PREP RC

wangjieava23 · 发表于 2011-5-21 09:58:56

Komatilites discovery was suprising in light of then-current geological theories about magmas, molten rock that forms in the Eath's mantle( the layer beneath the crust) and composes volcanic lava eruptions. Prior to 1960, geologists Bowen and Hess disagreed over wether or not the very high temperatures needed to produce magmas rich in magnasium could have existed on Earth. Hess suggested that the presence of water, probably released from minerals decomposing in the eath's mantle, might have meant that a high-magnesium magma could have existed at a lower temperature. But Bowern showed experimentally that the temperature were indeed nacessary. By 1960, it was generally accepted that volcanic rocks in such high levels of magnesium could not existed, and thus the dicovery of komatites changed geologists' assumptions about the characterics of the Earth's mantle around the time of the formation of komatiltes, between 2.5 and 4 billions years ago.

3 According to the passage, Hess and Bowen differed concerning whether or not the
A Methordology used by Bowen in conducting certain experiments was appropriate;
B high temperatures thought necessary to produce high-magnasium were in fact necessary
C Earth's mantle contained significant amounts of water when komatilites were formed
D presence of magnesium in lava changesd the physical properties of lava
E komatilites indentified in 1969 were actually Earth's oldest volcanic rocks.

答案： B

我认为： Prior to 1960, geologists Bowen and Hess disagreed over wether or not the very high temperatures needed to produce magmas rich in magnasium could have existed on Earth.
这句话说的是这个温度是不是存在，但是B中却说的是温度比不必要。意思上有很大差距。导致这个题没有答案。

PREP RC

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