Mid-ocean ridge
From Biocrawler, the free encyclopedia.
A mid-ocean ridge or mid-oceanic ridge is an uplifting of the ocean floor that occurs when convection currents beneath the ocean bed force magma up where two tectonic plates meet at a divergent boundary. The mid-ocean ridges of the world are connected and form a single global mid-oceanic ridge system that is part of every ocean and also by far the longest mountain range on Earth.
Discovery
Because the mid-ocean ridge is underwater, and not just underwater, but submerged at very deep depths in the middle of the oceans, its existence was not even known until the 1950s, when it was discovered through surveys of the ocean floor conducted by research ships.
More specifically, the Vema, a ship of the Lamont-Doherty Geological Observatory of Columbia University, traversed the Atlantic Ocean, recorded data about the ocean floor from the ocean surface. A team lead by Marie Tharp and Bruce Heezen analyzed the data and concluded that there was an enormous mountain chain running along the middle of the Atlantic. The mountain range was named the Mid-Atlantic Ridge; it remains the most famous part of the mid-ocean ridge.
At first, it was thought to be a phenomenon specific to the Atlantic Ocean, because nothing like such a massively-long undersea mountain chain had ever been discovered before. However, as surveys of the ocean floor continued to be conducted around the world, it was discovered that every ocean contained parts of the mid-ocean ridge.
Impact
Alfred Wegener had proposed the theory of continental drift in 1912. However, the theory had been dismissed by geologists because there was no mechanism to explain how continents could plow through ocean crust, and the theory became largely forgotten.
Following the discovery of the mid-ocean ridge in the 1950s, geologists faced a new task: explaining how such an enormous geological structure could have formed. In the 1960s, geologists began to propose the mechanism of sea floor spreading. Plate tectonics was a direct consequence of sea floor spreading, and the acceptance of plate tectonics by the majority of geologists resulted in a major paradigm shift in geological thinking.
Description and characteristics
Moving away from the mid-ocean ridge, ocean depth progressively increases until it reaches ocean trenches.
The area around the mid-ocean ridge is dominated by volcanic basalts.id:Mid Oceanic Ridge
