Geological Features and Rock Types in the U.S.

Sedimentary Rocks

Formed from compaction and cementation of sediments.

Igneous Rocks

Formed from cooling and solidification of magma or lava.

Metamorphic Rocks

Altered rocks due to heat, pressure, and chemicals.

Basaltic Magma

Low viscosity, high in iron and magnesium.

Andesitic Magma

Intermediate viscosity, between basalt and rhyolite.

Rhyolitic Magma

High viscosity, high in silica content.

Geosphere

Involves rock formation in Earth's crust and mantle.

Hydrosphere

Erosion and deposition of sediments by water.

Atmosphere

Weathering processes that break down surface rocks.

Biosphere

Biological processes forming sedimentary rocks like coal.

Mid-Ocean Ridges

Basaltic rocks form from rising mantle magma.

Rift Valleys

Volcanic rocks like basalt and rhyolite are present.

Subduction Zones

Produce andesite, basalt, and metamorphic blueschist.

Continental Collisions

Form metamorphic rocks like schist and gneiss.

Transform Boundaries

Associated with fractured and deformed rock formations.

Plutonic Rocks

Intrusive rocks formed from cooling magma underground.

Biochemical Sedimentary Rocks

Formed from organic material accumulation, like shells.

Chemical Sedimentary Rocks

Minerals precipitate from solution, like rock salt.

Regional Metamorphism

Occurs over large areas due to tectonic forces.

Gold Mining

Active in states like Nevada, Alaska, and Colorado.

Hydrothermal Activity

Mineral-rich fluids circulate, depositing gold as they cool.

Foliated Textures

Minerals align due to pressure in metamorphic rocks.

Non-foliated Rocks

Produced by localized heating, like marble and quartzite.

Gold Rush

Mid-19th century event leading to mining booms.