陆地地壳主要由花岗岩和其它轻质硅酸盐矿物构成，而海底则主要由黑色的高密度火山岩——玄武岩构成。
The dry land of the continents consists mostly of granite and other light silicate minerals, while the ocean floors are made up mostly of a dark, dense volcanic rock called basalt.
第四段：金星大气层密度非常之高，造成的压力相当于3000米海底压强。
Step4 section: Venus atmospheric density is very high and the pressure equivalent to 3000 meters underwater pressure.
反常的质量聚集区，或者指在月亮上，位于月海底下的高密度区域。
An area of abnormal MASS concentration (mascon) or high DENSITY on the MOON beneath the LUNAR MARIA.
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