My thoughts, complaints, photos, and reviews of geologic books, articles, etc...
Saturday, June 25, 2011
Accretionary Wedge #35: Favorite Geology Word
For this month's Accretionary Wedge, Evelyn Mervine from Georneys asked us the impossible... to settle on one favorite geology word. I've been mulling this question over off and on for the last week, and found myself sifting through words like yardgang, pingo, sandur, tor, felsenmeer, molasse, tuya, tombolo, doline, nunatuk, moulin, firnschnee, thalweg, polje, inselberg, tafoni, etc... probably a lot more I can't remember right now. Clearly I like words that are unique and often derived from another language, I'm especially partial to German-based terms. Hopefully I'll get around to blogging about each of these words and sharing my photos of them, although I don't have a good photo of a polje. Guess I need to take a trip to Eastern Europe!
However one word that has always fascinated me and drawn me to its country of origin is jökulhlaup. A term derived from the Icleandic for glacier (jökull) and burst or flood (hlaup), which we use to describe a glacially-derived outburst flood. They are often triggered by a tuya - also in my list - which is a subglacial volcanic eruption. These two events are excellent reasons why Iceland is called the land of 'fire and ice.' Here are two videos that illustrate this process in action following the eruption of Eyjafjallajökull in 2010.
I didn't become really fascinated with jökulhlaups until after I had read about the Wegner-esque experience of J. Harlen Bretz. Faced by similar dogmatic biases from the geologic community, Bretz challenged the status-quo and argued that the scablands of the western United States were created through a catastrophic flood. However, similar to Wegner, he failed to provide a 'smoking gun' that would convince his detractors. The origin of this flood (although, generally accepted as multiple flooding events) was later identified by J.T. Pardee as jökulhlaup events from Glacial Lake Missoula. Two excellent books on this topic are "Glacial Lake Missoula and its Humungous Floods" by David Alt and "Bretz's Flood" by John Soennichsen.
Fortunately for me, I also lack photographs of a jökulhlaup in action but here are a few photos taken while traveling through the scablands in 2000: