DSV Alvin
On August 6, 2004, the DSV Alvin dropped down near the Denson Seamount and collected basaltic rock to try to determine the age of the seamount. The search was difficult because the salty water had altered the volcanic rock over time, but they determined in lab tests that the Denson Seamount was about 18 million years old. The team used bathymetric mapping to render three-dimensional images of the Denson Seamount and its counterparts.