page_title: Big Chiwaukum
section_title: Geology
hierarchical_section_title: Big Chiwaukum / Geology
caption_attribution_description: English: Big Chiwaukum in the North Cascades of WA
context_page_description: Big Chiwaukum is a prominent 8,081-foot mountain summit located in Chelan County of Washington state. Big Chiwaukum is situated northeast of Frosty Pass, and within the Alpine Lakes Wilderness. Big Chiwaukum is the highest peak in the Chiwaukum Mountains, a subset of the Cascade Range. In the Wenatchee dialect, Chiwaukum means many little creeks running into one big one. Its nearest higher peak is Cashmere Mountain, 10.35 mi to the south-southeast. Precipitation runoff from Big Chiwaukum drains into tributaries of the Wenatchee River.
context_section_description: The Alpine Lakes Wilderness features some of the most rugged topography in the Cascade Range with craggy peaks and ridges, deep glacial valleys, and granite walls spotted with over 700 mountain lakes.  Geological events occurring many years ago created the diverse topography and drastic elevation changes over the Cascade Range leading to the various climate differences.
  Big Chiwaukum is composed of schist, part of the Nason terrane laid down 210 million years ago. During the Pleistocene period dating back over two million years ago, glaciation advancing and retreating repeatedly scoured the landscape leaving deposits of rock debris. The last glacial retreat in the Alpine Lakes area began about 14,000 years ago and was north of the Canada–US border by 10,000 years ago. The "U"-shaped cross section of the river valleys are a result of that recent glaciation. Uplift and faulting in combination with glaciation have been the dominant processes which have created the tall peaks and deep valleys of the Alpine Lakes Wilderness area.
caption: Big Chiwaukum
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