The key principle of plate tectonics is that the lithosphere exists as separate and distinct tectonic plates, which ride on the fluid-like (visco-elastic solid) asthenosphere.

• 板块构造的关键原则是，岩石圈以分离和明显的构造板块存在，这些构造板块飘游在流体似的（粘弹性固体状的）岩流圈之上。