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Cathodoluminescence (CL) images of quartz grains in the Appin Quartzite from the aureole of the Ballachulish Igneous Complex (Scotland) reveal a textural complexity that we interpret in the light of published models of the evolution of the contact aureole. Five distinct generations of quartz can be discriminated in CL. The oldest of these is a dark luminescing mottled quartz (Type 1 quartz) that occurs in the centres of pre‐existing grains, in samples collected from 210 m to 0.1 m from the contact. Dark mottled quartz is interpreted to be unrecrystallized material and has a regional metamorphic CL spectral signature. The onset of contact metamorphism resulted in grain growth visible in CL as a series of fine‐scale alternating bands of bright and dark luminescing material (Type 2 quartz), which we attribute to infiltration of repeated pulses of small amounts of H2O along grain boundaries. Close to the intrusion, a subgrain‐scale network of intragranular, bright luminescing features could have resulted from either intragranular microcrack‐controlled infiltration of H2O at high temperatures or intergranular cracking followed by grain growth (Type 3 quartz). Broad bands of bright material on grain boundaries in samples that are inferred to have undergone partial melting are interpreted as quartz crystallized from the melt phase (Type 4 quartz). The final stage in the textural development is marked by a series of aligned fractures, detected in CL by nonluminescing material (Type 5 quartz) and corresponding closely with trails of fluid inclusions. These fractures are interpreted as the pathways for late‐stage, low‐temperature, retrogressive fluids. 相似文献
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The Illawarra Region some 80 kilometres south of Sydney is characterised by a prominent coastal escarpment that rises to 700 m within 12 km of the coast and forms a locus for frequent, high intensity rainfall events. One of the most recent recorded events occurred on 17 August 1998 with rainfall intensities at several pluviometers exceeding 120 mm hr‐1 over a duration of one hour, with up to 249 mm falling in 3.5 hours during the main storm burst. Detailed pluviometer data indicate that the storm was non‐stationary and moved down catchment producing a widespread zone of 120 mm hr‐1 intensity rainfall over a 30 minute duration across mid‐lower catchment areas after similar intensity but longer duration rainfall in catchment headwaters. Slope‐area reconstructions of peak discharge indicate that small catchments on the escarpment within the zone of maximum intensity experienced close to 100% rainfall‐runoff relationships, with peak discharges correlated to short duration (<1 hr) peak rainfall intensities. Widespread erosion occurred particularly where urban development had encroached on natural water courses. Debris/hyperconcentrated flows originating from both anthropogenic and natural sediment sources caused damage to urban areas. This paper provides an overview of the spatial and temporal characteristics of the 17 August 1998 storm, the hydrologic and geomorphic response of the streams, and the nature of damage to urban areas. It reassesses the frequency of recent high‐magnitude rainfall/flood events in the region, discussing the relationships between rainfall intensities, estimates of flood magnitudes and stormwater channel capacities. 相似文献
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国际资本流动研究评述 总被引:4,自引:1,他引:3
资本流动研究是90年代以来区域经济地理学前沿的研究热点之一,本文通过经济学与地理学在国际资本流动研究方面的比较,指出了目前经济地理学研究中存在的问题,并建议加强资本流入的负面影响研究,外资流入的适度规模研究,资本流动过程研究和动力机制研究。 相似文献
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黑龙江省东部城市密集区城市流强度分析 总被引:11,自引:1,他引:10
本文在对现有城市流理论进行疏理的基础上提出强化城市流模型,依据城市流强度值的计算,将黑龙江省东部城市密集区的城市分为三级:城市流强度值较高的佳木斯,是该区域的集聚辐射中心,为区域性中心城市;城市流强度值中等的牡丹江,是区域次级集聚辐射中心,为次级区域性中心城市;鹤岗、双鸭山、鸡西、伊春、七台河等市有较低的城市流强度值,城市的集聚与辐射功能微弱,初步形成地方集聚辐射中心,仅为行政区中心。通过各城市的城市流强度分析,指出黑龙江省东部城市密集区目前存在城市流强度低、城市流强度结构不合理等问题,并运用本文提出的强化城市流模型给出区域强化城市流的对策。 相似文献
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基于计量经济学模型的内地赴澳门游客量预测 总被引:7,自引:0,他引:7
本研究选择中国大陆地区人均可支配收入、消费者物价指数、国内生产总值,以及澳门与大陆之间商品进出口总额、港币与人民币汇率等变量,建立计量经济学模型估计内地赴澳门游客的数量。模型数据来源于澳门、大陆和香港官方公布的历年季度数据。在建立公式化的预测模型之后,本文还对模型的拟合优度和预测精度给予评估,对模型的基本假设进行了检验。本研究成果可作为有关政府部门和企业的决策参考。 相似文献
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基于APSO—SVR的山岳风景区短期客流量预测 总被引:1,自引:0,他引:1
根据山岳风景区短期客流量小样本、非线性等特征,本文提出基于自适应粒子群算法(Adaptive Particle Swarm Optimization,APSO)的支持向量回归(Support Vector Regression,SVR)模型,融合SVR处理小样本、非线性预测特性和APSO优化SVR参数的能力对山岳风景区短期客流量进行预测。来自山岳风景区黄山2008年~2011年暑期相关日数据的验证结果表明:与PSO—SVR、GA—SVR和BPNN等模型相比,APSO。SVR模型的预测准确性更高、误差更小,是进行山岳风景区短期客流量预测的有效工具。 相似文献
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基于SEA的AGA-SVR节假日客流量预测方法研究 总被引:2,自引:0,他引:2
节假日旅游客流量由于游客在短期内大量集中于同一地点、不同节假日休假时间长短、所处季节等不同,呈现复杂非线性特征和明显季节性特点.本文提出一种基于季节指数调整(Seasonal Exponential Adjustment,SEA)的自适应遗传算法(Adaptive Genetic Algorithm,AGA)-支持向量回归 (Support Vector Regression,SVR)预测模型,即基于SEA的AGA-SVR模型,并用国内著名5A级风景区黄山2008~2012年节假日客流量数据对模型进行验证.研究结果表明,基于SEA的AGA-SVR预测模型能够准确处理节假日旅游客流量预测中的非线性和季节性问题,较AGA-SVR和GA-SVR等方法具有更高的预测精度,在旅游预测领域应用前景广阔. 相似文献