Rampart Lakes

by Inge Johnsson

Title

Rampart Lakes

Artist

Inge Johnsson

Medium

Photograph - Digital Capture, Watermark Not On Actual Print

Description

Rampart Lakes area of Alpine Lakes Wilderness, Washington
.....
The Alpine Lakes Wilderness is a large wilderness area spanning the Cascade Range of Washington state in the United States. The wilderness is located in parts of Wenatchee National Forest and Snoqualmie National Forest, and is approximately bounded by Interstate 90 and Snoqualmie Pass to the south and U.S. Route 2 and Stevens Pass to the north. The Alpine Lakes is the largest wilderness area near the population centers of Puget Sound, at approximately 390,000 acres. 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. These climate differences lead to vegetation variety defining the ecoregions in this area. The elevation range of this area is between about 1,000 feet (300 m) in the lower elevations to over 9,000 feet (2,700 m) on Mount Stuart.
The history of the formation of the Cascade Mountains dates back millions of years ago to the late Eocene Epoch. With the North American Plate overriding the Pacific Plate, episodes of volcanic igneous activity persisted. In addition, small fragments of the oceanic and continental lithosphere called terranes created the North Cascades about 50 million years ago.
During the Pleistocene period dating back over 2 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 Canadian 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.
The most common rock type in this area is intrusive igneous, which are highly fragmented granitics, this includes most of the Foss Lakes and Enchantment Lakes area. The other major rock types are sedimentary, metamorphics, ultrabasic rock complex and the extrusive igneous group that include basalt, andesite, and ryholite. The metamorphic rocks are primarily in the northern part and the southern area is made up of volcanic and sedimentary rocks. The Wenatchee Mountains are mostly composed of peridotite.

Uploaded

October 28th, 2012

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