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1.
Gemerská Poloma矿床是个重要的滑石矿床(储量20万吨),位于西喀尔巴阡山脉Germeric地区。部分滑石化的镁质碳酸盐体赋存在早古生代火山沉积杂岩体中(黑色片岩,变质泥岩),在Variscan变质作用(M1)过程中受到了绿泥石-黑云母带区域变质相的改造。这种原岩是石灰岩的矿体由白色-灰白或者灰色-黑色的菱镁矿与白云石1组成,被次生的白云石2和滑石脉切割。本次研究考察了两次变质事件(M1和M2)的几个连续的矿物组合,最早的组合包括铁白云石,镁菱铁矿与菱铁矿,(并与黑电气石,铁绿泥石,磷灰石,与伊利石-白云母伴生),它们以微小残留物形式产出在菱镁矿和白云石1中,其形成可能早于M1变质作用高峰期。M1变质事件的高峰期以富铁金云母,镁绿泥石1,镁电气石(黑电气石的边缘)和石英的组合为代表。在M1退变质作用过程中,发生了镁交代作用,开始是白云石1结晶,接下来形成菱镁矿,最后是以铁菱镁矿沿裂隙的形成而终。根据碳酸盐地质测温原理,M1变质事件的高峰期温度为460~490℃,变质矿物组合特征也支持这一测温结果。滑石,白云石2,与镁绿泥石2沿着镁碳酸盐岩石裂隙的发育,主要受到M2变质事件的影响,这个变质事件与较年青的Alpine造山事件有关。 菱镁矿流体包裹体的研究表明,成矿流体具有复杂的组成,可能以MgCl2组分为主,主要来 相似文献
2.
Martin RADVANEC Peter KOD 《岩石学报》2004,20(4):855-876
Kosice矿床是斯洛伐克第二大的菱镁矿床(150Mt),位于Gemeric的东部.其镁质碳酸盐矿体赋存于石炭纪石灰石和含白云石的石灰石中,同时下盘黑色片岩中也含有被铁质碳酸盐交代的薄层碳酸盐透镜体.在华力西期造山运动(M1)中,古生代岩石受到了低级变质作用(绿泥石带).镁交代作用始于白云岩1的结晶作用,其后形成菱镁矿,最终沿裂隙形成铁菱镁矿.铁质碳酸盐包括早期铁白云石-白云石,铁白云石和后期含方解石和石英的菱铁矿.根据碳酸盐矿物对地质温度计,白云石l结晶作用发生在300～340℃.这一结果与M1的变质矿物组合(绿泥石,白云母-伊利石)吻合.铁白云石的结晶作用发生在320～370℃.少量细脉中可见白云石2,绿泥石和伊利石-多硅白云母,它们是由于阿尔卑斯期造山运动M2变质作用形成的更晚的矿物组合.菱镁矿的流体包裹体(FI)研究,显示存在不同成分的热卤水,卤水成分变化相当于NaCl含量21～42
wt%,但其它成分的盐含量高于NaCl,溶解的CO2含量也有变化.两相包裹体均一温度(Th)的范围为164～217℃,含石盐子晶包裹体均一温度的范围为217～344℃.富CO2包裹体(盐度相当于NaCl含量1～22wt%,CO2的密度为0.28～0.77
g·cm-3,均一温度为289～344℃)在菱镁矿中是次要的,但这种包裹体在与矿石伴生的石英中是主要的,并且与含石盐子晶流体包裹体共生.在后期镁交代过程中流体中的CO2逐渐增加.和铁质碳酸盐伴生的石英中只有两相包裹体,包裹体中CO2含量有所变化,盐度范围为17～24
wt%的NaCl(或者34～36 wt%的MgCl2),均一温度为152～195℃.包裹体的数据结合碳酸盐地质温度计显示镁交代作用的压力范围是180～320MPa(7～12km),铁交代作用的压力范围是280～420MPa(10～16km),说明地热梯度约为25～35℃/km.包裹体浸出液的分析表明Cl/Br和Na/Br的比值存在变化,但仍旧说明富镁的卤水来源是上二叠纪和下三叠纪的分馏蒸发岩来源.铁质碳酸盐流体的高溴和高碘含量,说明在铁交代过程中周围黑色片岩的明显影响.菱镁矿和铁交代作用,表明交代流体中的碳和二氧化碳,主要是海洋沉积的来源.菱铁矿的"Sr/86Sr比值((0.71124～0.71140),说明锶的多来源,最初应是石炭纪和二叠纪的海水,但它被当地其它陆壳中的锶混染. 相似文献
3.
Kosice矿床是斯洛伐克第二大的菱镁矿床(150Mt),位于Gemeric的东部。其镁质碳酸盐矿体赋存于石炭纪石灰石和含白云石的石灰石中,同时下盘黑色片岩中也含有被铁质碳酸盐交代的薄层碳酸盐透镜体。在华力西期造山运动(M1)中,古生代岩石受到了低级变质作用(绿泥石带)。镁交代作用始于白云岩1的结晶作用,其后形成菱镁矿,最终沿裂隙形成铁菱镁矿。铁质碳酸盐包括早期铁白云石-白云石,铁白云石和后期含方解石和石英的菱铁矿。根据碳酸盐矿物对地质温度计,白云石1结晶作用发生在300~340℃。这一结果与M1的变质矿物组合(绿泥石,白云母-伊利石)吻合。铁白云石的结晶作用发生在320~370℃.少量细脉中可见白云石2,绿泥石和伊利石-多硅白云母,它们是由于阿尔卑斯期造山运动M2变质作用形成的更晚的矿物组合。 菱镁矿的流体包裹体(FI)研究,显示存在不同成分的热卤水,卤水成分变化相当于NaCl含量21~42wt％,但其它成分的盐含量高于NaCl,溶解的CO2含量也有变化。两相包裹体均一温度(Th)的范围为164~217℃,含石盐子晶包裹体均一温度的范围为217~344℃。富CO2包裹体(盐度相当于NaCl含量1-22wt％,CO2的密度为0.28~0.77 g·cm-3,均一温度为289~344℃)在菱镁矿中是次要的,但这种包裹体在与矿石伴生的石英中是主要的,并且与含石盐 相似文献
4.
本文总结并报导了斯洛伐克西喀尔巴阡山脉内侧的石炭纪岩石中产出的菱镁矿和滑石成因的最新资料.这些矿床赋存于Veporicum构造超单元中和该超单元与Gemericum的接触带中.北部Sinec成矿带是主要的菱镁矿和滑石矿化区,产出的主要矿床有Kokava,Sinec,Samo,Hnsta-Mutnik等矿床.而南部的Ochtina成矿带只产有菱镁矿床,主要矿床包括在Dubrava地体上的Dubrava,Mikov?JedL'vec;Luben韐,Ochtina,Kosice-Bankov,Banisko,Medvedia等矿床.菱镁矿形成于变质M1期石炭系中方解石被白云石和菱镁矿连续交代过程(北矿带成矿温度为280～400℃,南矿带成矿温度为370～420℃;Radvanec＆Prochska,2001;Kodera＆Radvanec,2002).Permoscythian蒸发卤水提供了Mg.成矿事件和华力西期碰撞后运动有关.拉伸构造和高热流值促使成矿热液系统的产生.滑石矿化则形成于稍晚的不同期变质事件(M2),成矿流体来源也与菱镁矿化不同.构造的、微构造的、变质的以及地质年代学的数据将滑石成矿作用和阿尔卑斯上白垩系的构造地热事件AD2联系在一起.AD2事件是阿尔卑斯碰撞(AD1)地壳加厚和变质核杂岩体起源的结果,体现在地壳不整合面上的区域拉伸,及开放系统中大规模热液流动.这一过程在更靠近Veporic热穹的北带区域(Sinec剪切带)很显著,而向着Veporic热穹的周围部分(南Ochtina带),M2变质过程和块滑石化则逐渐减弱.Sinec剪切带是北Sinec带中突出的AD2-AD3结构,白云石/菱镁矿透镜体(在M1期交代造成的)和相伴随的岩石夹杂在AD1中更坚硬的基底岩石之中.本研究证明了AD2中块滑石化的普遍性,滑石和白云石2形成于拉伸显微构造中(变质过程M2;温度为490～540℃,压力为240～330MPa).在Sinec带中AD3阶段的对偶剪切作用形成了该带中的滑石矿.它是AD2事件从去顶到区域扭压剪切的动力学转变过程的逐步延续.北Sinec带使AD3变形处于由坚硬岩石包围的软岩石的狭窄的剪切带中,而在南Ochtina带中AD3变形产生在由里面漂浮着坚硬碳酸盐块的软的岩石柱中.在Ochtina带中,在AD2和AD3阶段由于M2期较低的P-T条件和变形梯度导致了该区有经济价值的滑石矿化不发育.总之,现有的研究结果能用作阿尔卑斯型地体中菱镁矿和滑石找矿的基本标志. 相似文献
5.
VPRASANNAKUMAR MTKRUPENIN TYGULYAEVA VGPETRISCHEVA 《岩石学报》2004,20(4):821-828
印度南部和乌拉尔南部都有隐晶质菱镁矿产出，这两处矿床的产出地质环境相似，在矿物学和地球化学上具有广泛的相似性。印度南部的菱镁矿矿化主要与超镁铁质侵入杂岩体有关，并形成了部分已受变质的火山沉积地层。超镁铁质侵入杂岩体由纯橄岩，橄榄岩，辉石岩，辉长岩及它们的变质产物组成。在乌拉尔地区，菱镁矿床位于一个蛇绿岩带上的超镁铁岩地体中。隐晶质菱镁矿就以网脉状产出于超镁铁质岩地体上部的风化带中。印度和乌拉尔两个地区的矿床中的矿物组合都有菱镁矿，石英，方解石和白云石，但在印度南部的矿区中还含有滑石和菱铁矿。两个地区的菱镁矿矿石的质量都很好，所有的样品的主要成分都为菱镁矿(73～96％)，而方解石(1～3％)，白云石(0～7％)，菱铁矿(0～2％)，石英(0～5％)和滑石(O～2％)都只是次要矿物。次生的白云石和菱铁矿使一些矿石含有较高的CaO(最高达2．6％)和FeO(最高达1．6％)，石英和滑石等矿物则使矿石中的SiO2较高(5—8％)。滑石指示了低温成因，它的出现说明两个矿区的菱镁矿可能都是内生或外生的成矿流体在上升或下降的过程中在开放裂隙中沉淀而成的。本文研究表明，全球性的超镁铁岩中菱镁矿成矿事件与蛇绿岩带有关，这对菱镁矿的勘探有指导意义。 相似文献
6.
陕西大西沟喷流沉积型菱铁矿矿床地质特征及矿床成因 总被引：1，自引：0，他引：1
陕西大西沟铁矿床位于秦岭造山带山-柞盆地西北部,与银洞子大型银铅矿床毗邻。矿体主要赋存在泥盆系青石垭组中上段,容矿岩石为一套海相复理石碎屑岩和碳酸盐岩建造。矿床的金属矿物主要有菱铁矿、磁铁矿、黄铁矿,其次为黄铜矿、磁黄铁矿等;非金属矿物主要是重晶石、石英、铁白云石,其次为方解石、绢云母、绿泥石、黑云母、斜长石、钠长石、堇青石等,局部地段由于表生氧化和次生富集作用而形成针铁矿、赤铁矿、蓝辉铜矿等。与矿化有关的围岩蚀变较弱,主要有硅化、绢云母化、绿泥石化和碳酸盐化。基于野外地质观察、矿物共生组合和矿石结构构造的系统研究,将大西沟铁矿床的形成划分为3期6阶段,分别是:①喷流沉积期:硅质岩-黄铁矿-菱铁矿阶段(Ⅰ)、重晶石-磁铁矿阶段(Ⅱ);②热液改造期:堇青石-黄铁矿-磁铁矿阶段(Ⅲ)、石英-碳酸盐阶段(Ⅳ)、碳酸盐-硫化物-磁铁矿阶段(Ⅴ);③表生氧化期(Ⅵ)。流体包裹体显微测温结果表明,喷流沉积期Ⅰ阶段菱铁矿完全均一温度和盐度w(NaCl_(eq))峰值区间分别为230～270℃和13%～14.5%,Ⅱ阶段重晶石中流体包裹体的完全均一温度和盐度w(NaCl_(eq))峰值区间分别为220～290℃和9%～13%;热液改造期Ⅳ阶段菱铁矿和石英中气液两相包裹体均一温度峰值区间为240～300℃,盐度w(NaCl_(eq))为2.6%～15.7%;热液改造期Ⅴ阶段菱铁矿与石英中流体包裹体,除大量气液两相包裹体外,还发育有含子矿物多相包裹体,其中,气液两相包裹体均一温度峰值区间为290～340℃,盐度w(NaCl_(eq))为5.1%～13.4%,含子矿物多相包裹体均一温度峰值区间为380～440℃,盐度w(NaCl_(eq))为40.6%～59.7%。含子晶流体包裹体可能是流体不混溶或/和高盐度流体加入的反映。矿区内不同产状碳酸盐矿物的C、O同位素组成比较均一,δ~(13)C_(PDB)值集中在-3.58‰～-1.15‰之间,δ~(18)O_(SMOW)值为21.22‰～21.82‰,均表现出海相碳酸盐或海底喷流热液溶解海相碳酸盐的特征。大西沟矿床的地质、矿化和流体特征与海底热液喷流沉积型矿床一致,可能属于典型的喷流沉积型菱铁矿床,但后期受到秦岭造山作用的影响及热液叠加改造并形成磁铁矿和少量硫化物。大西沟菱铁矿矿床与邻近的银洞子铅锌矿组成一个较完整的喷流沉积成矿系统,两者可能分别代表了喷流沉积的边缘相和中心相。 相似文献
7.
双河金矿床位于华北克拉通南缘的卢氏金多金属矿集区,为一石英脉型金矿;矿体呈脉状产于中元古代宽坪群石英二云母片岩切层断裂中;金主要产在黄铁矿和多金属硫化物石英/铁白云石脉中。以含金石英矿脉为中心由内到外围岩蚀变主要发育硅化、黄铁矿化及碳酸盐化。流体成矿过程包括早、中、晚3个阶段,分别以无矿白石英、石英-黄铁矿-多金属硫化物-铁白云石组合和石英-方解石组合为标志,矿石矿物主要沉淀于中阶段。双河金矿流体包裹体类型丰富,不同成矿阶段的流体包裹体主要有H_2O-CO_2包裹体、H_2O包裹体、含子晶(NaCl、CaCO_3)包裹体和含C单质包裹体。显微测温学研究表明,成矿早阶段乳白色石英中包裹体类型有H_2O-CO_2包裹体和H_2O包裹体,H_2O-CO_2包裹体均一温度为220～350℃,盐度为3. 89%～16. 55%NaCleqv; H_2O包裹体均一温度介于220～285℃之间,盐度为1. 40%～1. 70%NaCleqv。成矿主阶段烟灰色石英中包裹体类型包括H_2O-CO_2包裹体、H_2O包裹体、含NaCl子晶包裹体和含C单质包裹体,其中H_2O-CO_2包裹体均一温度为189～345℃,盐度为3. 33%～20. 23%NaCleqv; H_2O包裹体的均一温度介于180～348℃之间,盐度为0. 88%～14. 97%NaCleqv;含NaCl子晶包裹体均一温度为210～359℃,盐度为30. 92%～42. 50%NaCleqv。氢氧同位素研究表明成矿流体来自岩浆水与变质水(δ~(18)O_水=5. 3‰～8. 6‰,δD=-72. 6‰～-38. 4‰);热液碳酸盐的δ~(13)C_(V-PDB)值为-7. 5‰～-5. 2‰,δ~(18)O_(V-SMOW)值为14. 7‰～17. 0‰。包裹体及C-H-O同位素的研究表明,流体的沸腾及水岩反应可能是双河金矿金沉淀的主要原因。 相似文献
8.
豫陕小秦岭脉状金矿床三期流体运移成矿作用 总被引：30，自引：27，他引：30
位于豫陕交界处的小秦岭脉状金矿是我国第二大黄金产出集中地。流体包裹体研究表明，脉状金矿床石英及碳酸盐矿物中流体包裹体主要有富CO2包裹体、CO2-H2O包裹体和H2O溶液包裹体等三种类型，各热液阶段形成的脉体内有不同的流体包裹体组合。脉状金矿体的形成经历了三期流体成矿作用，第一期形成乳白色石英大脉，它构成了矿脉的主体，流体的性质为富H2O热液，但无金的成矿；第二期(成矿期)流体为中低盐度CO2-H2O-NaCl热液，它叠加在了石英大脉之上，形成(块状)黄铁矿-浅色石英矿体和(网脉状)多金属硫化物-烟灰色石英矿体，成矿期内热液的温度、压力及流体组成的变化是金沉淀成矿的原因；第三期热液又转成低盐度的富水流体，形成石英-碳酸盐脉体，金矿化微弱。 相似文献
9.
苏北青龙山超高压变质榴辉岩流体包裹体特征与流体演化 总被引：3，自引：7，他引：3
根据青龙山超高压变质榴辉岩中流体包裹体的化学成分、矿物中的分布特征将岩石中的流体包裹体分为五类,即富N2包裹体、高盐度(22.4-略大于23.2wt%NaCl)的NaCl CaCl2 H2O体系流体包裹体、中高盐度(12.6-16.0wt%NaCl)的含Mg2 或Fe2 的NaCl H2O体系流体包裹体、中等盐度(6.4-10.5wt%NaCl)水溶液包裹体和低盐度(3.3-0.2wt%NaCl)的水溶液包裹体。富N2包裹体形成于超高压变质峰期阶段,高盐度的流体包裹体形成于超高压变质岩折返早期固体出溶体出溶阶段,中高盐度的流体包裹体形成于高压变质重结晶作用阶段,中等盐度的流体包裹体形成于角闪岩相变质重结晶作用阶段,低盐度的流体包裹体形成于折返晚期的绿片岩退变质作用阶段。超高压变质峰期阶段和折返早期的高盐度流体和中高盐度的流体主要来自继承原岩中的流体(如含NH4 矿物分解或片麻岩原岩中的有机质分解,名义上无水矿物中羧基水的出溶),晚期角闪岩相退变质阶段的中等盐度的流体除名义上无水矿物中羟基水的出溶外还有外来流体的加入,绿片岩相退变质作用阶段的流体主要为外来流体。 相似文献
10.
对南秧田层状矽卡岩型白钨矿石中石榴石及电气石石英脉型白钨矿石中石英流体包裹体岩相学特征研究表明,与成矿有关的包裹体主要有富液相、富气相和含子晶的流体包裹体3种类型.矽卡岩型矿石中石榴石及共生石英的包裹体均一温度为128～250℃,盐度w(NaCl) =0.7％ ～8.1％;电气石石英脉型白钨矿石中石英的流体包裹体均一温度范围为181～ 325℃,盐度w(NaCl)=1.57％ ～ 15.76％.两种类型矿石成矿溶液密度为0.75～0.95g/cm3,表明形成这两种类型矿石的成矿流体均属于中温、中-低盐度、低密度的流体.氢氧同位素结果显示其主要来源于地层水(变质水),后期受到了岩浆水的叠加改造作用.硫同位素落入沉积岩、变质岩及蒸发硫酸盐的硫同位素组成范围内. 相似文献
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S. Viswanathan K. Surya Prakash Rao B. Mahabaleswar 《Journal of the Geological Society of India》2013,82(6):621-627
Komatiites are mantle-derived ultramafic volcanic rocks. Komatiites have been discovered in several States of India, notably in Karnataka. Studies on the distribution of trace-elements in the komatiites of India are very few. This paper proposes a simple, accurate, precise, rapid, and non-destructive wavelength-dispersive x-ray fluorescence (WDXRF) spectrometric technique for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites, and discusses the accuracy, precision, limits of detection, x-ray spectral-line interferences, inter-element effects, speed, advantages, and limitations of the technique. The accuracy of the technique is excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Zr, Nb, Ba, Pb, and Th and very good (within 4%) for Y. The precision is also excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th. The limits of detection are: 1 ppm for Sc and V; 2 ppm for Cr, Co, and Ni; 3 ppm for Cu, Zn, Rb, and Sr; 4 ppm for Y and Zr; 6 ppm for Nb; 10 ppm for Ba; 13 ppm for Pb; and 14 ppm for Th. The time taken for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in a batch of 24 samples of komatiites, for a replication of four analyses per sample, by one operator, using a manual WDXRF spectrometer, is only 60 hours. 相似文献
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奥地利安东帕有限公司 《岩矿测试》2009,28(3):306-306
最新的流行病学研究表明,空气中较高浓度的悬浮细颗粒可能对人类的健康有不利的影响。根据该项研究显示,由于心脏病、慢性呼吸问题和肺功能指标恶化而导致死亡率的升高与细尘粒子有关。这些研究结果已经促使欧盟于1999年4月出台了限制空气中二氧化硫、二氧化氮、氧化氮、铅和颗粒物含量的法案(1999/30/EC),对各项指标包括对可吸入PM10颗粒的浓度提出了新的限制性指标。PM10颗粒是指可以通过预分级器分离采集的气体动力学直径小于10μm的细颗粒。目前研究的兴趣重点逐步偏向PM2.5这些更细微颗粒物,PM2.5这种颗粒物对健康有明显的不利影响。在欧盟指令2008/50/EC中,对PM10和PM2.5都提 相似文献
13.
E. M. Prasolov S. A. Sergeev B. V. Belyatsky E. S. Bogomolov K. A. Gruzdov I. N. Kapitonov R. Sh. Krymsky V. O. Khalenev 《Geochemistry International》2018,56(1):46-64
This paper reports the first results of a study of 11 isotope systems (3He/4He, 40Ar/36Ar, 34S/32S, 65Cu/63Cu, 62Ni/60Ni, 87Sr/86Sr, 143Nd/144Nd, 206–208Pb/204Pb, Hf–Nd, U–Pb, and Re–Os) in the rocks and ores of the Cu–Ni–PGE deposits of the Norilsk ore district. Almost all the results were obtained at the Center of Isotopic Research of the Karpinskii All-Russia Research Institute of Geology. The use of a number of independent genetic isotopic signatures and comprehensive isotopic knowledge provided a methodic basis for the interpretation of approximately 5000 isotopic analyses of various elements. The presence of materials from two sources, crust and mantle, was detected in the composition of the rocks and ores. The contribution of the crustal source is especially significant in the paleofluids (gas–liquid microinclusions) of the ore-forming medium. Crustal solutions were probably a transport medium during ore formation. Air argon is dominant in the ores, which indicates a connection between the paleofluids and the atmosphere. This suggests intense groundwater circulation during the crystallization of ore minerals. The age of the rocks and ores of the Norilsk deposits was determined. The stage of orebody formation is restricted to a narrow age interval of 250 ± 10 Ma. An isotopic criterion was proposed for the ore-bearing potential of mafic intrusions in the Norilsk–Taimyr region. It includes several interrelated isotopic ratios of various elements: He, Ar, S, and others. 相似文献
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Mining induced subsidence can significantly affect mining costs where major surface facilities and natural environment need to be protected. Overburden grout injection is a technology used to control coal mine subsidence by injecting the mine waste material extracted from the coal back into the inter-burden rock during longwall mining. The flowing slurry is here categorised as a nonlinear viscous cohesive (Bingham plastic) fluid. During longwall mining the grout slurry is pumped into the separated beds of the rock mass through a central vertical borehole, which is drilled deep into the inter-burden rock strata above the coal seam. However, a blockage can occur in the injection system when the slurry velocity falls below a certain critical threshold velocity, indicating a material phase change from cohesive-viscous to cohesive-frictional. In situ field injection tests through boreholes have been simulated at a smaller scale at the CSIRO laboratory in Brisbane by pumping the slurry through a radial disk (gap = 4 mm) from its centre. Laboratory experiments indicate a general, nonlinear, cohesive, viscous, frictional model for shear behaviour of the slurry, in which the material shear parameters are functions of the disk radial distance. Complete dimensional and dimensionless analytical solutions have been developed based on an approach related to Bingham–Herschel–Bulkley fluid mechanics. The derived formulae include relations for minimum pump pressure, local pressure and pressure gradient, wall shear stress, volume rate, velocity and velocity gradient. The theoretical results match the experimental measurements. The experiments covered slurries with maximum particle sizes of 0.5 to 2 mm with about 50% being larger than 100 µm. The viscosities at the various solids concentrations were measured with a standard torsion viscometer. This study differs from the previous research in several distinct aspects, namely, consideration of the variable shear parameters rather than fixed values, inclusion of total nonlinear behaviour, and implementation of a friction function to mimic behaviour of the deposited and consolidating stiff slurry, which can cause a significant pressure rise as a result of the increased shear resistance. 相似文献
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Between 1985 and 1991, two new mountain protected areas (MTNPA) covering more than 35,000 km2 and based on participatory management models — the Makalu-Barun National Park and Conservation Area, Nepal, and Qomolangma Nature Preserve, Tibet Autonomous Region — were successfully established through the collaborative efforts of Woodlands Mountain Institute and conservationists in China and Nepal. Characteristics common to both projects include the importance of establishing (1) effective rationales, (2) local support constituencies, (3) a senior advisory group, (4) a task force, (5) linkages between conservation and development, and (6) fund raising mechanisms. The lessons derived from the experiences of Woodlands Mountain Institute are of significant value to others in preserving MTNPA. Increased collaboration and communication between all interested in conservation, however, will remain a critical component for expanding mountain protected area coverage to throughout the world. 相似文献
19.
岩石密度和超高压岩石折返速率 总被引：1，自引：3，他引：1
在常温常压条件下对中国大陆科学钻CCSD主孔100-3000米岩心样品进行了密度测量,建立了密度连续剖面,并界定了不同超高压岩石的密度值。通过对比高温高压物性实验资料,岩石密度随着退变程度增强而降低,榴辉岩密度变化序列为3.52g/cm3→3.49g/cm3→3.07g/cm3→2.93g/cm3。超高压长英质岩石密度变化序列为3.00g/cm→2.80g/cm3→2.65g/cm3。上述实验资料是讨论不同折返阶段岩石所受浮力的基础,为研究折返速率大小提供了基本参数。本文通过折返板块运动平衡时,上浮力与粘滞力平衡这一关系式,定量研究了大陆俯冲板块的折返速率,认为密度差产生上浮力从而引起折返,温度对板块折返速率的影响最为显著;密度差大小、折返角度、折返板块大小对折返速率也有直接的影响。定量模拟分析表明,在温度高于850℃时,板块的折返速率可以超过100mm/a;当温度降至700℃时,折返速率则低于1.5mm/a。作者认为在折返早期,温度较高,板块快速折返至60-70km榴辉岩相深度;随着传导散热,温度降低,板块以较慢的速率折返至中下地壳。折返速率的估算表明,浮力是板块折返第一阶段(从>100km深部折返至<40km的中下地壳)的主要驱动力。 相似文献
20.
《Applied Geochemistry》2001,16(2):137-159
Five hundred and ninety-eight samples of terrestrial moss (Hylocomium splendens and Pleurozium schreberi) collected from a 188,000 km2 area of the central Barents region (NE Norway, N Finland, NW Russia) were analysed by ICP-AES and ICP-MS. Analytical results for Al, B, Ba, Ca, K, La, Mg, Mn, Na, P, Rb, Si, Sr, Th, U and Y concentrations are reported here. Graphical methods of data analysis, such as geochemical maps, cumulative frequency diagrams, boxplots and scatterplots, are used to interpret the origin of the patterns for these elements. None of the elements reported here are emitted in significant amounts from the smelting industry on the Kola Peninsula. Despite the conventional view that moss chemistry reflects atmospheric element input, the nature of the underlying mineral substrate (regolith or bedrock) is found to have a considerable influence on moss composition for several elements. This influence of the chemistry of the mineral substrate can take place in a variety of ways. (1) It can be completely natural, reflecting the ability of higher plants to take up elements from deep soil horizons and shed them with litterfall onto the surface. (2) It can result from naturally increased soil dust input where vegetation is scarce due to harsh climatic conditions for instance. Alternatively, substrate influence can be enhanced by human activity, such as open-cast mining, creation of ‘technogenic deserts’, or handling, transport and storage of ore and ore products, all of which magnify the natural elemental flux from bedrock to ground vegetation. Seaspray is another natural process affecting moss composition in the area (Mg, Na), and this is most visible in the Norwegian part of the study area. Presence or absence of some plant species, e.g., lichens, seems to influence moss chemistry. This is shown by the low concentrations of B or K in moss on the Finnish and Norwegian side of the (fenced) border with Russia, contrasting with high concentrations on the other side (intensive reindeer husbandry west of the border has selectively depleted the lichen population). 相似文献