Portal:Oregon/Selected article/61
Mount Thielsen, or Big Cowhorn is an extinct shield volcano in southern Oregon that has been so deeply eroded by glaciers that there is no summit crater and the upper part of the mountain is more or less a horn. Thielsen is a relatively old Cascade volcano and cone-building eruptions stopped relatively early. Damage caused during the last two or three ice ages remains visible. Thielsen's spire-like top is hit by lightning so often that some rocks on the summit have melted into a rare mineraloid called lechatelierite, a variety of fulgurite. The mountain itself has earned the nickname "the lightning rod of the Cascades." Diamond Lake lies to the west of Mount Thielsen and beyond lies Mount Bailey, a much less eroded and younger stratovolcano. Mount Thielsen is located directly north of Crater Lake. Its sharp peak is a prominent feature of the skyline visible from Crater Lake National Park. Both of the volcanoes are part of the Oregon High Cascades, a range that sections off the stratovolcanoes of Oregon that are younger than 3.5 million years. Climbing routes around the volcano led to tourism. In 2009, Thielsen was selected as Oregon's best hiking trail. Its skiing trails are also tourist attractions.