Deserts, Glaciers, and Climate - Essay Example

Deserts, Glaciers and Climate May 19, Deserts, Glaciers and Climate Geologically varied desert landscapes around the world, even though they share certain inherent traits. To be considered a desert area, the land must be less than 10 inches of annual precipitation, according to this definition, the deserts in South America and North Africa are similar to the Antarctic. But many people feel that the image of sand, rocks and rare animals and plants to be trademarks of deserts, some of the worlds harshest landscapes on the planet. Dunes are hills created by strong winds in the deserts in the Mojave and Sonoma in Southern California and parts of Arizona. The high rates of sand particles is much higher in the wasteland much of northern and central Africa, the Sahara and the Gobi Desert in Asia, where the dunes can reach over 1,000 feet tall. Geologists classify dunes with five characters. All dunes are essentially two parts: the shelter, which faces away from the wind, and battery, which faces the wind. Buttes and mesas beyond far above the flat landscape of American deserts. These functions are characterized by flat summits led by the desert winds and to help form the canyon walls many American deserts. Another geological phenomenon is widespread in the deserts of many alluvial fans, sand and sediment deposits that collects the fan-shaped formations caused by the sudden flash flood runoff. Corresponding to the fans is Arroyo, deep depressions in the desert floor, which also means that channels water from canals to the lowest point in a landscape. Several other corrosive form of geological formations of the landscape that is so strong wind and flooding. Blowers are deeply depressed areas in the desert near the floor because of continuing harassment and strong winds. Blowers can be identified that plants such as cactus species are anchored to the ground has settled on top of columns. Enough to eruption and erosion can cause hoodoos, which are rock formations and a long column that form the inner canyon. Flash floods and wind are responsible for moving sand and stone to create geological structures of the desert. Sand and sediment is often moved his way to the desert floor, where it hardens into what geologists call "the desert floor." Stone, sand and gravel heavy to be carried away by the wind live in small cracks and crevices where they cure in this "sidewalk." Sometimes, a chemical reaction between minerals that produce a brilliant reflection known as desert varnish. " A glacier is a semi-permanent or frozen ice bodies, consisting mainly of re-snow crystal moving under gravity. Glaciers are cool because they consist mainly ice and snow. However, researchers have found by drilling holes through the glaciers, the temperature inside are not all equal. Some glaciers are warmer than others, and the difference affects the behavior and ice movement. In one type of glacier ice is near its melting point in the interior. These glaciers, temperate glaciers known as low-and middle latitudes. Melt water and ice may exist together with the balance of temperate glaciers. High latitudes and altitudes, where the average annual temperature winter, the temperature of the glaciers remains low and little or no melting of the season. For a cold glacier is often called a polar glacier. Mountain glaciers produce a variety of distinctive morphologies. cirque basin are located on the head. Two circuses around the mountain, you can see a ridge to ridge, called Arête. About developing the mountain on all sides to exclude from its peak in the visible part of the Horn of Africa. When the glacier moves down from a circus, he looks across a valley with a channel section characteristic U-shaped and a floor that is normally well below the level of the lateral valleys. continental ice sheets can gouge the rock to form lakes, and some examples of very large glacial lakes formed are the Great Lakes, Lake Winnipeg and the Great Bear Lake. large glaciers and ice caps are more effective agents of erosion and cut deep valleys and lakes that small tributary glaciers. In the intersection between a minor and major glacier, there is usually a sudden change in elevation of the valley due to different depths of erosion. Like rivers, glaciers carry the load of sediment particles of various sizes. Unlike the power, but the glacier can carry out part of your pages to load and even the surface. Glacier can carry large stones and small pieces of tile. When the glacier deposited, mixed load of stone fragments (called up to) is not ordered, rounded or stratified flow deposits are so large. In most cases, stones and rock fragments that differ from the bottom up to the bedrock. Stones, rock fragments and sediment carried by the glacier can be deposited along its margins or at its terminus. These ridges are moraines, especially as lateral moraines along the edges and form a terminal moraine at the end, and the reduction or end moraines are formed as a glacier until a heterogeneous mixture of crushed stone sand, stones, pebbles and boulders deposited by a glacier. Erosion Sediment carried by the wind tends to be finer than that moved by water or ice. Because the density of air is far less than that of water, air cannot move as large a particle as water flowing at the same velocity. In most regions, the largest particles that can be lifted in the airstream are grains of sand. Though they are smaller in size, wind-blown particles are similar to waterborne sediments in the way they travel. The largest grains are transported through surface creep. As wind speed increases, smaller grains may be bumped or lifted into the air, where they experience saltation. Finer dust-sized particles may be carried aloft to heights of a kilometer or so, where they can travel along in suspension as long as the wind keeps blowing. Such particles can be carried all the way across the ocean. Mechanisms of wind erosion Flowing air erode the land surface in two ways. The first, abrasion, results surface creep Sediment transport in which the wind causes particles to roll along the ground. Global Climatic Change Earths climate system is complex, containing many interacting components and subsystems of the state of dynamic equilibrium. The climate is therefore subject to the influence of different processes, both natural and artificial. All of these processes, one causing the climate varies cyclically several different time. Before we can understand the human role in climate change, now and in the future, we must first try to understand how the natural processes of March to decide the climate control, climate change. To do this, we need to look back and see how the Earths climate has changed in geological history. At the beginning of the Cenozoic Era, the Earths surface has been largely free of ice. Sea level was higher (note that the south-eastern North America was under water) and sea water could flow freely between the Atlantic and Pacific. As the disc moves transferred to large masses of land near the current location, temperatures dropped and glaciers appeared at the poles. The last 800,000 years (the temperature graph blue stripe), that the climate has changed eight times between ice ages and warm interglacial period. On top of the last ice age 18,000 years ago, glaciers covered most of North America. The Earth is now warmer than it is at any time last 100,000 years, and approximately the same temperature as his last interglacial period 120,000 years ago. General circulation models allows us to incorporate different assumptions about the human factor, which means that the combustion of fossil fuels. The models differ in the details differ, they all predict that if concentrations of greenhouse gases stay where they are today, almost certainly an optimistic assumption, we can expect the temperature rise of 0.5 1 °, 5 ° C over a period of 50 years, roughly in line with what has already happened. But if consumption of fossil fuels continues to grow at an increasing rate, atmospheric carbon dioxide is expected to double by 2100 if not before. If this proves to be true, global climate models predict that global average temperatures rise by 1.5 ° and 4.5 ° C. The increase will not be uniform worldwide, but will always be much greater in the polar regions. The indirect effects of warming are difficult to quantify, but include rising sea levels caused by melting glaciers, increased intensity of hurricanes and typhoons, which feed on warm sea water, and significant changes in animal and plant populations as a result of death or migration. References Ehow, 2011. Desert Features, http://www.ehow.com/list_7629336_geological-features-desert-landscape.html Read More