Table T1. South Chamorro Seamount (Site 1200) coring summary.
Table T2. ION seismometer site (Site 1201) coring summary.
Table T3. Kuroshio Current (Site 1202) coring summary.
Figure F1. Location map showing sites drilled during Leg 195. The geochemical observatory was installed at Site 1200, and the International Ocean Network (ION) seismic observatory was installed at Site 1201. Site 1202 was drilled to study the history of the Kuroshio Current.
Figure F2. Bathymetric map of the southern Mariana forearc (250-m contour intervals) showing location of all forearc seamounts sampled to date. Site 1200 was drilled on South Chamorro Seamount during Leg 195.
Figure F3. Schematic cross section through the Mariana system showing various types of associations of serpentine mud volcanoes with faulting in the forearc wedge. Strike-slip faulting associated with along-strike extension and vertical tectonics related to seamount subduction both play a part in the tectonic deformation of the forearc and provide avenues for the ascent of slab-derived fluids and fault gouge from both the dècollement and the lithosphere of the overriding plate. Decarbonation reactions in the downgoing plate probably take place between ~15 and 20 km.
Figure F4. HMR-1 side-scan imagery of South Chamorro Seamount showing the location of six-channel seismic reflection profiles shown in Figure F5. Contour intervals are given in meters.
Figure F5. Multichannel seismic reflection profiles over South Chamorro Seamount (locations shown in Fig. F4).
Figure F6. Location of Holes 1200A-1200E drilled on the summit knoll of South Chamorro Seamount. Also shown is the location of the seafloor television survey conducted before drilling. Contours are given in meters.
Figure F7. Casing configuration for the geochemical observatory installed in Hole 1200C on South Chamorro Seamount.
Figure F8. Geochemical observatory (CORK) configuration in Hole 1200C, South Chamorro Seamount.
Figure F9. Close-up photograph of serpentine mud breccia from South Chamorro Seamount (interval 195-1200E-10H-2, 83-113 cm).
Figure F10. Photomicrograph of glaucophane (Gl) schist in serpentine mud (Sample 195-1200F-1H-4, 34-36 cm).
Figure F11. Photomicrograph of tremolite (Tr)-rich chlorite (Chl) schist in serpentine mud (Sample 195-1200F-1H-4, 36-38 cm).
Figure F12. (A) Al2O3 and (B) Mg/(Mg2+ + Fe2+) diagrams for Mariana forearc peridotites, showing degrees of partial melting. Conical and Torishima Seamount data are from Ishii et al. (1992) and Parkinson and Pearce (1998).
Figure F13. Pore water composition vs. depth curves for Holes 1200D, 1200E, and 1200F. A. Chloride. B. Sodium. C. Sodium/chloride. D. Potassium. E. Boron. Hole 1200E is closest to the vent community on the summit of South Chamorro Seamount; Hole 1200D is the most distant.
Figure F14. Location of seismic station coverage in the northwest Pacific region. At least five major plates with consuming boundaries interact in the northwest Pacific, causing subduction, backarc spreading, slab collisions, terrane accretion, and island arc development. Blue and yellow circles = land seismic stations. Orange circles = International Ocean Network (ION) seafloor observatories JT-1 and JT-2 (Japan Trench), WP-2 (northwest Pacific), and Site 1201 (this site). OHP = Ocean History Panel, IRIS = Incorporated Research Institutions for Seismology. TJN = Taejon, South Korea; INU = Inuyama, Japan; ISG = Ishigakijima, Japan; OGS = Chichijima, Japan; MCSJ = Minamitorishima, Japan; BAG = Baguio, Philippines; PATS = Ponphei, Micronesia; JAY = Ayapura, Indonesia; PMG = Port Moresby, Papua New Guinea.
Figure F15. Location map showing DSDP Sites 290, 294, 295, and 447 and ODP Site 1201 in the Philippine Sea. Also shown are magnetic lineations from Hilde and Lee (1984).
Figure F16. Reflection line O showing the location of Site 1201. Basement lies about 0.45 s (two-way traveltime) below seafloor and was reached at 512 mbsf.
Figure F17. Borehole seismometer instrument package deployed in Hole 1201D. BIA = borehole instrument assembly, OBH = ocean borehole seismometer.
Figure F18. Configuration of reentry cone, casing, and International Ocean Network seismic observatory components in Hole 1201D. MEG = multiple-access expandable gateway, ROV = remotely operated vehicle, PAT = power access terminal.
Figure F19. Remotely operated vehicle (ROV) landing platform installed in Hole 1201D. LBS = lithium battery system, SAM = storage acquisition module, UMC = underwater mateable connector.
Figure F20. Lithology, color, and natural gamma count vs. depth at Site 1201. Note the increase in zeolites with depth in the turbidites. In the lithologic graphic log, the following abbreviations are used, from left to right: c = clay, s = silt, s = sand, g = gravel.
Figure F21. Laboratory multisensor track measurements of (A) magnetic susceptibility, (B) density, and (C) natural gamma ray emission vs. depth at Site 1201. In the lithologic graphic log, the following abbreviations are used, from left to right: c = clay, s = silt, s = sand, g = gravel.
Figure F22. Logging results from Hole 1201D. Logging Units 1a-1d correspond to coarse turbidite units. In the lithologic graphic log, the following abbreviations are used, from left to right: c = clay, s = silt, s = sand, g = gravel.
Figure F23. (A) Mg, (B) Ca, (C) Na, and (D) K concentrations vs. depth in pore waters from Site 1201. In the lithologic graphic log, the following abbreviations are used, from left to right: c = clay, s = silt, s = sand, g = gravel.
Figure F24. Nannofossil ranges at Site 1201. The upper 25 m and the lower 45 m of the section are barren except for radiolarians and fish teeth. In the lithologic graphic log, the following abbreviations are used, from left to right: c = clay, s = silt, s = sand, g = gravel.
Figure F25. Magnetic inclination and declination record in pelagic sediments at Site 1201. Also shown is the best fit to the late Oligocene through late Miocene geomagnetic polarity timescale based on paleontological markers from the site. In the polarity column, black bands = normal and white bands = reversed polarity.
Figure F26. Sedimentation rates at Site 1201 based on biostratigraphic and magnetostratigraphic results at the site. In the lithologic graphic log, the following abbreviations are used, from left to right: c = clay, s = silt, s = sand, g = gravel.
Figure F27. V vs. Ti tectonic discrimination diagram for Site 1201 basalts. The basalts at Site 1201 are transitional between arc tholeiites and mid-ocean ridge basalts (MORB) or backarc island basalts (BABB). OIB = ocean island basalt.
Figure F28. Geological interpretation of the sediment and basement section at Site 1201.
Figure F29. Location of Site 1202 in the Okinawa Trough. The seafloor in the trough under the Kuroshio Current lies above the carbonate compensation depth. Stippled areas indicate upwelling.
Figure F30. North-south seismic profile EW95091 at Site 1202.
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