Why Didnt Granite Sink Down Into Eaths Mantel

The mantle is the mostly solid bulk of earth s interior.

Why didnt granite sink down into eaths mantel.

The mantle lies between earth s dense super heated core and its thin outer layer the crust. The mantle is about 2 900 kilometers 1 802 miles thick and makes up a whopping 84 of earth s total volume. The earth has gas. It eventually becomes cool and dense enough to sink back down into the mantle.

It reaches the location where warm mantle material rises and the mantle convection cell is complete. Unexpectedly helium hydrogen nitrogen and even carbon dioxide from microbes were found all along the borehole. They separate and sink down into the mantle leaving behind silica rich magma that has the right composition to form granite. At the bottom of the mantle the material travels horizontally and is heated by the core.

Oceanic crust being so thin is a very small fraction of the earth about 0 1 percent but its life cycle serves to separate the contents of the upper mantle into a heavy residue and a lighter set of basaltic rocks. It also extracts the so called incompatible elements which don t fit into mantle minerals and move into the liquid melt. There is no basalt under the continent s granite.