20世纪90年代以来中外区域规划研究的对比分析

区域规划是国家政府进行区域管理的重要手段和方式之一。为了落实科学发展观和对区域发展有效宏观调控,区域规划成为国家“十一五”规划的重要内容。本文对比分析了1990年代以来国外区域规划研究的主要进展、以及我国区域规划研究的特点与不足,以期为推动我国当前新一轮区域规划的理论研究和实践创新提供有益启示。     

Initiation and development of pull-apart basins with Riedel shear mechanism: insights from scaled clay experiments

Typical pull-apart structures were created in scaled clay experiments with a pure strike-slip geometry (Riedel type experiments). A clay slab represents the sedimentary cover above a strike-slip fault in the rigid basement. At an early stage of the development of the deformation zone, synthetic shear fractures (Riedel shears) within the clay slab display dilatational behaviour. With increasing basal displacement the Riedel shears rotate and open further, developing into long, narrow and deep troughs. The shear displacement and the low angle with the prescribed principal basal fault set them apart from tension gashes. At a more evolved stage, synthetic segments (Y-shears) parallel to the basal principal fault develop and accommodate progressive strike-slip deformation. The Y-shears connect the tips of adjacent troughs developed from the earlier Riedel shears, resulting in the typical rhomb-shaped structures characteristic for pull-apart basins. The Strait of Sicily rift zone, with major strike-slip systems being active from the Miocene to the Present, comprises pull-apart basins at different length scales, for which the structural record suggests development by a mechanism similar to that observed in our experiments.     

Topography as a major factor in the development of arcuate thrust belts: insights from sandbox experiments

We have used sandbox experiments to investigate and to illustrate the effects of topography upon the development of arcuate thrust belts. In experiments where a sand pack shortened and thickened in front of an advancing rectilinear piston, the geometry of the developing thrust wedge was highly sensitive to variations in surface topography. In the absence of erosion and sedimentation, the surface slope tended to become uniform, as predicted by the theory of critical taper. Under these conditions, the wedge propagated by sequential accretion of new thrust slices. In contrast, where erosion or sedimentation caused the topographic profile to become irregular, thrusts developed out of sequence. For example, erosion throughout a hinterland caused underlying thrusts to remain active and inhibited the development of new thrusts in the foreland. Where initial topography was irregular in plan view, accreting thrusts tended to be arcuate. They were convex towards the foreland, around an initially high area; concave towards the foreland, around an initially low area. Initial plateaux tended to behave rigidly, while arcuate thrust slices accreted to them. Thrust motions were radial with respect to each plateau. Within transfer zones to each side, fault blocks rotated about vertical axes and thrust motions were oblique-slip. At late stages of deformation, the surface slope of the thrust wedge tended towards a uniform value. Initial mountains of conical shape (representing volcanoes) also escaped deformation, except at depth, where they detached. Arcuate thrust slices accreted to front and back. Where a developing thrust wedge was subject to local incision, accreting thrust slices dipped towards surrounding areas of high topography, forming Vs across valleys.Arcuate structural patterns are to be found around the three highest plateaux on Earth (Tibet, Pamirs and Altiplano) and around the Tromen volcanic ridge in the Neuquén Basin of northern Patagonia. We infer that these areas behaved in quasi-rigid fashion, protected as they were by their high topography.     

Fluid-bearing alkaline carbonate melts as the medium for the formation of diamonds in the Earth''s mantle: an experimental study

We have experimentally studied the formation of diamonds in alkaline carbonate–carbon and carbonate–fluid–carbon systems at 5.7–7.0 GPa and 1150–1700 °C, using a split-sphere multi-anvil apparatus (BARS). The starting carbonate and fluid-generating materials were placed into Pt and Au ampoules. The main specific feature of the studied systems is a long period of induction, which precedes the nucleation and growth of diamonds. The period of induction considerably increases with decreasing P and T, but decreases when adding a C–O–H fluid to the system. In the range of P and T corresponding to the formation of diamonds in nature, this period lasts for tens of hours. The reactivity of the studied systems with respect to the diamond nucleation and growth decreases in this sequence: Na₂CO₃–H₂C₂O₄·2H₂O–C>K₂CO₃–H₂C₂O₄·2H₂O–C>>Na₂CO₃–C>K₂CO₃–C. The diamond morphology is independent of P and T, and is mainly governed by the composition of the crystallization medium. The stable growth form is a cubo-octahedron in the Na₂CO₃ melt, and an octahedron in the K₂CO₃ melt. Regardless of the composition of the carbonate melt, only octahedral diamond crystals formed in the presence of the C–O–H fluid. The growth rates of diamond varied in the range from 1.7 μm/h at 1420 °C to 0.1–0.01 μm/h at 1150 °C, and were used to estimate, for the first time, the possible duration of the crystallization of natural diamonds. From the analysis of the experimental results and the petrological evidence for the formation of diamonds in nature, we suggest that fluid-bearing alkaline carbonate melts are, most likely, the medium for the nucleation and growth of diamonds in the Earth's upper mantle.     

天津地区井水位年变异常研究

近年来 ,中国地震预报学者开始关注井水位的年变异常及其中短期预测意义问题 ,但井水位年变异常判别采用动态图像的定性对比方法 ,表现出一定的随意性。针对这种现状 ,文中引进概率论与数理统计中的随机过程理论与时间序列分析技术 (盛骤等 ,1989) ,提出了“井水位动态年周期法”与“相对时段速率比较法” ,解决了井水位年变异常的定量识别方法 ,并应用到天津井网 2 1口井的观测数据 (1985年以来 )分析中 ,证明了该方法的可行性与有效性。分析结果表明 ,天津井网中有 7口井在首都圈邻区 4次中强 (MS≥ 5 .8)地震之前 ,表现出 17井次的井水位年变异常 ,且多在震前 1.5～6个月内出现 ,从而再次证明了井水位年变异常具有一定的中短期预测意义     

陆面特征非均一作用参数化及其对区域气候影响的数值模拟试验

本文首先改进了陆地下垫面特征非均一性的次网格尺度参数化方法，然后利用三维地气耦合的区域气候模式，设计一系列值试验，研究了下垫面特征改变对区域气候环境变化的影响，主要分析了陆地表面特征变化对我国苏南附近地区夏季温度化的影响，结果表明采用地下垫面特征非均一作用的次网格尺度参数化方法对于改进数值模拟结果的质量有一定效果。     

登陆热带气旋的大暴雨天气与一般暴雨对比分析及其雨强增幅原因的初探

本文以９０１５号热带气旋登陆后造成的省淮以南大暴雨天气为例，与８闪一般暴雨天气的热力动力条件进行对比，分析它们之间的异同点，并利用二维点尺度力学模式对地面中尺度锋区引起民环流进行模拟试验，结果表明，在热带气旋伸向东北部一条辐合线的偏北旗帜的中尺度锋区驱动扰动涡旋，在涡旋的上升部位可对大暴雨有增幅作用。     

重复航空摄影测量方法在乌鲁木齐河流域冰川变化监测中的应用

介绍重复航空摄影测量对比成图方法在监测乌鲁木齐河流域冰川规模和形态要素变化中的应用，以及成图过程中对控制加密和精度等问题的处理。检验表明，航空摄影测量对比成图方法能较准确地量测冰川长度、面积和储量等全形态要素的变化量，可以用于区域冰川变化的监测研究。测量资料表明，１９６４～１９９２年间，乌鲁木齐河流域１５５条冰川的规模均在缩小，冰川末端平均后退率为１２．４％，面积平均缩小率为１３．８％，冰储量减少１５．５％。     

Size of a debris flow deposition: model experiment approach

 The prediction of the dangerous extent of a debris flow deposition is of vital importance, but difficult to achieve. Precise prediction of the depositional boundary of a debris flow event is impossible, but the size of a debris flow deposition could provide some estimates of the area, length, width, and thickness of a debris flow deposition. Based on in situ depositional experiments performed on a debris flow creek just after debris flows, a rule of thumb expressed by a group of equations containing the multiple-variate nonlinear functions is proposed in this paper. The interrelationships between the size and the causation also are discussed, and some empirical formulae to calculate the causative parameters for different regions are presented. Received: 24 April 1995 · Accepted: 21 June 1995     

氧化亚铁硫杆菌水文地球化学作用实验初步研究

在某些地球化学环境中，微生物对水─岩相互作用有重要影响。本文通过氧化亚铁硫杆菌与硫化物相互作用试验，初步研究了氧化亚铁硫杆菌作用引起水─岩介质变化特征，分析了氧化亚铁硫杆菌水文地球化学作用的一些规律。