Antarctic Drilling Project Set To Resume
The first planeload of scientists, technicians and drillers heads to Antarctica this week for the third and final season of drilling in the Cape Roberts project.
Over the next two months they hope to extract undersea rock and sediment from an era when major ice sheets were absent and the continent was up to 12 degrees warmer than it is today.
The six-nation project aims to recover up to 700m of core from a new drilling site on sea ice in the southwest corner of the Ross Sea.
The new site is 2km closer to land but in deeper water than last year’s drill site which produced 624m of core for scientific analysis.
Project leader Peter Barrett, head of Victoria University’s Antarctic Research Centre, said ice thickness was unlikely to be a problem this year.
“ But there’s a lot of variables when your are operating a 55 tonne drilling rig on two metre-thick sea ice 12km from the nearest land,” Dr Barrett said.
The ice is expected to be 1.9m thick by the time drilling starts. The minimum operating thickness is 1.5m.
The seafloor off Cape Roberts is a good location for drilling because of the accessibility of rock and sediment recording glacial and tectonic events for the past 60 million years. Elsewhere they are deeply buried.
“ What’s significant about this year is that we’ll be bringing up rock and sediment that is between 30 and 40 million years old – when the first major ice sheets formed in Antarctica.
“ The appearance of the first big ice sheets in Antarctica about 35 million years ago is the most significant climatic event on the planet in the past 100 million years.
“ It initiated global climate change and changes to plant and animal life. It also influenced the way the oceans circulate around the globe.”
This year’s core is expected to contain a record of all these events. Scientists are keen to track the fortunes of Antarctic plant life over the past 30 million years. Tundra-like vegetation appears to have persisted in Antarctica until about 15 million years ago, and this year’s core should provide valuable information about it.
Dr Barrett said the project had already contributed substantially to the understanding of global climate change and sea level fluctuations, glaciations, tectonics, and the formation of the Transantarctic Mountains and the Ross Sea.
When drilling is completed, by late November, the project will have produced a total of about 1400m of core that will be a permanent and valuable scientific reference. The core is sliced vertically with half stored in Germany and the other half stored in the United States.
This year’s operation will involve 61 scientists, 11 support crew, and 11 drillers. The contributing nations are Australia, Britain, Germany, Italy, New Zealand, and the United States.
The drill site, 130km northwest of Scott Base, is about an hour by helicopter from McMurdo Station and Scott Base.
Among the finds last year was the first evidence of large volcanic eruptions that occurred in the area about 25 million years ago. The evidence is contained in layers of volcanic debris that blanketed the ocean and settled on to the seafloor.
The thickness of the layers indicates that the ash cloud may have reached as high as 70km, and it suggests a far more spectacular history of volcanic activity than was previously suspected in Antarctica. The exact location of the volcanic source, or sources, is still unknown.
The first of two flights is scheduled to leave Christchurch Airport on Tuesday.