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Jean Poesen 《地球表面变化过程与地形》2018,43(1):64-84
Soil erosion is a geomorphological and, at the same time, a land degradation process that may cause environmental and property damage, loss of livelihoods and services as well as social and economic disruption. Erosion not only lowers soil quality on‐site, but causes also significant sediment‐related problems off‐site. Given the large number of research papers on this topic, one might therefore conclude that we know now almost everything about soil erosion and its control so that little new knowledge can be added. This conclusion can be refuted by pointing to some major research gaps. There is a need for more research attention to (1) improved understanding of both natural and anthropogenic soil erosion processes and their interactions, (2) scaling up soil erosion processes and rates in space and time, and (3) innovative techniques and strategies to prevent soil erosion or reduce erosion rates. This is illustrated with various case studies from around the world. If future research addresses these research gaps, we will (1) better understand processes and their interactions operating at a range of spatial and temporal scales, predict their rates as well as their on‐site and off‐site impacts, which is academically spoken rewarding but also crucial for better targeting erosion control measures, and (2) we will be in a better position to select the most appropriate and effective soil erosion control techniques and strategies which are highly necessary for a sustainable use of soils in the Anthropocene. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
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Environmental geology of Bath,England 总被引：1，自引：0，他引：1
G. A. Kellaway 《Environmental Geology》1995,26(3):189-191
The hot springs of Bath, England, have been of importance to man for hundreds of years. It was a famous spa in Roman times. Subsequently, the springs were used during the 17th through the 20th centuries and extensive urban and commercial properties were developed at Bath using the water for medical and tourist-oriented activities. With urban and commercial development in the area, man's impact on the environment was substantial and typical environmental problems included pollution, land subsidence, or stability that effected construction, drainage, highways, and canals. During the growth of Bath in the 18th and 19th centuries these environmental problems were described by geologist William Smith and Joseph Townsend. Bath and vicinity provides a unique example of environmental geoscience. 相似文献
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为有效地监测海岛山体滑坡,找到滑坡的诱发因素,以达到海岛地区防灾减灾的目的。本文以北长山岛为例,针对采石引起的滑坡,利用GPS、三维激光扫描、无人机遥感、位移传感器4种滑坡监测方法,联合建立了北长山岛山后村山体滑坡监测系统。通过对比分析这4种方法发现,在三维激光扫描点云数据密集的滑坡体中、下部选择三维激光扫描获取的滑坡体形态数据,在点云数据稀疏的滑坡体上部选择无人机遥测获取的滑坡体形态数据,精确获取了不同时期滑坡体的挖方量、滑移量;位移传感器获取的实时位移监测数据可得到滑坡体的实时滑移动态,发现在其监测数据突变时滑坡存在滑动的风险。研究还发现采石和降雨是引起山后村滑坡体滑移的两个最重要因素,采石导致滑坡体体积整体减小,降雨导致滑坡体上部拉张加速并引起碎石滑塌。由于监测区环境条件的限制,该系统只能进行滑坡体的表面变形监测。研究成果可为其他海岛滑坡的监测乃至预警提供借鉴和参考。 相似文献
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Ian S. Evans 《地球表面变化过程与地形》2021,46(1):24-46
It has been proposed that most cirques are source-area depressions of large, deep-seated rock-slope failures. Yet the close relation between cirques and climate is convincing evidence of the dominance of glacial erosion, rather than rock-slope failure, in mountain cirque development and distribution. Cirque floor altitudes have a lower limit that varies with snowfall by 1000 m or more between windward and leeward sides of mountain systems. Glaciation levels and equilibrium line altitudes implied by cirques vary in parallel with those for modern glaciers. Cirques are often found mainly on the poleward or leeward slopes of individual mountain ranges, as are modern small glaciers (because of solar radiation and wind effects on ablation and accumulation). Most rock-slope failures (RSFs: rock slides, rock avalanches and gravitational deformations) do not involve the deep-seated rotational movement that would produce a cirque form. Although some deep-seated RSFs with arcuate head scars may be confused with cirques, identification as a glacial cirque is more confident as the floor is longer, wider and more gently sloping. Some scars from major RSFs may resemble poor or moderately developed cirques, but tend to have steeper floors, to be more scattered and closely related to geology, whereas glacial cirques develop on all rock types. Deep-seated RSFs high on slopes can be associated with seismic shaking, but cirques develop without relation to seismicity. Degree of cirque development can be related to duration of exposure to glaciation. Often RSFs are found adjacent to cirques, or in glacial transfluences; only a proportion are well situated to develop into glacial cirques. Valley-head cirques are continued down-valley by glacial troughs. The ‘overdeepening’ (rock basins with reversed slopes) found in a large minority of cirques is not due to rock avalanching, fluvial or periglacial erosion. The RSF proposal should therefore be rejected in favour of the traditional glacial explanation, without any nivation stage being necessary. Rock-slope failure is one of several possible ways of initiating hollows for glacier accumulation, as well as an ancillary process of cirque extension or widening through collapse of glacially oversteepened slopes. Headward extension of adjacent cirques on a ridge leads to displacement of the divide, sometimes by 2 km or more, lowering ridge and summit altitudes and producing the ‘glacial buzzsaw’ effect. Where a relatively lower snowline has led to cirque erosion on all sides of a mountain, cirque intersection lowers summits further. The buzzsaw hypothesis is not applicable, however, where remnants of a preglacial summit surface survive. © 2020 John Wiley & Sons, Ltd. 相似文献
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Since sea level stabilized 7000 yr bp , shelf seas experiencing semi‐diurnal tides will have been affected by streaming four times per day. If tidal erosion of bedrock were even only marginally efficient, the ~10 million streamings since then should have left geomorphological imprints. We examine high‐resolution multibeam sonar data from three areas with extreme tidal currents. The Minas Passage (Bay of Fundy) experiencing 8‐knot surface tidal currents was surveyed in 2007 with a multibeam sonar. In an area near to transverse dunes, which are evidence for bedload transport, the data show local overhanging surfaces near to the sediment‐rock contact, potentially created by abrasion by saltating particles. However, they are uncommon. In the Straits of Messina, where surface currents reach 10 knots, surveying revealed ridges lying oblique to the flow that are not obviously broken into separate outcrops by erosion. In the Bristol Channel, UK, sonar data collected where currents reach 3·4 knots at 1·5 m above the bed reveal outcrops of limestone with superimposed sand dunes, but only minor rounding of blocks. Holocene tidal currents have apparently been generally ineffective at eroding bedrock. We examine this issue further by compiling extreme tidal streams around the UK and from them estimate shear stresses, representing a macro‐tidal environment where peak surface currents reach 9·7 knots. Those data are compared with shear stresses in mountainous rivers where long‐term rates of erosion are comparable with tectonic uplift rates and are thus geomorphologically significant. Whereas river stresses reach 102–103 Pa, the largest tidal stresses are generally 101 and only rarely approach 102 Pa, too small for quarrying to operate generally. However, the vertical faces in the Minas Passage may represent the onset of abrasion. Given this limited evidence for abrasion, we explore conditions in the geological past for tides that may have locally eroded bedrock. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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浙江自然地理环境与采石文化的关系 总被引：2，自引：0，他引：2
浙江是石材大省,采石文化源远流长,近年来陆续发现多个古代采石遗迹。浙江采石文化是在浙江特有的地质、地貌、水系、气候等自然地理要素的综合作用下产生和发展起来的。浙江的地质条件是区域采石文化发生和发展的前提条件。“七山一水二分田”的地貌格局对采石文化的产生和发展具有重要影响。山地丘陵本身就是潜在的采石场所,蕴藏着丰富的石材资源,平原中的孤丘、平原与山地丘陵过渡地带以及盆地边缘地带常常分布有采石场,而特殊的河口地貌、漫长曲折的海岸线和数量众多的岛屿都会在一定程度上对采石文化产生影响。纵横交错的水系为石材的运输提供了便捷,有利于采石文化的传播,而河流水利工程的建设也会对采石文化产生一定的影响。特殊的沿海气候条件也会对采石文化产生一定的影响。采石文化对自然地理环境会产生一定的反作用,影响并且改变当地的地貌、水文、植被等自然地理环境要素。人类的采石活动对自然地理环境的改变主要是通过采石场景观的形成和石材的使用两条途径来实现的。 相似文献
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The scope of this study is to evaluate the parameters of the gypsum–anhydrite strata karstification under the influence of
the quarry exploitation of Jaziv sulphur field (West Ukraine) accompanying by drainage. The quarry drainage provoked the enormous
depression cone forming with 100 km2 in area and the corresponding intensification of chemical denudation of the gypsum–anhydrite strata. The gypsum karstification
rate for the 29-year period of the quarry drainage was 0.06% with the dissolved rock volume of 1,328,507 m3 that is about 80 times higher than in natural conditions. For the drainage period (29 years) the karst denudation rate was
17,952 m3/km2 against the natural background of 231.3 m3/km2. The absolute value of artificial denudation for the studied massif area is 1.79 cm for 29 years or 0.062 mm/year while the
denudation rate under natural conditions would be 0.231 cm for 29 years or 0.0008 mm/year. The forecasted volumes of the surface-evident
collapses are evaluated using the relationship between the calculated amount of dissolved sulphate rocks and volumes of the
current surface-evident collapses. According to this evaluation, the current collapses correspond to about 34% only from the
dissolved rocks volume calculated for the drainage period. 相似文献
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Marissa H. Kelly Alison M. Anders Sara Gran Mitchell 《Geografiska Annaler: Series A, Physical Geography》2014,96(2):147-159
We explore the relationships amongst bedding dip, basin aspect, and glacial landforms using field observations and GIS analyses of the northwestern Uinta Mountains of Utah. We examine basins on opposing sides of three ice divides in which quartzite beds of the Mount Watson Formation maintain a near constant dip. These areas provide contrasting relationships between ice flow and bedding dip directions while holding rock type and climate constant. We map the occurrence of three glacial erosional landforms: cliffs showing evidence of quarrying, scoured surfaces polished by abrasion, and overdeepenings. Cliffs and overdeepenings are more common in basins where bedding dips up‐basin, while scoured surfaces are more prevalent where bedding dips down‐basin. The significance of jointing in controlling glacial erosional forms is well established and we propose that bedding, as well as joints, dictates the geometry of quarried blocks and influences the spatial patterns of process dominance. Where bedding dips up‐basin, the geometry of pre‐existing weaknesses favours quarrying creating both cliffs and overdeepenings. In contrast, where bedding dips down‐basin, block geometry does not favour the creation of overdeepenings via quarrying and exposed bedding planes are subjected to glacial abrasion, producing scoured surfaces. 相似文献