Free Flash Slideshow by cu3ox.com v1.1

Exploring the beautiful nature of California


California Nature: Sierra Nevadas


The Sierra Nevadas are a mountain range crossing from California to Nevada, between the California Central Valley and the Basin and Range Province. Sierra is Spanish for “saw tooth mountain range,” so knowledgeable Westerners usually avoid a redundancy by simply referring to “the Sierra Nevadas” or simply “the Sierras.”The Sierra runs 400 miles north-to-south, and is approximately 70 miles  across east-to-west. Notable Sierra features include Lake Tahoe, the largest alpine lake in North America; Mount Whitney at 14,505 feet the highest point in the contiguous United States; and Yosemite Valley sculpted by glaciers out of 100-million-year-old granite. The Sierra is home to three parks, 20 wilderness areas, and two national monuments. These areas include Yosemite, Sequoia and Kings Canyon National Parks. The Sierra Nevada Mountains contain some of the most beautiful landscapes in all the world. The terrain is so varied that one may start out in desert conditions and end up with the sound of crunching ice under foot and the ring of a distant ice ax in a remote frozen gully well above the timberline.
the sierra mountains often called the wandering lizard Heavy snow falls during most winters, and there are many permanent snow patches and several small glaciers. Glaciers were much heavier in the past, evidenced by the extensive erosion in the range, which has created spectacularly sculpted valleys and cirques. For the fisherman the Sierras are a playground of lakes, streams, and rivers that will delight the most zealous of anglers. For the hiker and or backpacker, the mountains have a system of trails and camps that are unrivaled anywhere else in the world. Cross country skiers will find outstanding snow conditions during most of the winter, and near perfect corn snow during the spring months. If you are a climber/mountaineer there are more than enough rock walls, high angle gullies, ridges, peaks and summits to last a life time. Table Mountains are an interesting feature of the Sierra Nevada foothills; these flat-topped mountains can be seen from Highway 168 as you drive toward Shaver Lake. Table Mountains are ribbons of solidified lava that once flowed from a volcanic eruption. The lava flowed easily down riverbeds as it became more diluted with water. Today, sections of these winding lava rivers continue to rise up from the foothills as the surrounding landscape gradually erodes away.
The Sierra Nevadas form a natural barrier along California's eastern border that forced most early emigrants to swing north into Oregon or south through Utah and Arizona. Impatient to make their fortune, many Forty-niners followed a more direct route, struggling across at Truckee Pass, which is the path Charles Crocker followed when he broke through the Sierra Nevadas in 1868 to create a transcontinental railroad.

It may be hard to imagine, but from 400 million to about 130 million years ago an ocean covered the area we know as the Sierra Nevada. Beneath the seafloor, geological processes were at work that would lead to the formation of the Sierra Nevada mountain range. Plate tectonics, the movement of the plates that form the earth’s crust played an important role in the formation of the Sierra Nevada, and is also responsible for the volcanic and seismic activity we experience today.
Mount Whitney part of the Sierra Mountains in California Picture the earth’s crust as being made up of puzzle pieces that glide over a layer of molten magma. As two pieces of the puzzle, the North American and Pacific plates, converge, the Pacific Plate drops under the North American Plate in a process called subduction. During the late Paleozoic Era, approximately 250 million years ago, the pressure and friction that resulted from the grinding of the plates as they moved past each other caused the crust of the Pacific plate to melt, forming plumes of liquid plutonic rock that eventually floated up toward the surface. These plutons came together to form the single, massive batholith, or deeply imbedded rock, that is the Sierra Nevada. As the batholith began to rise, about 80 million years ago, the layer of marine sedimentary rock that lay over the mountain was gradually eroded away and deposited in the valley. However, remnants of the marine rock, called roof pendants still cling to mountaintops. Because the uplift was greatest on the eastern side of the batholith, the mountain range tilts toward the west, creating a gradual western slope and a precipitous incline on the eastern side.
Once the mountains were formed, glaciers shaped the landscape. During the Pleistocene, there were many glacial periods in the Sierra Nevada. Glaciers are massive bodies of snow and ice that occur when snow accumulates more than it melts. As the snow begins to accumulate over the years, the crystals become compacted into ice. Rising temperatures in the day followed by freezing temperatures at night cause the crystals to refreeze and bond, forming a single mass of ice. The weight of the glacier causes it to flow downhill, often through canyons and stream channels, picking up sediment, rocks and boulders as it moves. Yosemite Valley was sculpted by several glacial events, one of which covered most of Half Dome. Glaciers form lake basins called cirques. These basins are formed when the glacier pulls rocks from an area below the mountaintop, near the beginning of the glacier, as it flows downward, forming a circular basin.
 
 
Website Created by Website Creations

About us      Privacy Disclaimer      Advertisers     Contact Us     Bookstore    Sitemap     Search    Floridian Nature