60秒科学:冰能给山拔高,你相信吗?

Moving glaciers¹ can cause erosion on mountains, but the coldest glaciers, frozen in place, protect mountains and allow them to grow taller. Cynthia Graber reports

冰川移动会侵蚀山地（冰川移动通常会导致出现角峰和冰斗谷），但是最冷的冰川被冻得固定在某个地方，就会保护山脉并且还会让它们“长高”。Cynthia Graber 报道

Glaciers slowly grind their way over mountains and plains, moving immense boulders² and carving³ out fjords. That’s true in temperate⁴ 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 counter-intuitive 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 actively⁵ 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 reveals 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 seal the mountains, protecting them from erosion. The scientists call the effect "glacial-armoring": an invaluable⁶ assist for peak performance.
 

1 glaciers   

冰河，冰川( glacier的名词复数 )

参考例句：

• Glaciers gouged out valleys from the hills. 冰川把丘陵地带冲出一条条山谷。
• It has ice and snow glaciers, rainforests and beautiful mountains. 既有冰川，又有雨林和秀丽的山峰。 来自英语晨读30分（高一）

2 boulders   

n.卵石( boulder的名词复数 )；巨砾；（受水或天气侵蚀而成的）巨石；漂砾

参考例句：

• Seals basked on boulders in a flat calm. 海面风平浪静，海豹在巨石上晒太阳。 来自《简明英汉词典》
• The river takes a headlong plunge into a maelstrom of rocks and boulders. 河水急流而下，入一个漂砾的漩涡中。 来自《简明英汉词典》

3 carving   

n.雕刻品，雕花

参考例句：

• All the furniture in the room had much carving.房间里所有的家具上都有许多雕刻。
• He acquired the craft of wood carving in his native town.他在老家学会了木雕手艺。

4 temperate   

adj.温和的，温带的，自我克制的，不过分的

参考例句：

• Asia extends across the frigid,temperate and tropical zones.亚洲地跨寒、温、热三带。
• Great Britain has a temperate climate.英国气候温和。

5 actively   

adv.积极地，勤奋地

参考例句：

• During this period all the students were actively participating.在这节课中所有的学生都积极参加。
• We are actively intervening to settle a quarrel.我们正在积极调解争执。

6 invaluable   

adj.无价的，非常宝贵的，极为贵重的

参考例句：

• A computer would have been invaluable for this job.一台计算机对这个工作的作用会是无法估计的。
• This information was invaluable to him.这个消息对他来说是非常宝贵的。