Chapter 23: Energy and Mineral Resources

The content distinguishes between renewable resources such as wind, solar, water, and biomass that replenish within human timescales, and nonrenewable resources including coal, oil, natural gas, and metallic deposits that formed over millions of years and cannot be easily replaced. Fossil fuels remain the dominant energy source globally, supplying over eighty percent of United States energy demand. Coal powered industrialization but now primarily generates electricity while contributing substantially to greenhouse gas emissions. Oil and natural gas accumulate in subsurface structural and stratigraphic traps beneath impermeable cap rock layers, identifiable through seismic reflection surveys. Unconventional extraction methods such as hydraulic fracturing of shale formations and oil sands mining have expanded supplies but introduce environmental hazards including groundwater contamination and induced seismicity. Nuclear fission of uranium provides low-carbon electricity without greenhouse gas emissions, though it confronts challenges of radioactive waste management, reactor safety, and high construction expenses. Renewable energy systems are expanding rapidly across multiple technologies. Solar applications range from passive building design to photovoltaic cell arrays and concentrated solar thermal systems. Wind installations represent the fastest-growing renewable sector, while hydroelectric facilities harness gravitational potential energy despite sedimentation concerns. Geothermal systems exploit subsurface temperature gradients in tectonically active regions, and biomass fuels derive energy from organic matter decomposition. The chapter then addresses mineral resource terminology, classifying deposits as resources when economically viable, reserves when proven and extractable, and ores when profitably concentrated. Igneous processes generate valuable deposits through magmatic differentiation producing chromite and platinum, pegmatitic crystallization concentrating rare elements, and hydrothermal circulation creating metallic veins and disseminated ore bodies. Metamorphic processes produce concentrated garnet and corundum, while hydrothermal activity at mid-ocean ridge black smokers creates massive sulfide accumulations and kimberlite intrusions transport mantle diamonds to the crust. Weathering and secondary enrichment upgrade low-grade parent rock into economic deposits, and stream or coastal processes concentrate dense minerals into placer accumulations that historically drove mineral rushes.