The Earth’s Interior
Crust:
- Oceanic crust: Thin: 10 km, Relatively uniform stratigraphy. ophiolite suite: Sediments, pillow basalt, sheeted dikes, more massive gabbro, ultramafic (mantle)
- Continental Crust: Thicker: 20-90 km average ~35 km, Highly variable composition, Average ~ granodiorite
Mantle: Peridotite (ultramafic)
- Upper to 410 km (olivine ® spinel), Low Velocity Layer 60-220 km
- Transition Zone as velocity increases ~ rapidly, 660 spinel -> perovskite-type SiIV –> SiVI
- Lower Mantle has more gradual velocity increase
Core: Fe-Ni metallic alloy
- Outer Core is liquid, No S-waves
- Inner Core is solid