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NeMO Date: July 11, 2000
Ship's Location:
45 54.8'N/129 58.5'W

 
         
         
  Science Report:
ROPOS dive 550 collected Imagenex sonar data to extend the surveys we have done in previous years. The Imagenex sonar allows us to make high resolution bathymetric maps with a pixel size of 2 meters that show much more resolution than bathymetry collected from a surface ship. These maps help us to put the observations and samples from ROPOS into a more meaningful spatial context. They help us to map out the extent of the 1998 lava flow, where it is intact or collapsed, and where the eruptive vents were. Knowing this helps us interpret the physical settings of the various vent sites we are visiting.

For example, from the data we collected on this dive we are now convinced that the vents at Marker 113, Joystick, Bag City, and Crevice are not on the 1998 lava flow, but actually on a slightly older flow to the west. The following ROPOS dive, 551, was primarily a fluid sampling dive (see photo on today's Interview) which visited all the major vent sites from Marker 33 in the north to Bag City in the south, and concluded with a few additional Imagenex tracklines.

 


Sulfide chimney (notice pyrite crystals in center).


Diffuse venting through cracks in the 1998 lava flow, with microbial mats.