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- Chapter contents
- Background and objectives
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Operations
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Lithology
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Structural geology
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Biostratigraphy
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Paleomagnetism
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Inorganic geochemistry
- Salinity, chloride, and sodium
- Pore fluid constituents controlled by microbially mediated reactions
- Major cations (Ca, Mg, and K)
- Minor elements (B, Li, H4SiO4, Sr, Ba, Mn, and Fe)
- Trace elements (Rb, Cs, V, Cu, Zn, Mo, Pb, U, and Y)
- δ18O
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Organic geochemistry
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Microbiology and biogeochemistry
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Physical properties
- References
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Figures
- F1. Hole locations.
- F2. 3-D seismic profile.
- F3. Core recovery and sand and silt distribution.
- F4. Core examples.
- F5. XRD data.
- F6. Pumice.
- F7. Gravel and sand.
- F8. Common clast types in gravel.
- F9. Chert clasts.
- F10. Gravel.
- F11. Ash layers and ash.
- F12. Pyritized and ash-filled burrows.
- F13. Pleistocene age sand, Unit IV.
- F14. Silt grains with isopachous rims of oriented clay.
- F15. CT number vs. depth.
- F16. Distribution of planar structures.
- F17. Planar structures, lithologic Unit I.
- F18. Deformation, lithologic Unit I.
- F19. Planar structures in the prism.
- F20. Deformation bands in the prism.
- F21. Projections of deformation bands.
- F22. Healed faults in bioturbated hemipelagic mudstone.
- F23. Sediment-filled veins.
- F24. Elements in fault Zone 1.
- F25. Brecciated mudstone in fault Zone 1.
- F26. Elements in fault Zone 2.
- F27. Structures in fault Zone 2.
- F28. Elements in fault Zone 3.
- F29. Structures in fault Zone 3.
- F30. Projections of fracture surfaces.
- F31. Foliated fault gouge in fault Zone 3.
- F32. Deformation in fault Zone 3.
- F33. Age and depth.
- F34. Age reversal from Zones NN12 to NN16.
- F35. Magnetic susceptibility and NRM, Holes C0007A–C0007C.
- F36. Magnetic susceptibility and NRM, Hole C0007D.
- F37. AF demagnetization and thermal demagnetization.
- F38. Inclinations isolated from discrete samples.
- F39. Magnetic inclination, inferred polarity, and biostratigraphy.
- F40. Salinity, Cl, Na, and Na/Cl.
- F41. pH, SO4, alkalinity, and Ba.
- F42. NH4, PO4, and Br.
- F43. Ca, Mg, K, H4SiO4, Rb, and Cs.
- F44. Li, B, and Sr, Mn, Fe, and Mo.
- F45. Cu, Zn, V, Pb, U, and Y.
- F46. δ18O profile.
- F47. Methane, ethane, and C1/C2.
- F48. CaCO3, TOC, TN, C/N, and TS.
- F49. Microbial cell abundance.
- F50. SYBR Green I–stained cells.
- F51. Density and porosity.
- F52. Discrete sample measurements.
- F53. Thermal data.
- F54. Temperature time series.
- F55. Shear strength.
- F56. L*, a*, and b*.
- F57. Magnetic susceptibility.
- F58. NGR.
- F59. Hole correlations.
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Tables
- T1. Coring summary, Holes C0007A–C0007C.
- T2. Coring summary, Hole C0007D.
- T3. Lithologic summary, Holes C0007A–C0007C.
- T4. Lithologic summary, Hole C0007D.
- T5. XRD data, Holes C0007A–C0007C.
- T6. XRD mineralogy, Holes C0007A–C0007C.
- T7. XRD data, Hole C0007D.
- T8. XRD mineralogy, Hole C0007D.
- T9. Calcareous nannofossil range chart, Hole C0007C.
- T10. Calcareous nannofossil range chart, Hole C0007D.
- T11. Nnannofossil events.
- T12. Uncorrected geochemistry.
- T13. Uncorrected minor elements.
- T14. Uncorrected trace elements and δ18O.
- T15. Headspace hydrocarbon gases.
- T16. Sample depth and processing.
- T17. CaCO3, TOC, TN, C/N, and TS.
- T18. Sample depth and processing.
- T19. Thermal conductivity.
- T20. Temperature measurements.
- PDF file
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doi:10.2204/iodp.proc.314315316.135.2009
Microbiology and biogeochemistry
Sample processing
To study microbiological and biogeochemical characteristics in sediments at Site C0007, samples were obtained from 120 different depth locations (Table T18). For high-resolution enumeration of cell abundance, 3 cm3 of sediment was collected from core section ends on deck. All whole-round core sample processing was carried out after X-ray CT scanning and was completed within 1 h after core recovery on deck.
Cell abundance
Cell abundance in sediments at Site C0007 was enumerated by microscopic direct count of SYBR Green I–stained cells. The vertical profile of cell abundances showed that 108 cells/cm3 was consistently observed in core sediments to 484 m CSF (Fig. F49). Most observed cells were small coccoids, and some short rods were also observed as minor components. The fluorescent intensity of SYBR Green I–stained cells in upper sediment layers (0–159 m CSF) was observed to be brighter than those in other layers. At 102.7 m CSF (Section 316-C0007C-11X-2), a significant decrease of cell abundance was observed (6.57 × 107 cells/cm3; see Fig. F49). Despite the cell abundance decrease at this horizon, the observed coccoid cells were relatively large with bright fluorescent signals. Large coccoids were also observed in the gravel layer (Section 316-C0007D-17H-1; see Fig. F50). Cell abundance in the gravel layer was estimated to be 7.45 × 108 cells/cm3, which was the most abundant microbial population in samples from Site C0007. These upper sedimentary layers consist of permeable sands and silt, in which nutrient flux (e.g., organic matter and sulfate) via fluid circulation may support microbial activity (see “Inorganic geochemistry”). In sediments below 200 m CSF, some small proliferations of microbial population were observed at thrust fault-associated layers. For example, 5.83 × 108 cells/cm3 were present in fault zone materials at 417.9 m CSF (Section 316-C0007D-27X-1) (Fig. F49). Similar to the sand and gravel layers described above, the cell abundance proliferations suggested that the flux of nutrient energy that supports the population of microbial community is high at the fault zone. The average cell abundance enumerated by onboard microscopic direct count of SYBR Green I–stained cells was 3.67 × 108 ± 1.86 × 108 cells/cm3 (N = 27).
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