南极冰原下的巨大峡谷

湖南岳阳市华容县第二中学 戴 洵

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难词探意

1.subglacial topography冰川下的地形

2.canyon/'kænjən/n.峡谷

3.ice sheet冰原

4.expansive/ɪk'spænsɪv/adj.广阔的

5.destabilize/'diː'steɪbəlaɪz/v.使不稳定

Scientists have been studying Antarctica for over a century,but details as basic as what it looks like beneath all that ice have largely remained a mystery.Now,Earther reports that a team of scientists from Denmark,Norway,the Netherlands,and the UK has published the most detailed data yet on the continent's subglacial topography near the South Pole.

As they report in the journal Geophysical Research Letters,central Antarctica is home to three large canyons,one of which is deeper than the Grand Canyon and nearly as wide at some points.The researchers made the discovery by flying a plane with radar over the South Pole,a spot that isn't covered by imaging satellites.They expected to find mountains beneath the ice sheet,but the expansive canyons they found between the mountains came as a surprise.

Of the three canyons,two hadn't been documented previously.The largest,the Foundation Trough,measures 218 miles long,up to 22 miles wide,and 6,260 feet deep,putting it up there with the planet's most impressive canyons.

The discoveries are significant on their own,but the real purpose behind the research is to better understand how the West and East Antarctic Ice Sheets will react to rising temperatures.Human-caused climate change has destabilized some of the continent's ice,and the West Antarctic Ice Sheet especially has been slowly melting to the sea.If patterns continue,the coastal glaciers supporting the large ice sheets could fall down,causing sea levels to rise a minimum of 10 feet.If this happens,the canyons could be a major factor in the speed and direction of ice flow from central Antarctica to the coast.

The event isn't likely to happen in the near future,but further study of Antarctica's topography will allow scientists to better predict when it might.

Reading Check

1.Which of the following have scientists known little before?

A.The shape of Antarctica.

B.The condition of Antarctica's ice.

C.What it looks like underneath Antarctica's ice.

D.What Antarctica looks like.

2.How did researchers know one canyon is deeper than the Grand Canyon?

A.By going there many times.

B.By using radar in a plane.

C.By taking planes.

D.By analysing satellites' pictures.

3.What's the attitude of researchers to their findings?

A.Confused.B.Worried.

C.Disappointed.D.Shocked.

4.What's the aim of the study?

A.To know rising temperatures' effect on ice sheets.

B.To find the sizes of three canyons.

C.To find whether the ice is becoming thin.

D.To know how some Antarctic ice sheets are appearing.

Language Study

Difficult sentence

If patterns continue,the coastal glaciers supporting the large ice sheets could fall down,causing sea levels to rise a minimum of 10 feet.

【翻译】__________________________________________________________________

【点石成金】这是一个主从复合句。句中If引导条件状语从句；supporting the large ice sheets为现在分词短语作定语修饰名词短语the coastal glaciers；现在分词短语causing sea levels to rise a minimum of 10 feet作结果状语。