Clean ice and dirty ice

 

I was looking through my old slides from Axel Heiberg Island in the Canadian Arctic when I came across these two.  These are two glaciers within a kilometre or so -- one which is virtually free of dirty ice, let alone till, and the other flanked by a very distinct morainic ridge and with layer after layer of dirty ice, filled with englacial debris.

It's not so mysterious -- glaciological principles are at play here. But it is intriguing nonetheless that one glacier can advance and retreat across the landscape leaving virtually no trace of its coming and going, while another (right next door) leaves quite a dramatic legacy of sediments and landforms.