学科分类
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6 个结果
  • 简介:Gullysystemsandwatershedsaregeomorphicunitswithclearboundariesthatarerelativelyindependentofbasinlandscapesandplayanimportantroleinnaturalgeography.InordertoexplorethemorphologicalcharacteristicsofgullysystemsandwatershedsintheDry-HotValley[SouthWest(SW)China],gulliesareinterpretedfromonlineGoogleimageswithhighresolutionandwatershedsareextractedfromdigitalelevationmodelatascaleof1:50,000.Theresultsshowthat:(1)Thereare17,382gullies(withatotalareaof1141.66km^2)and42watershedsinthestudyarea.(2)Theaveragegullydensityofthestudyarea(D)is4.29km/km^2,gullyfrequency(F)is14.39gullies/km^2,thebranchingratio(B)is5.13,thelengthratio(L)is3.12,andthecoefficientofthemainandtributarygullies(M)is0,06.Thedegreeofgullyerosionisstrongtoextremelystrong,themaindevelopmentintensityofgullyerosionrangesfromintensetomoderate,andthetypeofgullysystemistributary.(3)Thewatershedareas(A)arebetween0.39and96.43km^2,thereliefratio(R)isfrom0.10to0.19,thecircularityratio(C)isfrom0.30to0.83,thetextureratio(T)isfrom0.82to39.35,andthedominantgeomorphologicaltexturetypeisfine.(4)ThereisaquantitativerelationshipbetweenFandD:F=0.624D2(R=0.84)andTiscloselyrelatedtoD,F,M(R2>0.7).A,RandCarerelatedtoM(R2>0.5).Thedevelopmentofgullysystemsistheresultofcouplingeffectsbetweenmultiplefactors.Inthisarea,thedegreeoferosionandtheconditionofthemainandtributarygulliescanbecontrolledbythedegreeoftopographicbreakageinthewatershed,whichprovidessometheoreticalbasisfortheevaluationofgullyerosionbythelatter.Inaddition,thescale,relief,andshapehaveasignificantimpactonthelocationsofthemainandtributarygullies.Fortributarygullies,attentionshouldbepaidtotheinterceptionandcontrolofrunoffandsedimentinthesmallconfluencebranchesinordertopreventgullyexpansionandheadadvance.Thesefeaturescaninformthedevelopmentoftargetedmea

  • 标签: MORPHOLOGICAL characteristics Quantitative RELATIONSHIPS GULLY system
  • 简介:Emeishan大陆人洪水暗岩,在云南,贵州和西南中国的四川省普遍,是一根二叠的披风羽毛的火山喷出物,并且与暗岩联系的本国的铜辉铜矿矿化作用在云南和贵州省的边阶区域是很普通的。矿化作用发生在凝灰岩置闰和在暗岩爆发的主要时期期间被形成的陆上的沉积岩置闰。矿体被stratigraphic位置和差错控制。在矿石的金属矿石矿物主要是本国的铜,辉铜矿和tenorite,与黄铜矿,bomite,黄铁矿和孔雀石的小数量,并且有时与大量沥青,碳和植物碎片。几十年矿床在二个省的附近的区域是分布式的,当他们中的大多数是小规模的存款或仅仅矿石出现时。由把矿石的铅同位素组成与各种各样的时期的墙岩石,盖子和基岩的作比较,在这类矿床的铜的来源在这篇论文被学习。结果显示出那:(1)从十存款的矿石的Pb同位素组成从上面的部分与上面的二叠的Xuanwei形成,更低的二叠的系列的石灰石和含碳的、寒武纪的沙岩页岩的siliceous-argillaceus岩石和直肠沉积的岩石和白云石的绝对不同中央原生地Kunyang组。这显示矿石铅既不从盖子岩石也不从基岩被导出;(2)尽管Neo原生地Siman白云石和硅石清淡,并且在Kunyang组的更低的部分的白云石在到在这些岩石中的矿石,领先和铜内容的Pb同位素组成是类似的是很低的,他们没做大贡献到铜矿化作用;(3)矿石作为暗岩有一样的Pb同位素组成,后者在铜正在被充实。这些事实显示铅和铜从暗岩被导出。根据地区性的地质的数据和矿床的geological-geochemical特征,形成矿石的材料从暗岩外面被沥滤,这被建议。厚度和暗岩和地区性的构造动力学的埋葬的深度能影响大规模铜存款的形成。因此,在有大厚度的发达暗岩的地方,为这类矿床的探索应该从西方的云南在区域被进行到西方的四川,�

  • 标签: 玄武岩 自然铜-辉铜矿 矿床 成矿