Applications: Resources, Hazards, and Environmental Geology
What this domain tests
Applications asks you to use geology in practical settings: mineral and energy resources, groundwater supply and contamination, geologic hazards, engineering decisions, climate proxies, and map interpretation. Expect straightforward calculations and scenario-based reasoning.
Resources and energy
Ore deposits form by magmatic segregation, hydrothermal veins, placers, and sedimentary processes such as banded iron formations and evaporites. Fossil fuels require source rock, reservoir rock, seal, and trap. Coal records ancient swamps; oil and gas form from marine organic matter. Geothermal and hydroelectric power depend on geologic setting.
Water and contamination
An aquifer stores and transmits water; a confining layer restricts flow. Darcy's law is Q = KIA, where K is hydraulic conductivity, I is hydraulic gradient, and A is cross-sectional area. Contaminants move down the hydraulic gradient. Dense non-aqueous liquids sink; sorption and dilution can retard a plume. Monitoring wells must screen the correct interval.
Hazards, engineering, and maps
Seismic hazard depends on distance, magnitude, and local site conditions; soft soils amplify shaking, and saturated sand can liquefy. Landslide risk increases with steep slopes, weak material, and water. Geologic maps show contacts, strike and dip, faults, and units; cross sections test three-dimensional reasoning. Climate proxies include ice cores, tree rings, isotopes, and pollen.
Worked example
A aquifer has K = 10 m/day, gradient I = 0.01, and cross-sectional area A = 100 m2. Q = KIA = 10 x 0.01 x 100 = 10 m3/day. If porosity is 0.2, seepage velocity = Q/(A x n) = 10/(100 x 0.2) = 0.5 m/day. The plume moves down gradient, but sorption or dilution may slow its arrival at a well.
Traps
- Porosity is storage; permeability is flow.
- Magnitude measures energy; intensity measures local effects.
- An aquifer is not an underground river.
- Ore is rock that can be mined at a profit; grade and economics matter.
- Climate proxies are indirect evidence, not direct temperature readings.