Leicester geologist and New Zealand colleagues discover evidence for gigantic volcanic eruption in Antarctica

Posted by lcb14 at Feb 21, 2017 11:30 AM |
Professor John Smellie has returned from another field season in Antarctica, this time working with the New Zealand Antarctic Programme on a large volcano known as Mt Morning.
Leicester geologist and New Zealand colleagues discover evidence for gigantic volcanic eruption in Antarctica

View of the field area – a sombre isolated crag 1000 m-high overlooking the Ross Ice Shelf. It is formed entirely of volcanic rocks.

Using information obtained during a previous reconnaissance-level study, the new project was designed to document lava—ice interactions and Antarctic ice sheet evolution extending back millions of years. The fieldwork was focused on a spectacular 12 km-long crag that towers 1000 m above the Ross Ice Shelf, an enormous featureless mass of floating ice hundreds of metres thick and almost 1000 km across. Camps were pitched on the ice shelf and, although the ice is almost static in the field area, it was unnerving to hear frequent very deep-seated cracking noises taking place under the tents when trying to go to sleep.

Field camp at Mt Morning. The camp is extensively buried by snow blown in during a storm.
Field camp at Mt Morning. The camp is extensively buried by snow blown in during a storm.

Access to the rocks in the cliff proved to be exhausting, with the field party of three geologists and a field assistant encountering extensive knee-deep soft snow on the ice shelf itself and very mobile ice-cored scree on the steep slopes below the crags. Each day involved laboriously climbing between 300 and 1000 metres just to get to rock.

John working on rocks formed during a gigantic volcanic eruption that occurred several million years ago.
John working on rocks formed during a gigantic volcanic eruption that occurred several million years ago.

Fortunately the weather was very stable, with predominantly calm sunny conditions and temperatures of minus 5 – minus 15°C, much warmer than John’s fieldwork in Antarctica last year. On only two days did wind speeds exceed 25 knots but they resulted in one campsite becoming extensively buried by blown snow. That made digging out the tents during a camp move both time consuming & tiring. However, because of the good weather, the study was completed in 3 weeks instead of the four weeks that were planned, and enabled the team to be uplifted ahead of schedule. Although many of the rock formations proved to be different to what was anticipated, an exciting & unexpected result was the discovery of evidence for an enormous hitherto unknown volcanic eruption. Major challenges facing the team now are (1) to understand why the eruption took place and why its eruptive style was so different from those at other Antarctic volcanoes, and (2) to deduce the environmental effects and any hemispheric or possibly even global impacts of such a large eruption: the South Polar Region is highly sensitive to environmental perturbations. An additional unusual aspect of this year’s fieldwork was the presence of a camera team who followed the geologists and made a film about the project that will be screened on television later in 2017.

View looking down into the ‘igloo toilet’. Chilly………
View looking down into the ‘igloo toilet’. Chilly………
The food pit, used to contain all the frozen food, partially buried by fresh snow. The flags were used to locate the pit in case it became completely buried.
The food pit, used to contain all the frozen food, partially buried by fresh snow. The flags were used to locate the pit in case it became completely buried.

New Zealand geologist Adam Martin sampling rocks for isotopic dating while being filmed.
New Zealand geologist Adam Martin sampling rocks for isotopic dating while being filmed.
New Zealand geologist Dougal Townsend sitting in the large communal tent used for cooking and gathering during bad weather.
New Zealand geologist Dougal Townsend sitting in the large communal tent used for cooking and gathering during bad weather.

Nearing the end of a long laborious climb to get at in situ rock.
Nearing the end of a long laborious climb to get at in situ rock.

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