科学家发现火星上有花岗岩的证据-凯发k8官网

科学家发现火星上有花岗岩的证据
文章来源:未知 文章作者:enread 发布时间:2013-11-19 06:22 字体: [ ] 
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researchers now have stronger evidence of 1(花岗岩) on mars and a new theory for how the granite -- an 2 rock(火成岩) common on earth -- could have formed there, according to a new study. the findings suggest a much more geologically complex mars than 3 believed. large amounts of a mineral found in granite, known as feldspar(长石), were found in an ancient martian volcano. further, minerals that are common in basalts(玄武岩) that are rich in iron and 4, ubiquitous on mars, are nearly completely absent at this location. the location of the feldspar also provides an explanation for how granite could have formed on mars. granite, or its eruptive equivalent, rhyolite, is often found on earth in tectonically active regions such as subduction zones. this is unlikely on mars, but the research team concluded that prolonged magmatic activity on mars can also produce these compositions on large scales.
 
"we're providing the most compelling evidence to date that mars has 5 rocks," said james wray, an assistant professor in the school of earth and 6 sciences at the georgia institute of technology and the study's lead author.
 
the research was published november 17 in the advance online publication of the journal nature geoscience. the work was supported by the nasa mars data analysis program.
 
for years mars was considered geologically simplistic, consisting mostly of one kind of rock, in contrast to the diverse geology of earth. the rocks that cover most of mars's surface are dark-colored 7 rocks, called basalt, a type of rock also found throughout hawaii for instance.
 
but earlier this year, the mars curiosity rover surprised scientists by discovering soils with a composition similar to granite, a light-colored, common igneous rock. no one knew what to make of the discovery because it was limited to one site on mars.
 
the new study 8 the evidence for granite on mars by using remote sensing techniques with 9 spectroscopy to survey a large volcano on mars that was active for billions of years. the volcano is dust-free, making it ideal for the study. most volcanoes on mars are blanketed with dust, but this volcano is being sand-blasted by some of the fastest-moving sand 10 on mars, 11 away any dust that might fall on the volcano. inside, the research team found rich deposits of feldspar, which came as a surprise.
 
"using the kind of infrared spectroscopic technique we were using, you shouldn't really be able to detect feldspar minerals, unless there's really, really a lot of feldspar and very little of the dark minerals that you get in basalt," wray said.


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1 kyqyu     
adj.花岗岩,花岗石
参考例句:
  • they squared a block of granite.他们把一块花岗岩加工成四方形。
  • the granite overlies the older rocks.花岗岩躺在磨损的岩石上面。
2 dyayl     
adj.火的,火绒的
参考例句:
  • igneous rocks do not contain fossils.火成岩不含化石。
  • the rocks here are igneous and do not fracture along predictable lines.这儿的石头都是火成岩,石头的裂缝极不规则。
3 bkzzzc     
adv.以前,先前(地)
参考例句:
  • the bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
  • let me digress for a moment and explain what had happened previously.让我岔开一会儿,解释原先发生了什么。
4 briz8     
n.镁
参考例句:
  • magnesium is the nutrient element in plant growth.镁是植物生长的营养要素。
  • the water contains high amounts of magnesium.这水含有大量的镁。
5 364046b2e83064504a868979ba228811     
花岗石的,由花岗岩形成的
参考例句:
  • a batholith has been defined as a huge intrusive mass of granitic rock. 岩基的定义是巨大的花岗石侵入岩体。
  • a granitic rock composed chiefly of quartz and mica. 一种由石英和云母构成的花岗石。
6 6eayr     
adj.大气的,空气的;大气层的;大气所引起的
参考例句:
  • sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。
  • clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。
7 blgzq     
adj.火山的;象火山的;由火山引起的
参考例句:
  • 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。
8 9b89e6dcb4e889ced090a1764f626d1c     
n.长枕( bolster的名词复数 );垫子;衬垫;支持物v.支持( bolster的第三人称单数 );支撑;给予必要的支持;援助
参考例句:
  • he used a couple of bolsters to elevate his head. 他用两个垫枕垫头。 来自《简明英汉词典》
  • the double-row piles with both inclined and horizontal bolsters also analyzed in consideration of staged excavation. 本文亦分析了考虑开挖过程的安置斜撑与带支撑的双排桩支护结构。 来自互联网
9 dx0yp     
adj./n.红外线(的)
参考例句:
  • infrared is widely used in industry and medical science.红外线广泛应用于工业和医学科学。
  • infrared radiation has wavelengths longer than those of visible light.红外辐射的波长比可见光的波长长。
10 8a48dcdac1abf28807833e2947184dd4     
沙丘( dune的名词复数 )
参考例句:
  • the boy galloped over the dunes barefoot. 那男孩光着脚在沙丘间飞跑。
  • dragging the fully laden boat across the sand dunes was no mean feat. 将满载货物的船拖过沙丘是一件了不起的事。
11 ihczz4     
adj.范围广大的,一扫无遗的
参考例句:
  • the citizens voted for sweeping reforms.公民投票支持全面的改革。
  • can you hear the wind sweeping through the branches?你能听到风掠过树枝的声音吗?
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