February 9, 2014
Over the last two days we have been busy taking dredge samples from the Mertz Glacier region. Sites for bottom dredging were chosen based on the seismic data we collected earlier in the week that showed where rocks from specific time periods were exposed at the surface. Our goal was to bring up rock samples from the Eocene and Oligocene Epochs and the boundary between the two, which marks a time when there was a significant change in global climate. The dredges successfully recovered bedrock along with its veneer of glacial till, with our best achievement being the recovery of rocks from the Eocene/Oligocene boundary. Igneous, metamorphic, and sedimentary rocks were all found in the dredge material. The marine geologists on board were very excited with the results of the dredging, and we have a lot of samples to bring back for further lab analysis.
Dredging was also a great excuse to get outside and get dirty because, in addition to the rocks, the dredges recovered large volumes of marine mud from the seafloor. It was a collaborative effort to sort through all of the mud, pick out rocks of all sizes, and wash the mud back over the side into the ocean. Three hours later, the sorting was done and the back deck was cleared of mud; only a group of salty, happy, and tired marine geologists remained. Back in the lab our time has been spent carefully cleaning, sorting and cataloging the specimens. In addition to rocording information about the specimens here on the Palmer, the samples must also be packed away for later lab analysis at our home institutions.