Geology Cafe

Humans - Agents of Erosion

Face it! Human have become the most significant force of erosion. This change to a human-dominated planet has occurred in the past few hundred years, with the greatest change having taken place in the last century. Energy and water demands have been major driving forces for changes to our landscapes. Areas that were basically wilderness 200 years ago are now sites of cities, reservoirs, highways, mines, and landfills. Agriculture consumes the greatest share of landscape resources, but it its the growing population with economic demands of our country and the world that consumes our resources.

mines, oil fields, cities, highways, dams, hydraulic mining, infrastructure, landfills, limestone, salts, gold, metals, aggregate, mercury
Permanente Limestone Mine A large limestone quarry in the Santa Cruz Mountains near San Jose, CA. The limestone is primarily used in the manufacture of cement. Limestone is baked in kilns to produce lime. Large amounts of energy are used to produce cement. Worldwide, cement manufacturing releases large amount of carbon dioxide into the atmosphere.
Downtown San Francisco - nearly everything that makes up an urban landscape is extracted from the earth, and large quantities of energy resources and water are used in the process of building and maintaining a city! This large pit is a granite aggregate quarry near Aromas, CA. Aggregate is used in all forms of construction and is the largest consumer market for earth materials. Fortunately, aggregate mining is not as polluting as other forms of mining.
Metal mining consumes large amounts of land, water, and energy resources. This is Vulcan Mine in the Mojave National Reserve. The mine was a source of iron during the national emergency of WW2. The mine was abandoned shortly after the war, but the mining scar is a permanent addition the desert landscape. This view shows the New Almaden Mercury Mining District in the foothills of San Jose (Almaden-Quicksilver County Park). Over a million liters of mercury were extracted from the New Almaden area, most of which was dissipated into the watersheds of the Sierra Nevada, used for gold extraction during the Gold Rush years.
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8/28/2012