川西北金木达矿床地质地球化学特征研究   总被引：7，自引：2，他引：5  

张晓军  贾永胜等 《地质与勘探》2002,38(3):28-32

金木达金矿床产于川西北地区阿坝把块西南缘,与中基-中酸性岩脉在空间上有密切关系。通过对该矿床的野外地质观察和室内测试研究。确定了该矿床的产出地质背景和矿化特征,划分了成矿期次,并根据同位素和流体包裹体等地球化学特征的研究。初步提出了该矿床矿质具有地层和岩浆岩两种来源的新观点。  相似文献   

Mineralogical controls on porosity and water chemistry during O2-SO2-CO2 reaction of CO2 storage reservoir and cap-rock core     

《Applied Geochemistry》2016

Reservoir and cap-rock core samples with variable lithology's representative of siliciclastic reservoirs used for CO₂ storage have been characterized and reacted at reservoir conditions with an impure CO₂ stream and low salinity brine. Cores from a target CO₂ storage site in Queensland, Australia were tested. Mineralogical controls on the resulting changes to porosity and water chemistry have been identified. The tested siliciclastic reservoir core samples can be grouped generally into three responses to impure CO₂-brine reaction, dependent on mineralogy. The mineralogically clean quartzose reservoir cores had high porosities, with negligible change after reaction, in resolvable porosity or mineralogy, calculated using X-ray micro computed tomography and QEMSCAN. However, strong brine acidification and a high concentration of dissolved sulphate were generated in experiments owing to minimal mineral buffering. Also, the movement of kaolin has the potential to block pore throats and reduce permeability. The reaction of the impure CO₂-brine with calcite-cemented cap-rock core samples caused the largest porosity changes after reaction through calcite dissolution; to the extent that one sample developed a connection of open pores that extended into the core sub-plug. This has the potential to both favor injectivity but also affect CO₂ migration. The dissolution of calcite caused the buffering of acidity resulting in no significant observable silicate dissolution. Clay-rich cap-rock core samples with minor amounts of carbonate minerals had only small changes after reaction. Created porosity appeared mainly disconnected. Changes were instead associated with decreases in density from Fe-leaching of chlorite or dissolution of minor amounts of carbonates and plagioclase. The interbedded sandstone and shale core also developed increased porosity parallel to bedding through dissolution of carbonates and reactive silicates in the sandy layers. Tight interbedded cap-rocks could be expected to act as baffles to fluids preventing vertical fluid migration. Concentrations of dissolved elements including Ca, Fe, Mn, and Ni increased during reactions of several core samples, with Mn, Mg, Co, and Zn correlated with Ca from cap-rock cores. Precipitation of gypsum, Fe-oxides and clays on seal core samples sequestered dissolved elements including Fe through co-precipitation or adsorption. A conceptual model of impure CO₂-water-rock interactions for a siliciclastic reservoir is discussed.  相似文献   

基于黏弹滑移界面理论揭示套管中模式波的传播特征          下载免费PDF全文

陈雪莲  唐晓明  李盛清  李疾翎  江灿  刘临政 《地球物理学报》1954,63(9):3562-3571

目前固井质量评价主要是利用套管中模式波的幅度或衰减变化判断套管与水泥间的胶结状况.在超声测量频段（70~500 kHz）,现有声波测井仪器工作时在套管中激发的模式波类似薄板中的对称兰姆波（拉伸波）或反对称兰姆波（弯曲型兰姆波）.本文将黏弹滑移界面理论应用到套管和水泥的耦合界面,探讨了套管中的准兰姆波（包括拉伸波和弯曲型兰姆波）与套管后物质的耦合方式,拉伸波与套后物质主要以剪切刚度耦合,即便是0.01 mm的微环也会使得拉伸波的衰减明显降低,接近套后是流体时的响应特征;而弯曲型兰姆波与套管后物质主要以法向刚度耦合,这使得在套后胶结轻质水泥时弯曲型兰姆波对微环不敏感,在套后耦合常规水泥时微环的存在又会使得弯曲型兰姆波的衰减明显增强,衰减的增加说明其与套后物质的声耦合更紧密,也表明微环与常规水泥的等效声阻抗适当降低,更有利于弯曲型兰姆波传播时与套后介质实现法向刚度的匹配.拉伸波和弯曲型兰姆波对同一胶结状况的不同响应特征也为固井质量综合评价时区分不同的水泥胶结状况提供了可能.  相似文献   

Synthesis of Non‐Toxic Triethyl Citrate Plasticizer by Esterification of Renewable Citric Acid Using Modified Zeolite          下载免费PDF全文

Kakasaheb Y. Nandiwale  Sanjay P. Borikar  Vijay V. Bokade 《洁净——土壤、空气、水》2015,43(6):927-931

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A look with μCT technology into a treasure trove of fossils: The first two fossils of the millipede order Siphoniulida discovered in Cretaceous Burmese amber (Myriapoda,Diplopoda)     

《Cretaceous Research》2017

Millipedes (Diplopoda) are an important fossil group of land arthropods in the Palaeozoic. However, there is a gap in the Mesozoic, with only slightly more than a dozen fossils being known, until the much more recent fossil records mainly from Cenozoic Dominican and Baltic ambers become available. Burmese amber, precisely dated to the Late Cretaceous, is known for an apparently rich but still undescribed millipede fauna, and might represent the ideal bridge to close this gap in the millipede fossil record. In addition, modern micro-computed tomography (μCT) technology allows complex 3D reconstructions of objects fossilized in amber. Here we utilize μCT technology to describe the first millipedes from Burmese amber, which are also the first two fossil representatives of the order Siphoniulida. Siphoniulida, with two known species and just nine recorded specimens, are the rarest and least known of the 16 extant orders of the Diplopoda. Records are known from Sumatra, Guatemala and Mexico. The two new fossils described here represent two distinct species, Siphoniulus muelleri sp. nov. and S. preciosus sp. nov., and indicate a wider distribution of this order in the Cretaceous. The holotype of S. muelleri sp. nov. was well-enough preserved so that characters of the head, such as the incisura lateralis, not investigated before in extant representatives of the order, could be studied. This study highlights the possibilities and challenges provided by μCT technology in investigating Diplopoda fossilized in amber.  相似文献   

微破裂弹性回跳模型和一次地震的三种波     

赵复垣  张国栋  王泽之 《华南地震》2009,29(4):64-71

经典弹性回跳模型是历史上最有影响的地震模型之一．热力学弹性回跳模型对经典弹性回跳模型进行了合理的补充。根据存在着震前超低频应力一密度波和临震微破裂波的设想．进一步补充了热力学弹性回跳模型．新模型或可称为“微破裂弹性回跳模型”。这个模型与很多实测结果符合得很好。因为大多数地震都要经历应变累积、微破裂和主破裂三个阶段．所以,一次地震一般都会先后出现三种不同类型的波,即：超低频应力一密度波（应变波）、微破裂波以及普通地震波。这一认识对深入理解地震现象以及对地震的监测和预警都是有意义的．  相似文献   

华东地区地震活动加速指数AI算法应用探讨     

郑建常  冀东普  王鹏  王峰吉  赵金花 《地震》2010,30(3):129-139

应用改进的地震活动加速指数AI算法对华东地区1970年以来M_S≥5.0地震进行了回顾性统计检验。结果表明, AI指数能够量化地给出中强地震前小震活动的相对增强或减弱变化程度; 在小震目录较为完整的情况下, 中强地震震中区及其附近地区震前1年的小震活动与之前三年的活动背景相比, 会出现较明显的“加速”或“减速”现象。  相似文献   

黄土孔隙微结构的计算机图像处理分析方法   总被引：2，自引：0，他引：2  

刘红玫 《高原地震》1999,(3)

通过对液化前后黄土中各类孔隙含量的定量测试及数理分析,主要介绍了黄土孔隙微结构的计算机图像处理方法,并对得到的液化前后黄土中各类孔隙含量的变化情况与液化试验结果进行了分析。  相似文献   

坑(井)-地多参数电磁接收系统          下载免费PDF全文

陈凯  金胜  魏文博  邓明  叶高峰 《地球物理学报》2019,62(10):3803-3818

坑（井）-地多参数电磁接收系统在地面、坑道、井中三维空间观测天然场源及人工源电磁信号,观测装置接近或穿过矿体,借助动源、大功率发射可获得更加明显的异常值,旨在加大探测深度的基础上提高深部分辨率,同时获取电阻率、极化率、复阻抗等参数.为坑（井）-地电磁成像方法现场数据采集提供硬件设备支持,针对坑道、井中电磁观测的特殊需求,开发了由不极化电极、非接触电极、小型感应式线圈、微型三分量音频磁传感器、地面-坑道电磁接收机、井中电磁接收机等组成的坑（井）-地多参数电磁接收系统,解决了传统不极化电极坑道硬岩表面接地困难和传统感应式磁传感器难以适应坑道狭窄空间的问题;通过多层次的室内、弱干扰条件下野外测试验证了接收系统的各项技术指标,接收机通道全频段噪声水平接近10 nV/rt（Hz）,微型三分量音频磁传感器体积压缩至32 cm×32 cm×32 cm;强干扰条件下的矿山试验验证了接收系统的可靠性、适用性及先进性.  相似文献   

On species distribution modelling,spatial scales and environmental flow assessment with Multi–Layer Perceptron Ensembles: A case study on the redfin barbel (Barbus haasi; Mertens, 1925)     

《Limnologica》2017

Inconsistent performance of Species Distribution Models (SDMs), which may depend on several factors such as the initial conditions or the applied modelling technique, is one of the greatest challenges in ecological modelling. To overcome this problem, ensemble modelling combines the forecasts of several individual models. A commonly applied ensemble modelling technique is the Multi–Layer Perceptron (MLP) Ensemble, which was envisaged in the 1990s. However, despite its potential for ecological modelling, it has received little attention in the development of SDMs for freshwater fish. Although this approach originally included all the developed MLPs, Genetic Algorithms (GA) now allow selection of the optimal subset of MLPs and thus substantial improvement of model performance. In this study, MLP Ensembles were used to develop SDMs for the redfin barbel (Barbus haasi; Mertens, 1925) at two different spatial scales: the micro–scale and the meso–scale. Finally, the potential of the MLP Ensembles for environmental flow (e–flow) assessment was tested by linking model results to hydraulic simulation. MLP Ensembles with a candidate selection based on GA outperformed the optimal single MLP or the ensemble of the whole set of MLPs. The micro–scale model complemented previous studies, showing high suitability of relatively deep areas with coarse substrate and corroborating the need for cover and the rheophilic nature of the redfin barbel. The meso–scale model highlighted the advantages of using cross–scale variables, since elevation (a macro–scale variable) was selected in the optimal model. Although the meso–scale model also demonstrated that redfin barbel selects deep areas, it partially contradicted the micro–scale model because velocity had a clearer positive effect on habitat suitability and redfin barbel showed a preference for fine substrate in the meso–scale model. Although the meso–scale model suggested an overall higher habitat suitability of the test site, this did not result in a notable higher minimum environmental flow. Our results demonstrate that MLP Ensembles are a promising tool in the development of SDMs for freshwater fish species and proficient in e–flow assessment.  相似文献