地质工艺孔原地浸出采矿方法与技术

地质工艺孔原地浸出采矿法是一种利用地质工艺孔和化学试剂采矿的新型方法,通过生产试验,对工艺孔结构,布孔方式,施工技术,成井工艺等问题进行了讨论。     

Mineralogical and geochemical characteristics of hydrothermal alteration and episyenitization in the Königshain granites, northern Bohemian Massif, Germany

The late-Hercynian granites of Königshain underwent multistage hydrothermal processes. Extensive high-temperature late-magmatic alteration is, for example, indicated by low Zr/Hf and an REE pattern displaying the tetrad effect. Intensive post-magmatic alteration of the granite occurred along brittle structures. At least two main stages of post-magmatic hydrothermal alteration are involved. The first high-temperature stage, which is characterized by albitization and/or quartz leaching (episyenitization), resulted from fluid–rock interaction with late-magmatic fluids that very probably mixed with external low-salinity fluids. Quartz dissolution was triggered by vapour condensation and/or the cooling of these fluids (below 450??°C) along brittle structures. The high porosity resulting from quartz leaching during stage 1 assisted subsequent circulation of low-temperature fluids at stage 2; the latter is characterized by the chloritization and illitization of episyenites. Almost all major and trace elements were enriched or depleted during one of the main alteration stages. However, Zr, Hf, Th, and Ti were immobile during post-magmatic alteration. The significant depletion of LREE and the enrichment of HREE in albitized samples is controlled by the dissolution of monazite and the new formation of HREE-rich polycrase-(Y) or aeschynite-(Y) during post-magmatic stage 1. Negative Ce anomalies of episyenites are associated with illitization and suggest oxidizing conditions during stage 2.     

Subaerial leaching process of sedimentary bauxite and the discussion on classifications of bauxite deposits

Bauxite is the ultimate fine-grained products of chemical weathering,and thus it is closely linked with the intense chemical weathering. Based on variations of parent rock and weathering processes,the weathering products can be subdivided into laterite and terra rossa,of which the former is formed by weathering of aluminosilicates and the latter is produced by the weathering of carbonates. During the intense chemical weathering,minerals in original subaerial sediments(parent rocks)would suffer a series of processes(dissolution,hydrolyzation,hydration,carbonation,and oxidation)and be destroyed or transformed,leading to formation of new minerals. In the favorable environment,continuously intense chemical weathering would cause the loss of most mobile elements(e.g., K,Na,Ca,Mg,Si)and the enrichment of Al,resulting in the formation of bauxite. Although sedimentary bauxites are closely linked with the weathering curst,they show obvious differences in formation processes. Sedimentary bauxites are composed of intense chemical weathering products that are transported from outside of the basin and re-deposited in the basin,while most weathering crusts are transformed from saprolite and/or deluvium in-situ,and they can only form low-grade bauxites. Sedimentary environments also differ in bauxite ore layers and bauxitic claystone layers. Bauxite ore layers are formed in the subaerial environment and controlled by the leaching process of groundwater in the vadose zone. Based on the analysis of bauxitization,this study proposes to use multiple parameters,such as provenance,sedimentation and mineralization,to build the new classification of Chinese bauxite deposits. In this classification,lateritic and karstic types of bauxite deposits are autochthonous or parautochthonous saprolite and/or deluvium,while sedimentary type is dominated by heterochthonous provenance.     

察尔汗盐湖地下卤水动态规律研究

建立了描述采卤过程中地下卤水运动规律的数学模型,并用有限元素法进行了数值迭代求解。在此基础上,用等值线比较法,根据1988年3月—1989年6月间65个观测点上每月一次的地下卤水的水位观测数据,对首采区中312个剖分节点上的渗透系数等水文地质参数进行了修正和反求。经修正反求后地下卤水水位的模拟值与实测值之间的相对误差由原来的14．3％改善为7.7％。     

Lake Shira, a Siberian salt lake: ecosystem structure and function. 3. The use of bioluminescent biotests to monitor ecological status

The specific composition, vertical distribution and daily migration of plankton in a meromictic salt lake, Lake Shira, have been investigated. The main structural components of the ecosystem are bacteria, algae and crustaceans. Since the late 1970s, blue-green algae are reported as dominant. Nowadays the phytoplankton is dominated byLyngbya contorta, Microcystis ichtyoblabe (Cyanophyta),Cyclotella tuberculata (Bacillariophyta) andDictyosphaerium tetrachotomum (Chlorophyta). The zooplankton of Lake Shira comprisesArctodiaptomus salinus (Copepoda),Brachionus plicatilis andHexarthra oxiuris (Rotatoria). Investigation revealed a stratified vertical distribution of all dominant species exceptCyclotella with a maximum at a depth of 12–15 m during the summer growth period. Zooplanktons differ in the pattern of distribution and daily migration, but most zooplankton tend to concentrate near the surface. The possible reasons for the vertical distribution of the plankton are discussed.     

江苏盐城滨海盐沼湿地沉积物有机碳含量及碳储量研究

全球范围内有植被定植的海岸带栖息地(红树林、盐沼和海草床)是巨大的沉积物有机碳碳库,同时也是自然生态系统中最密集的碳汇之一,在全球碳循环中发挥着重要作用。针对江苏盐城海岸盐沼湿地沉积物有机碳的研究,区域上的稀疏性和偏向性限制了其作为区域碳汇能力的可靠估计。本研究采用47个100 cm深沉积柱样的现场调查数据,探讨了江苏盐城海岸盐沼湿地沉积物有机碳含量、密度和储量特征。结果表明,0～100 cm深度沉积物有机碳平均含量和平均密度分别为1.68%和23.07 kg/m³,不同盐沼群落沉积物有机碳含量和密度存在一定的差异,其中有机碳平均含量大小排序依次为互花米草>芦苇>盐地碱蓬,有机碳密度排序为芦苇>互花米草>盐地碱蓬。总体而言,3种盐沼群落沉积物有机碳含量的垂向变化趋势与有机碳密度变化趋势具有一致性,芦苇和互花米草表聚性明显。沉积物有机碳含量与其理化性质有关,互花米草群落沉积物有机碳含量具有明显的粒度控制效应,而其他群落不显著。3种盐沼湿地类型0～100 cm深度沉积物总碳储量约为6195.27×10³Mg C。研究成果揭...     

中国九个内陆盐湖卤虫的品系特征

分析了中国９个内陆盐湖卤虫的生物学测定值,孵化特性,蛋白质含量和脂肪酸组成,不同品系的卤虫在卵径,无节幼体体长,脱壳卵和无节幼体干重等生物学测定值方面存在着极其显著的差异（Ｐ〈０．０１）。     

黄河三角洲互花米草整治对潮滩湿地防灾功效和沉积动力的影响

互花米草作为黄河三角洲外来入侵物种, 2010年开始爆发式蔓延, 2020年面积最大时可超6 000 hm²,对潮间带生物多样性造成了严重影响。自2020年起,黄河三角洲自然保护区开始大规模的互花米草整治与盐地碱蓬生态修复工作。互花米草具有较强的消浪、缓流、促淤、固滩能力,短期内、大范围的植被去除,可能导致波流和沉积动力环境的突变。基于现场观测数据和考虑植被作用的浪、流、沙耦合数值模型,研究分析了互花米草整治和盐地碱蓬修复对黄河三角洲湿地动力过程的影响,重点关注风暴作用下黄河三角洲潮滩湿地的防灾减灾能力和沉积效应变化。研究结果表明,互花米草可有效抵御极端风暴潮,最大风暴潮位衰减率可达15 cm/km。互花米草整治将导致湿地防灾减灾能力显著下降,堤前风暴潮峰值可抬升10～30 cm,同时潮间带的泥沙捕集能力大幅下降。受限于植被密度、高度,盐地碱蓬完全修复后湿地衰减风暴潮、捕集泥沙的能力显著低于原互花米草湿地。研究建议,互花米草整治工程应考虑短期内植被去除导致的近岸风暴潮抬升、侵蚀加剧等潜在风险。     

Origin and development of tafoni in Tunnel Spring Tuff,Crystal Peak,Utah, USA

Bedding‐parallel tafoni are well developed over much of the surface of the Tunnel Spring Tuff (Oligocene) exposed in 300‐m‐high Crystal Peak, an inselberg. The Tunnel Spring Tuff is a crudely stratified, non‐welded rhyolite ash‐flow tuff with > 30 per cent porosity. Clasts of Palaeozoic dolomite, limestone and quartzite make up 10 per cent of the tuff. The tafoni are remarkable because of their size (up to 20 m wide but rarely wider than 4 m), shape of the openings (spherical, arch‐like or crescent‐shaped) and abundance (up to 50 per cent of an outcrop face). They are actively forming today. Calcite is abundant (10 to 40 per cent by weight) in tafoni as an efflorescence in spalling flakes of tuff on their roofs and walls. Halite and gypsum generally make up less than 0·01 per cent of the efflorescence. The absence of corroded quartz and feldspar grains in spall fragments indicates that chemical weathering is unimportant in development of the tafoni. Calcite, aragonite, halite and gypsum dust from modern salt pans less than 20 km from Crystal Peak are potential sources of salt in the tuff, but the prevailing winds are in the wrong direction for significant amounts of these evaporite minerals to reach the inselberg. Calcite is the only evaporite mineral present in the tafoni in more than trace amounts, and this mineral is readily available within the tuff itself as a result of rock weathering. We propose that meteoric water containing carbonic acid infiltrates the tuff, dissolves carbonate clasts, and migrates to the steep flanks (>20°) of the peak through abundant megapores and micropores. There it evaporates and precipitates calcite. Crystallization pressure spalls off grains and sheets as the physical manifestation of salt weathering. The quasi‐uniform spacing of tafoni suggests that a self‐organization process is active in the water flow. Copyright © 2000 John Wiley & Sons, Ltd.     

Seasonal drivers and patterns of sediment temperatures in a New England salt marsh

Salt marshes are globally important ecosystems and thus their resilience to climate change holds societal importance. To date, studies addressing salt marsh responses to climate change have focused on sea-level rise and biogeochemical feedbacks with increasing inundation. Less is known about how salt marsh sediment temperatures, which impact physical, biological, and chemical ecosystem processes, will respond to climate change. In this study, we present multi-depth sediment temperature and porewater level data from low-, mid-, and high-marsh sites at a New England salt marsh for a 1-year period and investigate how salt marsh sediment temperatures respond to atmospheric and oceanic forcing. We use spectral analyses to identify the frequencies at which sediment temperatures vary and link the temperature variations to specific forcing mechanisms. We find that all sites across the marsh responded to air temperature with roughly equal amplitude whereas the responses to radiative heating and ocean tides varied spatially. The high-marsh site is more sensitive to radiative heating than the mid- and low-marsh sites. The low-marsh is affected by tidal processes and inundation whereas the high- and mid-marsh sites are not. In addition, we find that the bulk thermal diffusivity of the saturated sediments decreases with distance from the tidal channel. These factors contribute to considerable temporal and spatial variability in sediment temperatures with elevation, distance from the tidal channel, and time of year (season) being most important.