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Rediscovering Ross Island 2012: Lava Sampling on the North Shore

Written by Ken Sims.

After all the requisite training we are now sampling the volcanic rocks on Ross Island. Yesterday while the other team members were completing their environmental training, Phil Kyle and I flew out to Lewis Bay (Plate 1 and 2) to sample the lava flows from Mount Bird that are exposed in cliffs around the bay. These lava flows erupted from Mount Bird, which is an older volcano that is almost entirely covered by ice.

Plate 1: Flying with Scotty Pentecost the pilot in a A-Star helicopter operated by contractor PHI with Mt Erebus in the background. Photo by Ken Sims.
Plate 2 Co-PI Phil Kyle riding in the A-star helicopter on the way over to Lewis Bay on the north side of Ross Island. Photo by Ken Sims.

Unfortunately, we could not land at any of these sea cliffs because the sea ice below them is too thin and rotten and therefore unsafe to land on, and they cannot be accessed from above because they are overhung by large calving glaciers. There were many ice cracks and as a result, lots of seal holes and of course seals. This is an unusual year for sea ice in the vicinity of Ross Island. We are clearly too late this year to find favorable conditions to land and safely undertake sampling in this area (Plate 3).

Plate 3: The effects of a large calved serac on the sea-ice in Lewis Bay. One can see where the calving glacier struck the sea ice and caused a ripple effect as the wave propagated outward. This was one of many indicators that the sea ice was too thin to safely land on. Photo by Ken Sims.

As a result, we changed our objective for the day and flew across the bay over to the sea cliffs below Mt Terror where we started working on our planned transects up the north and east ridges of Mt Terror. Overall it was a very successful day and we collected some key samples for our study (Plates 4 and 5).

Plate 4: Some of the basaltic lava flows of the lower flanks of Mt Terror that form the sea cliffs along Cape Tennyson with Mt Erebus in the background. Photo by Ken Sims.

Weather providing, tomorrow we (myself, Erin, Paul and Dan) are flying back to Mt. Terror and will start to work our way up the East Ridge which has numerous cinder cones and lava flows which have never been studied. The forecast looks great!

Plate 5: Phil Kyle using a GPS to determine the location of the lava flow we had just sampled at Cape Tennyson on the shore of Lewis Bay. Photo by Ken Sims.