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- Contents
- Title page
- Publisher's notes
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 Expedition 333 participants
- Abstract
- Introduction
- Overview of the NanTroSEIZE complex drilling project
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Background
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Sites C0011 and C0012
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NanTroSLIDE Ancillary Project Letter
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Principal results
- Preliminary scientific assessment
- References
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Table
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Figures
- F1. Bathymetric map.
- F2. Spliced composite profile.
- F3. Detailed bathymetry and structure, Site C0018.
- F4. Schematic sedimentary log, Hole C00018A.
- F5. Top of MTD 2.
- F6. Shear zone at base of MTD 2.
- F7. Fluidized ash layer, corresponding to MTD 4.
- F8. Chaotic style of internal deformation in MTD 6.
- F9. Cyclic succession of turbidites.
- F10. XRD data, Hole C0018A.
- F11. SiO2, Al2O3, CaO, Fe2O3, MgO, and TiO2, Site C0011.
- F12. Bedding dip angles and deformation structures, Site C0018.
- F13. Lower-hemisphere equal-area projections, Site C0018.
- F14. Appearance of slump fold.
- F15. Appearance of shear zone.
- F16. Physical properties, porosity, shear strength, and resistivity, Site C0018.
- F17. Interstitial water and sulfate, Hole C0018A.
- F18. Pore water constituents, Hole C0018A.
- F19. More pore water constituents, Hole C0018A.
- F20. Methane, ethane, and C1/C2 ratios, Site C0018.
- F21. CaCO3, TOC, TN, TOC/TNat, and TS, Hole C0018A.
- F22. Lithology on seismic profile, Site C0018.
- F23. APCT-3 temperature measurements.
- F24. Bathymetric map, Sites C0011, C0012, and C0018.
- F25. Lithology on seismic background, Sites C0011 and C0012.
- F26. Sedimentary log, Holes C0011C and C0011D.
- F27. XRD data, Holes C0011C and C0011D.
- F28. Ash alteration state across unit boundaries.
- F29. Units I and II lithologic and textural differences, Hole C0011D.
- F30. SiO2, Al2O3, CaO, Fe2O3, Na2O, K2O, and P2O5, Site C0011.
- F31. Bedding dip angles and deformation structures, Holes C0011C and C0011D.
- F32. Lower-hemisphere equal-area projections, Holes C0011C and C0011D.
- F33. Magnetic susceptibility and remanent magnetization, Site C0011.
- F34. Resistivity and porosity, Site C0011.
- F35. Penetrometer and vane shear, Site C0011.
- F36. P-wave velocity, Holes C0011D and C0011B.
- F37. Interstitial water and sulfate, Site C0011.
- F38. Interstitial water constituents, Site C0011.
- F39. More interstitial water constituents, Site C0011.
- F40. Methane concentration, Holes C0011C and C0011D.
- F41. CaCO3, TOC, TN, TOC/TNat, and TS, Holes C0011C and C0011D.
- F42. Sedimentary log, Holes C0012C and C0012D.
- F43. XRD data, Holes C0012C and C0012D.
- F44. SiO2, Al2O3, CaO, Fe2O3, MgO, MnO, and P2O5, Site C0012.
- F45. Bedding dip angles and deformation structures, Holes C0012C and C0012D.
- F46. Remanent magnetization and magnetic susceptibility, Sites C0011 and C0012.
- F47. Bulk density, porosity, and grain density, Site C0012.
- F48. Mudstone porosity, Sites C0011 and C0012.
- F49. P-wave velocity, Site C0012.
- F50. Interstitial water and sulfate, Site C0012.
- F51. Interstitial water constituents, Site C0012.
- F52. More interstitial water constituents, Site C0012.
- F53. Methane, ethane, and C1/C2, Holes C0012C, C0012D, and C0012E.
- F54. CaCO3, TOC, TN, TOC/TNat, and TS, Holes C0012C, C0012D, and C0012E.
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doi:10.2204/iodp.pr.333.2011
NanTroSLIDE Ancillary Project Letter
Scientific objectives
Expedition 333 drilled and sampled the slope basin seaward of the megasplay that is characterized in 3-D seismic data by stacked mass transport deposits (MTDs) (Strasser et al., 2011) (Fig. F3). The aim of the coring was to establish the submarine landslide history and reconstruct transport dynamics. Core from Site C0018 (proposed Site NTS-1A) was to be integrated with 3-D seismic interpretation and data from nearby NanTroSEIZE sites to determine the relation of submarine landslides to tectonic evolution. By establishing a better physical understanding of tectonic processes and slope failures, we planned to also gain a general understanding of failure-related sedimentation patterns and the significance of episodic mass transport events. Ultimately, this could help us assess the tsunamigenic potential of tectonic landslides. The primary goals of drilling Site C0018 were
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To establish a well-dated Quaternary mass-movement event stratigraphy and
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To sample the distal part of an exceptionally thick MTD for analyzing its rheological behavior to constrain sliding dynamics and tsunamigenic potential.
These aim at providing answers to the following questions:
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What is the frequency of submarine landslides?
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What is the source materials of the MTDs?
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What is the importance of accretionary wedge remobilization versus surficial processes?
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What controls type, size, and magnitude of turbitides and MTDs and how do they change through time?
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How do large MTDs relate to the timing of splay fault activity as inferred from NanTroSEIZE Stage 1 drilling (Strasser et al., 2009)?
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What are the dynamics of large submarine landslides and can we infer their tsunamigenic potential?
By addressing these questions, we aimed to isolate tectonic processes influencing magnitude and occurrence of submarine landslides along active subduction zone margins and to understand their potential for triggering catastrophic events in terms of both hazards (tsunamigenic landslides) and sediment mass transfer within the context of margin evolution.
Drilling strategy
Site C0018 (proposed Site NTS-1A) (water depth = 3100 m) is located on a margin-perpendicular transect 4.5 km southwest of the NanTroSEIZE Stage 1 drilling transect (Fig. F1). It is located 5 km south-southwest of Site C0008, which was drilled into a small slope basin seaward of the megasplay fault (Kinoshita, Tobin, Ashi, Kimura, Lallemant, Screaton, Curewitz, Masago, Moe, and the Expedition 314/315/316 Scientists, 2009). Site C0008 results show the utility of using the ages of MTDs to reconstruct slope failure activity related to megasplay fault movements (Strasser et al., 2009). Apart from the deepest section, Site C0008 lacks clear evidence for MTDs because of a significant hiatus in its upper part, suggesting erosion related to a prominent slope collapse structure seaward of the megasplay fault (Strasser et al., 2011; Conin et al., 2011). On the basis of new 3-D seismic data interpretation, the Ancillary Project Letter proponents have identified a lower slope basin that (1) better represents the depocenter for downslope mass transport, (2) is clearly characterized by stacked MTDs as seismically imaged by acoustically transparent to chaotic bodies with ponded geometries (Fig. F3), and (3) includes a large, as thick as 180 m, MTD. Expedition 333 drilled at a location where the MTD bodies wedge out and where basal erosion is minimal. Continuous coring with hydraulic piston coring system (HPCS) and extended shoe coring system (ESCS)/extended punch coring system (EPCS) to ~350 mbsf allowed sampling of the MTDs across the most complete and longest stratigraphic succession.
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