The lowermost mantle layer is above the core mantle boundary (CMB) and composed of D" region and ultra-low velocity zone (ULVZ)."

地幔底层由具有高地震波速和高密度的D″区和超低速带（ULVZ）组成。

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Surprisingly, precious metals instead appear relatively abundant on the planet's surface and in the underlying mantle layer. [Infographic: Tallest Mountain to Deepest Ocean Trench].

令人惊讶的是，在地球表面和下面的地幔层里贵金属反而比较丰富。

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All are slowly moving because the plates float on a denser sem-iliquid mantle, the layer between the crust and Earth's core.

所有板块都在缓慢移动，因为它们漂浮在密度更大的半流体地幔上，也就是地壳和地核之间的那一层。

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The scientists examined two Martian meteorites that formed in the planet's mantle, the layer under the crust.

MSN: Scientists say parts of Mars interior are as wet as Earth's