New data on mineralogy and metallogeny of scarns in the Pitkyaranta ore region

A wide application of modern precision research techniques to the studies of Pitkyaranta ores allowed us to find increased contents of indium (to 0.33%), silver (447 g/t), gold (0.2–0.4 g/t), and palladium (0.2 g/t). A series of rare minerals previously not found here was also discovered. Among ore minerals, these are roquesite, zavartskite, electrum, stutzite, altaite, bismite, glaucodot, cervelleite, hedleyite, pavonite, cannonite, plantnerite, lindkvistite, ashoverite, etc. The discovery of roquesite and electrum is the most important in terms of metallogeny. Roquesite (indium sulfide) is found in Karelia for the first time. The highest indium contents in direct correlation to those of zinc are characteristic for polymetallic ores of the Pitkyaranta ore fields with sphalerite as the concentrating mineral (to 0.5% of In). The predicted zinc resources are evaluated to ∼2.5 million t for the Pitkyaranta group of ore deposits, and to 400 000 t for the Hopunvaara region. Respectively, the resources of indium amount to ∼2400 t (total) and 600 t for the Hopunvaara region.     

Authigenic zeolites in the sedimentary mantle of the world ocean

The paper deals with results of general and systematic analysis of data from deep-sea drilling (360 stations) and a personal study carried out by the authors on the distribution and facies location of authigenic zeolites in the sedimentary mantle of the World Ocean.The scheme of zeolite distribution, compiled for the Holocene—Pleistocene, Miocene, Eocene and Cretaceous periods confirmed the previously established global stratification of zeolites. It showed that the main mass of phillipsite was formed during the Pleistocene—Holocene, while clinoptilolite was a predominant mineral in Eocene and Cretaceous rocks. Both zeolites were wide-spread in the Oligocene and Miocene. Facies location and paragenesis of associated minerals as well as the original material of their formation are different for phillipsite and clinoptilolite.The most probable reasons for vertical stratification of oceanic zeolites of global significance are changes of the character of volcanism in time and general evolution of sedimentation in the World Ocean.     

Geochemical types of Volkhovites and possible diamond resource potential of areas occupied by Holocene fluidisites

Volkhovites—tektite-like glasses—have been detected in the Holocene glacial drift along the right bank of the Volkhov River. A cryptomagmatic model of their formation and pre-Holocene age of volkhovite melts, cinder, and frothed glasses has been suggested (Skublov et al., 2007). Four geochemical types of volkhovites are distinguished: (1) manganous (Mn, Fe, Cr, V, Si, Nb, Pb, H), (2) magnesian (Mg, Al, Ti, F, B), (3) potassic (K, Rb, Cs), and (4) calcic (Ca, REEs, Ba, U, Th, Ta, Hf, Y, Sc, Cl). In light of the geochemical data, volkhovites are regarded as natural silicate glasses of kimberlite-carbonatite composition. Their types are called kimberlitic (Mn type), kimberlitic-carbonatitic (Mg type), lamproitic-carbonatitic (K type), and carbonatitic (Ca type). Volkhovites are suggested to be indicators of undiscovered diamond mineralization of kimberlite or carbonatite (Chagatai) types.     

Fluid inclusion studies of the Abawso gold prospect,near the Ashanti Belt,Ghana

The major Ghanaian lode gold deposits are preferentially aligned along the western and eastern contacts of the Kumasi Basin with the Ashanti and Sefwi Belts, respectively. The investigated area of the Abawso small-scale concession, covering the workings of the old Ettadom mine, is situated 3 km west of the lithological contact of the Birimian metavolcanic rocks of the Akropong Belt in the east with the Birimian metasedimentary rocks of the Kumasi Basin in the west. The rocks of the Abawso concession represent a steeply NW-dipping limb of a SE-verging anticline with an axis plunging to the SW. Quartz veining occurs predominantly in the form of en échelon dilatational veins along NNE–SSW-striking shear zones of a few metres width and shows evidence of brittle and ductile deformation. Also stockwork-style quartz veining occurs in the vicinity of the main shaft of the old Ettadom mine. Hydrothermal alteration includes sericitisation, sulphidation and locally carbonatisation. The auriferous quartz veins mainly follow the trend of brittle to ductile deformed quartz veins; however, some occur in stockwork. Fluid inclusion studies reveal a large number of H₂O inclusions along intragranular trails in auriferous quartz vein samples, as well as an overall dominance of H₂O and H₂O-CO₂ inclusions over CO₂ inclusions. Textural observations and physico-chemical fluid inclusion properties indicate post-entrapment modifications for all quartz vein samples due to grain boundary migration recrystallisation. This process is interpreted to be responsible for the generation of the CO₂ inclusions from a H₂O-CO₂ parent fluid. In comparison with mineralisation at the Ashanti and Prestea deposits, which are characterised by CO₂±N₂ inclusions, the observed inclusion assemblage may be due to a shallower crustal level of mineralisation, or different degrees and styles of recrystallisation, or a less pronounced development of laminated quartz veins due to comparably restricted pressure fluctuations. Furthermore, the microthermometric observations allow the reconstruction of a possible retrograde P-T path, depicting near-isothermal decompression in the P-T range of the brittle/ductile transition.Editorial handling: E. Frimmel     

Kinetics and Equilibrium Sorption Studies of 4-Nitrophenol on pyrolyzed and activated oil shale residue

Sorption of the organic pollutant 4-nitrophenol (4-NP) by pyrolyzed and activated Jordanian oil-shale was studied. Pyrolyzed oil shale was prepared using a fluidized bed reactor at 520 °C in the presence of nitrogen. Physical activation was carried out by treating the pyrolyzed oil shale with CO₂ at 830 °C, while chemical activation was achieved by using KOH and ZnCl₂ as impregnating agents. Batch kinetics and isotherm studies were conducted to evaluate the sorption process. Effects of contact time, initial sorbate concentration, sorbent concentration, temperature, pH and inorganic salts (NaCl and KCl) on the sorption process by the different sorbents were considered. Chemically activated oil shale, pretreated with ZnCl₂, gave the highest uptake of 4-NP. The isotherm experimental data fit reasonably well to Langmuir, Freundlich and Redlich-Paterson models. Three kinetic models, namely the Morris-Weber, Lagergren, and Pseudo-Second-Order model (PSOM), were applied to represent the experimental results for both pyrolyzed and ZnCl₂-oil shale sorbents.     

我国页岩气资源及影响因素

在世界面临能源短缺的背景下,页岩气作为油气勘探的一个新领域,越来越得到世界各国的重视。我国页岩气资源丰富,许多盆地或地区具有页岩气大规模成藏的地质条件,对页岩气的研究显得尤为重要。该文介绍了我国页岩气资源储量、分布及开采面临的问题,概述了页岩气地质特征。在此基础上探讨了我国页岩气的影响因素,认为我国页岩气主要受有机碳含量、成熟度、裂缝的发育程度、地层压力的控制;页岩气与煤层气同属于非常规天然气,其赋存形态、成因类型、富集规律具有很多相似之处,因此可将页岩气与煤层气进行对比研究。     

Comparative Planetary Space Physics

It has been 60 years since the space physics as new branch of geophysics started to grow in 1957 when the space age was opened by a small satellite called sputnik. The knowledge of Earth and planetary space has been significantly extended and deepened, but the questions we are facing today are more challenging. A consensus reached is that we have to regard the Earth (planet) as an integrated system including all spheres from the inner core to the magnetosphere, and we should try to investigate some questions standing on the ground of interdisciplinary study, especially those questions related to Earth’s (planetary) evolution. Space environment as the outer part of a planetary system, commonly exists in all planets but also exhibits strong diversity. Here, we introduce the short history of basic ideas and methods of comparative study, the advantages on understanding of some issues of global scale, and the prospect from comparative perspective.     

基于实践调研的区域地理教学路径探索——以“天兴洲的综合开发方案”项目式学习为例

目前,中学地理实践活动往往局限于校园与课堂之内,可施展的空间和适用的主题都十分有限。在区域地理学习中,学生可进行"知行合一"的机会更加难得。本文以"天兴洲的综合开发方案"为项目主题,在天兴洲野外真实的环境中开展实践调研,拓展学生的活动空间,延展项目式学习的主题范畴,探索基于实践调研开展区域地理教学的有效路径。     

改进Faster R-CNN的遥感图像多尺度飞机目标检测

为了提高遥感图像中多尺度飞机目标的检测精度,本文提出一种基于改进Faster R-CNN的遥感图像飞机目标检测方法。该方法借助多层级融合结构,将深层次的语义特征与浅层次的细节特征相结合,生成多种尺度的既具有精确的位置信息又具有深层次的语义特征的特征图;再借助Faster R-CNN的多尺度RPN (Region Proposal Network)机制,通过对RPN中候选区域尺度的修正,从而提高遥感图像中多尺度飞机目标的定位精度;最后利用Faster R-CNN的分类回归网络,得到飞机目标检测结果。在高分辨率遥感图像中进行了实验,对3种特征提取网络ZF、VGG-16以及ResNet-50进行改进,改进后的精度分别提高了11.34%、9.87%以及1.66%,并且生成的检测框更加贴合飞机目标。实验结果表明,本文方法适用于遥感图像多尺度飞机目标检测,在提高目标定位精度的同时降低了目标漏检现象。     

山西高家山铝土矿稀土元素地球化学特征及意义

山西沁源县高家山铝土矿床是山西省地质调查院于2013年发现的大型铝土矿床。本文通过对高家山铝土矿的研究,分析并研究铝土矿样品的稀土元素含量和地球化学特征,探讨稀土元素对于本区铝土矿成因和环境的指示意义。研究表明:该区铝土矿体的ΣREE总量较大,轻稀土元素相对富集,具有明显的Eu负异常;利用稀土元素图解大致反映出底板碳酸盐岩是本区铝土矿床的主要物质来源,铝土矿形成于被动大陆边缘地带海相或海陆过渡相环境。ΣREE与Al2O3含量相关性不大。本区矿床稀土元素含量达到或超过综合利用标准,具有巨大的潜在经济价值。