冻土区管土相互作用研究综述

管道是长距离输送天然气或石油的最经济有效的工具之一,当管道穿越冻土区时,将面临土体冻胀融沉作用引起的管道弯曲变形和破坏,管土之间的相互作用为冻土区管道设计和运营的重要考虑因素。简述目前世界上主要的穿越冻土区管道工程（罗曼井管道、俄罗斯远东地区管道、美国阿拉斯加管道及中国寒区管道网）的设计理论发展,归纳总结了管土相互作用室内外相关试验、数值模拟分析理论和方法等方面的研究成果和发展现状,并针对冻土区管土相互作用的研究提出进一步的研究展望。     

The difference between oceanic and continental tholeiites: a fluid dynamic explanation

Continental tholeiites have higher SiO₂, K₂O and light rare earth element contents and more evolved isotopic characteristics than their oceanic counterparts. These differences can be explained if the compositions of the parent magmas to both types of tholeiites are similar but if continental magmas assimilate significant amounts of continental crust en route to the surface. Although there is little doubt that most continental tholeiites have assimilated crustal material, the lcoation and mechanism of assimilation remain uncertain. Longhi (1981) has argued that magmas derived directly from the mantle should crystallize little orthopyroxene. The abundance of orthopyroxene in most continental layered intrusions suggests that they have crystallized from magmas which have assimilated continental crust. Since orthopyroxene is an early crystallizing phase in layered intrusions, this assimilation must occur early, before the magma enters the chamber. Assimilation can occur at the margins of the dykes which feed magma chambers, depending on the nature of the flow. If the flow is turbulent the high temperatures at the centre of the dyke will extend to the margins and the magma will erode the dyke walls. If the flow is laminar, a conductive profile develops at the margin and the flowing magma chills against the walls, protecting them from thermal erosion. The nature of flow in a dyke can be predicted from the Reynolds number, the criteria for turbulence. Reynolds number calculations suggest that the flow of primitive magmas in continental dykes will be fully turbulent and, if this is the case, assimilation of low melting point components in the walls of the dyke is inevitable. It is therefore suggested that many of the geochemical characteristics of continental tholeiites result from melting at the walls of dykes as primitive magmas ascend through the crust.     

西藏普兰、吉隆沟一带藏南拆离构造新认识

西藏普兰、吉隆沟一带藏南拆离构造发育较为完整,主滑脱面位于基底聂拉木岩群与盖层肉切村群及绒沙组之间,但部分地段被中新世二长花岗岩侵蚀。调查研究认为,藏南拆离构造具有长期、多期活动性,不仅在中新世有多次强烈活动,而且在古生代至中生代长期伸展拉张作用过程中就已逐步形成并不断活动,至少在早石炭世、早二叠世、早三叠世、晚三叠世、早侏罗世等均有过较强烈至强烈的活动。     

An accumulation theory approach to the explanation of regional disparities in underdeveloped countries

This article argues that the current explanations (polarization and polarization reversal theories) for the existing and widening regional disparities found in the developing countries are unsatisfactory and lead to unhelpful policy initiatives. It accepts the existance of polarisation and equalization mechanisms but argues that the influence of the historically and spatially differentiated socio-economic structure is the proper focus of attention.     

The lithostratigraphy of the Les Echets basin, France: tentative correlation between cores

Two new long sediment cores (EC1 and EC3), recovered from different locations within the infilled basin at Les Echets, France, provide a new high-resolution record of terrestrial and lacustrine responses to climatic changes during Marine Isotope Stages (MIS) 3 and 2. The lithologies of the cores are described in detail and correlated with each other by stratigraphic marker horizons, fluctuations in organic matter and AMS radiocarbon ages. The tentative correlation of the new cores to those described and analysed by de Beaulieu et al. (1980) and de Beaulieu & Reille (1984a) provides a preliminary chronostratigraphic framework. Sedimentation during MIS3 started with accumulation of sands and silts and was followed by alternating gyttja and clayey gyttja silts. Exceptionally high sedimentation rates during MIS2 led to the infilling of the basin. Alternating organic-rich and minerogenic-rich sediments appear to coincide with changes in pollen assemblages (de Beaulieu & Reille 1984a) and suggest that millennial-scale climatic changes controlled lake productivity and catchment stability during most of MIS3.     

On self-similarity of premonitory patterns in the regions of natural and induced seismicity

Anticipating the scale invariance of rock fracturing processes, we applied Keilis-Borok’s algorithm M8, originally designed for identifying times of increased probability (TIPS) of occurrence of strong earthquakes (M < 8.0), retrospectively to Koyna earthquakes which occurred in the region after the impoundment of the Shivaji Sagar reservoir in 1962. The algorithm which enables diagnosis of TIPS from the 7th year onwards after the commencement of the earliest available data set showed that the 5.3 magnitude earthquake of 20 September 1980 indeed occurred within a time of increased probability. This result, apart from its potential application to recognizing future TIPS in the region, points to selfsimilarity between the premonitory patterns of natural and induced earthquakes and to scale-invariant nature of their processes. Further, a typical precursory rise in seismicity followed by a relative quiescence was also found to precede all the three larger earthquakes of the sequence.     

Ethnic and economic regions in Slovakia: A statistical and visual exploration of contemporary patterns

When Czechoslovakia was formed after World War I from the remains of the Austro-Hungarian Empire, the national boundaries imposed at the time did not accurately portray the areal extent of some ethnic groups. This was particularly true for the Hungarian minority which was established along the southern border of Slovakia. Because of this boundary arrangement, ethnic and economic divisions have resulted within Czechoslovakia and have continued in the new state of Slovakia. This paper analyzes the contemporary regional extent of the major ethnic groups in Slovakia at the district and commune levels. It also analyzes these ethnic patterns in light of a number of economic characteristics. Methods include mapping and analysis of various statistical tests using 1991 Czechoslovak census data. A strong relationship between Hungarian communes and agricultural employment is shown as well as a connection between employment in industry and Slovak ethnic regions. These findings suggest that the Hungarian minority has experienced a substantial geopolitical shift from the group in power to a peripheral society within Slovakia that continues to exhibit higher levels of agricultural reliance than the majority of ethnic Slovakian regions.     

煤层气井排采过程中煤粉运移规律研究

研究煤粉运移规律并以此制定减少煤粉产出的措施是保证煤层气井高产、稳产的关键。基于煤粉颗粒在煤岩通道中的运动学和动力学分析,建立了煤储层中煤粉随流体运移的数学模型,并依据现场调研资料研究煤粉粒径、通道孔径等因素对煤粉运移的影响。实例分析结果表明,煤储层中煤粉颗粒运移的临界流速表征了煤层气井开始产出煤粉的特征值,当流体流速达到临界流速时煤粉即发生运移。随煤粉颗粒和通道(喉道)半径不断减小,煤粉运移临界流速逐渐降低,颗粒更容易运移,将加重煤层气井的煤粉产出量。骨架煤粉颗粒的增大和相邻颗粒质心连线与通道方向间夹角的减小使得通道孔壁变得更加粗糙,煤粉运移临界流速逐渐提升,这会减轻煤层气井的出煤粉问题。该研究首次系统而定量的分析了煤储层中煤粉运移规律,为控制煤层气井出煤粉量和采取合理的排采作业方法提供了重要依据。     

A tentative explanation of the origin of “transform faults” (with a critical remark on the term)

The offsets on the ocean floor, usually called “transform-faults” are not shear faults common in solid Hookian rocks, but reflect the viscous Newtonian properties of laminar flow at the time when the upwelling magma along the spreading center was still in a liquid state. During spreading this liquid is carried away with the walls of the spreading center. This movement creates a pattern of stream lines in the liquid which run parallel to the direction of spreading. “Transform faults” are initiated along zones where a larger rate of shear disturbs the process of solidification. Consequently the strength of the basalt after solidification will be impaired along these zones. These weak zones will fracture under the thermo-elastic stresses during the final stage of cooling.The history of the term “transform fault” is discussed and the name “spreading offset” is proposed.     

Carbon solubility in core melts in a shallow magma ocean environment and distribution of carbon between the Earth’s core and the mantle

The solubility of carbon in Fe and Fe-5.2 wt.% Ni melts, saturated with graphite, determined by electron microprobe analysis of quenched metal melts was 5.8 ± 0.1 wt.% at 2000 °C, 6.7 ± 0.2 wt.% at 2200 °C, and 7.4 ± 0.2 wt.% at 2410 °C at 2 GPa, conditions relevant for core/mantle differentiation in a shallow magma ocean. These solubilities are slightly lower than low-pressure literature values and significantly beneath calculated values for even higher pressures [e.g., Wood B. J. (1993) Carbon in the core. Earth Planet. Sci. Lett.117, 593-607]. The trend of C solubility versus temperature for Fe-5.2 wt.% Ni melt, within analytical uncertainties, is similar to or slightly lower (∼0.2-0.4 wt.%) than that of pure Fe. Carbon content of core melts and residual mantle silicates derived from equilibrium batch or fractional segregation of core liquids and their comparison with our solubility data and carbon content estimate of the present day mantle, respectively, constrain the partition coefficient of carbon between silicate and metallic melts, in a magma ocean. For the entire range of possible bulk Earth carbon content from chondritic to subchondritic values, of 10⁻⁴ to 1 is derived. But for ∼1000 ppm bulk Earth carbon, is between 10⁻² and 1. Using the complete range of possible for a magma ocean at ∼2200 °C, we predict maximum carbon content of the Earth’s core to be ∼6-7 wt.% and a preferred value of 0.25 ± 0.15 wt.% for a bulk Earth carbon concentration of ∼1000 ppm.     

HyLogger-3, a visible to shortwave and thermal infrared reflectance spectrometer system for drill core logging: functional description

Australian Geological Surveys are the custodians of a major national asset in the form of historically drilled and archived drill cores of the top few kilometres of the continent acquired by government agencies and companies over many decades. The AuScope National Virtual Core Library (NVCL) component of the AuScope Earth Model comprises geological/rock samples, technology, people and database/delivery infrastructure located in six nationally distributed nodes and is aimed at extracting additional value from this asset. The technology components of the NVCL comprise an integrated suite of hardware (HyLogger-3) and software (TSG-Core) systems for the imaging and hyperspectral characterisation of drill cores in their original core trays and the interpretation of their contained oxide, carbonate, hydrous and anhydrous silicate mineralogy. The HyLogger-3 includes state-of-the-art Fourier Transform Spectrometers that continuously measure calibrated spectral reflectance from nominal 10 by 18 mm fields of view. These spectra are in turn passed through a series of automatic and semi-automatic pre-processing and mineralogical unmixing algorithms. These, along with numerous other tools in TSG-Core, output a variety of mineralogical and image products for use by scientists in many branches of the earth sciences. This paper provides a functional overview of the HyLogging hardware and software tools available in each of Australia's Geological Surveys.     

用陆块旋转解释藏东南渐新世-中新世伸展作用——来自点苍山及邻区变质核杂岩的证据

沿红河断裂带(RRFZ)分布的点苍山变质核杂岩是一个不完整的变质核杂岩,它由两个特征迥异的单元组成,包括被同构造二长花岗岩侵入角闪岩相构造岩组成的下盘和绿片岩相的拆离断层带。下盘岩石包括具有高温构造组合,具有指示左行走滑剪切运动方向的L型糜棱岩或LS型糜棱岩。拆离断层带是一个上盘向E到SE伸展剪切的低温剪切带,由具有剪应变和压应变的典型S-L糜棱岩构成。低温构造岩也包括发育于下盘的几个糜棱岩化似斑状二长花岗岩侵入体。变质核杂岩与西侧覆盖未变质的中生代沉积岩并置,东部受第四纪断层作用影响为沿洱海分布的更新世—全新世沉积盆地。通过对点苍山变质核杂岩的构造研究,结合邻区变质核杂岩的地质年代学及古地磁学分析,我们认为:位于东南亚红河断裂和实皆断裂带之间的扇形区域内出现的变质核杂岩与渐新世—中新世时期区域性伸展作用有关,而伸展作用是由印支地块的差异性旋转产生的,其原因是由于约33Ma开始斜向俯冲的印度板块的顺时针旋转和回退所致。     

Manufacturing establishment linkage patterns and the implications for peripheral area development: the case of Devon and Cornwall

This paper examines the significance for economic development in Devon and Cornwall of the material and business service linkages of manufacturing establishments. Using data from a survey of 366 manufacturing plants in Devon and Cornwall, the paper considers the extent to which differing types of establishment possess local suppliers and markets. It is found that local linkage is most marked in independent firms, relatively small plants and ones with decision-making freedom at the local level. This suggests that self-sustained growth requires a mobilisation of indigenous potential via growth in small and independent firms where linkage potential is greatest.     

Migration patterns of Neolithic settlements on the abandoned Yellow and Yangtze River deltas of China

Archaeological records of the Neolithic settlements on the eastern China coast between 35°N and 30°N, an area covering the abandoned Yellow River and the Yangtze River delta plains, reveal that Neolithic people moved from the Yellow River basin onto the northern coast for fishing, hunting and dry-land agriculture ~ 7000 yr ago. Marine transgression interrupted their activities on the low-lying (2-5 m in elevation) coastal wetlands between 6000 and 5000 yr ago, after which they reclaimed their land near the river mouths. Their migration routes on the southern Yangtze delta plain indicate another scenario: early Neolithic communities moved onto the plain for wet-rice cultivation. Despite relative sea-level rise from 7000 to 4000 yr ago, a large number of settlements were established on the lowlands between the eastern Chenier Ridges and the western Taihu Lake depression. The Chenier Ridges, with ~ 1.0 m higher topography than the adjacent coastal area, played a role in sheltering the Neolithic people. Subsequently, settlements waned considerably, possibly due to further marine inundation combined with cold climate. The present study shows that migration patterns of the Neolithic settlements are closely associated with a gradually rising sea level between 7000 and 4000 yr ago.     

Gravity trends and the growth of Australia: A tentative correlation

Gravity anomalies of wavelength 20 to 100 km mainly reflect density variations in the non‐sedimentary part of the crust. Elongate highs and lows of this wavelength can be used to divide the Australian continent into areas within each of which the elongate anomalies are subparallel. The relative ages of the gravity trends in adjacent areas can be inferred: those oblique to the boundary between areas are likely to be older, and those parallel, younger than the boundary. The inferred relative ages of gravity‐trend areas found using this procedure are consistent with the ages of the first major deformation of cratons inferred from geology and isotopic dating. The Australian continent is thought to have grown by the addition of areas of crust in the order suggested by analysis of the gravity trends. In regions of sedimentary cover the positions of the boundaries of the gravity‐trend areas are at present the best estimate of the extent of the geologically defined cratons.     

The role of economic sectoral structure as a policy mechanism towards more resilient peripheral regions: the case of South Africa

The role of economic sectoral structure in regional growth and development is widely acknowledged. However, there has been scarce reflection on its role as a policy instrument, particularly for peripheral regions. In reaction, this paper investigates the role of economic sectoral structure as a policy instrument towards more resilient peripheral regions. Through a multiple country policy analysis, the paper determines to what degree economic sectoral structure is reflected in regional development policies of 18 countries with predominantly rural characteristics and lagging regions. Moreover, the role of economic sectoral structure towards more resilient regions is quantified and measured for a specific peripheral region case in South Africa as developing country exhibiting poor economic resilience. The paper highlights related variety as a key ingredient for a region to reach a state of dynamic stability between adaptation and adaptability towards enhanced long-term resilience capacity of the peripheral region. The research concludes that policy focus should support the maintenance of the sectors and industries of comparative advantage on the regional scale, but strongly focus on sectoral comparative advantage within the national scale (if present) to establish a more robust region. This will establish and strengthen the identified peripheral growth centres as centres of national competitiveness and specialisation. Primary policy actions as emanated from the literature and the multiple country policy analysis will promote more efficient sectoral composition as key towards more resilient peripheral regions. It is acknowledged that these policy actions must be informed by a detailed regional economic analysis for different peripheral regions to determine inherent and latent economic potential and link with interdependent industries. This paper will highlight that regional policy should become more explicit by exploiting the role of economic and natural resources as growth engines for the peripheral regional economy in a more effective way through a multi-centred territorial structure.

     

中国新疆及周边国家和地区典型矿床特征对比研究

中国新疆及周边国家和地区是全球性中亚巨型成矿域的重要组成部分。黑色岩系矿床、斑岩矿床、块状硫化物矿床、陆相火山岩金矿床、与富碱性侵入岩有关矿床和砂岩铜矿等几种重要的典型矿床类型在该成矿域均已有不同程度的发现,特别是近几年来在该成矿域相继发现多个大型和超大型矿床的事实,说明中亚成矿域具有独特的成矿特点和巨大的找矿潜力。笔者通过分析研究中国新疆及周边国家和地区大型或超大型矿床的成矿规律和典型矿床特征,对新疆及相邻地区的大型或超大型矿床的找矿方向提出了见解。     

岩浆核杂岩和变质核杂岩特征对比及控矿实例——南秦岭牛山-凤凰山变质核杂岩和牛山北岩浆核杂岩构造群落及控矿模式

以南秦岭牛山-凤凰山变质核杂岩和牛山北岩浆核杂岩为例, 通过核杂岩的构造群落、变质程度、岩浆侵位与变形时代、构造层次与演化、控矿特征与控矿构造-蚀变岩相填图及测年研究, 对比2类核杂岩的特征及其控矿作用。结果表明, 2类核杂岩有相似的结构样式, 但构造群落和演化差别较大。牛山-凤凰山变质核杂岩核部为新元古代武当岩群和耀岭河岩组中深变质岩, 其中可见新元古代石英闪长岩和加里东期辉石岩-辉绿岩株, 说明是在新元古代或加里东期形成的。核杂岩与外围震旦系—泥盆系浅变质岩间由剥离断层及韧性剪切带分割。志留系梅子垭岩组为浅变质强变形的岩片组合, 发育多层次韧性剪切、固态流变、滑脱-逆冲-走滑变形3期新生面理及其置换。而牛山北岩浆核杂岩核部和外围是浅变质岩, 在核部和外围填图、测试时发现新元古代、早古生代、三叠纪、侏罗纪4期侵入岩, 与岩浆核杂岩相关的有三叠纪—早侏罗世二长花岗岩株和晚侏罗世花岗岩脉2期侵入岩。研究发现, 与岩浆核杂岩伴随的岩浆侵位、韧性剪切变形与热变质增温-变斑晶加大-自然金沿S2面理分布-金矿化热液蚀变等的时代均集中在晚三叠世—侏罗纪, 指示了时代较新的陆内造山期岩浆核杂岩的脆-韧性剪切变形-立交桥式岩浆-热力垂向增生-热液蚀变成矿时空关联特点及深部找矿方向。     

Migration in a transitional economy: Beyond the planned and spontaneous dichotomy in Vietnam

Migration is frequently portrayed as a negative force in its relationship with economic and social development. This negative perception is exhibited through describing population movements as either ‘forced’ (e.g. political and environmental refugees) or ‘voluntary’ movements (e.g. economic and uninhibited relocation). This paper examines the limitations of this conceptual dualism. It points out that the dualistic approach, widely used in the context of developing countries, simplifies a highly complex phenomenon by ignoring its essential heterogeneity and spatial and temporal dynamics. As such, it is limited in explaining and understanding the globally diversified, historically and politically contextualised situations. Focusing on the migratory experiences of contemporary Vietnam, the study identifies major patterns and trends of population mobility in the country in the past fifty years. It shows that despite the state’s continued attempts to reshape the spatial distribution of population over recent historical periods, the policy outcomes with respect to population mobility have been swayed as much by individuals and their families in pursuit of their own aspirations and livelihoods as by state plans. The Vietnam case has provided evidence of a much more complicated relationship between migration and livelihoods than the conceptual dichotomy assumes, and the opportunity for a richer set of policy options. We argue that the evidence from Vietnam, and elsewhere, warrants an integrated approach to studying migration, combining analysis at the macro- and micro-levels with the nexus lying at the critical decision-making point of the individual or household.     

用陆块旋转解释藏东南渐新世-中新世伸展作用——来自点苍山及邻区变质核杂岩的证据

沿红河断裂带(RRFZ)分布的点苍山变质核杂岩是一个不完整的变质核杂岩,它由两个特征迥异的单元组成,包括被同构造二长花岗岩侵入角闪岩相构造岩组成的下盘和绿片岩相的拆离断层带。下盘岩石包括具有高温构造组合,具有指示左行走滑剪切运动方向的L型糜棱岩或LS型糜棱岩。拆离断层带是一个上盘向E到SE伸展剪切的低温剪切带,由具有剪应变和压应变的典型S-L糜棱岩构成。低温构造岩也包括发育于下盘的几个糜棱岩化似斑状二长花岗岩侵入体。变质核杂岩与西侧覆盖未变质的中生代沉积岩并置,东部受第四纪断层作用影响为沿洱海分布的更新世-全新世沉积盆地。通过对点苍山变质核杂岩的构造研究,结合邻区变质核杂岩的地质年代学及古地磁学分析,我们认为:位于东南亚红河断裂和实皆断裂带之间的扇形区域内出现的变质核杂岩与渐新世-中新世时期区域性伸展作用有关,而伸展作用是由印支地块的差异性旋转产生的,其原因是由于约33Ma开始斜向俯冲的印度板块的顺时针旋转和回退所致。