Earth And Space Science Final 💗

Rock Classification and Formation

  1. Rock Types: Classified by how they form.

    • Igneous Rock: Formed from cooling of molten rock (magma/lava).

    • Sedimentary Rock: Formed from compaction and cementation of material.

  2. Composition of Earth's Crust: Mostly igneous rocks, more sedimentary visible at the surface.

    • Igneous Types: Divided into Intrusive (cool slowly with large crystals) and Extrusive (cool quickly with small crystals).

    • Textures:

      • Porphyritic: Both large and small crystals, formed from two cooling rates.

      • Glassy: No crystals due to rapid cooling.

      • Vesicular: Contains holes from gas bubbles.

  3. Rock Characteristics:

    • Felsic: Light color, low density, high silica, continental crust.

    • Mafic: Dark color, high density, high iron, oceanic crust.

Volcanoes and Lava

  1. Types of Lava: Mafic, Felsic, Andesitic affecting volcanic characteristics.

  2. Volcanic Hazards: Ash is dangerous, can cause climate impact, pyroclastic flows, and mudflows.

  3. Andesitic Volcanoes: Located at subduction zones, highly explosive.

  4. Hot Spots: Form from magma plumes, example: Hawaiian Islands.

Plate Tectonics

  1. Definition: Earth's crust divided into plates that float and move on the mantle, causing geological activity (volcanoes/earthquakes).

  2. Plate Boundaries: Three types: divergent, convergent, transform.

  3. Physical Layers of Earth: Identified layers based on composition and phenomena.

Sedimentary Rocks

  1. Sediment Definition: Material that can be deposited and lithified.

  2. Types of Sedimentary Rocks:

    • Clastic: From pre-existing rocks (examples: clay, sand, gravel).

    • Organic/Chemical: Formed from biological material or chemical processes.

  3. Environmental Indicators: Sediment size indicates energy conditions during formation.

Faults and Earthquakes

  1. Fault Types:

    • Normal Fault: Caused by tension, occurs in divergent boundaries.

    • Reverse Fault: Caused by compression, found in convergent boundaries.

    • Strike-Slip Fault: Caused by lateral movement of plates.

  2. Elastic Rebound Theory: Explains how stress causes rocks to break and release energy, creating earthquakes.

  3. Seismic Waves: Types include P-waves (primary), S-waves (secondary), and surface waves (L-waves).

    • P-waves travel through both solid and liquid; S-waves only through solids; L-waves cause surface damage.

  4. Epicenter Determination: Requires multiple seismographs to triangulate location based on wave arrival times.