At high pressures such as under an ice cap, they reckon that rocks cannot expand to turn into liquidmagma even if they are hot enough.
他们认为在冰帽的强大压力下，即使温度很高，岩石也不可能成为液体熔岩。
2
Buoyancy is a force that causes lighter material to rise through surrounding denser material. The hot liquidmagma rises towards the surface through the more dense rock.
浮力是密度较高的物质把密度较低的物质往上升的力量，所以炽热的岩浆会通过密度较高的岩石上升到地面。
3
It is formed from liquidmagma, the molten rock still found at the core of the planet, cooled slowly to form a substance approaching the hardness and durability of diamond.