皖南青阳及周边地区农业地质背景

根据农业上的应用需求,对皖南青阳及周边地区区域农业地质背景（包括区域地貌背景、地层和岩浆岩背景、地质构造和地球化学背景）进行了综合研究,并以此总结提出区域农业发展的地质制约因素和有利条件以及应该注意的地化因素的潜在影响。     

Seafloor topography and landform characteristics of Zengmu Shoal waters and their evolvement

The topography data of the Zengmu Shoal and its adjacent area are acquired by the SeaBat-8111 multibeam system.The full survey covering over the Zengmu Shoal area gives us new knowledge about the area. It is a flat underwater platform consisting ofcoral reefs, its fathom line is like a trap in near SN direction and its shape is like an isosceles triangle with the acute angle pointing to the north. The east and west sides ofthe shoal are steep while its south side is more gentle. As viewed from geological evolution, the Zengmu Shoal is a typical biologic coral landform caused by tectonic uplift.     

The rate of denudation of some British lowland landscapes

Developments in dating techniques applicable to the late Tertiary and Quaternary are giving us the ability to date past land surfaces. Where reasonable assumptions about the nature of such past surfaces and their partial preservation may be made, they can be reconstructed. This permits the contouring and measurement of the subsequent dissection, allowing not only calculation of the average rate of erosion over the elapsed time, but also information on the pattern of incision. Two examples where this has been attempted are present; both are dissected till surfaces in eastern England, one of Anglian and the other of Devensian age. The approach quantifies the disparity between the incision of valleys and the general denudational lowering of the surface which characterizes many landscapes. The technique is not only of academic interest, but potentially forms a useful line of approach to the assessment of the safety of the burying toxic wastes. © 1997 by John Wiley & Sons, Ltd.     

Terraces Development and Their Implications for Valley Evolution of the Jinsha River Since Late Pleistocene near Longjie,Yunnan

The drainage evolution and valley development of the Jinsha River is an important issue constantly concerned by researchers in geology and geomorphology. Despite hundreds of years of research, there is a big dispute on the formation time and the evolution process of the fluvial valley. Fluvial terraces are very important geomorphic markers for studying the formation and evolution of the fluvial valley. Through field investigation combined with Electron Spin Resonance (ESR) dating, we confirmed that 5 fluvial terraces were formed, and then preserved, along the course of the Jinsha River near the Longjie, which are all strath terraces. Among them, T5 developed on the base rock, with an age of (78±12) ka; all T4~T1 developed on the lacustrine sediments, named Longjie Group by Chinese, with an age of (29±1.4) ka, (26±2.4) ka, (23±1.4) ka, (18±1.7) ka, respectively. Compared with the global and regional climate change history, the terraces are all the result of the river responding to the climate change. T5 formed at MIS 5/4, and T4~T1 formed at the period of regional climate fluctuation. The relationship of terraces and the Longjie Formation, combined with sedimentary characteristics analysis demonstrate that the Longjie Formation is landslide dammed lake sediment. The landslide and blocking events.seriously influenced the valley evolution, inhibiting the river incising, and making the valley evolution defer to the mode of “cut-landside-damming-fill-cut” in the period of Late Pleistocene. Synthesized studies of the terraces and the correlative sediments indicate that the formation of the Jinsha River valley may have begun in the late Early Pleistocene.     

Ecohydrologic feedbacks controlling sizes of cypress wetlands in a patterned karst landscape

Many landforms on Earth are profoundly influenced by biota. In particular, biota play a significant role in creating karst biogeomorphology, through biogenic CO₂ accelerating calcite weathering. In this study, we explore the ecohydrologic feedback mechanisms that have created isolated depressional wetlands on exposed limestone bedrock in South Florida – Big Cypress National Preserve –as a case study for karst biogeomorphic processes giving rise to regularly patterned landscapes. Specifically, we are interested in: (1) whether cypress depressions on the landscape have reached (or will reach) equilibrium size; (2) if so, what feedback mechanisms stabilize the size of depressions; and (3) what distal interactions among depressions give rise to the even distribution of depressions in the landscape. We hypothesize three feedback mechanisms controlling the evolution of depressions and build a numerical model to evaluate the relative importance of each mechanism. We show that a soil cover feedback (i.e. a smaller fraction of CO₂ reaches the bedrock surface for weathering as soil cover thickens) is the major feedback stabilizing depressions, followed by a biomass feedback (i.e. inhibited biomass growth with deepening standing water and extended inundation period as depressions expand in volume). Strong local positive feedback between the volume of depressions and rate of volume expansion and distal negative feedback between depressions competing for water likely lead to the regular patterning at the landscape scale. The individual depressions, however, are not yet in steady state but would be in ~0.2–0.4 million years. This represents the first study to demonstrate the decoupling of landscape-scale self-organization and the self-organization of its constituent agents. © 2018 John Wiley & Sons, Ltd.     

典型地貌景观指数的多尺度效应分析 ——以山西省运城市为例

 景观指数作为定量描述景观特征的指数,具有明显的尺度效应。进行景观指数的尺度效应研究,对进一步理解格局与尺度之间的关系具有重要意义。本文以TM影像为基础,选择山西省运城市平原、丘陵、山地及综合地貌4种不同地貌类型,对7个常用景观指数进行了多尺度效应分析。结果表明:不同地形上斑块密度(PD)、景观形状指数(LSI)、结合度(COHESION)3个指数有明显的粒度效应,随粒度的增加呈现逐渐减少的变化趋势;最大斑块指数(LPI)、周长面积比分维数(PAFRAC)、景观聚集度(CONTAG)和Shannon多样性指数(SHDI)4个指数随粒度的增加几乎不发生变化。不同地貌的景观指数随幅度的变化规律比较复杂,景观形状指数(LSI)随幅度的增加呈现逐渐增加的趋势,其余6个指数在较小幅度范围内变化比较复杂,但随着幅度的增大有逐渐趋于平稳的趋势。针对研究区不同地貌类型,其景观指数在不同粒度和幅度下有较大区别,可以根据景观指数值的大小来区分地貌的复杂程度。     

深圳市人造旅游资源客源市场分析及开发利用研究

介绍深圳市旅游业发展概况,总结出资源开发利用中存在的主题内容过多集聚、技术含量偏低等主要问题,对深圳市一级、二级、三级旅游客源市场分别进行了回归分析,指出了深圳市旅游业发展的主导方向,应以高新科技为依托,加强对“参与性娱乐层面”和“文化性生活层面”旅游吸引物的创意与营造,重点吸引回头客。提出了旅游业可持续发展的若干建议。     

The Fractal Characteristics of Drainage Networks and Erosion Evolution Stages of Ten Kongduis in the Upper Reaches of the Yellow River,China

The fractal characteristics of drainage in the ten kongduis of the upper Yellow River were obtained using the box counting dimension, and the evolution stages of the watershed topography were defined by different ranges of the fractal dimensions of river networks (Dg). The results show that the fractal scaleless range of the Maobula River is 20–370 m based on a combination of artificial judgment, correlation coefficient test and fitting error. Other kongduis show good fractal characteristics in this fractal scaleless range as well. The box counting dimension can be used as a quantitative index of watershed topography fractal characteristics. The fractal dimension of stream networks is independent of the threshold contributing area used for extracting the drainage networks from the DEM. The values of Dg in the upper ten kongduis are in the range of 1.08?1.14. Both the runoff yield and the sediment yield are positively and linearly related with Dg. The positive relation between the sediment yield and Dg reflects the effect of landform features on sediment yield in the young and/or mature stages of landform evolution of the study area. By revising the critical value of Dg, the value of Dg of the basin in the young evolution stage is less than 1.06, while it is more than 1.06 for the basin in mature or old evolution stage. The upper ten kongduis are in the mature stage of landform evolution.     

Controls on the location,morphology and evolution of complex esker systems at decadal timescales,Breiðamerkurjökull,southeast Iceland

This paper uses detailed mapping of eskers to address three questions which are important for reconstructing meltwater behaviour beneath contemporary and ancient ice masses: ‘What controls the morphology of simple and complex esker systems?’, ‘How do esker systems evolve through time?’ and ‘Are esker patterns compatible with groundwater controlled hydraulic spacing of esker tunnels?’. Esker crestlines and widths are mapped on the Breiðamerkurjökull foreland for eight time slices between 1945 and 2007, from high resolution (~50 cm) aerial photography, permitting their long‐term morphological evolution to be analysed in a high level of detail. We find that complex eskers develop where meltwater and sediment is abundant, such that sediment clogs channels, forming distributary eskers. Isolated eskers are simpler and smaller and reflect less abundant meltwater and sediment, which is unable to clog channels. Eskers may take several decades to emerge from outwash deposits containing buried ice and can increase or decrease in size when ice surrounding and underlying them melts out. It has been suggested that groundwater–channel coupling dictates the spacing between eskers at Breiðamerkurjökull. Our results do not dispute this, but suggest that the routing of sediment and meltwater through medial moraines is an additional important control on esker location and spacing. These results may be used to better understand the processes surrounding esker formation in a variety of geographical settings, enabling a more detailed understanding of the operation of meltwater drainage systems in sub‐marginal zones beneath glaciers and ice sheets. Copyright © 2015 John Wiley & Sons, Ltd.     

Schmidt‐hammer exposure‐age dating (SHD) of snow‐avalanche impact ramparts in southern Norway: approaches,results and implications for landform age,dynamics and development

Schmidt‐hammer exposure‐age dating (SHD) was applied to the problem of dating the diachronous surfaces of five distal river‐bank boulder ramparts deposited by snow avalanches plunging into the Jostedøla and Sprongdøla rivers in the Jostedalsbreen region of southern Norway. Approaches to local high‐precision linear age calibration, which controlled in different ways for boulder roundness, were developed. The mean age (SHD_mean) and the maximum age (SHD_max) of surface boulders were estimated for whole ramparts, crests and distal fringes. Interpretation was further assisted by reference to R‐value distributions. SHD_mean ages (with 95% confidence intervals) ranged from 520 ± 270 years to 5375 ± 965 years, whereas SHD_max ages (expected to be exceeded by <5% of surface boulders) ranged from 675 to 9065 years. SHD ages from the Jostedøla ramparts tended to be older than those associated with the Sprongdøla, rampart crests were younger than the respective distal fringes, and use of relatively rounded boulders yielded more consistent SHD ages than angular boulders. The SHD_mean ages indicate differences in recent levels of snow‐avalanche activity between ramparts and provide insights into rampart dynamics as boulders are deposited on rampart crests and, in smaller numbers, on the distal fringes. SHD_max ages provide minimum age estimates of rampart age (i.e. the time elapsed since the ramparts began to form) and suggest that at least some of the ramparts have been developing since the early Holocene. Copyright © 2015 John Wiley & Sons, Ltd.