Natural Gas Hazard (CO2, 222 Rn) within a Quiescent Volcanic Region and Its Relations with Tectonics: The Case of the Ciampino-Marino Area, Alban Hills Volcano, Italy

Groundwater surveys were performed by detailed(around 300 sites) grid-analysis of water temperature, pH, redox potential, electrical conductivity, ²²²Rn, alkalinity and by calculating the pCO₂, throughout the Ciampino and Marino towns in the Alban Hills quiescent volcano (Central Italy). Following several episodes of dangerous CO₂ exhalation from soils during the last 20 years and earlier ashistorically recorded, the work aimed at assessing the Natural Gas Hazard (NGH) including the indoor-Rn hazard. The NGH was defined as the probability of an area to become a site of poisonous peri-volcanic gas exhalations from soils to the lower atmosphere (comprising buildings). CO₂ was found to be a ``carrier' for the other poisonous minor and in trace components (H<sub>s</sub>S, CH<sub>4</sub>, <sup>222</sup>Rn, etc.). This assessment was performed by extrapolating in the aquifer CO<sub>2</sub> and <sup>222</sup>Rn conditions, and discriminating sectors where future CO<sub>2</sub> flux in soils as well as indoor-Rn measurements have to be noted. A preliminary indoor-Rn survey was performed at about 200 sites. The highest values were found in the highest pCO<sub>2</sub> and high <sup>222</sup>Rn values in groundwater. This indicates convection and enhanced permeability in certain sectors of the main aquifer, i.e., along the bordering faults and inside the gas-trap of the Ciampino Horst., where ``continuous gas-phase micro-macro seepage mechanism' is invoked to explain the high peri-volcanic gases flux.     

佛坪自然保护区植物群落物种多样性与海拔梯度的关系

用多元统计分析方法研究了佛坪自然保护区植物群落多种性及群落各生长型多样性特征沿海拔梯度的变化。结果表明：1）植物群落的Shannon指数与Simpson指数及物种丰富度与海拔梯度均呈显著负相关关系;2）乔木层的物种多样性沿海拔梯度的变化则体现了“中国高度膨胀”的规律,即中等海拔高度上多样性高而低海拔和高海拔多样性较低;3）灌木层丰富度指数在1600-1700m之间有个很不明显的峰值,而其它4个指标沿海拔呈单调的下降趋势;4）草本层植物多样性呈先降后升的趋势,在中等海拔高度较低。     

Geostatistical mapping of geomorphic variables in the presence of trend

Mapping geomorphic variables geostatistically, specifically by kriging, runs into difficulties when there is trend. The reason is that the variogram required for the kriging must be of residuals from any trend, which in turn cannot be estimated optimally by the usual method of trend surface analysis because the residuals are correlated. The difficulties can be overcome by the use of residual maximum likelihood (REML) to estimate both the trend and the variogram of the residuals simultaneously. We summarize the theory of REML as it applies to kriging in the presence of trend. We present the equations to show how estimates of the trend are combined with kriging of residuals to give empirical best linear unbiased predictions (E‐BLUPs). We then apply the method to estimate the height of the sub‐Upper‐Chalk surface beneath the Chiltern Hills of southeast England from 238 borehole data. The variogram of the REML residuals is substantially different from that computed by ordinary least squares (OLS) analysis. The map of the predicted surface is similar to that made from kriging with the OLS variogram. The variances, however, are substantially larger because (a) they derive from a variogram with a much larger sill and (b) they include the uncertainty of the estimate of the trend. Copyright © 2006 John Wiley & Sons, Ltd.     

关于建设省级地理空间数据交换中心的思考

省级地理空间数据交换中心是国家空间信息基础设施建设的核心内容之一。本文针对现阶段在我国建设省级地理空间数据交换中心的问题，分析了其基本建设内容，提出了需解决和应用的关键技术。     

中国兴农网用户认证模块设计

中国兴农网自市场信息模块设立以来,吸引了越来越多的用户发布和浏览信息,而对这些信息及发布人行为的管理渐渐纳入日程。该文介绍了为中国兴农网信息发布系统提供的一个安全的用户认证系统,在实际操作中,PHP语言与Oracle数据库的结合使用较好地实现了这一目标,有效地实现了用户的管理,包括注册、修改、授权、删除等功能,并且通过用户的认证,安全地控制了农网市场信息的发布流程。该文从设计思路出发,探讨了功能设计、程序设计语言、数据库的选择与实现等几个具体的问题。     

Eruptive history and petrologic evolution of the Albano multiple maar (Alban Hills, Central Italy)

A comprehensive volcanological study of the Albano multiple maar (Alban Hills, Italy) using (i) ⁴⁰Ar/³⁹Ar geochronology of the most complete stratigraphic section and other proximal and distal outcrops and (ii) petrographic observations, phase analyses of major and trace elements, and Sr and O isotopic analyses of the pyroclastic deposits shows that volcanic activity at Albano was strongly discontinuous, with a first eruptive cycle at 69±1 ka producing at least two eruptions, and a second cycle with two peaks at 39±1 and 36±1 ka producing at least four eruptions. Contrary to previous studies, we did not find evidence of magmatic or hydromagmatic eruptions younger than 36±1 ka. The activity of Albano was fed by a new batch of primary magma compositionally different from that of the older activity of the Alban Hills; moreover, the REE and ⁸⁷Sr/⁸⁶Sr data indicate that the Albano magma originated from an enriched metasomatized mantle. According to the modeled liquid line of descent, this magma differentiated under the influence of magma/limestone wall rock interaction. Our detailed eruptive and petrologic reconstruction of the Albano Maar evolution substantiates the dormant state of the Alban Hills Volcanic District. Electronic Supplementary Material Supplementary material is available for this article at Editorial responsibility: J. Donnelly-Nolan An erratum to this article can be found at     

北京沙河地区地面沉降及抗浮设防水位的探讨

论述了北京沙河高教园区项目在建设中将遇到的地面沉降及抗浮设防水位的确定问题,并提出了相应的解决措施。     

Metamorphic evolution of the Naga Hills eclogite and blueschist, Northeast India: implications for early subduction of the Indian plate under the Burma microplate

Tectonic slices and lenses of eclogite within mafic and ultramafic rocks of the Early Cretaceous–Eocene Naga Hills ophiolite were studied to constrain the physical conditions of eastward subduction of the Indian plate under the Burma microplate and convergence rate prior to the India–Eurasia collision. Some of the lenses are composed of eclogite, garnet-blueschist, glaucophanite and greenschist from core to margin, representing a retrograde hydrothermal alteration sequence. Barroisite, garnet, omphacite and epidote with minor chlorite, phengite, rutile and quartz constitute the peak metamorphic assemblage. In eclogite and garnet-blueschist, garnet shows an increase in Mg and Fe and decrease in Mn from core to rim. In chlorite in eclogite, Mg increases from core to rim. Inclusions of epidote, glaucophane, omphacite and quartz in garnet represent the pre-peak assemblage. Glaucophane also occurs profusely at the rims of barroisite. The matrix glaucophane and epidote represent the post-peak assemblage. The Fe³⁺ content of garnet-hosted omphacite is higher than that of matrix omphacite, and Fe³⁺ increases from core to rim in matrix glaucophane. Albite occurs in late stage veins. P – T pseudosection analysis indicates that the Naga Hills eclogites followed a clockwise P – T path with prograde metamorphism beginning at ∼1.3 GPa/525 °C and peaking at 1.7–2.0 GPa/580–610 °C, and subsequent retrogression to ∼1.1 GPa/540 °C. A comparison of these P – T conditions with numerical thermal models of plate subduction indicates that the Naga Hills eclogites probably formed near the top of the subducting crust with convergence rates of ∼ 55–100 km Myr⁻¹, consistent with high pre-collision convergence rates between India and Eurasia.     

SOFTWARE REVIEWS

AMOS—Analysis of MOment Structures . James Arbuckle CLIMATEDATA–Summary of the Day . (Version 1.10). HYDRODATA–U.S.G.S. Daily Values (Version 2.0). The MAP SETS (includes EUROPEAN MAPSET, US MAPSET and WORLD MAPSET). James Taylor     

Expanding coastal urban and industrial seascape in the Great Barrier Reef World Heritage Area: Critical need for coordinated planning and policy

Coastal freshwater and tidal wetland habitats are being transformed as a result of increasing demand for commercial, residential and tourism activities. The consequence is a habitat seascape complex, comprising a mosaic of natural and engineered coastal features. This study used the freely available mapping tool (Google Earth) to define the extent of coastal engineering structures in the Great Barrier Reef World Heritage Area (GBR; Australia), a marine ecosystem of global biodiversity and cultural significance. Continuing threats to the heritage estate concomitant with expanding urban and industrial developments has raised concerns directed at the future conservation and resilience of the reef ecosystems, along with maintaining expected human lifestyles and livelihoods it provides. The data here shows that break walls and pontoons/jetties dominate development, contributing to approximately 10% (equivalent) of the coastline linear length. Most (60%) development occurs along the coastline or within the first few kilometres upstream along estuaries. While conservation and protection of natural coastal habitats is still preferred for the objective of fisheries production and biodiversity, managers must consider seascape implication/benefits more broadly when approving new marine infrastructure rather than a case-by-case approach which further contributes to an ad hoc mosaic seascape of natural and engineered habitats. Not only within the GBR heritage estate, but more broadly, coastal managers need to regard wider seascape connectivity processes during the assessment of any new development. There is an urgent need for policy and planning instrument reform that is inclusive of accumulative impacts of urban and industrial development in this heritage estate. Opportunities to include eco-friendly (green engineering) solutions, in the repair and revitalisation of existing artificial structures, is necessary in any new proposed urban and industrial development and expansion.