4.27.2018
Made it back to the lower 48. The samples remained frozen throughout the trip and will remain frozen until we start processing them. This trip has been a whirlwind – but fun. Dave and Peter made this an extremely successful sampling! Alaska is such a beautiful place and a great place to study. I did not see any polar bears, even though the last day I claimed I saw something peculiar that looked like a white animal (it was likely just piled up snow). We did see some arctic foxes, musk oxen, and moose though!
The landscape in this area is so beautiful and very interesting things happen in permafrost. Last summer I wrote about solifluction lobes and polygon wedges but this spring I want to introduce pingos. Pingos are another modification of the landscape due to the uniqueness of the freeze/thaw cycles and permafrost. It was hard to get a good photograph of these pingos but they were abundant!
Pingos are mounds of earth-covered ice. They are formed from the draining of a lake or from groundwater. If we recall some of the unique properties of water, 1) water is densest at 4° and 2) less than 4° it expands
then we can understand why pingos form in permafrost environments. Basically, when a lake drains (the bottom of the lake stays ~4° until drained) where this condensed water then freezes and expands up wards creating an ice hill! With a warming climate, there are fractures that form in the active layer of permafrost which induces more melting. This melting can cause a pingo to collapse which, in turn, can then act as another lake! Pingos can host animals, act as a navigational point, or be used for site seeing or for hunting purposes.
More to come as I start processing this fancy dirt! – Kali
