Monitoring and Management Options in the Preservation of Urban Waterlogged Deposits,Nantwich, UK

A baseline survey in 2007 characterized the physical and chemical conditions for preservation within waterlogged remains at Nantwich. Installation of eighteen dipwells has allowed a five-year monitoring programme to be conducted from 2011. Two add-on projects supplemented this monitoring programme by examining the different methods for redox measurement, and for soil moisture measurement using Time Domain Reflectometry (TDR).

Initial results show two main zones of preservation, with reducing conditions attributed to location of the deposits in the floodplain, and a second zone uphill with more variable conditions for preservation. This study shows that sediment-coring programmes combined with dipwell installations can provide useful data to assess and monitor in situ preservation conditions, which can help to formulate management strategies for conservation of waterlogged archaeological deposits. This paper focuses on the efficacy of the methodology, referencing in particular comparative monitoring techniques and lists a series of recommendations for future studies.     

唐代铁佛残块及汉代铁剑的科学分析及有机硅在其保护中的应用

章介绍了两件铁质物的科学分析及其用有机硅进行保护的过程,通过金属腐蚀速率的实验说明了有机硅可以有效减缓铁器的腐蚀速率,并结合相关资料证实了有机硅在铁质物何护中应用的可行性。     

试论沅水下游旧石器遗存

本对沅水下游17个地点的旧石器的地理埋藏、自然环境、化面貌、时代特征进行了分析,并与相邻的澧水化类群和（氵舞）水化类群进行了比较,认为这批旧石器的时代为旧石器时代早期偏晚至旧石器时代中期,属华南砾石石器传统,并指出沅水下游旧石器属于澧水化类群,兼具澧水、（氵舞）水两大化类群之间的某些过渡性特征。     

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.