Rock Blog Part 2

My previous post introduces the origins of the earth being a molten ball of fire bombarded by meteorites.  It has taken billions of years to calm and cool before any form of life began; for the oceanic and continental crusts to form, for landmasses to clash and crumple up to create our mountains and oceanic rift valleys, for earthquakes and volcanoes to form and reform the landscape, a phenomenon which to this day sometimes catastrophically provide evidence of the colossal molten turbulence below.   A thin layer of crust which has compressed and hardened into rock encases this colossal magma ball.  Billions of years worth of continual layering from life’s detritus still doesn’t detract from the fact it is a veritable peach skin encasing 12,756.32 km (7,926.41 miles) measuring from the equator to the core of violently hot magma. Earth centreThe crust measures just 7 kilometers (4.34 miles) to 48.28032 Kilometres (30 miles) thick.  Slightly shorter through the poles, 7,901 miles (12,715.43 km), gives the earth a very fractionally squashed shape.  I’m not a maths bod at all, but if you’d like to work out the volume using πr2 and whatever else it is to calculate the quantity of earth’s molten fluid, help yourself.  Suffice to say that there are millions of tonnes of magma at temperatures exceeding 5000 degrees and pressures at the core reaching 3.3 million times the atmospheric pressure at the surface. More recent findings since these made 20 years ago now state temperatures here can actually exceed 55000 degrees Celsius, (which is nearly 10,000 Fahrenheit).   That’s hotter than the surface of the sun.  In fact parts can even reach 1000 degrees hotter – something to think about when you’re stuck in traffic.  If this has wetted your appetite, then topics such as earths’ magnetism and avalanches at the Earth’s core might be further topics of interest.  This background however, is in preparation and to help understand the factors behind some of the beautiful rock and mineral formations in a forthcoming post.

Post by Jennie Trueman

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