Sublime

craton,

FLINT Siliceous stone (sedimentary rocks that contain silica from silica-secreting organisms such as diatoms and some types of sea sponges) that reflects sun and heat well. The Pouilly-Fumé wines of the Loire Valley are generally produced from flint-based soils.

biology. That is, surface life is the descendant of life deep within Earth.

Arádottir had brought along a rock core to show me the end result. The core, which was roughly two feet long and a couple of inches in diameter, was the dark color of the lava fields. But the black rock—basalt—was pocked with little holes, and these holes were filled with a chalky white compound—calcium carbonate. The white deposits represented, if