Posts Tagged ANDRILL

Reflections of a Sound Matthew Wood Aug 25

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When you’re spending US$15M to drill a hole, you want to make sure it’s in the right place.

In the austral summer of ’05/’06, it was still a year until bits would start chewing through rock beneath the McMurdo Ice Shelf (MIS) in the first phase of the ANtarctic DRILLing (ANDRILL) Project. The international science team was busy wrapping up a multi-season geophysical reconnaissance effort, using multichannel seismic reflection profiling to hone in on the ideal site for the next season’s drilling. Using carefully-positioned geophone arrays and controlled (but by no means insignificant) explosive seismic sources, they remotely ‘imaged’ the sedimentary sequence that has gradually accumulated over the last 14 Ma beneath (what is currently) the McMurdo Ice Shelf. Accommodation space for these sediments was initially provided by regional subsidence related to extension across the Terror Rift, and later, from crustal flexure in response to the emplacement of the Ross Island alkalic volcanics.

MIS Project Setting

The ANDRILL MIS core was an unprecedented achievement in Antarctic science: 98% of the 1285 m sub-sea floor drilled sequence was recovered as core, sampling glacimarine sediments that document the Late Cenozoic, continental-scale fluctuations of Antarctica’s ice sheets. Currently at the drill site, the 85 m thick McMurdo Ice Shelf floats above 850 m of McMurdo Sound seawater (which posed a formidable logistical challenge for both seismic profiling and drilling). But as the sediments testify, this area has periodically hosted an expanded, grounded East Antarctic Ice Sheet, and at other times, sea ice-free, open water marine conditions. Following drilling, seismic reflection was again utilised to generate a down-hole vertical seismic profile, to more accurately tie the major lithological boundaries observed in the core to the major, and numerous second-order, seismic reflectors. This allowed the ‘ground-truthed’ geology of the drill site to be extrapolated laterally across the wider study area.

Dhiresh Hansaraj Erebus

Dhiresh Hansaraj was fortunate enough to contribute to both of these exciting field seasons. Interested in geophysics from early in his undergraduate studies, Dhiresh required little persuasion to take up a Master’s project with the ANDRILL team that involved the acquisition, processing and interpretation of MIS seismic data. Following university, he didn’t allow the lack of industry work in Wellington to stop him from pursuing a career in the scientific field he had learned and loved on the ice, and now co-runs his own seismic processing house, Black Mountain Seismic Ltd, which uses entirely New Zealand made software. His experience is a refreshing exception in an industry that generally lures our postgraduates overseas to work for the resource exploration and production giants.

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Photo (c) Dhiresh Hansaraj 2005. Figures from Scientific Logistics Implementation Plan for the ANDRILL McMurdo Ice Shelf Project

All Journeys Begin With a First Step Matthew Wood Jan 18


’Great God! This is an awful place…’Man and Iceberg

So wrote Robert Falcon Scott in January of 1912 upon discovering that the Norwegian, Roald Amundsen, had beaten him to the South Pole.

A rather unfair review you might say, but then again, Scott was about to find out just how unforgiving a place the white continent can be. From the stoic characters of the heroic age of exploration through to the scientists and support staff of modern Antarctic programs, those who seek to work on the ice quickly learn that Antarctica can be a place of both serene beauty and uncompromising harshness.

While Antarctica’s capacity to pitilessly claim the lives of the unfortunate or unprepared has long been understood and respected, it is only recently that we have begun to appreciate the extent to which mankind’s collective actions have put this delicate environment in grave danger of collapse.

The global implications of rapid environmental change at the poles make Antarctic science, in my opinion, one of the most important endeavours of the modern world.

So, why make a podcast? After flirting with work in academia and industry I recently found myself wanting to try my hand at science media and communication. I guess I realised that I had become more comfortable as an ‘armchair’ scientist, fervently enjoying the works of popular science writers like Richard Leakey, Simon Singh, Richard Dawkins and many others. I’m also a big fan of the podcasting format and an avid listener of shows like Philosophy Bites, by David Edmonds and Nigel Warburton, and Science Talk: The Podcast of Scientific American, hosted by Steve Mirsky — shows that I highly recommend and that have clearly influenced the style of Journeys. In order to bring the stories of any specialist discipline to the masses there is a clear challenge to strike a balance between maintaining the interest of both the layman and those with existing knowledge. I hope this podcast will succeed in distilling the essence of each science story, but I would of course recommend any referenced source material to those seeking further information.

I first worked with the Antarctic Research Centre (ARC) as a field assistant on the Victoria Land coastal glaciers in late 2003, following my undergraduate study in geology at Victoria University of Wellington. After this unforgettable experience I maintained a keen interest in what happens on the ice and continued to work closely with colleagues in the ARC through research and teaching.

The man at the helm of the ARC is Professor Tim Naish, a man well known in geological circles for his application of cyclostratigraphic principles, developed in the Wanganui basin and the Canterbury coast of New Zealand, to the ice sheet fluctuations across the continental margin of southern Victoria Land in Antarctica (the Cape Roberts Project and more recently ANDRILL). In this first episode Professor Naish recounts his early impressions of Antarctic fieldwork, outlines the history of the ARC to date and considers the direction in which it is currently heading.

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Photo (c) Matthew Wood 2003

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