Does a Young Galápagos Submarine Lava Flow Look Like?
lava flows with the MR1 side-scan sonar system is one thing but
actually seeing them is even better!
Engels has been busy measuring the lengths and areas of the 33
lava flows we have mapped on the flanks of Fernandina and Isabela.
She has determined that these flows are large they average
14 km in length and have areas of about 630 square kilometers.
MR1 sonar backscatter map for the area north and west of Fernandina.
Darker areas of strong acoustic reflections from young lava flows and steep
slopes facing the sonar fish. The red box shows the area blown up in the
towed the camera across a narrow part of the lava flow so that
we would see different parts of the seafloor covered with both
lava and sediment. The side-scan image shows the young, dark
lava flow outlined in blue. It has flowed over an older, sediment-covered
lava flow outlined in orange.
The colored areas along the camera track (above) show the different types of
lava or sediment-covered seafloor we observed. Yellow indicates sediment-covered
areas, blue is pillow lava flows, and green is sheet lava flows. We were surprised
to find that the lava flow has sediment on it along most of the survey track.
The few centimeters of sediment dusting the tops of the flow indicate that it
may be hundreds to perhaps one thousand years old but thats young
in geological terms.
along the camera tow track as you look at photos of the seafloor
in the slide show. The slides are in chronological order,
starting from the left end of the camera track. Each photograph
is approximately 4 meters by 6 meters in size.