玄武岩
It may indicate that the Martian mantle is wetter than Earth's or that younger lavas melted at different temperatures or pressures than the older basalts. 或许代表火星的地函比地球的更潮湿，或是较年轻的熔岩与较古老的玄武岩是各在不同的温度或压力下熔化。
