Ellsworth Blog 10

5th January and time to take down the tinsel and Christmas decorations! The New Year continues to bring clear weather with temperatures generally around -10 C and lots of sunshine. One recent day was exceptionally warm and actually saw us pulling the radar while stripped to our base thermals, a rare occurrence at 80 degrees South.
Work continued over the festive break and now our attention is on the more distant massifs of the Independence Hills and Marble Hills. Each involves a commute of over an hour and the journey is very different. In the case of the Independence Hills two people travel on backward-facing seats on a Komatic, a sledge based on a Greenlandic Inuit sledge. We go over a long snowdrift via a pass in the Patriot Hills. Two skidoos pull the sledge up and the backward-facing view is special. It is like taking off in a plane and seeing the horizon widen and spread out in front of you. At first there is a view of an ice slope, then of the glacier surface, then nearby mountains and finally the whole vista of the southern Ellsworth Mountains – all in a minute or two. Skidoos are then attached to the front and back for the descent onto the next glacier. Since the journey to the Independence Hills is into the prevailing wind the skidoos travel parallel to the alignment of the sastrugi. The journey to the Marble Hills is across the alignment of the sastrugi and is slow and bumpy; we tend to ride with driver and pillion for comfort and security.
The Independence Hills are partly volcanic and we work on a complex of moraines overlooked by magnificent cliffs towering some 500 m above us. We have discovered that the flow of the glacier in front of the cliffs changes direction as the overall ice thickness changes during glacial cycles in response to sea-level changes. The radar work shows that some of the moraine is trapped in an embayment as the ice moves first one way and then in the opposite direction. So we are hopeful of being able to date the oldest material to see if it survived the last interglacial warm period.
Marble Hills continue to impress. At a new site the initial surprise is a hole. You step off the skidoo at the main ice margin and then walk DOWNHILL for a vertical distance of 140 m. The shape of the topography and the winds are able to keep the basin clear of ice. Anywhere else in the world and a hole like this would contain a lake or be filled in with gravel. The climb back to the skidoos at the end of the day with rucsacs full of rock samples was hard. We have made good discoveries in the Marble Hills. We have found buried glacier ice beneath deposits at altitudes about 300 m above the present ice and at higher altitudes are some of the oldest deposits in the region. It will be interesting to find out how long a history we are unravelling. Our instinct is that the ice sheet has changed in thickness to a certain degree but that it has persisted for a long time even by Antarctic standards. The cosmogenic dating should help enlighten us.
Today there is little wind and Stuart was about to fly his remote control plane with a camera to take vertical photographs, the whole flight being pre-planned with GPS. Andy and I had just installed a small met station on a pole drilled into the blue ice and we saw a plane in the distance. At first we thought Stuart had had great success but it morphed into a Chilean Hercules plane, probably checking out their abandoned base which is now largely beneath snow. Inspired by the Hercules, Stuart got his plane airborne and has successfully got vertical photos of our detailed test site. Great news!

Our uplift date back to Rothera is 14th January so we are busy tying up loose ends in the science programme. Malcolm and Scott are beginning to prepare for our departure and plan the storage of camping equipment, skidoos, etc so that the latter survive the winter and can be re-discovered next year. The suspension of one of the skidoos gave out today and Malcolm and Andy are replacing a major part just now. We do not want to ship ou t a heavy skidoo if we can avoid it.
A few more days of good weather?

Advertisements

2 thoughts on “Ellsworth Blog 10

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s