Thursday, August 2, 2018

Week 5 - Convergent plate: Gunn




North Cascades National Park
https://www.britannica.com/place/North-Cascades-National-Park 

My trip this week is taking me to the North Cascade Mountains, as I’ve grown up with them all around me in Washington state, I figured I’d get a closer look and learn more about them. 
Geologists believe that the North Cascades were created in the South Pacific Ocean, and drifted due to oceanic plate movements. They merged together by the rock formations colliding into the North American Continent, which thrust the older rocks from the South Pacific onto the younger rocks that had already existed. 


Then further movement from the Juan de Fuca plate compression, made the ocean’s crust (which is relatively thinner and made from basalt) move under the continental crust (which is thicker and made from granite). As this subduction happened, it went deeper into the Earth and started to melt, which sent magma upward and outward to solidify this mountain range. The North Cascade mountains is said to be from a combination of subduction and transform faulting. 

Ring of Fire
https://en.wikipedia.org/wiki/Ring_of_Fire

These mountains are apart of the ring of fire, which is a ring around the Pacific Ocean, known for its mountains and volcanoes--and are the most active. 
Three major domains make up the North Cascades
https://geomaps.wr.usgs.gov/parks/noca/nocageol4a.html 

This range is broken up into three domains, known as the Western Domain, Metamorphic Core Domain and the Methow Domain. Most of my visits to this area consist of the Western Domain as it’s the easiest for me to get to. The rocks here are layered by faulting in a short amount of time, and also display folding.

References: 

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