金是通过什么方式搬运与沉淀的     

B·M·比留阔夫  E·B·比留阔夫 《地质与资源》2000,9(2):94-96

数十年来,金在不同的地质作用过程中的迁移与沉淀机理一直是许多矿床地质学家和地球化学家们争论的焦点。根据最近的地质与地球化学研究,对如下几个问题进行了探讨:(1)什么样的含水络合物最有利于金的迁移与搬运;(2)为什么金富集在脉型矿床中;(3)在什么样的物理-化学条件下,金的含水络合物可以得到充分溶解;(4)为什么绝大多数金矿床的形成范围集中在340℃~400℃.在热液成矿流体中,金可能是以AuHS(H₂S)₃⁰形式进行迁移,温度的降低会使溶液中90%的金沉淀,这能够解释这些含金石英脉为什么形成在一个很窄的温度范围内.  相似文献   

伊犁河流域林业生态建设基地淡灰钙土土壤特征研究   总被引：7，自引：0，他引：7  

艾合买提·那由甫  徐海量  李吉玫  张占江 《干旱区地理》2006,29(6):867-871

在伊犁河流域林业生态建设基地,随机挖土壤剖面11个,依照土壤发生层分层取样,同时观察其颜色、结构、干湿度、松紧度、孔隙大小及植物根系的分布等生态特征,以此来鉴别土壤质地、土壤发育状况,并测定土壤中的盐分和养分。分0~10 cm、10~20 cm、20~30 cm、30~40 cm共4层取样,测定土壤容重,并分别在灌水前及灌水后不同日期测定了土壤含水量。实验结果表明:在伊犁河流域林业生态建设基地淡灰钙土土壤剖面发育微弱;含盐量低;有机质含量平均只有0.80%,全N、全P含量较少,全K含量较高,速效N、速效P含量较低,速效K含量较高;0~10 cm和10~20 cm的土壤容重分别为1.35~1.62 g/cm3和1.36~1.50 g/cm3之间。灌水后土壤含水量普遍都有所提高,其中0~10 cm土层土壤含水量比灌水前增加了59.31%,10~20 cm、20~30cm和30~40 cm土层的土壤含水量分别比灌水前增加了37.74%、27.29%和6.36%。  相似文献   

基于GRACE卫星和GLDAS系统的地下水水位估算模型——以和田地区克里雅河流域为例     

孙倩  阿丽亚·拜都热拉 《地理科学进展》2018,37(7):912-922

地球重力场的变化是导致陆地水储量变化的重要因素之一,利用GRACE(Gravity Recovery and Climate Experiment)重力场恢复与气候实验重力卫星数据,结合GLDAS(Global Land Data Assimilation Systems)全球陆面数据同化系统和实测地下水位数据,反演和田地区克里雅河流域11年间四季和田地区的陆地水储量动态变化,模拟计算地下水等效水高变化趋势,构建了地下水水位估算模型。研究结果表明：和田地区春、夏两季的陆地水储量呈现出增加趋势,而秋、冬两季出现亏损状态;GRACE地球重力卫星所反演的陆地水储量比GLDAS同化系统所模拟的水资源变化更为剧烈,但2类数据的动态变化拟合度很高;GLDAS水资源等效水高二阶微分、GLDAS水资源变化倒数一阶微分、GRACE陆地水储量变化倒数变化、地下水储量变化一阶微分的敏感程度最高,构建的多元逐步回归模型明显优于线性函数,且水位深度越浅,该估算模型的适用性越高。  相似文献   

Soil gas radon–thoron monitoring in Dharamsala area of north-west Himalayas, India using solid state nuclear track detectors     

GULSHAN KUMAR  ARVIND KUMAR  VIVEK WALIA  JITENDER KUMAR  VIKASH GUPTA  TSANYAO FRANK YANG  SURINDER SINGH  BIKRAMJIT SINGH BAJWA 《Journal of Earth System Science》2013,122(5):1295-1301

  相似文献   

Development of a technique to decompose heterogeneous mapping units in a categorical map of the biotic environment using correlated categorical data     

WILLIAM DE GENST  FRANK CANTERS  WOLFGANG JACQUET  SOPHIE VERMEERSCH 《International journal of geographical information science》2013,27(6):591-614

In this article a technique is presented to estimate the proportions of different map categories in a series of heterogeneous mapping units, using information on the degree of spatial correlation with other categorical data. The technique has been applied to decompose ecotope complexes in a categorical map of the biotic environment in Flanders, using secondary information on land cover and soil type. Because the conditional probability of an ecotope occurring given a certain soil type depends on the frequency with which the ecotope occurs in an area, determining the probability of occurrence of an ecotope from the conditional probabilities can lead to predictions that contradict prior knowledge about the composition of the different mapping units. A measure expressing the affinity of an ecotope for a soil type is proposed and is used as an alternative to conditional probability in the estimation procedure. The proposed method has been tested in a study area for which detailed field observations were collected, and proves to work well if reliable a priori knowledge about the composition of complex mapping units is available.  相似文献   

Environmental dynamics and luminescence chronology from the Orlovat loess–palaeosol sequence (Vojvodina,northern Serbia)          下载免费PDF全文

SLOBODAN B. MARKOVIĆ  ALIDA TIMAR‐GABOR  THOMAS STEVENS  ULRICH HAMBACH  DRAGAN POPOV  NEMANJA TOMIĆ  MLADJEN JOVANOVIĆ  FRANK LEHMKUHL  HOLGER KELS  RASTKO MARKOVIĆ  MILIVOJ B. GAVRILOV 《第四纪科学杂志》2014,29(2):189-199

  相似文献   

Aragonite loss in a cold‐water coral mound: mechanisms and implications     

TRACY D FRANK  JÜRGEN TITSCHACK  MIEKE THIERENS 《Sedimentology》2011,58(3):670-690

Selective dissolution of aragonitic grains is emerging as a volumetrically significant process that affects a broad range of modern carbonate settings. This study explores mechanisms and implications of aragonite loss in Challenger Mound, a giant cold‐water coral (Lophelia pertusa) mound of Pleistocene age, which lies on the continental slope off south‐west Ireland. A comprehensive sampling scheme allowed the integration of petrographic data with geochemical analyses of sediment and pore water. The mound remains virtually unlithified and consists of stacked, fining‐upward cycles of silty coral floatstone–rudstone and bafflestone grading into wackestone. Whereas calcitic grains appear unaltered, aragonitic grains are corroded and fragmented. Aragonite dissolution is attributed to organic matter oxidation at/near the sediment–water interface and, at greater depths, to the initial stages of bacterially mediated sulphate reduction, when alkalinity production is outpaced by the generation of H⁺. Pore water profiles indicate that undersaturated waters are diffusing towards the mound interior from two centres of sulphate reduction: one located in the upper 10 m of the sediment column and a second that lies below an erosional unconformity which marks the base of the mound. Continued aragonite dissolution is expected to gradually lower the diagenetic potential of the Challenger Mound and delay lithification until deep burial, when solution‐compaction processes come into play. Despite a fundamental role in predestining the final taphonomic and textural characteristics of Challenger Mound, the processes described here are expected to leave little trace in the geological record due to a lack of cementation and calcitization. Assuming that similar processes have been active throughout the Phanerozoic, results imply that the understanding of diagenetic processes in carbonate systems may be incomplete.  相似文献   

克孜尔水库跨断层形变变化速率的非均匀性特征分析     

祖丽菲亚·尼亚孜  买买提·伊布拉音  王爱倩  陶茂松  翟世龙  古丽娜·吐尔逊  阿依古丽·沙吾提  常金霞 《内陆地震》2011,25(2):152-157

对克孜尔水库跨断层垂直形变近40年的资料和水平形变近32年的资料进行了分析。研究发现,①跨断层形变的变化速率具有明显的不均匀性,根据数据序列走势,变化速率的不同可分为6个阶段;②水库施工对跨断层形变有一定的影响,水库蓄水对跨断层形变有显著的影响;③水库蓄水达到正常库容量后的新平衡状态下,跨断层形变速率变化几乎是无干扰背景下变化速率的2倍;④区域应力场的增强对跨断层形变趋势性转折有显著性影响。  相似文献   

哈密晚二叠世双壳类化石发现及地质意义     

玉苏甫.肉孜  张雄华  杨在峰  王君良  文琴 《新疆地质》2011,29(1):43-46

哈密路白山地区黄岗一带原划为大热泉子组中,发现时代属晚二叠世的Palaeanodonta castor,P.fischeri,Palaeomutela urumqiensis,Pneglecta P.verneuili,Oligodon keerjiensis,等淡水双壳类化石,其动物群面貌与乌鲁木齐和吐鲁番上二叠统梧...  相似文献   

散乱点云数据的分割方法探究     

马符讯  那地曼·艾尼瓦尔  林欢 《测绘与空间地理信息》2014,(10):148-151

数据分割是点云数据处理流程中的一项关键技术,本文针对点云数据分割这一问题,分析了基于几何模型的分割法、欧几里德簇分割法和区域生长分割法三种点云数据分割方法的原理和算法流程,并利用实际工程数据检验了三种分割方法的效果。针对以上三种方法的优势及缺陷,本文实现了附条件的欧几里德簇分割法,该算法对欧几里德簇分割法和区域生长分割法进行融合改进,利用同一点云数据对该算法与上述算法进行比较分析,最后用一处复杂建筑物点云数据对该算法的分割效果进行再次检验,分割效果较为明显,再次证实了该算法具有较强的实用性。  相似文献