口岸城市入境旅游流空间扩散路径实证研究——以上海市为例

本研究以东部典型入境口岸城市上海为研究对象,以市场调查资料为数据来源,从节点、方向及路径三个角度研究上海市入境旅游流的路径转移扩散规律。研究结果显示,以上海作为入境1：7岸的入境旅游流扩散人次排前十的节点城市依次为：北京、西安、杭州、成都、南京、桂林、广州、昆明、苏州、深圳;按照旅游流扩散方向可将入境旅游流扩散方向分为四类：北向、南向、西北向和西南向,并在每个方向上分别归纳出4条扩散路径,其中上海→北京→西安这→路径人数比例最高,上海→成都→西安→北京次之,上海→西安→北京处于第三位;同时研究显示,入境旅游流的扩散存在着路径依赖及路径依赖锁定现象。     

江南水利、河网与市镇——以菱湖镇及周边地区为中心(9—20世纪)

本文以菱湖镇为中心讨论了江南水乡市镇大型聚落在千年历史进程中形态演化的空间过程。菱湖镇的发展依托于唐末在此修筑的凌波塘;宋元时期,菱湖镇处于江南运河河网的枢纽,移民逐渐增多;明代以来,菱湖地区的水系逐渐被分割,形成局部河网;清初杨树坝修筑之后,菱湖镇的河网向死水化方向发展,民国时期在此河网基础上形成镇中固定的街市;明清时期菱湖镇及周边地区的农业经营以桑基鱼塘模式为主,形成了高度破碎化的河网,周边地区桑基鱼塘农业经济的发展依托菱湖镇供应粮食、肥料等生产资料和蚕丝集中交易市场。     

Particle size distribution of lithic assemblages and taphonomy of Palaeolithic sites

Lithic debris derived from knapping and used tools can be assimilated to simple sedimentary particles that may undergo size sorting when exposed to geomorphic processes such as streamflow or overland flow. Sorting can be identified by comparing the size distribution of archaeological assemblages to that of experimental core reduction sequences. A new database including different types of raw material (mainly flint and quartzite) and Palaeolithic debitage (blade, Levallois, discoid, on anvil, and shaping) has been built for this purpose. Palaeoeskimo data have also been added to illustrate microlithic industries. For all the debitages and raw materials, the particle size of knapping products >2 mm in width fits with a power-law distribution and shows only minor fluctuations, the range of which is always <15% between experiments (all steps of the chaîne opératoire included up to the final tool). A lithic assemblage derived from block/core knapping or blank/preform production will display a particle size distribution close to the experimental distributions if not subsequently modified. Modifications may originate either from sedimentary processes or from anthropogenic factors. To help distinguishing amongst these, data on the impact of both water flows on sedimentary particles or experimental assemblages, and anthropogenic processes such as importation-exportation (of core, preforms or finished tools) or uneven spatial distribution of the different steps in core reduction and tool production within a site, are reviewed. By contrast to anthropogenic modifications, sedimentary processes are generally typified by strong impoverishment in or selective accumulation of fine-grained (<10 mm) artefacts together with a low intra-site variability (spatial homogenization) or a downslope size trend. Archaeological case studies taken from French Palaeolithic site are then detailed. Evidence for lithic redistribution implies that care should be taken in archaeological site analysis since sorting may impact significantly the initial techno-typological balance of the assemblage.     

‘Encabsulation’: Horse-Drawn Journeys in Late-Victorian Literature

Recent scholarship has pursued the figure of the urban flâneur or flâneuse across the literature of the nineteenth century with spectacular results. In this article I turn the attention away from the solitary city stroller to the urban passenger by looking at one of the primary ways in which Victorians moved around London. In 1900 there were some 50,000 horses working in London, although by 1914 with the coming of motorized transport that number was down to 1400. Experiential perceptions of the city, of space and time, changed accordingly, as did the very nature of the city street. So the most compelling evidence of what Victorian cab journeys could and sometimes did feel like lies in their contemporary depiction. Although it draws upon detailed reports drawn from contemporary newspapers and applies some of the postmodern ideas of such theorists of urban geography as Michel de Certeau and Henri Lefebvre, the article is mainly concerned with literary representations of the horse-drawn cab, of the ‘hansom’ in particular. To journey across the city in a horse-drawn cab is shown to have run the risk of moral misunderstanding, sinister hijacking, financial humiliation and – more enticingly – of erotic encounter.     

Long‐term stability of fracture systems and their behaviour as flow paths in uplifting granitic rocks from the Japanese orogenic field

In granitic rocks, fracture networks typically provide pathways for groundwater flow and solute transport that need to be understood to assess the long‐term performance of deep underground storage or disposal facilities such as radioactive waste repositories. However, relatively little is known about the long‐term processes of fracturing and/or the longevity of flow paths (FP) in granitic rocks distributed within orogenic belts. To clarify these issues, Japanese plutons of different ages and in situ fractures in granite at the Mizunami Underground Research Laboratory (MIU) located in central Japan were studied. Detailed structural characterization and geochemical analysis of in situ fracture fillings sampled from a depth of 300 m were carried out to clarify the relationship between fracturing and mineral infilling processes. Different plutons show identical episodes of fracturing and fracture filling, consisting of: brittle tensile fracturing, due to decreasing temperature through the ductile–brittle transition after plutonic intrusion (Stage I); relatively rapid uplifting (ca. a few mm/year) accompanied by hydrothermal water circulation, which produced uncrushed layered mineral fillings (Stage II); and a period of low‐temperature meteoric water circulation following exposure after uplift (Stage III). The parageneses of carbonate mineral fracture fillings and their carbon isotopic compositions (¹⁴C, δ¹³C) show that there were distinct episodes of carbonate mineral precipitation during the rapid uplifting of a pluton. The carbonate minerals that formed during each episode incorporated carbon from a distinct source. The evolution of fillings identified here enables development of a specific model of fracturing and persistence of fluid‐conducting systems in the plutons of the orogenic field.     

The new Siberia

This paper assesses relationships between Scottish ice climbing and daily weather conditions between 1961 and 1990. Synoptic air flow and instrumental climate data from Braemar and Fort Augustus were analysed in relation to first ascents of ice climbs in the Cairngorms, and on Ben Nevis and Creag Meagaidh. Lagged weather variables were calculated and stepwise logistic regression was used to estimate optimum models for both areas. Significant variables are anticyclonicity, low minimum air temperature and northerly or easterly airflow (Cairngorms, P = 0.0006); and northerly or easterly airflow, low minimum air temperature and low precipitation (Ben Nevis and Creag Meagaidh, P < 0.0001). A five‐day cold spell is optimum for Ben Nevis and Creag Meagaidh. A week with relatively little precipitation is beneficial in both areas. Air flow direction is more influential than vorticity, the optimum predictors of ice conditions using synoptic data alone are a persistent easterly component (beneficial), and a persistent southerly and westerly component (detrimental), P < 0.0001.     

Fracture‐focused fluid flow in an acid and redox‐influenced system: diagenetic controls on cement mineralogy and geomorphology in the Navajo Sandstone

Differential cement mineralogy is influenced by depositional textures, structural deformation, pore fluid chemistry, and ultimately influences landscape evolution by introducing heterogeneities in erodibility. In Southern Utah, the region West of the Kaibab uplift known as Mollies Nipple (Mollies) in Grand Staircase‐Escalante National Monument exhibits a complex history of fluid–sediment interactions, which has resulted in a localized zone of anomalous diagenetic iron sulfate (jarosite) mineralogy in a well‐exposed dune–interdune deposit within the Navajo Sandstone. Mineralogy and geochemistry of cements within this region are examined using reflectance and imaging spectroscopy, field investigations, microscopy, and whole‐rock geochemical analyses. These data show that the in‐situ jarosite cement is localized to a plane along the highest ridge of the butte, providing an armor along with other secondary cements, which controls the butte's geomorphic evolution. The jarosite cement is associated with other mineralogies suggesting that the sulfate was one of the latest fluid‐related precipitates in the paragenetic sequence. It was preceded by a regional bleaching event, precipitation of clay cements, some localized concretionary iron oxide precipitation, and formation of deformation bands. At least one generation of dense iron oxide mineralization is associated with cataclastic brittle deformation predating the sulfate precipitation. Trace element geochemistry of cements shows certain metal oxide populations associated with extremely high (>2000 ppm) arsenic values. We interpret the combination of spatial mineral distribution, observed paragenetic sequence, and trace element geochemistry to suggest this region experienced acid sulfate diagenesis along fracture‐controlled fluid conduits related to weathering of proximal, unidentified, sulfides, or H₂S associated with deep source beds. Jarosite is highly soluble, and its presence suggests that abundant fluid flow has not occurred in this region since its formation. This terminal cement‐forming event must have occurred prior to sandstone exhumation and erosion to form the current extreme landscape at Mollies. This site exhibits the influence that fluid geochemistry, sedimentary mineralogy, and structural fabric have on geomorphic evolution.     

Geophysical and geochemical evidence of large scale fluid flow within shallow sediments in the eastern Gulf of Mexico,offshore Louisiana

We analyse the fluid flow regime within sediments on the Eastern levee of the modern Mississippi Canyon using 3D seismic data and downhole logging data acquired at Sites U1322 and U1324 during the 2005 Integrated Ocean Drilling Program (IODP) Expedition 308 in the Gulf of Mexico. Sulphate and methane concentrations in pore water show that sulphate–methane transition zone, at 74 and 94 m below seafloor, are amongst the deepest ever found in a sedimentary basin. This is in part due to a basinward fluid flow in a buried turbiditic channel (Blue Unit, 1000 mbsf), which separates sedimentary compartments located below and above this unit, preventing normal upward methane flux to the seafloor. Overpressure in the lower compartment leads to episodic and focused fluid migration through deep conduits that bypass the upper compartment, forming mud volcanoes at the seabed. This may also favour seawater circulation and we interpret the deep sulphate–methane transition zones as a result of high downward sulphate fluxes coming from seawater that are about 5–10 times above those measured in other basins. The results show that geochemical reactions within shallow sediments are dominated by seawater downwelling in the Mars‐Ursa basin, compared to other basins in which the upward fluid flux is controlling methane‐related reactions. This has implications for the occurrence of gas hydrates in the subsurface and is evidence of the active connection between buried sediments and the water column.     

Investigation of coupled hydraulic–geomechanical processes at the KTB site: pressure‐dependent characteristics of a long‐term pump test and elastic interpretation using a geomechanical facies model

The German Continental Deep Drilling Program comprising a pilot borehole down to 4000 m and a main borehole down to 9101 m in southeast Germany (KTB) is continuing to provide a unique opportunity for the identification of important factors and processes in deep‐seated fluid and energy transfer. In situ stress conditions significantly impact flow, transport and exchange characteristics of fracture networks that dominate the permeability of crystalline reservoir rocks. In this paper, several scales of information are combined to present a fully three‐dimensional hydraulic finite element model of the principal KTB fault zones, and linked to a geomechanical model describing the alteration of the hydraulic parameters with stress changes caused by fluid extraction. The concept of geomechanical facies is introduced to define and characterize architectural elements in the subsurface system. Evaluation of a long‐term pump test in the KTB pilot hole, June 2002–July 2003, coupled with a geomechanical model gives an insight into some of the elastic and nonelastic processes controlling hydraulic transport in the basement rocks. Trends in the decline of the permeability and the degree of storage in the system could only partially be explained by elastic processes, clearly indicating the importance of nonelastic processes. A number of inelastic processes are suggested as areas for further research.     

Temporal Patterns and Effects of Surface‐Water Diversions on Daily Flows and Aquatic Habitats: Bega‐Bemboka River,New South Wales,Australia

An understanding of the nature and magnitude of hydrological, physical habitat and physico‐chemical effects resulting from surface‐water diversions in river systems is essential for effective management of water resources. For most coastal‐draining rivers in New South Wales, however, there are few data available on irrigation diversions, their hydrological impacts and environmental effects. This paper therefore presents an analysis of mean daily surface‐water diversions for pasture irrigation from approximately three years of metered data and the resultant effects on daily flows and aquatic habitats in the Bega‐Bemboka River. The period of analysis of the hydrological effects of irrigation diversions is extended to the full length of record (approximately five years) for gauging stations most affected by irrigation diversions, using Maintenance of Variance Extension Type 1 (MOVE.1) modelling techniques. The annual mean, median and peak daily rates of water diversion by metered surface‐water licences used to irrigate 925 ha of dairy pasture are 10.5 Ml d^?1, 7.3 Ml d^?1 and 41.5 Ml d^?1, respectively. Diversion effects on flow duration statistics are such that the measured 90th and 95th daily flow duration percentiles at the gauging station most affected by upstream irrigation diversions are equivalent to the 97th and 99th flow duration percentiles, respectively, under MOVE.1 modelled natural flow conditions. While diversions for irrigation over the three‐year data period account for only 6.6% of total flow volumes, diversions as a proportion of daily surface‐water inflows increase exponentially under decreasing flow rates. Median and maximum daily diversion rates attain 91% and 118%, respectively, of total surface‐water inflows to the diversion‐affected reach when upstream inflows range from 15 to 20 Ml d^?1. This exponentially‐increasing relationship between daily diversion rates and declining surface‐water inflows suggests that ‘rule of thumb’ guidelines on sustainable diversion limits based on mean or median annual percentage diversion volumes need to be applied cautiously to river systems with no or limited capacity to manipulate flows to meet downstream consumptive demands.