Wind, Dust, and Deserts Represent

Wind, Dust, And Deserts

Deserts represent a third of the landscape on Earth, and are created as a result of the lack of water (Planet Earth 2006, film documentary). Every desert has one thing in common; the intense daytime sun. In Australia, the most arid continent on Earth, and in the daytime temperatures rise five degrees per hour, and by noon, is a threat to any surface life (Planet Earth). The Gobi Desert is one of the most interesting, because it is a constantly frozen desert. One would think that the presence of snow would equate to moisture, but the Gobi air is so cold that the snow never melts (Planet Earth). With the intensity of the sun during the day, the snow literally evaporates, and no moisture is absorbed into the sand dunes (Planet Earth). One of the reasons for the Gobi's lack of water is the Himalayas, to the south. The massive mountain range, which prevents rain clouds from moving over the Gobi (Planet Earth). As a result, the south side of the Himalayas, where the water from rain spills over the mountainside, is a lush and green area (Planet Earth).

The Sahara Desert in North Africa is the largest desert in the world. There are constant winds blowing across the Sahara, which have eroded what were once a continuous rock formation, leaving in its stead broken sections of sharp rock formations scattered across the region (Planet Earth). Over time, with the constant blowing winds and the sand being blown against the rock formations, they, too, will erode into sand (Planet Earth). The Colorado Plateau, in the Southwestern United States, is geologically comparable to the Sahara (Baars 2000, p. 143). On the Plateau, the change from an environment where there was once water to one without water was an abrupt change (p. 143). Evidence of the transformation is seen in the sandstone formations (p. 143), which, like the Sahara, are eroding, although the erosion is perhaps not as remarkable as that in the Sahara, indicating only that the Colorado Plateau is a relatively new desert in terms of the eons of the planet's evolution.

"The sandstone formations represent the desert accumulations of this interval of time. The lower of the great windblown deposits is the Wingate Sandstone, which is nearly everywhere a reddish cliff-forming formation that directly overlies the Chinle Formation. The sandstone is usually cross-stratified with the expected steeply dipping individual beds in variably shaped bundles that typify windblown deposits. In a few localities the small-scale, low angle cross-bedding of stream deposits can be differentiated from the normal texture of the formation. Thus, conditions varied, at least seasonally, within the great southwest desert of the Early Jurassic time (p. 143)."

The deserts of the American Southwest are not completely dry, and for that reason we find cacti, which, during the yearly monsoonal rain season, absorb the water. In the Sahara, we find no such water or plant life, and the rainfall is sporadic, not enough to give life to vegetation. The Sahara gives rise to massive windstorms, with dust rising 500 meters high, and reducing visibility for days at a time (Planet Earth). Satellite imaging of the Sahara show river patterns, where thousands of years ago, the Sahara could have been green, and could have supported an agrarian society (Druy 2001, p. 179).

One of the most arid deserts on earth is Chile's Atacama Desert, where it rains once every 50 years (Planet Earth). There are cacti and animal life, which get their water from the cacti (Planet Earth). The moisture that forms on the cacti is as a result of a cold ocean current, which creates a fog over the Atacama at its ocean perimeter (Planet Earth). The fog and cold air form dew on the cacti (Planet Earth). Otherwise, the Atacama is a dry, arid, and hostile environment. The soil conditions of the Atacama Desert are extremely low in organic carbon and nitrogen levels (Maier, Pepper, and Gerba 2009, p. 128). Like the Gobi, the Atacama is the product of a high mountain range, the Andes, which block the moisture from reaching the Atacama (Bowman 1915, p. 85).

Egypt's White Desert is a marked with strange looking rocks, that are white, and are being constantly assaulted by sandy winds blowing against them and eroding them. The erosion of what were clearly once massive rock formations, has taken place over eons (Planet Earth). Today, the rocks are in the process of being reduced to sand, but make for an interesting geological study.

All of the deserts of the world are different, but have sand, sun, dust, and wind in common. They are often the product of the environments that border them, and prevent rainfall or moisture from reaching them. Geologic studies reveal that these deserts were very different places as recently as 5,000 years ago. The periods of Earth's evolution are recorded in the rock sediments, and can be identified from satellite images. As the Earth evolved, and mountain ranges rose from the depths of the Earth, pushed forward by shifting plates and separating continents, it impacted the conditions of what eventually became desert regions on Earth.

The deserts are hostile environments for mankind, but they are not without life. Insects, and even elephants and lions can be found in some of the most hostile deserts like the Sahara and the Gobi deserts. It is impossible to predict what changes these deserts will undergo in the future as climate change impacts the Earth's environments. Yet there is much to be learned from these deserts about the history of the Earth, and about the evolution of other planets in our galaxy and the universe.

Buried beneath the sands of the desert are fossil records that reveal the life that once roamed these arid lands. The different layers of rock can be identified by their different color compositions, show that abrupt changes occurred as well as changes that occurred slowly, taking thousands of years to bring about the changes that we see in the deserts today. We can see the changes happening today.

"In 2005, a gigantic, 35-mile-long rift broke open the desert ground in Ethiopia. At the time, some geologists believed the rift was the beginning of a new ocean as two parts of the African continent pulled apart, but the claim was controversial. Now, scientists from several countries have confirmed that the volcanic processes at work beneath the Ethiopian rift are nearly identical to those at the bottom of the world's oceans, and the rift is indeed likely the beginning of a new sea . . . The new study, published in the latest issue of Geophysical Research Letters, suggests that the highly active volcanic boundaries along the edges of tectonic ocean plates may suddenly break apart in large sections, instead of little by little as has been predominantly believed. In addition, such sudden large-scale events on land pose a much more serious hazard to populations living near the rift than would several smaller events, says Cindy Ebinger, professor of earth and environmental sciences at the University of Rochester and co-author of the study. "This work is a breakthrough in our understanding of continental rifting leading to the creation of new ocean basins," says Ken Macdonald, professor emeritus in the Department of Earth Science at the University of California, Santa Barbara, and who is not affiliated with the research. "For the first time they demonstrate that activity on one rift segment can trigger a major episode of magma injection and associated deformation on a neighboring segment. Careful study of the 2005 mega-dike intrusion and its aftermath will continue to provide extraordinary opportunities for learning about continental rifts and mid-ocean ridges (eScience News 2009, online)."