When people hear of “geologic time,” they are trained to think of millions of years. Big things can happen in far less time.
Instant Manhattan: Imagine covering Manhattan with sand almost 500 feet deep. (Some might consider that a good idea, but this is about geology, not politics.) Explosions under the sea, described by Nature (485, 31 May 2012, page 551, doi:10.1038/485551f), produced that much sand instantaneously in Norwegian waters, according to a drilling survey. “At the start of the most recent ice age, pressurized sand exploded through cracks in the sea floor at the bottom of the North Sea, producing a body of sand large enough to bury Manhattan under 160-metre-high dunes.” Some 10 cubic kilometers of sand erupted through these cracks rapidly.
Diamonds by overnight delivery: In January, popular science sites like Live Science and PhysOrg repeated the surprise that kimberlite eruptions, which bring diamonds from deep in the mantle to the surface, are much more rapid than previously thought. Both articles used the word “rapid” several times. Kimberlite eruptions are the deepest known events that bring magma to the surface. Due to buoyancy and other physical processes now considered, the magma accelerates as it rises.
Off by three orders of magnitude: Science Daily reported another geological process that was much more rapid than thought:
The depths of Earth are anything but peaceful: large quantities of liquids carve their way through the rock as fluids, causing magma to form. A research team led by the University of Münster, has shown that the fluids flow a lot faster through solid rock than previously assumed. In the Chinese Tian Shan Mountains, fluids pushed their way to Earth’s mantle from great depths in just 200 years rather than in the course of tens or even hundreds of thousands of years….
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