Mondo Knows Facts
Seafloor spreading builds new ocean crust
Magma rises at mid ocean ridges and pushes the older plates outward Harry Hess proposed in the early 1960s that hot mantle rock wells up beneath ridges and cools into new basalt. The crust then moves away on both sides, which matches the magnetic stripes recorded on either flank. Atlantic crust grows by roughly two to three centimetres a year. It sits in Mondo's science collection, one of 200 facts that each trace back to the reference below.
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Facts that can change over time are reviewed and updated. If something here looks wrong, Mondo would rather know than be confidently incorrect.
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More facts like this
Wegener proposed that continents driftMatching fossils and coastlines convinced him, but he lacked a mechanismIndia colliding with Asia raised the HimalayaThe impact crumpled crust upward and the mountains are still risingSubduction recycles old ocean floorDense seafloor sinks into the mantle and its water triggers volcanic arcsIceland is a landmass where tectonic plates drift apart above sea levelIceland sits directly atop the Mid-Atlantic Ridge where the North American and Eurasian plates diverge.The Great Rift Valley is a continuous trench splitting East AfricaExtending over 6,000 kilometres from the Middle East to Mozambique, the rift is slowly splitting Africa.The San Andreas is a transform faultTwo plates slide past each other sideways, which is why the fault produces quakes
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Tags: geology, tectonics, ocean
Seafloor spreading builds new ocean crust: the short answers
- Where does this come from, and can I check it?
- Magma rises at mid ocean ridges and pushes the older plates outward. The figure is taken from USGS, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
- Is this really a science fact?
- Yes. It sits on the Science shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
- What else can I read about it?
- The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.