单词：alluvial horizon
alluvial horizon的用法和样例：
例句
- Reportedly, the site is mainly underlain by alluvial deposits of Quaternary Age comprising sand and clay.据报道，站点由主要强调包括沙子和黏土的四个一组的年龄冲积层。
单词：alluvial horizon 相关文章
Conditions on Mars were so harsh that it was hard to imagine any life surviving there. The idea of sophisticated aliens was wiped out. We know that conditions on Mars today are not very good for life.
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These discoveries raised the stakes. Here was a planet similar to our own. Mars might not have cities or civilizations. But it could be home to other smaller life forms like microbes. Chris McKay is N
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I think it is exciting. Because it would imply that if life arose independently on Mars. The implication is that life is pervasive throughout the universe. This is why Mars has so obsessed scientists.
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In 2001 a new NASA probe was launched. Called Odyssey, it was sent to Mars to carry out the most detailed analysis ever of the planet’s surface. What it has discovered may be about to answer one of
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But even if there had been water, life doesn't start overnight. Even a simple microbe is the product of complex chemical systems that take millions of years to evolve. Had the water lasted long enough
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Rice had seen the same thing in Iceland, one of the few places on Earth with similarities to Mars. It too is extremely cold, and most of the water is frozen into glaciers. And also like Mars, buried u
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For Mars to have rivers, it must once have had streams, rain, clouds and an atmosphere, a planet just like the Earth today-if these were rivers. They had to be sure. The answers would come in 1998 wit
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William Boynton is professor of planetary sciences at the University of Arizona. And he's dedicated his life to looking for water on Mars. The link between life and water is very strong. Even here in
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Of course, any terraforming is still a long way off. The next few expeditions to Mars will definitely be made by machines. NASA, are sending 2 rovers, capable of travelling over 100 meters a day in se
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Well, hearing that Odyssey had found subsurface water on Mars was enormously exciting for somebody who is involved in planning to send humans to Mars. Water has a number of important uses for us. At t
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Life on Earth is basically proteins and DNA, so we can wonder if there is life on Mars will also be DNA and proteins, the same type of DNA, the same type of proteins. One might think that DNA is such
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But there was something even better. Odyssey may not just have found ice. There may also be liquid water, and that means, there could be living creatures there too. Right now, there might be liquid wa
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But they never got there. The first disappeared into deep space. Another missed its target when its coordinates were confused. One NASA control center was working in metric, the other in feet and inch
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The ground here is permafrost, a mixture of soil and ice frozen together. A group of Russian scientists have teamed up with NASA to drill down into it in search of microorganisms. It's work that's bee
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One of these wavelengths corresponds to hydrogen, another wavelength would be iron. Another wavelength would be oxygen. And so you go to the part of the spectrum you are interested in and you see you'
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Conservation Project at Risk from Mai Mai Attack The hunt continues for the Mai Mai militia that attacked a DRC conservation project in June. Six people were killed, as well as 14 endangered animals called Okapi, or forest giraffe. The attack occurre
VOA标准英语2012年(七月)
Better known for its diamond fields, gold exploration and mining in Sierra Leone is on the increase. The British company, Cluff Gold, has announced it will build a mechanized gold mine in the southern Kangari hills after finding large deposits of gol
VOA标准英语2010年(四)月
They may be a little safer here. But the food in the forest is far less nutritious than on the riverbanks. If they want to eat well and avoid wolves this winter, they'll need to keep on moving. As the elk move gradually downwards, they follow the riv
自然百科2012年
By Naomi Schwarz Dakar 04 December 2007 Diamonds from Sierra Leone have fueled the country's gruesome civil war and enriched warlords. Now, the government and activists are trying to make sure the profits from Sierra Leone's post-conflict diamonds he
VOA常速英语2007年（十二月）