Mob
Member
The ocean floor is mainly made of basalt and other igneous rocks, forming what’s called oceanic crust. When tectonic plates spread apart, magma rises up, creating mid-ocean ridges, which play a big role in shaping the Earth. At these spots, hot hydrothermal fluids vent minerals into the ocean, forming deep-sea deposits and supporting unique life forms that thrive without sunlight. Fascinating discoveries about life and geology are still being made in these remote areas. For example, along the Juan de Fuca Ridge, new crust forms, cools as it moves east, and eventually gets pushed under the continental plate at the Cascadia Trench 
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