Editing North Cascades National Park (section)

=== Geology ===
North Cascades National Park was named after the [[North Cascades]] mountains, which are a subsection of the [[Cascade Range]] that extends from northern California into British Columbia. The North Cascades are the northernmost section of the range and unlike their southern counterparts that consist of [[Tertiary]] to [[Holocene]] volcanic rocks, the North Cascades are composed primarily of [[Mesozoic]] crystalline and [[metamorphic rock]]s.<ref name=wsdnr>{{cite web|title=North Cascades|publisher=Washington State Department of Natural Resources|url=https://www.dnr.wa.gov/programs-and-services/geology/explore-popular-geology/geologic-provinces-washington/north-cascades|access-date=March 29, 2018}}</ref> Though most rocks in the park are from the more recent Mesozoic, the oldest rocks are 400&nbsp;million years old, dating from the [[Devonian]].<ref name=nc>{{cite web|title=Geology of North Cascades|publisher=North Coast and Cascades Science Learning Network|url=http://www.nwparkscience.org/node/874|archive-url=https://web.archive.org/web/20180622193345/http://www.nwparkscience.org/node/874|url-status=usurped|archive-date=June 22, 2018|access-date=June 22, 2018}}</ref> A complex assemblage of various rock formations have repeatedly been eroded, reburied, subjected to fracturing and heat, creating a geological puzzle that is one of the most complicated and least understood geological records in North America. These forces are ongoing and the region continues to see uplift and faulting.<ref name=nc/>

Evidence from the fossils and magnetism found in the rocks indicates that the [[terrane]]s composing the North Cascades drifted thousands of miles north until they impacted the [[North American Plate]] 90&nbsp;million years ago.<ref name=nc/> The collision between the rocks caused fracturing and folding as well as uplift and the terranes were further fractured into north or south trending faults.<ref name=nc/> The uplifted rocks mostly eroded away; 40&nbsp;million years ago the heavier [[basalt]]ic rocks of the ocean floor started to push the lighter [[granite|granitic]] rocks that are the core of the mountains upward, a process that continues.<ref name=nc/><ref name=geologic>{{cite web|title=Geologic Formations|publisher=National Park Service|url=http://www.nps.gov/noca/naturescience/geologicformations.htm|access-date=March 30, 2018}}</ref> Subjected to intense heat, rocks deep underground near the collision zone became recrystallized into granitic rocks, which comprise the backbone of the highest peaks.<ref name=nc/> Continued uplift and erosion and finally the action of glacial ice on the landscape during the [[Holocene]] exposed the rocks visible today.<ref name=nc/><ref name=wsdnr2>{{cite web|title=Glaciation and Erosion|work=North Cascades|publisher=Washington State Department of Natural Resources|url=https://www.dnr.wa.gov/programs-and-services/geology/explore-popular-geology/geologic-provinces-washington/north-cascades#glaciation-and-erosion.1|access-date=June 22, 2018}}</ref>

Much harder and more durable than the younger volcanic rocks of the southern Cascades, the North Cascades are consequently more rugged, with steep terrain being the norm due to heavy erosion from water and ice.<ref name=tabor>{{cite book|last=Tabor|first=Rowland|author2=Ralph Haugerud|title=Geology of the North Cascades: A Mountain Mosaic|publisher=Mountaineers Books|url=https://books.google.com/books?id=56UH5XauGSsC&q=Geology%20of%20the%20North%20Cascades%3A%20A%20Mountain%20Mosaic&pg=PA7|pages=7–8|isbn=978-0898866230|date=May 14, 1999|access-date=March 30, 2018}}</ref> Continued rising in conjunction with erosion from water and ice has created deep valleys and significant vertical relief that is comparable to much taller mountain ranges.<ref name=tabor/>