The Rock cycle

The Rock Cycle at a Glance

Melting and Cooling

Imagine you are a rock. You’ve been sitting where you are for a couple hundred thousand years, and suddenly, you’re pushed to the bottom of the crust to the surface of the mantle. Things have been hot before, but never quite this hot. You melt slowly, and join a mass of magma that’s pooling beneath the surface of the earth. Years later, the magma finds its way to a vault, and cools there slowly over thousands of years. You begin to be solid once more. You form crystals. None of them are in any particular order, but it’s nice to have a definite shape once again.

Heat and Pressure

Okay, so you’ve sat in your magma vault as a piece of granite for quite a while now. You’re getting pushed deeper and deeper by rock forming above you. The pressure builds, and as you get lower, so does the heat. It’s excruciating, but not nearly as much so as the heat that made you magma. Over time, the heat and pressure slowly turn you into something different. You’re more compact now, smoother, and harder. Not to mention you’ve got a nice shiny finish. Nice.

Erosion and Deposition

Alright, so now you’re a piece of gneiss (metamorphic granite). Over a period of thousands of years, you’re pushed to the surface by rock that’s forming underneath you. Once on the surface of the earth, you suffer a multitude of humilities, including pieces of you coming off from rain, water, falls, and being sandblasted by wind. Now that you’re pretty much completely sediment, you deposit in many different places. You are compacted by the pressure of other sediment. You chunk together, and are now a piece of sandstone.