ODP Leg 176: Return to Hole 735B

Figure 11


FMS images of lower oceanic crust gabbros from Hole 735B.


The transition from iron-titanium (Fe-Ti) oxide gabbros to a magmatic breccia zone and into a unit of olivine gabbros is recorded in both the FMS and laterolog data. The Fe-Ti oxide unit shows pronounced subhorizontal igneous laminations with 20 to 100 cm thick intervals of olivine gabbros. The magmatic breccia zone is characterized by a gradual increase in resistivities due to the decrease in Fe-Ti minerals. The olivine gabbro unit is marked by high resistivities (> 10,000 ohm-m) and a lack of deformation.