January 16th, 2014
It’s another tent-bound day due to snow, low visibility and contrast, our second in a row. We get occasional glimpses of the Patriot and Marble Hills, and they are caked in a fresh layer of snow. It looks perfect for skiing, but not great for our work. This is our third day of inactivity due to weather (since arriving just over a week ago) and the reality of our unusually good weather last season is starting to set in. Still, we’ve managed four good days work since arriving last week and we’re well on track to achieving our key objectives for this field season.
So what is our plan? The key priority and the main reason for a second field season is to quantify the changes in blue ice areas over the course of a year so we can learn how the moraines are forming today. This means the 3-D laser scans Stuart produced last year need to be re-measured to account for surface change, as does the entire grid of glacial poles that were installed last season to determine the amount of surface melting that has occurred around the glacier, as well as the total amount the glacier has moved the poles. John and Kate spent the first few days obtaining laser scanner data from the Patriot Hills. At first the cold and windy weather and damaged seals within the laser scanner unit caused problems with condensation and frustration. However, all came good a couple days ago and they were successful getting the data they need. Today, in near whiteout conditions, they are pressing on heroically to obtain their GPS data!
Shasta and I are focusing on the long-term evolution of the ice sheet and formation of blue ice moraines. Over the past year we have been working on rock samples David and I collected last season to determine the age of these surfaces. The rocks contain rare cosmogenic nuclides that accumulate within rock minerals when exposed at the land surface. By measuring the concentration of one or two of these rare nuclides we can determine when the glacier deposited the rock; in this way we can track, for example, the thinning of the ice sheet through time. In some cases we can determine whether a rock has been continuously exposed at the surface without interruption, or whether the rock has been periodically buried by ice; this information allows us to build a more complete picture of how the ice sheet has evolved through time. The preliminary data obtained from last season is now helping to guide our sampling for this season.
So what have we learned? Well, without going into too much detail, we now know that elevated blue-ice moraines have survived for hundreds of thousands of years. We know there are parts of the mountains where warm, erosive ice conditions existed and other parts that have been buried by ice frozen to the bed of the glacier, thereby preserving the underlying material. Our focus this year is to better understand this interaction between cold- and warm-based ice through mapping the landforms and further sampling of rocks for exposure dating. A key priority is to visit parts of the Marble Hills that we did not manage to visit last season. It is about a 40 km round trip, so we’ll be spending a lot of time this season on skidoos! So far we’ve managed two successful trips there and we reckon another 3 – 5 should see us finished with this site. Unfortunately, given the distances involved, we need pretty stable weather to carry out our work at Marble Hills and by the look of it now, it’s going to take a good few days to get rid of all that new snow! At least the forecast looks favorable!
A couple of days ago with weather prohibiting travel to Marble Hills, we took the opportunity of being in this remote part of Antarctica to collect data for another researcher. We set ourselves the challenge of extracting a 30 cm block of debris-rich ice from below the blue ice surface at the Patriot Hills. This is to study microbes that may survive beneath the ice sheet. Since blue ice areas are locations where ice and debris from the bed of the glacier make their way to the surface it may be an easy alternative to study microbes without drilling to the bottom of the ice sheet! The ideal tool for the job is a chainsaw but we didn’t have one (the idea came at the last minute before leaving the UK). So we’ve been left to devise our own way of extracting these blocks with the tools on hand…a fun little project! With a circular saw, ice drill, angle grinder, ice axes, rock hammers and chisels, we finally managed to excavate a 40cm block of ice from below the surface. It was quite satisfying getting this chunk of ice out in one piece!
Well, the stoves are on and it is nearly time for another freeze-dried culinary delight! That’s it for now!