Tarka and I were sat on our sleds early this afternoon, resting and eating after another 80-minute stint of walking on crampons over blue ice. As I chewed on an energy bar there was a loud crack or bang, like a rifle shot or a firework going off, and a definite shock wave. I'd noticed the ice making pinging, popping and cracking noises as we walked over it for a couple of days, but I'd never actually felt anything.

"Did you feel that?", I asked Tarka. "I love that", he said, "my wife hates it and gets all jumpy, but I feel like a glacier chiropractor, helping click all those thousands of tons of ice under pressure back into place. I always imagine the glacier sighing with relief afterwards."

Today was another character-building one, with difficult weather throughout (low cloud cover, flat light and a cold headwind coming off the plateau) and undoubtedly the hardest section of travel we've encountered, namely the blue ice climb past Mount Buckley and Mount Bowers - both part of Buckley Island - at the top end of the Beardmore Glacier. The vertical ascent was only about 200 metres, but it was a short, sharp, steep climb over a fractured surface that had us both working like shire horses.

Incidentally, we spotted Mount Saunders on our big map of the Beardmore when we were writing route notes for our return journey last night. Sadly it's too far east of us for a detour, but I had no idea it was here, and I have no idea who it's named after.

The other happening of note today was finding a man-made object near the foot of the craggy rocks of Mount Bowers, the rusted remains of a tin can. Any markings on it were long gone, and it was impossible to tell its age or where it came from, but it looked ancient and I know that Captain Scott stopped here to "geologise" for a day, so you never know. His team found fossilised ferns in the rock nearby, and I often feel a bit guilty that we're racing through a place that would surely be Mecca for most geologists and glaciologists.

I'll sign off now as I'm cooking, I'm tired and it's late, but we leave a depot tomorrow night and then hang a left and head due south on the plateau for the Pole, so it's an exciting transition for us. Watch this space.