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Some geologists，however，on the basis of observations concerning mantle　xenoliths， argue that the mantle is　not layered，but that heterogeneity is created by fluids rich in "incompatible elements" （elements tending toward　liquid rather than solid state）percolating upward and transforming　portions of the upper mantle　irregularly，according to the vagaries of the fluids’ pathways.

但是，某些地质学家，以对地幔捕虏岩体（xenolith）所作的观察为依据，指出地幔并非是分层排列的，相反，地幔的异质性是由那些富含“不相容成分”的流质构成的，这些成分趋向于流体而非固体的状态，自下而上渗透扩散，并依照这些流质流向的任意性，不规则地将上部地幔的某些部分予以改变。

The best evidence for the layered-mantle thesis is the well-established fact that volcanic rocks found on oceanic islands，islands believed to result from mantle plumes arising from the lower mantle，are composed of material fundamentally different from that of the midocean ridge system， whose source，most　geologists contend，is the upper mantle.

= The best evidence for the layered-mantle thesis/ is the well-established fact/ that volcanic rocks found on oceanic islands/，islands/ believed to result from mantle plumes/ arising from the lower mantle/，are composed of material/ fundamentally different from that of the midocean ridge system/， whose source/，most geologists contend/，is the upper mantle.

最好的证据/对于地幔分层论来说/是这样一个确凿的事实/即火山岩石在海洋岛屿上发现的/，这些岛屿被认为是mantle plume（形成的）/从下层地幔升上来的/，是由物质构成/与中部海脊的物质根本不同的/，其成因/，大多数地质学家认为/，是上部地幔。

延伸阅读：

托福阅读理解材料分析（一）

托福阅读理解材料分析（二）

托福阅读理解材料分析（三）

更多阅读资料：
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