BH1-6, ET1-5 induced seismicity experiment Relation of Fluid BH5-6 Establish relative timing of fault Flow to Faulting movement and fluid flow Sedimentation and Diagenesis Reference ET7 Determine stratigraphy, physical Sediment Section properties, response to sea level outside of thermal effects of vents Diagenetic All Established porewater, organic All Determine porewater, organic Reactions sites geochemistry, sulfur isotope profiles, sites geochemistry, sulfur isotope carbonate nodules record thermal profiles, use carbonate nodules to gradient establish paleo-thermal gradient
To 169 Projected Logging Plan (Table 2)