Wanderlust World Wanderlust World Mountains and valleys shape both continents and the seafloor, but the processes, scales, and environments differ dramatically.
| Aspect | Seafloor Features | Land Features |
|---|---|---|
| Scale | Vastly larger. Mid-ocean ridges span 65,000 km; abyssal hills cover 30% of Earth's surface. | Smaller individual ranges; total mountainous area ~24% of land. |
| Elevation/Depth | Measured from seafloor: seamounts rise 1,000–4,000 m; trenches plunge 11,000 m. | Measured from sea level: Everest 8,848 m; valleys rarely below -400 m (Dead Sea). |
| Age | Young: oceanic crust <200 Myr (constantly recycled at subduction zones). | Old: continental crust up to 4 Gyr; mountain belts can be hundreds of Myr old. |
| Composition | Basalt, gabbro (mafic); pillow lavas, sheeted dikes. | Granite, sedimentary, metamorphic (felsic to mafic). |
| Erosion | Slow: bottom currents, turbidity currents, bioturbation. No subaerial weathering. | Rapid: water, wind, ice, gravity, biology—sculpts peaks quickly. |
| Climate Role | Guide deep/ocean currents, upwelling, heat transport. | Force orographic precipitation, block air masses, create rain shadows. |
Seafloor topography controls ocean circulation, nutrient upwelling, and carbon sequestration—fundamentally regulating Earth's climate. Mapping it (only ~25% at high resolution) is a frontier of planetary science.