The measurements of the elastic wave velocity of lower crustal rocks may provide valuable information on the composition and physical properties of the lower crust.

下地壳岩石的波速测定可以提供有关下地壳物质组成及物理性质的重要信息。

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In lower crust, faults often consist of a series of secondary fractures.

发育于地壳浅层中的脆性断层常常由一系列次级小断层所构成。

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The primitive Pb was mainly derived from the lower crust and upper mantle;

矿床中的 原 始铅主要来源于地壳深部或上地幔；

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There were servants to address one's every material need, dinner in white tie and lavish gowns, and rules designed to keep the upper crust on top and the lower classes in their place.

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As exotic-auto makers redefine what a superluxury car can be, their executives are attempting a delicate balancing act: maintaining the exclusive cachet of their upper-crust brands while pursuing new wealthy customers that lower-end luxury rivals are currently scooping up.

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And those estimates are of what mining companies have concrete plans to get at numbers that are significantly lower than the colossal quantities of reserves buried throughout the Earth's crust.

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