玄武巖
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. 或許代表火星的地函比地球的更潮濕，或是較年輕的熔巖與較古老的玄武巖是各在不同的溫度或壓力下熔化。
