Ice ages and the thermal equilibrium of the earth,II

The energy required to sustain midlatitude continental glaciations comes from solar radiation absorbed by the oceans. It is made available through changes in relative amounts of energy lost from the sea surface as net outgoing infrared radiation, sensible heat loss, and latent heat loss. Ice sheets form in response to the initial occurrence of a large perennial snowfield in the subarctic. When such a snowfield forms, it undergoes a drastic reduction in absorbed solar energy because of its high albedo. When the absorbed solar energy cannot supply local infrared radiation losses, the snowfield cools, thus increasing the energy gradient between itself and external, warmer areas that can act as energy sources. Cooling of the snowfield progresses until the energy gradients between the snowfield and external heat sources are sufficient to bring in enough (latent plus sensible) energy to balance the energy budget over the snowfield. Much of the energy is imported as latent heat. The snow that falls and nourishes the ice sheet is a by-product of the process used to satisfy the energy balance requirements of the snowfield. The oceans are the primary energy source for the ice sheet because only the ocean can supply large amounts of latent heat. At first, some of the energy extracted by the ice sheet from the ocean is stored heat, so the ocean cools. As it cools, less energy is lost as net outgoing infrared radiation, and the energy thus saved is then available to augment evaporation. The ratio between sensible and latent heat lost by the ocean is the Bowen ratio; it depends in part on the sea surface temperature. As the sea surface temperature falls during a glaciation, the Bowen ratio increases, until most of the available energy leaves the oceans as sensible, rather than latent heat. The ice sheet starves, and an interglacial period begins. The oscillations between stadial and interstadial intervals within a glaciation are caused by the effects of varying amounts of glacial meltwater entering the oceans as a surface layer that acts to reduce the amount of energy available for glacial nourishment. This causes the ice sheet to melt back, which continues the supply of meltwater until the ice sheet diminishes to a size consistent with the reduced rate of nourishment. The meltwater supply then decreases, the rate of nourishment increases, and a new stadial begins.     

我国新能源发展障碍与应对: 全球现状评述

以化石能源为主的能源消费模式已经难以满足可持续发展的要求, 改善能源消费结构、减少对化石能源的依赖势在必行。在此背景下, 发展环境友好、地域分布相对均衡且潜力无限的新能源成为各国共识。新能源包括太阳能、风能、生物质能、地热能、海洋能、氢能、天然气水合物、核能、核聚变能等共9种类型。由于种类繁多、资源禀赋和物化特征差异悬殊, 开发利用新能源需要面对比化石能源复杂得多的规划、管理和技术问题。如果措施不当, 不但会造成经济损失, 而且可能会威胁到人类安全。在全面深入了解全球新能源发展现状的基础上, 认真总结各国经验教训, 制定合理的发展战略, 是开发利用新能源的先行性工作, 具有重要意义。本文对国内外新能源资源情况、技术水平、总体发展现状进行分析, 并对我国新能源发展过程中的制约因素进行深入剖析, 结合我国国情提出新能源发展的对策建议。     

地热水资源开发与环境保护

作为巨大的清洁能源,地热水资源已被大量开发及利用。但是清洁能源并不清洁,其由地下深处带到地表的一些化学物质等对地面环境势必造成严重的负面影响即危害。在介绍了地热水资源概况及开发利用现状基础上,对地热水资源开发及利用所带来的环境及环境地质问题进行了简单的介绍,特别是地面沉降、热污染及地热水资源衰减等,并分析了这些环境地质问题产生的机理。对地热水资源开发利用中存在的问题做了简要总结,并为地热水资源的合理开发、科学利用及可持续发展提出加强勘查评价工作,提高利用效率等五余个建议和对策。     

天然气水合物的环境效应

天然气水合物是近些年来发现的一种新型超级洁：争能源，因其在能源勘探、海底灾害环境和全球气候变化研究中的重要性而日益引起世界各国的高度重视。本文综述了天然气水合物在形成、分解过程中的加剧全球气候变暖、海底灾害和影响海洋生物等环境效应；指出将地质历吏时期的重大事件与天然气水合物产生的这些环境效应结合将成为今后的主要研究方向。     

Geochemistry of coalbed gas – A review

Coals are both sources and reservoirs of large amounts of gas that has received increasing attention in recent years as a largely untapped potential energy resource. Coal mining operations, such as ventilation of coalbed gas from underground mines, release coalbed CH₄ into the atmosphere, an important greenhouse gas whose concentration in the atmosphere is increasing. Because of these energy and environmental issues, increased research attention has been focused on the geochemistry of coalbed gas in recent years. This paper presents a summary review of the main aspects of coalbed gas geochemistry and current research advances.     

Water and energy

The science and engineering required for harnessing the energy from falling water are well established; the basic concepts are understood by the general public, and up to the last decade, there was strong public acceptance in developing water resource projects to provide an economic, reliable, and renewable source of electric power. At this time, however, water development projects are being critically analyzed with regard to overall justification on an economic, environmental and social basis. Further, various alternative power sources are being considered, which are widely variable with regard to economic justification, environmental effects, social and political problems, technology, reliability, and practical utilization.The purpose of this paper is to present a brief, nontechnical review of the principles of hydropower in order to give a non-water specialist an understanding of its overall potential and capabilities as well as problems related to its development. The paper considers the association between water and energy as related to hydropower, but it does not attempt to analyze the use of water in developing other forms of energy from thermal sources. The discussion presents a brief summary of (1) the historical background and physical concepts of hydropower; (2) the elements of hydropower engineering; (3) the overall availability of hydropower on a worldwide basis; (4) the integration of hydropower projects into multipurpose water development programs; (5) the environmental aspects of hydropower development; (6) and a case study of the Columbia River development.     

Large and giant hydrocarbon accumulations in the transitional continent-ocean zone

The petroleum resource potential is considered for the Atlantic, West Pacific, and East Pacific types of deepwater continental margins. The most considerable energy resources are concentrated at the Atlantic-type passive margins in the zone transitional to the ocean. The less studied continental slope of backarc seas of the generally active margins of the West Pacific type is currently not so rich in discoveries as the Atlantic-type margin, but is not devoid of certain expectations. In some of their parameters, the margins bounded by continental slopes may be regarded as analogs of classical passive margins. At the margins of the East Pacific type, the petroleum potential is solely confined to transform segments. In the shelf-continental-slope basins of the rift and pull-apart nature, petroleum fields occur largely in the upper fan complex, and to a lesser extent in the lower graben (rift) complex. In light of world experience, the shelf-continental-slope basins of the Arctic and Pacific margins of Russia are evaluated as highly promising.     

Methyl bromide: ocean sources, ocean sinks, and climate sensitivity

The oceans play an important role in the geochemical cycle of methyl bromide (CH3Br), the major carrier of O3-destroying bromine to the stratosphere. The quantity of CH3Br produced annually in seawater is comparable to the amount entering the atmosphere each year from natural and anthropogenic sources. The production mechanism is unknown but may be biological. Most of this CH3Br is consumed in situ by hydrolysis or reaction with chloride. The size of the fraction which escapes to the atmosphere is poorly constrained; measurements in seawater and the atmosphere have been used to justify both a large oceanic CH3Br flux to the atmosphere and a small net ocean sink. Since the consumption reactions are extremely temperature-sensitive, small temperature variations have large effects on the CH3Br concentration in seawater, and therefore on the exchange between the atmosphere and the ocean. The net CH3Br flux is also sensitive to variations in the rate of CH3Br production. We have quantified these effects using a simple steady state mass balance model. When CH3Br production rates are linearly scaled with seawater chlorophyll content, this model reproduces the latitudinal variations in marine CH3Br concentrations observed in the east Pacific Ocean by Singh et al. [1983] and by Lobert et al. [1995]. The apparent correlation of CH3Br production with primary production explains the discrepancies between the two observational studies, strengthening recent suggestions that the open ocean is a small net sink for atmospheric CH3Br, rather than a large net source. The Southern Ocean is implicated as a possible large net source of CH3Br to the atmosphere. Since our model indicates that both the direction and magnitude of CH3Br exchange between the atmosphere and ocean are extremely sensitive to temperature and marine productivity, and since the rate of CH3Br production in the oceans is comparable to the rate at which this compound is introduced to the atmosphere, even small perturbations to temperature or productivity can modify atmospheric CH3Br. Therefore atmospheric CH3Br should be sensitive to climate conditions. Our modeling indicates that climate-induced CH3Br variations can be larger than those resulting from small (+/- 25%) changes in the anthropogenic source, assuming that this source comprises less than half of all inputs. Future measurements of marine CH3Br, temperature, and primary production should be combined with such models to determine the relationship between marine biological activity and CH3Br production. Better understanding of the biological term is especially important to assess the importance of non-anthropogenic sources to stratospheric ozone loss and the sensitivity of these sources to global climate change.     

天然气水合物研究现状与未来挑战

人类在21世纪后期面临着油气资源枯渴,寻求洁净高效的新能源成为科学界追求的目标。为此,近三十年来,世界各国相继投入了大量的资金和人力开展新能源研究。目前,人们在一种重要的新能源---气水合物的基础研究、地质调查、勘探开发等领域取得了较大的进展;但尚存在许多急待解决的重大理论问题,如天然气水合物形成与分解的动力学过程和地质条件,气水合物资源量计算办法,经济型天然气水合物开采、开发模式,气水合物对全球气候的影响等。天然气水合物作为化石燃料,具有巨大潜力;作为甲烷碳库,是海底地质灾害的诱因;作为温室气体,对全球气候变化有着重要的影响作用。天然气水合物研究未来面临挑战。     

浅地幔系统的动力学作用

近年来地幔地球物理三维成像为地下深部构造和物质运动提供了大量数据和信息,促进了人们对浅地幔系统物质运动的特征和动力学作用的认知。按照运动的方向不同,浅地幔系统的物质运动可分为三种主要形式:水平运动、向上涌动和向下沉动。浅地幔系统物质向下运动由地球引力势能引起,其他方向的运动主要由热能和动能引起。除了动力来源之外,浅地幔系统物质运动的方向还取决于岩石圈和软流圈的物质属性,因为高黏度介质阻挡物质运动,而低黏度介质加速物质运动。软流圈物质的水平蠕动差异,产生了岩石圈的伸展、拆离和推覆等复杂构造,速度和动能较大软流圈物质的蠕动,一定会带动岩石圈板块物质的运动和变形。软流圈物质的向上涌动又可以进一步细分为上涌运动、上拱运动和穿刺运动三种方式,它们对上方岩石圈的作用效果是不同的。浅地幔系统的物质下沉运动有多种形式,包括俯冲、拆沉和交代作用,也经常伴随有软流圈物质上涌,在微观上是一种对偶运动。这种对偶运动造成了克拉通地壳的底垫和岩石圈的陆根。软流圈大规模的物质运动,包括大洋中脊物质上涌、大陆碰撞造山和大洋俯冲的前陆拉张,在全球地震层析成像图上都有清晰的反映。中国东南沿海一带是浅地幔系统物质运动的一个特殊地区,可能是由于白垩纪伊佐奈崎板块俯冲,激发东亚大陆边缘软流圈上涌,然后又造成大陆边缘岩石圈局部拆沉等一连串动力学作用叠加形成的。     

应用于海洋环境和海洋工程的光纤传感技术

随着海洋经济的高速发展,加强海洋国防安全、提高海洋资源开发能力和保护海洋生态环境作为相辅相成的三个方面日益受到重视。有效的传感检测技术是保证海洋安全、高效资源开发、防止污染、维持生态平衡、实时监测等方面至关重要的技术,也成为当前海洋领域内研究的热点。基于光纤传感器相比较于传统电传感器的独特优势,本文从海防及民生安全、海底自然灾害预测、海洋能源有效勘探、海洋工程安全监控,及海洋环境在线监测等几个方面阐述适用于海洋环境的光纤传感技术原理、系统及特点,为光纤传感技术在海洋中的大力推广起到一个抛砖引玉的作用。     

A consistent algorithm for quasigeostrophic energy and energy flux analysis

The energy flux vector is familiar to geophysical fluid dynamics, but only in the abstract. Equations for computing the energy balance and the energy flux vector (S) for a quasigeostrophic numerical ocean model are provided in both analytic and finite difference form. The multilayer model includes wind, lateral and bottom friction, and bathymetry. The finite difference approximation to the analytic energy balance is consistent with the finite difference approximation to the quasigeostrophic potential vorticity equation. An application of the algorithms to a simple steady ocean gyre illustrates their use. This choice of the flux vector (from an infinity of possibilities) has several advantages: it is computationally convenient; it is capable of field measurement; it has nice mathematical properties in the limit of small amplitude motion; and it facilitates intuition about the dynamics.     

Climate change impacts on U.S. Coastal and Marine Ecosystems

Increases in concentrations of greenhouse gases projected for the 21st century are expected to lead to increased mean global air and ocean temperatures. The National Assessment of Potential Consequences of Climate Variability and Change (NAST 2001) was based on a series of regional and sector assessments. This paper is a summary of the coastal and marine resources sector review of potential impacts on shorelines, estuaries, coastal wetlands, coral reefs, and ocean margin ecosystems. The assessment considered the impacts of several key drivers of climate change: sea level change; alterations in precipitation patterns and subsequent delivery of freshwater, nutrients, and sediment; increased ocean temperature; alterations in circulation patterns; changes in frequency and intensity of coastal storms; and increased levels of atmospheric CO₂. Increasing rates of sea-level rise and intensity and frequency of coastal storms and hurricanes over the next decades will increase threats to shorelines, wetlands, and coastal development. Estuarine productivity will change in response to alteration in the timing and amount of freshwater, nutrients, and sediment delivery. Higher water temperatures and changes in freshwater delivery will alter estuarine stratification, residence time, and eutrophication. Increased ocean temperatures are expected to increase coral bleaching and higher CO₂ levels may reduce coral calcification, making it more difficult for corals to recover from other disturbances, and inhibiting poleward shifts. Ocean warming is expected to cause poleward shifts in the ranges of many other organisms, including commercial species, and these shifts may have secondary effects on their predators and prey. Although these potential impacts of climate change and variability will vary from system to system, it is important to recognize that they will be superimposed upon, and in many cases intensify, other ecosystem stresses (pollution, harvesting, habitat destruction, invasive species, land and resource use, extreme natural events), which may lead to more significant consequences.     

The use of deposit modeling in the assessment of potential resources as exemplified by Caledonian stratabound sulfide deposits

Models for massive Caledonian sulfide deposits, formed in island are and ocean floor environments, are defined in terms of their deposit size and grade distribution, as well as the relation between the total amount of sulfides that could be potentially concentrated and the amount likely to be found in the largest deposit. Given the mineral resource and geological attributes of the island are and ocean floor models, the similarity between the models and unknown areas with a potential for these types of sulfide concentrations can be evaluated. This similarity is expressed as a favorability index whose distribution is probabilistically combined with the metal distribution of the model. This paper was presented at the International Geological Correlation Program (IGCP) Project 98: “Standards for Computer Applications in Resource Studies” held at Taita Hills, Kenya, November 8–15, 1977.     

地幔柱研究中几个问题的探讨及其找矿意义

本文在简要回顾地幔柱研究历史的基础上,针对近年来研究中提出的一些科学问题进行初步的探讨,提出了识别古老地幔柱的地质一环境一地球化学综合判别原则,提出了存在地幔柱的第3种类型,而埃达克岩很可能是第3类地幔柱的典型产物之一,指出了地幔柱对于成矿作用影响的双重性,也指出了地幔柱研究将对成矿学研究产生深刻的影响及其对于地质找矿的意义。中国西南部地区以二叠纪峨眉山玄武岩为标志的峨眉地幔柱最终喷发于海陆过渡相环境,具有与俄罗斯西伯利亚地幔柱类似的成矿条件和含矿性,有着良好的找矿前景。     

An integrated GIS and hydrochemical approach to assess groundwater contamination in West Ismailia area, Egypt

Groundwater is a very important resource across Ismailia area as it is used in domestic, agricultural, and industrial purposes. This makes it absolutely necessary that the effects of land use change on groundwater resources are considered when making land use decisions. Careful monitoring of groundwater resource helps minimize the contamination of this resource. This study developed a GIS-based model to assess groundwater contamination in the West Ismailia area based on its hydrochemical characteristics. The model incorporated five different factors which are standardized to a common evaluation scale. The produced factor maps include the depth to the water table, the potential recharge, the soil type, the topography, and the thickness of saturation. These maps are combined in ERDAS Imagine, ARC INFO, and ARC GIS software using geostatistics and a weighted overlay process to produce the final groundwater potential risk map. The model output is then used to determine the vulnerability of groundwater to contamination by domestic, agricultural, and industrial sources. The produced risk maps are then combined with the groundwater contamination potentiality map using an arithmetic overlay in order to identify areas which were vulnerable to contamination. The results of this study revealed that the groundwater is highly vulnerable to contamination that may result from the inappropriate application of agrichemicals and domestic and industrial activities. The produced integrated potential contamination maps are very useful tools for a decision maker concerned with groundwater protection and development.     

页岩气钻探冲洗液体系的研究与应用

中国页岩气资源开发潜力巨大,近年来页岩气勘探开发力度不断加大,对钻探工艺和技术的要求不断提高。页岩气地层岩性主要为泥岩、砂岩、页岩、碳质板岩、灰岩,该类地层胶结性差、破碎、井壁强度低,钻进中易出现孔壁失稳,发生坍塌、卡钻、埋钻等孔内事故,需要研制具有强抑制性、低成本、绿色环保的冲洗液体系来保证施工安全。本文通过对页岩气井壁稳定机理的探究,优选出一种适用于页岩地层双聚防塌和成膜防塌低固相冲洗液体系,该体系由抑制剂、防塌剂、降失水剂、润滑剂、封堵剂、流型调节剂等处理剂组成,具有良好的抑制性和胶结性。现场应用取得了良好的效果,保证了项目的顺利施工。     

Advection and removal of Pb and stable Pb isotopes in the oceans: a general circulation model study

Natural Pb-isotope variability in the oceans encodes information about the sources of continental material to the oceans, about ocean circulation, and about Pb removal. In order to use this information, we must understand the natural cycle of Pb in the oceans, which is overprinted by large anthropogenic input. In this study we use ²¹⁰Pb, which has not been significantly anthropogenically perturbed, to investigate oceanic Pb. GEOSECS ²²⁶Ra and model-derived atmospheric fluxes of ²¹⁰Pb are used to input ²¹⁰Pb into an ocean general circulation model. Irreversible scavenging of this ²¹⁰Pb onto settling biogenic particles and at the seafloor are tuned so that the model replicates the observed pattern of ²¹⁰Pb in the oceans. The best-fit model run provides a map of the variability of residence time for Pb. The global average residence time of Pb in this model is 48 yr, but there is over an order of magnitude variation between areas of high and low productivity. This is expected to enhance provinciality of Pb isotope ratios in the oceans. Because stable Pb isotopes are expected to behave in seawater in a similar fashion to ²¹⁰Pb, the pattern of removal of ²¹⁰Pb derived by the model can be used to investigate the behavior of stable Pb isotopes. We use a simplified input of Pb consisting of five point sources representing major rivers and a disseminated dust input. Although this simplified input scheme does not allow precise reconstruction of Pb concentration and isotopes in the oceans, it allows us to answer some first-order questions about the behavior of Pb as an ocean tracer. With a total Pb input of 6.3 × 10⁷ mol/yr (Chow T. J. and Patterson C. C., “The occurrence and significance of Pb isotopes in pelagic sediments,” Geochim. Cosmochim. Acta26, 263-308, 1962), the model predicts natural seawater Pb concentrations averaging 2.2 pmol/kg. Even in the absence of anthropogenic input, the model ocean exhibits a near-surface maximum in Pb concentration. And the model suggests natural Pb concentrations in the Northern Hemisphere an order of magnitude higher than in the Southern Hemisphere. A point source of Pb is suggested to dominate the seawater Pb inventory close to the source but is reduced to typically less than 10% of the inventory by the time that Pb is advected out of the originating ocean. This length scale of advection for Pb isotope signals confirms their potential as tracers of ocean circulation. Assuming an 8% dissolution of dust, their input to the open ocean are seen to be a significant portion of Pb inventory throughout the oceans and make up >50% of the Pb inventory in the model’s Southern Ocean. Finally, a preliminary investigation of the response of Pb-isotope distributions to changes in boundary conditions between glacial and interglacial times illustrates that significant variation in the Pb isotopes are expected in some regions, even for reasonably small changes in climate conditions.     

基于整装勘查区的大型能源资源基地区划研究

生态文明建设和资源安全保障是我国可持续发展的核心问题,而开展能源资源基地规划调查,进行资源潜力、技术经济和地质环境综合评价,是将两者进行有机衔接的有效手段。本次研究以服务2019～2021资源基地调查选区为目的,开展了主攻矿种与样品的选择,在此基础上利用学科研究法完成能源资源基地的初步划分,再采用比较研究法对划分方案进行了修正,最后通过数理研究法进行了基地筛选。基于以上研究,将我国矿产资源基地分为矿产资源勘查基地、矿产资源开发基地和矿产资源后备基地三类,并筛选出37个大型能源资源基地。     

多波束测深技术在洋中脊构造地貌解译中的应用

多波束测深技术在国际上是海洋科学研究、海底资源开发和海洋工程建设中的重要技术手段。基于对国内外多波束 地形数据的广泛调研,对洋中脊附近洋底构造地貌形态进行分析研究。文中利用不同扩张速率洋中脊附近的50 m分辨率的多 波束地形数据,基于数字地形空间分析方法,利用不同滑动窗口和阈值自动识别来提取洋中脊附近地形面的最大、最小曲率 以及坡度,并以此对洋中脊进行构造解译。对中大西洋洋中脊和东太平洋洋隆两个实验结果的定量分析表明,基于地形曲面 曲率和坡度的洋中脊构造解译方法是有效且可行的,其结果为洋中脊构造样式解译提供重要参考。但是相比之下,