Figure 1. Bathymetry of the Atlantis II Transform Fault (data from Dick et al., 1991) displaying the transform valley, transverse ridges, median tectonic ridge and the northern and southern ridge-transform intersection (RTI). Solid circles marks the position of Hole 735B atop the Atlantis Bank.
Figure 2. Three-dimensional shaded-relief image of the Atlantis Bank (looking northeast) along the wall of the Atlantis II Transform Fault (data from Dick et al., 1991). The image shows Sites 1104, 1105A, and 1106 drilled on Leg 179 and Hole 735B drilled on Legs 118 and 176. Image shows the transform valley, transverse ridges with the Atlantis Bank (highest region), and the termination of the median tectonic in the axis of the transform valley.
Figure 3. Summary of visually defined lithologic intervals and syntheses units of Hole 1105A. Only the main lithologic rock types are illustrated.
Figure 4. Close-up core photograph showing a planar interface between layers of massive medium-grained gabbro and massive coarse-grained gabbro.
Figure 5. Close-up core photograph showing an interval with high concentration of Fe-Ti oxide minerals in coarse-grained gabbro.
Figure 6. Digital photomicrograph of medium-grained olivine gabbro with adcumulate texture. Field of view is 2.75 mm (plane-polarized light).
Figure 7. Photomicrograph of contact between fine-grained olivine gabbro with granular texture and a medium-grained olivine gabbro. Field of view 23 mm (plane-polarized light).
Figure 8. FMS image over the depth interval 93 to 100 mbsf in Hole 1105A with correlated lithologic units and oriented dips. Conductive areas appear in dark shades, whereas light shades are attributed to resistive zones.
Figure 9. Filtered whole-core magnetic susceptibility measurements. All measurements of pieces smaller than the sensing interval of the susceptibility loop, as well as all measurements within 5 cm of the end of a piece have been removed. A simplified graphic lithology column, highlighting only those intervals where Fe-Ti oxide have been reported is plotted to the left. Lithologic unit boundaries are also shown adjacent to the graphic lithology plot and embedded in the magnetic susceptibility plot. The dashed line represents a weighted moving average through the magnetic susceptibility data. Lithologic unit average magnetic susceptibilities are Unit I, 828 SI; Unit IIA, 3406 SI; Unit IIB, 3010 SI; Unit III, 780 SI; Unit IV, 3472 SI.
Figure 10. Poikilitic clinopyroxene enclosing anhedral plagioclase grains in medium-grained olivine gabbro. Field of view = 5.5 mm (cross-polarized light).
Figure 11. Highly strained ribbon grains of plagioclase in mylonitic fine-grained matrix. Field of view = 5.5 mm (cross-polarized light).
Figure 12. Site map in the eastern Indian Ocean showing the location of Ninetyeast Ridge and NERO Site 1107 and other ODP sites in the region (from Pierce, Weissel, et al., 1989). Contour is 3000 mbsl.
Figure 13. Schematic illustration of cased borehole configuration at Hole 1107A.
To 179 Operations Synopsis-Introduction to the Hammer Drill-In Casing System
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