Field Update: Dec. 1, 2010

Many people think that when they come to McMurdo Station that they have set foot on the continent of Antarctica, but technically we know that Ross Island is a volcanic edifice located offshore, surrounded by ice and water and isolated from the coast. The figure below shows the distribution and relative ages of the volcanic edifices around southern McMurdo Sound and Ross Island, which include Minna Bluff, Black Island, White Island, Mount Discovery, the Brown Peninsula, Mount Morning, and the Royal Society Mountains, among others (such as Mount Bird, Mount Terror, Mount Erebus on Ross Island). The location of features in the vicinity of Ross Island and some of the images contained in this blog can be found on this figure.

The view to the southeast from McMurdo Station, on the tip of the Hut Point Peninsula on Ross Island, crosses Black and White islands and leads to Minna Bluff, a promontory extending to the southeast from Mount Discovery that is known for its high winds. The ice flowing northward from the Skelton Glacier out of the Transantarctic Mountains, goes around the tip of Minna Bluff, known as Minna Hook, to form the southern end of the “shear zone” that continues northward to Cape Crozier below Mount Terror.

To the north of Minna Bluff, closer to Ross Island, is White Island, with Mount Nipha forming the central region of the island. White Island, located southeast of the Hut Point Peninsula, is largely ice and snow covered.

We traversed past the northeast side of White Island on our way out to the Coulman High camp from McMurdo Station earlier in the season. Some of the glacial ice that rounds Minna Hook is focused into the region behind and between White Island and Black Island where it becomes trapped. ANDRILL proposed a drill site in this region, the Southern McMurdo Ice Shelf (SMIS), as part of the inaugural Southern McMurdo Sound portfolio, but this site was not selected for drilling at that time.

The figure at the start of this blog shows the two locations that were drilled by ANDRILL, namely, the McMurdo Ice Shelf (MIS) project site, where we drilled 1285 meters of rock core with 98% core recovery, with an age of ~13 million years at the base, and the Southern McMurdo Sound (SMS) project site, where we drilled 1138 meters of rock core with 98% recovery, with an age of ~20 million years at the base.

White Island is located right next to Black Island, in front of Minna Bluff. The satellite up-link for Ross Island is located on Black Island across the ice.

Black Island lies just to the left (east) of Mount Discovery, which is a prominent feature to the south of McMurdo Station and Ross Island.

During the helicopter trip back to town last week I was able to take some pictures of the NASA Columbia Scientific Balloon Facility (CSBF), located by William’s Field, out on the ice shelf between McMurdo Station and Black Island. The CSBF launches stratospheric balloons as part of the NASA Long Duration Ballooning (LDB) program. The balloons measure 400 feet in diameter expand to a volume of 40 million cubic feet, and ascend at a rate of about 900 feet per minute to a float altitude of 125,000 feet. The balloons circumnavigate Antarctica between 70 and 80 degrees south latitude because of the Antarctic wind pattern that starts in December. All of the main buildings of the CSBF are assembled on sleds, which allow them to be moved around and stored on nearby berms during the winter months.

You can see another perspective on the features I’ve just described through this series of three airborne images, which show the LDB facility in the foreground, looking southwards toward Minna Bluff, in the gap between White Island and Black Island, and then from LDB towards Black Island and Mount Discovery as we flew by in the helicopter back to McMurdo. The LDB facility is one of the few places in the world where high altitude balloons are launched into the upper atmosphere carrying scientific payloads. To ensure safety, the launches are carefully planned.

Out at the ANDRILL Coulman High Site #2 camp the work continues, with the second hole through the ice shelf being used for camera runs and gravity coring today in preparation for the deployment of the second mooring. Once the mooring is deployed, the camp will mover to Site #3.

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