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来源：雅诚德英语网
This sediment layer is enriched in the rare metal iridium and other elements that are relatively abundant in a meteorite but very rare in the crust of Earth.
这一沉积层富含稀有金属铱，以及其他在陨石中较丰富而在地壳中十分罕见的元素。
This sediment layer is enriched in the rare metal iridium and other elements that are relatively abundant in a meteorite but very rare in the crust of Earth.
这一沉积层富含稀有金属铱，以及其他在陨石中较丰富而在地壳中十分罕见的元素。