Geology Reference
In-Depth Information
layerings on the basalt seafloor. You could lie by that cool, blue ocean on the first white
sandy beaches, rich in resistant quartz grains eroded from the gray granite. But you would
quickly suffocate in the heavy atmosphere, rich in nitrogen and carbon dioxide but lacking
the slightest whiff of life-giving oxygen.
The invention of continents—landmasses constructed of sturdy granite crust—was but a
sideshow in Earth's grand evolutionary pageant. Granite terrains, formed by deep heating
and partial melting of the ubiquitous near-surface basalt, were like growing gray scabs on
the otherwise pristine, submerged black skin of our planet. Gradually, the thickening rafts
of granite, floating as they did on top of the denser basaltic basement, were able to rise
aboveoceanlevelandthusprovidedtherootsofallthegreatcontinents—whatweperceive
today in our anthropocentric view as the solid Earth.
