Earth science
Minerals and water
Minerals and Mohs, water cycle, groundwater, soil.
Basics
Minerals
Naturally occurring, inorganic, crystalline solids. Silicates dominate the crust. Mohs hardness: talc 1 … diamond 10. Rocks are mineral aggregates. Ores, stone, and soil parent material start here.
Water cycle
Evaporation and transpiration → condensation and precipitation → runoff and infiltration. Most fresh water is ice or groundwater. A watershed drains to one outlet. Floods when rain or melt exceeds what soil and channels can take.
Groundwater
The water table is the top of saturation. Aquifers yield water; clay confines it. Over-pumping causes subsidence and saltwater intrusion. Karst: dissolving limestone, caves, sinkholes.
Formulas
Darcy's law (idea)
Groundwater discharge. Head gradient and hydraulic conductivity K.
Symbols
-
Khydraulic conductivity -
dh/dlhydraulic gradient
Watershed budget
Precipitation = runoff + evapotranspiration + storage change.
Symbols
-
Pprecipitation -
ETevapotranspiration
Key table
| Mohs (excerpt) | talc 1, gypsum 2, calcite 3, quartz 7, diamond 10 |
|---|---|
| Fresh water | ~2.5% of Earth’s water; most of that is ice |
In this field
Rocks and plate tectonics
Rock cycle, earthquakes, volcanoes, plate boundaries.
Atmosphere and weather
Layers, wind, clouds, fronts.
Oceans, climate, time
Currents, carbon, climate vs weather, relative and absolute age.
Hazards and resources
Volcanoes, slides, storms; fuels and ores.
Geologic time and carbon
Relative and absolute ages, the carbon cycle.
Weathering, soil, and the water cycle
Weathering, erosion, soil profiles, and the water cycle.
Earth’s magnetic field
The dynamo, the dipole, inclination and declination, paleomagnetism and seafloor stripes.
Glaciers and sea level
Glacier budget, isostasy, sea level, and glacial deposits.
Groundwater
Porosity, permeability, water table, Darcy, aquifers and aquitards.
Seismic waves
P, S, and surface waves, travel-time curves, magnitude, and Earth’s interior sketch.