Grand Canyon 'formed recently' 大峡谷是'近年才形成的'
媒体英语会带大家一起学习 BBC 撰稿人在报道世界大事时常用到的单词和短语。
世界著名的美国亚利桑那州的大峡谷可能比先前想象的历史要短得多。新的科研显示这一世界奇的形成仅有五至六百万年的时间。这比先前的说法要短得多。以前的研究声称大峡谷已经有七千万年历史。以下是 BBC 科学事务记者 Jonathan Amos 发回的报道：
Millions of tourists are drawn each year to the Grand Canyon to see its impressive rocks, which record nearly two billion years of Earth history. Running for almost 450km and to a depth of 1,800m, it is almost too vast to take in.
Its huge scale has also been problematic for scientists who've spent years gathering data from different locations through the canyon to try to work out its true age.
Some of the most recent investigations had indicated an ancient origin, while others thought it was much younger.
Now a new study in the Nature Geoscience journal pulls it all together. It finds, yes, the Grand Canyon has very old segments, but the full system was only cut into the form we know today by the Colorado River just over five million years ago.