环境同位素在水循环研究中的应用

环境同位素广泛存在于自然界水体中,在降水、地表水、地下水、土壤水和植物体内相互转化的水循环过程中,同位素的分馏效应导致不同水体具有不同的同位素含量。利用不同水体同位素含量之间的差异,可研究它们之间的相互转化方式及转化量。介绍了环境同位素在大气降水和降水-地表水-地下水“三水”之间转化中的研究进展,并阐述了其在水循环应用中存在的问题及应用前景。     

轨道系统动力模型及环境振动评价

分析了轨道系统的动力模型组成,总结了轨道系统动力问题的发展历史及已有的计算方法和理论模型,分析了轨道系统模型的计算机理以及由此所引起的环境振动的评价方法.     

矿山环境问题诱发的环境效应研究

在矿山环境问题分类研究的基础上,文章分析了矿山环境问题与环境效应的因果对应关系及各类矿山环境问题的环境效应,将矿山环境问题所诱发的环境效应划分为占用与破坏土地资源、水资源损毁、矿山次生地质灾害以及自然景观与生态破坏四大类,并依据其影响程度对各类环境效应进行了量化等级划分,对应不同的影响程度将环境效应分为强烈、严重、中等、弱四个等级,为矿山环境调查、评价、修复治理、信息系统建设和科学管理等提供了重要科学依据。     

论环境地质工作

本文阐述了资源与环境在可持续发展中的作用,指出了资源与环境间互相关联、互相影响的关系,说明了地质作用是资源与环境形成的源泉,从而论证了地质学是可持续发展的重要组成部分。文中详细论述了地质环境与环境地质的内涵,探索了地质环境的自然属性与社会属性,并进而讨论了环境地质学科的分类,文章用“以地质环境为实,以环境地质求真”来反映地质环境与环境地质之间的关系。本文还详细叙述了环境地质工作与地质环境行政管理工作的内涵及其相互之间的关系,指出了地质环境是环境地质工作的对象,环境地质学科是环境地质工作的理论基础。环境地质工作内涵广泛,是一项系统工程,而地质环境行政管理则是一项以环境地质工作为基础、社会公共服务为主体的行政管理工作。文章还提出了做好环境地质工作应给予组织上的保证。     

Emerging technologies and safety concerns: a condensed review of environmental life cycle risks in the nano-world

The functionalities of nano-materials are accompanied by features that are in collision with the postulates of environmental friendliness and sustainability. Nano-related research, part of which is nano-safety, is gaining momentum worldwide, but there is a limited body of knowledge about mechanisms such as the degradation, surface modification and transformation of nanoparticles. This study aims to provide a brief survey on the challenges that researchers and engineers face when attempting to assess the environmental impacts of nano-based products. The applicability of the life cycle assessment method to nanotechnology is briefly explored. The advancement of nano-specific life cycle approaches capable of evaluating the sustainability of these emerging technologies depends on further research on material inventories, the energy efficiency of manufacturing processes, the transport and fate of nanoparticles in the environment, health risks and mitigation techniques. Specialized nano-based product-related databases are still needed to track engineered nano-materials (ENMs) in the environment and to facilitate life cycle inventories and assessment. Permissible exposure limits for key ENMs in the workplace and standardized handling protocols for ENMs are not widely available. Properties that increase their toxicity and bioaccumulation are being increasingly investigated. The dissemination of information to the general public related to risk management is rather sporadic, and the suitability of current regulation for controlling environmental pollution by ENM is subject to continued discussion. Taking into account the environment health and safety challenges mentioned, a suitable expertise and information dissemination network is proposed to take the responsible application of nanotechnology forward in the developing world context.     

地下水环境平衡的理念在高水压隧道设计中的应用

将维持地下水环境平衡的设计理念应用于高水压隧道的设计中。对设计中防排水参数和抗水压衬砌计算方法进行了探讨。以梨树湾隧道为实例介绍了具体设计方法。该隧道施工结果表明：应用地下水环境平衡的理念设计高水压隧道,对于保护环境、降低隧道造价、加快施工速度都是合理、安全和有效的。     

早期成岩过程中铁元素地球化学循环研究进展

铁是海洋沉积物中重要的氧化还原敏感性元素之一,是早期成岩过程中地球化学循环变化的重要动力因素。早期成岩过程中,表层沉积物中铁氧化物的赋存形态主要可分无定形(弱晶型)铁氧化物和晶型铁氧化物,且前者的含量主要决定着沉积物中铁氧化物的还原活性;铁氧化物可以通过与硫酸盐还原产生的硫化物反应进行还原,还能在铁还原菌的参与下被表层沉积物中的有机质还原,沉积物中活性铁含量、有机质含量、沉积速率、植物根系导氧作用及底栖生物的扰动均能对铁还原率造成影响。早期成岩过程中可以形成黄铁矿,形成机理主要有:1)沉积物中先前形成的硫复铁矿(Fe_3S_4)等前体物质通过加硫反应形成;2)硫过饱和的球粒胶体通过脱水、成核、结晶以及聚合作用而成单个草莓状黄铁矿或初始自行黄铁矿微晶成核、生长、聚集、固化的小型黄铁矿微球团并入更大的胶体状黄铁矿结核、草莓状黄铁矿分组,从而形成黄铁矿集合体;黄铁矿化度(DOP)可作为区分古海洋氧化还原环境的指标。对铁同位素的研究表明,异化还原作用(DIR)过程中产生的铁同位素值偏低;页岩中黄铁矿的铁同位素在2.3Ga附近发生的突变反映了第一次大气氧气增高事件。磁学参数对铁相变化具有良好的反应,环境磁学在早期成岩过程研究中的应用,有助于快速划分铁还原带、研究环境中重金属循环行为。     

Modeling environmental influences on the locations of Irish early medieval ringforts

For the past two decades, archaeologists have been constructing predictive archaeological models to determine the occurrence probability of archaeological sites. Here, the technique has been used to explore the environmental factors that may have had an influence on the distribution of ringforts in Ireland. In the Inny River catchment of the Irish midlands, locational information, together with corresponding environmental variables, were assembled in a geographic information system. The analysis showed that ringfort sites have a distinctive locational pattern and cluster on moderately fertile, well‐drained soils on gently sloping land surfaces (slopes of 4–9%) between 80 and 150 m above mean sea level. To test the practical applicability of the model, the results were extended to two separate areas adjoining the Inny River catchment (Blackwater valley and Lough Ramor catchment) in the form of a probability surface. The model predicts relatively low densities of ringforts in the Blackwater valley and much higher probabilities of occurrence in the Lough Ramor catchment. These predictions are broadly consistent with recorded site distributions. © 2006 Wiley Periodicals, Inc.     

Limestone–marl alternations as environmental archives and the role of early diagenesis: a critical review

Limestone–marl alternations and other micritic calcareous rhythmites have long appealed to sedimentologists, as they appeared to directly reflect high-frequency environmental change. In particular, when orbital forcing gained popularity amongst sedimentologists and paleoclimatologists in 1980s, such rhythmites seemed to offer an ideal tool for high-resolution chronostratigraphy and environmental reconstruction. However, in spite of the fact that orbital forcing has become a routine interpretation of calcareous rhythmites, and that the processes of formation of calcareous rhythmites are considered well understood, research in the past 10 years again has questioned their primary origin and their direct interpretability. Detailed petrographic, paleontological, and geochemical data from numerous successions through geological time provided the basis for testing whether or not the regular alternation of limestone beds and marl or shale interlayers represents bimodally fluctuating environmental conditions in a direct way. In particular, these data, supplemented by box model simulations, imply that post-depositional alteration (diagenesis) has the potential to not only seriously distort primary environmental signals, but also to mimic primary signals. This questions the use of micritic calcareous rhythmites for high-resolution chronostratigraphy and for environmental interpretations where independent data of diagenetically inert parameters are not available. Diagenetic changes appear to have a yet widely underestimated influence on the appearance of limestone–marl alternations and other calcareous rhythmites. The aim of the present review is to summarize new approaches and give an overview of our research results in this field of the past decade. This review also aims at pointing to still enigmatic aspects that need to be addressed before the interpretation of micritic calcareous rhythmites can be considered a reliable tool for high-resolution chronostratigraphy and paleoenvironmental interpretation. “This difference [between shale and limestone] does not find definite expression in the chemical composition but appeals to the eye.” Gilbert (1895)     

浙江省农业地质环境调查项目工作进展综述

浙江省农业地质环境调查是浙江省人民政府与国土资源部中国地质调查局合作开展的,旨在服务于浙江农业的基础性、战略性、应用性的区域地质调查工作.项目开展以来,通过土壤地球化学、农业地质背景、浅层地下水、农产品安全现状、农业产业结构和布局、主要特色农产品立地地质背景及海岸带地质环境的调查研究,在农业生态地质填图与土壤地质分类、农产品安全现状评价、名特优农产品适生地质环境建模、土壤元素时空演变、重金属在土壤-植物系统中迁移富集机理、污染元素同位素示踪技术应用、多参数综合地球化学制图方法及信息系统空间分析技术和三维显示技术应用等方面的研究,取得了一系列重要的新进展和新成果.     

Evaluation of dynamic properties of geosynthetic reinforced clay samples for environmental impact practices

A series of tests were conducted to investigate the improvement of damping properties of clay samples with geosynthetic inclusions. Flexible thermoplastic polymer synthetics improve damping properties of clay samples. Resonant column tests were conducted to measure the low strain shear modulus and damping ratio of laboratory prepared synthetic inclusion clay specimens. The shear modulus and damping ratio of the reinforced clay samples were investigated considering geosynthetic type (geotextile and geomembrane), number of geosynthetic sheets, and confining pressure. The test results demonstrated that the geomembrane and the number of geosynthetic sheets significantly improved the shear modulus and damping ratio of reinforced clay samples compared with those of the unreinforced clay samples.     

地球早期碳循环与大氧化事件

碳是影响地球宜居性的重要元素,地表系统和地球深部之间的碳循环作用对于全球气候的变化具有非常重要的影响.现今地球主要通过俯冲作用和火山作用调节全球碳循环过程,然而地球早期的碳循环过程和现今地球存在显著的差异.本文结合前人的相关研究成果,综合探讨了地球原始碳的来源、地球早期碳循环过程及其与大氧化事件的联系等问题.地球是从太...     

强夯加固机理及其环境影响的数值分析

采用大变形几何非线性有限元法分析强夯加固机理及其振动对环境影响。在强夯计算模型中,引入P波阻尼和S波阻尼的概念来说明土体的材料阻尼特性,同时运用改进人工边界法来模拟波在人工边界上的传播。采用速度和加速度作为强夯振动对环境影响的评价标准,得出强夯的最小安全距离。隔振沟是一种有效的隔振方法,分析了隔振沟隔振效果的各种影响因素,对实际工程具有一定的参考价值。     

An apparent magmatic cycle in the Tasman geosyncline

The igneous events of two geosynclines within the N.S.W. portion of the Tasman Orthogeosyncline are compared, not according to the actual ages of the igneous rocks, but on the basis of their position with respect to the development of the geosyncline. Thus, Cambrian volcanic rocks in one depositional area are compared with Lower Devonian in the other, Ordovician and Silurian with Middle Devonian‐Lower Carboniferous, and Devonian with Permian. Intrusive rocks are fitted into this scheme, and their ages discussed. Such a comparison reveals an apparent igneous cycle, and speculations on the cause of such a cycle are outlined.     

Climatology of a glacial cycle

A “glacial cycle” is defined as a major global climatic oscillation of the order of 10⁵ yr, developed within an “ice age” sensu lato which may last 10⁶–10⁷ yr and which recurs at widely spaced intervals in geologic time (ca. 2 × 10⁸ yr). The ice age situation thus only persists during 5–10% of all geologic time and is preconditioned by geotectonics and not by extraterrestrial controls.     

An archaeology of fear and environmental change in Philadelphia

This paper examines how mechanisms of social control function to mediate human-environment relations and processes of environmental change in the city. Using the Fairmount Park System of Philadelphia as a case study, I argue that a history of social control mechanisms, both formal and informal, maintained viable socio-environmental urban relationships. Their decline over the last several decades has produced a legacy of fear towards the city’s natural environment that has had, and continues to have, profound socio-spatial and ecological implications. I argue that these changes have their origin in a set of racially motivated decisions made during the volatile years of the late 1960s and early 1970s and that African American women, in particular, have been impacted disproportionately by their consequences. Fear of crime in the natural environment and suspicion of environmental change have resulted in the exclusion of local women and children from what was, historically, a politically and socially viable public space. In this context, urban ecological change is locally understood as more an issue of social control than one of environmental concern.     

Analysis of the environmental sensitivities of a typical dynamic epikarst system at the Nongla monitoring site, Guangxi, China

Nongla, a typical karst dynamic system (KDS) monitoring site, is located at Nongla Village, Mashan County, Guangxi, China. The data from a Greenspan CTDP300 multichannel data logger indicates that the KDS is highly sensitive to environmental changes. Multi-day and diurnal physico-chemical composition of epikarst spring water is quite different under different climatic conditions. During a day with no rainfall, water temperature and air temperature have similar variations. Electrical conductivity (EC) has good positive correlation with pH value and water temperature. During rainstorms, the physico-chemical composition of the spring water is initially strongly effected by dilution, pH and EC drop rapidly. However, half to one hour later, EC returns to normal and the CO₂ effects will be the dominant physical effect. This is due to the high fissure rates and high permeability in the epikarst zone. Dilution effects were observed during the entire rainstorm event,whereas, it only acts during the earliest period of light rain. Therefore, it is necessary to examine the water–rock–CO₂ combination as a whole system to explain the hydrochemical behavior of epikarst processes.