Exciting news! Last night on the transit from Rankin Bank to Bright Bank, we found what appears to be a paleoshoreline -- the remains of an earlier seashore that existed when the sea level was lower than it is today.
The geologists and archaeologists on this expedition are using several tools to survey and map their study area. Argus is fitted with a sub-bottom profiler which uses sound waves to create a picture of the geological structure beneath the sea floor. Data from the multi-beam sonar is used to create very detailed 3-D maps of the sea bed's surface. And of course, the high definition video camera on Argus enables the team to see the underwater landscape as if they were walking on the sea floor.
According to project archaeologist David Robinson, who led last night's watch in the control van, data from both the multi-beam and the sub-bottom profiler suggest that an area around 100 to 115 meters deep may once have been a seashore. A series of long vertical steps look like they may have been created by the movement of waves, which carve out a trough and deposit material farther up. This is the same profile we see on modern beaches.
As Argus criss-crossed the study area, the pictures we could see from the high-definition camera also provided evidence of an ancient coastline.
More work will need to be done to investigate this area further and confirm whether these features are actually paleoshorelines as we suspect. However this early finding is very exciting!