tailieunhanh - Encyclopedia of Global Resources part 114

Encyclopedia of Global Resources part 114 provides a wide variety of perspectives on both traditional and more recent views of Earth's resources. It serves as a bridge connecting the domains of resource exploitation, environmentalism, geology, and biology, and it explains their interrelationships in terms that students and other nonspecialists can understand. The articles in this set are extremely diverse, with articles covering soil, fisheries, forests, aluminum, the Industrial Revolution, the . Department of the Interior, the hydrologic cycle, glass, and placer mineral deposits. . | 1058 Saudi Arabia Global Resources Field studies suggest that sandstone constitutes approximately 30 percent of the three principal types of sedimentar y rock exceeding the abundance of limestone approximately 20 percent but less commonly seen than shale approximately 50 percent . History Sandstone has been studied seriously for more than two hundred years especially in terms of its distribution in rivers. It has been used historically as a building material in many famous structures from ancient times to the present day. Obtaining Sandstone Individual sandstones can be analyzed as to their particular environment of deposition. For instance the siliceous sandstone variety is indicative of deposition in a low-lying region that experienced intense chemical weathering while the presence of arkose is suggestive of rapid erosion and deposition in a region lacking severe chemical weathering. In the geologic study of sandstone particular emphasis is placed on analyses of physical and chemical properties. A typical review would include the degree of angularity roundness sphericity size and mineralogy of individual sand-size grains. The manner of sand grain arrangement is helpful in determining the amount of interstices a sandstone may contain known as porosity and the amount of fluid that can pass through a volume of sandstone known as permeability . Porosity and permeability are important in evaluating a sandstone s potential as an oil natural gas or freshwater reser voir. Uses of Sandstone As quarried material sandstone has long been employed in the construction industry. In crushed form sandstone finds common usage in the manufacture of bricks concrete mortar and plaster and is a primar y resource employed in the foundr y abrasive filterpurification potter y metallurgical and glass-making industries. Indirectly sandstones are important to society as they commonly form underground reservoirs containing reserves of crude oil natural gas or potable groundwater. Tar sand .