线形沙丘成因不能排除被风侵蚀
文章来源:未知 文章作者:enread 发布时间:2012-02-27 03:20 字体: [ ]  进入论坛
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Linear dunes1, widespread on Earth and Saturn's moon, Titan, are generally considered to have been formed by deposits of windblown sand. It has been speculated for some time that some linear dunes may have formed by "wind-rift" erosion, but this model has commonly been rejected due to lack of sufficient evidence. Now, new research supported by China's NSF and published this week in GSA BULLETIN indicates that erosional origin models should not be ruled out. The linear dunes in China's Qaidam Basin have been proposed to have formed as self-extending lee dunes(背风沙丘) under a unidirectional wind regime owing to a high level of total silt2(淤泥,泥沙) , clay, and salt content or cohesiveness3 of sediments4, and they have undergone southward lateral5 migration6 at rates of up to 3 m/yr.

New GSA BULLETIN research examines the sediments, internal structures, and optically stimulated7 luminescence ages of the linear dunes in the central Qaidam Basin approximately 80 km north of the city Golmud. The study's findings suggest that the linear dunes are most likely of erosional origin similar to yardangs(风蚀土脊) with orientations8 controlled by strikes of joints10.

According to the study's lead author, Jianxun Zhou of the China University of Petroleum11's State Key Laboratory of Petroleum Resource & Prospecting12, "If the control of tectonic(建筑的) structures on the orientation9 of wind-eroded ridges13 is taken into account, morphodynamic interpretations14 for the wind-rift model may become much simpler. No one has considered the possibility of erosional origin for the linear dunes on Titan. Nearly all researchers consider the linear dunes on Titan to be of depositional origin, but their morphodynamic interpretations are complicated and their relationships to wind directions are in dispute. If an erosional origin is considered, the morphodynamic interpretations of the linear dunes on Titan can also be greatly simplified."



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1 dunes 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。
2 silt tEHyA     
n.淤泥,淤沙,粉砂层,泥沙层;vt.使淤塞;vi.被淤塞
参考例句:
  • The lake was almost solid with silt and vegetation.湖里几乎快被淤泥和植物填满了。
  • During the annual floods the river deposits its silt on the fields.每年河水泛滥时都会在田野上沉积一层淤泥。
3 cohesiveness 4807a765b18b29ba2251c7458c5cf14a     
n. 粘合,凝聚性
参考例句:
  • The Bogor Goals concern APEC's credibility, cohesiveness and future development. 茂物目标事关亚太经合组织的信誉、凝聚力和未来发展。
  • One of the most important properties of a work team is cohesiveness. 工作小组的最重要特征之一是凝聚力。
4 sediments 8b3acb612b624abdf2c2881bc6928565     
沉淀物( sediment的名词复数 ); 沉积物
参考例句:
  • When deposited, 70-80% of the volume of muddy sediments may be water. 泥质沉积物沉积后,体积的70-80%是水。
  • Oligocene erosion had truncated the sediments draped over the dome. 覆盖于穹丘上的沉积岩为渐新世侵蚀所截削。
5 lateral 83ey7     
adj.侧面的,旁边的
参考例句:
  • An airfoil that controls lateral motion.能够控制横向飞行的机翼。
  • Mr.Dawson walked into the court from a lateral door.道森先生从一个侧面的门走进法庭。
6 migration mDpxj     
n.迁移,移居,(鸟类等的)迁徙
参考例句:
  • Swallows begin their migration south in autumn.燕子在秋季开始向南方迁移。
  • He described the vernal migration of birds in detail.他详细地描述了鸟的春季移居。
7 stimulated Rhrz78     
a.刺激的
参考例句:
  • The exhibition has stimulated interest in her work. 展览增进了人们对她作品的兴趣。
  • The award has stimulated her into working still harder. 奖金促使她更加努力地工作。
8 orientations 0fe4bdb2d2133dafeb851bee3d9c63d0     
n.方向( orientation的名词复数 );定位;(任职等前的)培训;环境判定
参考例句:
  • Welfare comparisons are also hindered by differences in orientations among economic systems. 经济制度之间倾向性的差别也会妨碍福利的比较。 来自辞典例句
  • Their different value orientations led to different results in literary creation. 价值取向的分野亦导致了不同的创作局面。 来自互联网
9 orientation IJ4xo     
n.方向,目标;熟悉,适应,情况介绍
参考例句:
  • Children need some orientation when they go to school.小孩子上学时需要适应。
  • The traveller found his orientation with the aid of a good map.旅行者借助一幅好地图得知自己的方向。
10 joints d97dcffd67eca7255ca514e4084b746e     
接头( joint的名词复数 ); 关节; 公共场所(尤指价格低廉的饮食和娱乐场所) (非正式); 一块烤肉 (英式英语)
参考例句:
  • Expansion joints of various kinds are fitted on gas mains. 各种各样的伸缩接头被安装在煤气的总管道上了。
  • Expansion joints of various kinds are fitted on steam pipes. 各种各样的伸缩接头被安装在蒸气管道上了。
11 petroleum WiUyi     
n.原油,石油
参考例句:
  • The Government of Iran advanced the price of petroleum last week.上星期伊朗政府提高了石油价格。
  • The purpose of oil refinery is to refine crude petroleum.炼油厂的主要工作是提炼原油。
12 prospecting kkZzpG     
n.探矿
参考例句:
  • The prospecting team ploughed their way through the snow. 探险队排雪前进。
  • The prospecting team has traversed the length and breadth of the land. 勘探队踏遍了祖国的山山水水。
13 ridges 9198b24606843d31204907681f48436b     
n.脊( ridge的名词复数 );山脊;脊状突起;大气层的)高压脊
参考例句:
  • The path winds along mountain ridges. 峰回路转。
  • Perhaps that was the deepest truth in Ridges's nature. 在里奇斯的思想上,这大概可以算是天经地义第一条了。
14 interpretations a61815f6fe8955c9d235d4082e30896b     
n.解释( interpretation的名词复数 );表演;演绎;理解
参考例句:
  • This passage is open to a variety of interpretations. 这篇文章可以有各种不同的解释。 来自《简明英汉词典》
  • The involved and abstruse passage makes several interpretations possible. 这段艰涩的文字可以作出好几种解释。 来自《现代汉英综合大词典》
TAG标签: wind sand erosion
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