Types of Natural Resources? Renewable aka Perpetual. Nonrenewable. Potentially Renewable. Some important points to Review: Au Cu SnO 2. Gabbro.

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1 Some important points to Review: Practice all definitions List / discuss examples of all internal & external processes Understand general concepts of Plate Tectonics: SFS, plate boundaries, locations, examples, associated geologic hazards and resources Discuss / describe common Geologic Hazards (focus on E-quakes, Tsunamis and Mass Wasting) What can we do to reduce damage? Make a list here for each one. Describe all types of E-Quake Waves: how are they useful? Damage from E-Quakes, a function of what? What causes Tsunamis? Where most likely to occur? Main causes of Mass Movement? How do humans make things worse? Why Santa Cruz Mountains so susceptible? Also look over Volcanoes and Coastal Processes SOIL AND SOLID NON-FUEL MINERAL RESOURCES Au Cu SnO 2 Gabbro Marble Slate Resources Renewable Nonrenewable or Nonrenewable Mineral Resources Types of Natural Resources? Renewable aka Perpetual Nonrenewable Potentially Renewable Direct solar energy Winds, tides, flowing water Fossil fuels Potentially Renewable Metallic minerals (iron, gold, copper, aluminum) Non- Metallic minerals & rocks (clay, sand, marble, slate) These two are sometimes Called: Solid Nonfuel Mineral Resources What s Environmental Degradation? Fresh air Fresh water Fertile soil Plants and animals (biodiversity) Fig. 1.11, p. 11 1

2 Nonrenewable Mineral Resources: A general term for concentrations of solid, liquid or gaseous materials in or on the earth s crust that can be converted to useful materials at an affordable price. Reserves: A known nonrenewable mineral resource that can be extracted and profitably developed with available technology under existing political and economic conditions. Definition.. Part I: Soil A Potentially Renewable Resource Most valuable natural resource after water? Although potentially renewable, it is produced very slowly, if topsoil erodes faster than it is renewed, soil becomes a nonrenewable resource. Most of the world s crops are grown on cleared grassland (e.g. US Midwest) and deciduous forest soils. Factors determining type of soil and rate of development: Residual and Transported Soil Parent Material Slope Climate Plants & Animals Time 2

3 Soil Profile: Soil Erosion Natural process/rock cycle that occurs to all soils Causes (human activities)? Mature soils have distinct layers or zones called Soil Horizons; cross-sectional views of soil horizons are called Soil Profiles. farming, logging, mining, construction, overgrazing, urbanization, clear-cutting, fires, off-road vehicles Case Study: Colorado Kansas Dust Bowl New Mexico Oklahoma Areas of serious concern Areas of some concern Stable or non-vegetative areas Texas Estimated Rates of Soil Erosion: Before Humans: ~9 billion metric tons/yr Current estimates ~24 billion metric tons/yr MEXICO 3

4 Lamar, Colorado 1934 Soil Erosion Continues to be a Concern READ this page on your own The US is losing soil 10 times faster -- and China and India are losing soil 30 to 40 times faster -- than the natural replenishment rate. Source: Cornell University Estimated that ~8.1 million Km 2 (12 times size of Texas) desertified in the last 50 years. Each year an area the size of ~Greece. Human activity causes 10 times more erosion of continental surfaces than all natural processes combined. Web Link The economic impact of soil erosion in the United States costs the nation about $37.6 billion each year in productivity losses. Damage from soil erosion worldwide is estimated to be $400 billion per year. Web Link 4

5 Soil Conservation: reducing soil erosion, restoring soil fertility & producing greater yield Conservation tillage farming: disturb soil as little as possible; machines till subsurface soil w/out breaking up topsoil or inject seeds into unplowed soil. As of 2004 used on ~38% of US cropland. (USDA) Terracing: converting a slope into a series of step-like platforms; retains water and reduces erosion. Crop Rotation: successive planting of different crops in the same area to improve soil fertility and help control insects, diseases and erosion. Soil Conservation: reducing soil erosion, restoring soil fertility & producing greater yield Contour farming: planting crops in rows that run perpendicular to slope of land, plow along the contour of the slope; can reduce soil erosion by 30-50% on gentle slopes. Strip cropping: alternating rows of two or more crops; keeps soil covered and reduces erosion, legumes restore soil fertility. Wind Breaks: planting trees or large shrubs along the margins of the field 5