Impact of transition zones, variable fluid viscosity and anthropogenic activities on coupled fluid-transport processes in a shallow salt-dome environment

In the Schleswig–Holstein region (S–H) of Germany, most observed near-surface saline ground waters originate from dissolution of shallow salt domes. Previous numerical simulations of thermohaline flow clarified the major mechanisms controlling large-scale density-driven flow. It has been found that, in addition to topographically driven flow, gravitational and thermohaline convection are the primary mechanisms for extensive solute exchange between shallow and deep aquifers. Geological features such as glacial channels control recharge/discharge processes at the surface. Here we address several previously unresolved issues: (i) the impact of a permeable unit (transition zone) between the salt and adjacent units; (ii) the role of variable brine viscosity in affecting regional- (i.e. km-) scale heat and mass patterns; and (iii) the influence of anthropogenic activities such as pumping stations on density-driven flow. We found that geophysical factors play a major role in determining the dynamics of fluid processes. The transition zone significantly influences the flow field and the distribution of heat, slowing the formation of highly concentrated salty plumes. The impact of variable fluid viscosity on the coupled heat and brine flow is twofold. In a colder and highly concentrated environment, such as a shallow salt-dome crest, it retards brine flow. In a less saline environment, variable fluid viscosity enhances thermally induced upward fluid flow. Groundwater extraction from production wells only affects brine and heat flow locally within the upper aquifers.     

盐文化主题旅游产品的市场价值挖掘与深度开发研究——以大英死海、自贡盐都为例

论文理清了盐文化旅游资源市场价值观演交的脉络.认为旅游产品化是实现盐文化潜在资源显性化的必然,主题挖掘已经成为盐文化旅游产品差异化的当然选择.选取了大英死海和自贡盐都作为两个典型案例,得出盐文化主题旅游产品的显性市场价值在于文化性和娱乐性,其隐性市场价值是游客休闲体验性和社会文化生态性.最后基于后现代旅游语境下的"社会-游客"双核市场价值观,提出了深度开发策略.     

Microclimate and Salt Crystallization in the Crypt of Lecce’s Duomo

Ancient masonry structures are often damaged by soluble salt crystallization, which is activated by even small microclimatic variations. Unsuitable environmental conditions can accelerate this process, affecting the type and the quantity of salts and the consequent damage to the masonry. Therefore the importance of monitoring salt diffusion to control salt crystallization and microclimate over time is widely recognized. This study proposes an integrated monitoring methodology to obtain information on the relationship between salt efflorescence and microclimate in the Crypt of the Duomo of Lecce (South Italy). By combining ion chromatography, powder X-ray diffraction analysis, and Raman microscopy with environmental monitoring and deterioration maps, salt components were identified and efflorescence diffusion on masonry was monitored over time. Due to this approach, a possible explanation for the process is finally given.     

Effectiveness of Phosphocitrate as Salt Crystallization Inhibitor in Porous Materials: Case Study of the Roman Mosaic of Orpheus and the Beasts (Perugia,Italy)

Salt crystallization in porous materials constitutes one of the major causes of decay of buildings/archaeological sites in a wide range of environments. Desalination is among the most common methodologies of conservative treatment for salt decay. However, classic desalination techniques might be not suitable for long-term conservation. During the past decade interest has been an increasing towards crystallization inhibitors as a new means of controlling crystallization damage. This study deals with the first in-field application of an environment-friendly inhibitor system— phosphocitrate (PC). In particular, the case study of the Roman mosaic of Orpheus and the Beasts in Perugia (Italy) is presented. The inhibitor is completely soluble in water or alcohol, non-toxic, and easy to apply, thus enabling its use in accordance with the volatile organic compounds emission control and safety during the conservation works. Relevant samples from control and treated mosaic areas were collected and analyzed comparatively by means of Fourier transform-infrared spectroscopy, scanning electron microscopy, and energy dispersive spectrometry to study the potential of the inhibitor system in preventing/controlling salt damage in such archaeological site.     

“钻石理论”与格尔木盐湖化工产业集群的竞争环境

本文运用吩析产业集群的“钻石理论”,根据实地调查获得的大量资料,分别从要素条件、需求条件、产业关联和市场环境等方面分析了格尔木盐湖化工产业集群面临的竞争环境,并就进一步优化竞争环境提出了一些对策。     

Diverse origins and timing of formation of basinal brines in the Gulf of Mexico sedimentary basin

A review of five different field areas in the Gulf of Mexico sedimentary basin (GOM) illustrates some of the potentially diverse chemical and physical processes which have produced basinal brines. The elevated salinities of most of the formation waters in the GOM are ultimately related to the presence of the Middle Jurassic Louann Salt. Some of these brines likely inherited their salinity from evaporated Mesozoic seawater, while other saline fluids have been produced by subsequent dissolution of salt, some of which is occurring today. The timing of the generation of brines has thus not been restricted to the Middle Jurassic. The mechanisms of solute transport that have introduced brines throughout much of the sedimentary section of the GOM are not entirely understood. Free convection driven by spatial variations in formation water temperature and salinity is undoubtedly occurring around some salt structures. However, the driving mechanisms for the broad, diffusive upward solute transport in the northern Gulf rim of Arkansas and northern Louisiana are not known. In the Lower Cretaceous of Texas, fluid flow was much more highly focused, and perhaps episodic. It is clear that many areas of the Gulf basin are hydrologically connected and that large‐scale fluid flow, solute transport, and dispersion have occurred. The Na‐Mg‐Ca‐Cl compositions of brines in the areas of the Gulf Coast sedimentary basin reviewed in this article are products of diagenesis and do not reflect the composition of the evaporated marine waters present at the time of sediment deposition. Large differences in Na, Ca, and Mg trends for waters hosted by Mesozoic versus Cenozoic sediments may reflect differences in: (i) the sources of salinity (evaporated seawater for some of the Mesozoic sediments, dissolution of salt for some of the Cenozoic sediments); (ii) sediment lithology (dominantly carbonates for much of the Mesozoic sediments, and dominantly siliciclastics for the Cenozoic sediments); or (iii) residence times of brines associated with these sediments (tens of millions of years versus perhaps days).     

明清两淮盐务道员建置新考

盐务道员是明清政府为管理食盐产销设立的重要职官。万历末年,明廷为催征盐课以供辽饷,先后创设整饬、疏理两淮盐法道。天启以后,党争剧烈,道臣清理盐法成效不彰,崇祯朝致力恢复运司专管盐法的旧制。清代重新调整盐官制度,合并运使、盐道为“管盐法道运使”,又新设监管场产的“分巡盐务道”和职司岸销的“通省盐法道”。盐务道员由朝廷差遣官变为地方盐务机构,与专管盐课钱粮的运司衙门共同成为包衣盐差的直属办事机构。皇帝为独揽两淮利权,又令两江总督兼总理盐法,与包衣盐差相互制约。道光年间,盐差因整顿不力奉裁,盐政改归总督管理。咸同军兴以后,运司、盐道的职权被招商、督销等局侵夺,两淮利权遂归总督,成为晚清督臣专权的财政基础。     

Geochemical impacts to prehistoric iron-rich siliceous artifacts in the nearshore coastal zone

In the Middle Atlantic region of the United States, landscapes drowned by sea level rise contain scores of prehistoric archaeological sites. These sites provide archaeologists with a rare opportunity to investigate various geologic processes. During the transition from a terrestrial to an offshore setting, the materials associated with an archaeological site are exposed to a series of geochemical processes inherent to the formation of tidal marsh. The duration of the geochemical exposure to tidal marsh is largely dependent on the rate of marine transgression. Here we describe the stages associated with the sulfidization and sulfuricization scheme and the impact to iron-rich lithic artifacts from naturally drowned archaeological sites. Sulfidization and sulfuricization should also impact buried archaeological materials as a result of anthropogenic dredge spoil dumping and the creation of man-made tidal marshes along modern coastlines. Our results indicate that the surfaces of an iron-rich artifact, as well as its interior are visually and geochemically altered by prolonged exposure to the anaerobic conditions of a tidal marsh. Not only should researchers be cautious about making lithic material identification on artifacts found within coastal tidal marsh areas, but museum curators should be aware of the damaging impact of long-term aerobic storage. The geochemical tidal marsh scheme that has altered or corroded iron-rich lithic artifacts in the nearshore zone is an expression of a process that has impacted numerous earlier prehistoric sites currently located on the continental shelf or beneath the coastal estuaries around the world.     

金代解盐使司银铤浅析

本文中的两笏金代解盐银铤,均出土河南省西峡县。经考证,与陕西临潼出土的两笏金代“解盐使司”银铤,出自同一铸地,是金代盐商向解盐使司购买钞引的入纳银铤。它不仅记录了明确的铸造时间、地点和重量,而且对金朝的盐池管理机构、金银铺号、榷货盐司的官吏等方面的记载详尽,为研究金代的盐课税制、金银行会制度、客商制度、白银在当时经济生活中的地位、作用及流通中所设置的管理机构、流通方式等提供了实物资料。     

Solubility of quartz in crustal fluids: experiments and general equations for salt solutions and H2O–CO2 mixtures at 400–800°C and 0.1–0.9 GPa

The solubility of quartz has been measured in a wide range of salt solutions at 800°C and 0.5 GPa, and in NaCl, CaCl₂ and CsCl solutions and H₂O–CO₂ fluids at six additional P–T conditions ranging from 400°C at 0.1 GPa to 800°C at 0.9 GPa. The experiments cover a wide range of compositions along each binary. At P–T conditions where the density of pure water is low (0.43 g cm^?3), addition of most salts produces an enhancement of quartz solubility at low to moderate salt concentrations (salt‐in effect), although quartz solubility falls with further decrease in X_H2O. At higher fluid densities (0.7 g cm^?3 and greater), the salt‐in effect is generally absent, although this depends on both the cation present and the actual P–T conditions. The salt‐in effect is most readily produced by chloride salts of large monovalent cations, while CaCl₂ only produced a salt‐in effect at the most extreme conditions of high‐T and low‐P investigated (800°C at 0.2 GPa). Under most crustal conditions, the addition of common salts to aqueous fluids results in a lowering of quartz solubility relative to that in pure water (salt‐out effect). Comparing quartz solubility in different fluids by calculating X_H2O on the basis that all salts are fully associated under all conditions yields higher quartz solubility in solutions of monovalent salts than in solutions of divalent salts, absolute values are also influenced by cation radius. Quartz solubility measurements have been fitted to a Setchenow‐type equation, modified to take account of the separate effects of both the lowering of X_H2O and the specific effects of different salts, which are treated as arising through distinct patterns of non‐ideal behaviour, rather than the explicit formation of additional silica complexes with salt components. Quartz solubility in H₂O–CO₂ fluids can be treated as ideal, if the solvation number of aqueous silica is taken as 3.5. For this system the solubility (molality) of quartz in the binary fluid, S is related to its solubility in pure water at the same P–T conditions, S^o, by: Quartz solubility in binary salt systems (H₂O–RCl_n) can be fitted to the relationship: where salt concentration mRCl_n is expressed as molality and the exponent b has a value of 1 except under conditions where salting‐in is observed at low salt concentrations, in which case it is <1. Under most crustal conditions, the solubility of quartz in NaCl solutions is given to a good approximation by: We propose that quartz solubility in multicomponent fluids can be estimated from an extended expression, calculating X_H2O based on the total fluid composition (including dissolved gasses), and adding terms for each major salt present. Our experimental results on H₂O–NaCl–CO₂ fluids are satisfactorily predicted on this basis. An important implication of the results presented here is that there are circumstances where the migration of a fluid from one quartz‐bearing host into another, if it is accompanied by re‐equilibration through cation exchange, may lead to dissolution or precipitation of quartz even at constant P and T, with concomitant modification of the permeability structure of the deep crust.