i. built from ejected gas-rich lava fragments. Steep slope of loose cinders. They have small size and short eruption periods.
Minerals with same composition but different crystalline structures. E.g. graphite & diamond both composed of carbon.
reaction of mineral with water. Hydrogen ion attacks and replaces other ions. E.x hydrolysis of Feldspar to clay minerals.
exposure to atmospheric oxygen.
Factors controlling soil formation:
1. Climate: Most influential control. Key factors are temperature and precipitation.
2. Time: Amount of time soil formation caries for different soils depending on geologic and climate conditions.
3. Plants & Animals: influence soil physical & chemical properties. Microorganisms, worms.
4. Topography: steep vs. gentle slopes.
Between 60° and 90° away from the equator in regions of low precipitation.
between 30° and 60° away from the equator in the rain shadow of large mountains.
between 20° and 30° from the equator with hot temps, extremely dry conditions and sparse vegetation
Fan shaped deposit of sediment at the mouth of a canyon, steep to gentle gradient
Fan-shaped deposit of sediment formed where a stream enters a lake or ocean and slows.
Molds and casts of tunnels, tubes, and scooped-out areas are often interpreted as burrows or feeding traces.