SSS 2008-09-30
时间：2018-12-24 作者：英语课 分类：Scientific American(九)月
This is Scientific American's 60-Second Science. I'm Cynthia Graber. This will just take a minute.
The Earth’s crust is old. Billions of years old. So old that it’s nearly impossible to imagine. And now scientists have discovered what may be the oldest whole rocks ever known. Geologists 1 at Carnegie Mellon University published the results of the research in the September 26th issue of the journal Science.
The rocks come from an area of the Hudson Bay in northern Quebec. In 2001 the geologists identified the site as a possible repository of very old rocks. It is made up of folds of volcanic 2 and what are called metasedentary rocks. And it’s surrounded by three-and-a-half-billion-year-old tonalite.
Researchers collected rocks and measured minute isotopic 3 variations in rare earth elements called neodymium and samarium. According to dating techniques, the rocks could be 4.28 billion years old. It’s rare to find rocks that date back to when the Earth’s mantle 4 was forming. It was quite a tumultuous time, and most rocks were smashed up into tiny pieces again and again. Learning more about these whole rocks could help us gain a better understanding of the very beginnings of our planet.
Thanks for the minute for Scientific American's 60-Second Science. I'm Cynthia Graber.
- Geologists uncovered the hidden riches. 地质学家发现了地下的宝藏。
- Geologists study the structure of the rocks. 地质学家研究岩石结构。
- There have been several volcanic eruptions this year.今年火山爆发了好几次。
- Volcanic activity has created thermal springs and boiling mud pools.火山活动产生了温泉和沸腾的泥浆池。