科学60秒:冰川作甲,山峰长高
来源：沪江听写酷
2011-05-20 00:06
文章较难，大家听写填空即可~
Glaciers slowly grind their way over mountains and plains, moving immense boulders and ___1___ fjords. That’s true in temperate regions, where glaciers—glacially—flow downhill. Over thousands of years, the frozen masses can scrape miles off of mountains. Researchers call it the glacial buzz-saw.
But for the very coldest climes, researchers now offer a ___2___ view of glaciers – they actually help mountains grow. The finding was published in the journal Nature.
A team led by scientists from the University of Arizona studied mountains in remote areas of Patagonia in South America.The Andes are actively growing. Hot rocks are shoved to the top, and erosion brings them back down the sides.The team collected 146 samples of rocks from mountainsides and then dated the rocks’ so-called cooling age, which ___3___ when the rock was exposed by erosion.
They found that erosion happened faster in the warmer mountains to the north, and more slowly in the colder mountains in the south. Turns out that when glaciers are cold enough they don’t move much. Instead, they ___4___ the mountains, protecting them from erosion. The scientists call the effect "glacial-armoring": ___5___.
Glaciers slowly grind their way over mountains and plains, moving immense boulders and ___1___ fjords. That’s true in temperate regions, where glaciers—glacially—flow downhill. Over thousands of years, the frozen masses can scrape miles off of mountains. Researchers call it the glacial buzz-saw.
But for the very coldest climes, researchers now offer a ___2___ view of glaciers – they actually help mountains grow. The finding was published in the journal Nature.
A team led by scientists from the University of Arizona studied mountains in remote areas of Patagonia in South America.The Andes are actively growing. Hot rocks are shoved to the top, and erosion brings them back down the sides.The team collected 146 samples of rocks from mountainsides and then dated the rocks’ so-called cooling age, which ___3___ when the rock was exposed by erosion.
They found that erosion happened faster in the warmer mountains to the north, and more slowly in the colder mountains in the south. Turns out that when glaciers are cold enough they don’t move much. Instead, they ___4___ the mountains, protecting them from erosion. The scientists call the effect "glacial-armoring": ___5___.
carving out
counter-intuitive
reveals
seal
an invaluable assist for peak performance
冰川沿着山坡、平原一路缓缓磨啊磨，久而久之，砾石易位，峡湾成形。在温带确实是这样，千万年的时间，冰川能把山顶磨掉数英里。研究人员称之为为“冰山锯”。
不过，对于寒冷至极的地区，研究人员倒是提出了反直觉的观点——冰川实际上有助于山脉增高。该研究发现刊登于《自然》上。
在来自亚利桑那大学的科学家的带领下，一支科考队对南美洲巴塔哥尼亚偏远地区的山脉进行了考察。考察发现，安第斯山脉海拔正上涨。地下贮热岩先被喷到山顶部，然后又因冰川的侵蚀作用被甩到山坡上。科考队收集了山坡上146个岩石样本，并测定了这些岩石的冷却年代，从而可以了解其由于冰川侵蚀而被暴露的年代。
研究人员发现，越往北越温暖的地方，冰川侵蚀速度较快，而较冷的南方则较慢。也就是说，冷到一定程度，冰川也就不太移动了，反而会冰封山脉，使其不受侵蚀。科学家称之为“冰川护甲”：山脉增高的大功臣丫~