Logbook: August 26, 2006

Position: 45°55.1’N/129°59.5’W

Taking a hot fluid sample from a black smoker chimney at the Main Endeavour Vent Field. (click image for larger view)

As you can see from our current position we’ve come about 130 nautical miles south southwest from where we started the expedition. Early this morning we finished our second ROPOS dive at the Endeavour segment and started heading for Axial volcano where we will work for the rest of the cruise. The main goals for the ROPOS dives at Endeavour were to recover and deploy several RAS instruments, which are devices capable of taking a sample of hydrothermal vent fluid about once a week for a year. This is one way of monitoring the behavior of seafloor hot springs during most of the year when we are not on site here to look for changes that might be related to earthquake swarms or volcanic activity. ROPOS also collected vent fluid samples from several nearby sites for comparison with the RAS results and samples taken in previous years. Endeavour segment is known for its spectacular black smoker vents, many of which have formed huge sulfide chimneys (up to 30 m high).