Observation of water vapor in the stratosphere of Jupiter with the Odin space telescope     

T. Cavalié  F. Billebaud  M. Dobrijevic  J. Brillet  Å. Hjalmarson  U. Frisk  E.A. Bergin  The Odin Team 《Planetary and Space Science》2008,56(12):1573-1584

The water vapor line at 557 GHz has been observed with the Odin space telescope with a high signal-to-noise ratio and a high spectral resolution on November 8, 2002. The analysis of this observation as well as a re-analysis of previously published observations obtained with the submillimeter wavelength astronomy satellite seem to favor a cometary origin (Shoemaker-Levy 9) for water in the stratosphere of Jupiter, in agreement with the ISO observation results. Our model predicts that the water line should become fainter and broader from 2007. The observation of such a temporal variability would be contradictory with an IDP steady flux, thus supporting the SL9 source hypothesis.  相似文献   

中国西部铂矿床类型与找矿方向探讨     

涂怀奎 《化工矿产地质》2004,26(4):220-227

中国铂矿资源严重不足,主要分布在中国西部,根据原生矿床特征可划分为4类：①硫化物型;②铬铁矿型;③辉石岩型;④层控型。寻找铂矿新类型和富铂(岩石)资源,应成为解决中国铂矿资源紧缺的重要任务。铂矿找矿方向：地台与地槽接合部位,特别是围绕着基性、超基性岩内外接触带,铂的预富集岩带与层控型铂矿带,另外还有砂铂型铂矿发育区有望扩大找铂前景。  相似文献   

黑河流域水资源合理开发利用的研究   总被引：4，自引：0，他引：4  

黑河流域水资源粽合考察队 《中国沙漠》1987,7(4):12-21

黑河流域是我国干旱区一个较大的内陆河流域,集水面积约13万平方公里,主流长821公里,发源于祁连山,穿越河西走廊,流泄于内蒙古西部高原。本文对黑河流域水资源、土地资源、草场资源的数显和质量进行评价。同时分析了流域水资源潜力及开发利用引起的环境变化。指出目前水资源开发已影响到中游绿洲建设规模和下游绿的安全。研究认为现阶段水资源开发利用应使经济发展和保护环境两者之间的关系相协调。实行以流域为整体的开发,采取有效的工程措施,加强中、下游水资源利用的宏观控制与管理,实行分区定量分配和综合治理,从而提高流域水资源利用的经济、环境和社会效益。  相似文献   

中英联合洞穴探险及冠岩地下河系的新观察   总被引：1，自引：1，他引：0  

岩溶洞穴探险队 《中国岩溶》1986,5(2):135-140

<正> 洞穴探险是指使用某些专门的探洞装备和技术,考察一般情况下人们不能进入或不容易进入的洞穴。近十多年来,英、美等一些国家已利用洞穴探险技术,为洞穴学研究服务。他们的探洞技术发展很快,装备也不断更新。在洞穴测绘、洞穴摄影、洞穴潜水、攀登技术、洞内安全措施以及洞内生活方面积累了不少的经验,取得了大量洞穴学研究的资料和成果。我国的岩溶区面积和洞穴数量居世界之首,但洞穴考察程度还很低,尤其在南方岩溶峰丛山区,发育有较多危险的天窗、竖井、落水洞,以及一些充水的洞穴。   相似文献   

Morphological controls on the dynamics of carbonate landscapes under a mediterranean climate          下载免费PDF全文

Franck Thomas  Vincent Godard  Olivier Bellier  Esmaeil Shabanian  Vincent Ollivier  Lucilla Benedetti  Magali Rizza  Nicolas Espurt  Valéry Guillou  Fabrice Hollender  Stéphane Molliex  ASTER Team 《地学学报》2017,29(3):173-182

The influence of the morphological setting on the denudation of carbonate landscapes and the respective contributions of mechanical and chemical weathering processes are still debated. We have addressed these questions by measuring ³⁶Cl concentrations in 40 samples from the Luberon mountain, SE France, to constrain the denudation of various landscape elements. We observe a clear contrast between the local denudation rates from the flat summit surface, clustered around 30 mm/ka, and the basin‐average denudation rates across the flanks, ranging from 100 to 200 mm/ka. This difference highlights the transient evolution of the range, whose topography is still adjusting to previous uplift events. Such a pattern also suggests that carbonate dissolution is not the only driver of denudation in this setting, which appears to be significantly controlled by slope‐dependent processes.  相似文献   

苏北云台群含蓝晶石岩石矿物组合特征及其地质意义   总被引：2，自引：0，他引：2  

徐安中 《江苏地质》1998,22(1):10-14

中上元古界云台群中的石英岩类、某些片岩类是含蓝晶石的层位。与蓝晶石共生的黄玉、天蓝石、磷钙铝石、叶腊石、金红石等矿物构成高压变质带里原岩为泥质、泥砂质的白片岩或类白片岩的一套矿物组合。它们将成为今后岩石学研究的新领域,同时也是今后寻找金刚石、刚玉、磷、镁等矿产的线索之一。  相似文献   

昆中断裂东段不同时代蛇绿岩特征及形成环境   总被引：2，自引：0，他引：2  

解玉月 《青海国土经略》1998,(1)

沿昆中断裂带分布的两套不同类型的蛇绿混杂岩,均属非典型的蛇绿岩套残块(片),是昆中断裂带在漫长的地质演化过程中残留在陆块边缘的洋壳物质。它们在空间上分布于不同的构造部位,时间上分属于元古代和晚古生代。  相似文献   

赛坝沟金矿成矿特征及控矿条件     

付青元  李宝林 《青海国土经略》1998,(1)

通过对青海赛坝沟岩金矿床的地质特征及其成矿地质条件的研究,笔者认为该矿床的成因类型为“与岩浆侵入及火山岩有关的中温热液矿床”。  相似文献   

Transient surface liquid in Titan’s polar regions from Cassini     

A.G. Hayes  O. Aharonson  R.L. Kirk  L.C. Wye  E.P. Turtle  G. Mitri  E.R. Stofan  C. Elachi  the Cassini RADAR Team 《Icarus》2011,211(1):655-671

Cassini RADAR images of Titan’s south polar region acquired during southern summer contain lake features which disappear between observations. These features show a tenfold increases in backscatter cross-section between images acquired one year apart, which is inconsistent with common scattering models without invoking temporal variability. The morphologic boundaries are transient, further supporting changes in lake level. These observations are consistent with the exposure of diffusely scattering lakebeds that were previously hidden by an attenuating liquid medium. We use a two-layer model to explain backscatter variations and estimate a drop in liquid depth of approximately 1-m-per-year. On larger scales, we observe shoreline recession between ISS and RADAR images of Ontario Lacus, the largest lake in Titan’s south polar region. The recession, occurring between June 2005 and July 2009, is inversely proportional to slopes estimated from altimetric profiles and the exponential decay of near-shore backscatter, consistent with a uniform reduction of 4 ± 1.3 m in lake depth.Of the potential explanations for observed surface changes, we favor evaporation and infiltration. The disappearance of dark features and the recession of Ontario’s shoreline represents volatile transport in an active methane-based hydrologic cycle. Observed loss rates are compared and shown to be consistent with available global circulation models. To date, no unambiguous changes in lake level have been observed between repeat images in the north polar region, although further investigation is warranted. These observations constrain volatile flux rates in Titan’s hydrologic system and demonstrate that the surface plays an active role in its evolution. Constraining these seasonal changes represents the first step toward our understanding of longer climate cycles that may determine liquid distribution on Titan over orbital time periods.  相似文献   

Regional geomorphology and history of Titan’s Xanadu province     

J. Radebaugh  R.D. Lorenz  R.L. Kirk  J.I. Lunine  R.M.C. Lopes  T.G. Farr  B. Stiles  H. Zebker  L. Wye  K.L. Mitchell  R.D. West  The Cassini Radar Team 《Icarus》2011,211(1):672-685

Titan’s enigmatic Xanadu province has been seen in some detail with instruments from the Cassini spacecraft. The region contains some of the most rugged, mountainous terrain on Titan, with relief over 2000 m. Xanadu contains evolved and integrated river channels, impact craters, and dry basins filled with smooth, radar-dark material, perhaps sediments from past lake beds. Arcuate and aligned mountain chains give evidence of compressional tectonism, yet the overall elevation of Xanadu is puzzlingly low compared to surrounding sand seas. Lineations associated with mountain fronts and valley floors give evidence of extension that probably contributed to this regional lowering. Several locations on Xanadu’s western and southern margins contain flow-like features that may be cryovolcanic in origin, perhaps ascended from lithospheric faults related to regional downdropping late in its history. Radiometry and scatterometry observations are consistent with a water-ice or water-ammonia-ice composition to its exposed, eroded, fractured bedrock; both microwave and visible to near-infrared (v-nIR) data indicate a thin overcoating of organics, likely derived from the atmosphere. We suggest Xanadu is one of the oldest terrains on Titan and that its origin and evolution have been controlled and shaped by compressional and then extensional tectonism in the icy crust and ongoing erosion by methane rainfall.  相似文献