The shapes of some mountain peaks in the Canadian Rockies     

D. M. Cruden  Xian-Qin Hu 《地球表面变化过程与地形》1999,24(13):1229-1241

Different mountain shapes in sedimentary sequences in the Canadian Rockies were enhanced by glacial erosion and have been modified postglacially by gravity-driven slope processes. Slope modification by both glacial erosion and postglaciation landslides is related to rock structure, particularly bedding dip, rock mass strength and slope geometry. Five mountain peak shapes in monoclinal sequences each fall into different ranges of bedding dips. Castellate (1) and matterhorn (2) mountains occur in sub-horizontal beds and their slopes on all sides follow combinations of bedding planes and joints. The overall slopes are generally 37 to 65° and oblique to both bedding and joints. Slopes in sub-horizontal beds may be controlled by their rock mass strength. Cuestas (3) develop in gently to moderately dipping beds. Dip slopes and steeper, normal escarpments form their cataclinal and anaclinal sides respectively, with the dihedral angle between them about 90°. Hogbacks (4) in moderately to steeply dipping beds have similar slope angles on both cataclinal and anaclinal slopes. Cataclinal slopes are either dip slopes or underdip slopes but anaclinal slopes are often steepened escarpments; the dihedral angle between the slopes is usually less than 90°. Dogtooth (5) mountains occur in steeply dipping to sub-vertical beds and the dihedral angle can be as low as 60°. Slope gradients in inclined beds are closely related to landslides, whose modes are controlled by bedding dips. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

蛇蟠岛野人洞景区某危岩体地质灾害风险分析与防治对策     

张精依  张中俭  罗昕  郑子琦  杨志法 《地质灾害与环境保护》2020,(1):57-62

我国山地旅游资源丰富。随着山地旅游资源的快速发展,山地旅游区地质灾害频发。以浙江省蛇蟠岛国家矿山公园野人洞景区某危岩体为例,在进行现场工程地质调查的基础上,根据2016年度该景区统计的客游量计算得出该研究区属于发生地质灾害高风险区的结论,并提出了“可绿化的加锚钢筋混凝土板与浆砌块石混合体”的防治对策。这对于其它山地景区的同类问题具有一定参考价值。  相似文献   

河南省十大温泉地热地质特征     

黄光寿  郭丽丽  黄凯 《地质与资源》2020,29(1):91-100

为了在河南省隆起山地区寻找地热资源,对隆起山地区出露的十大温泉地热地质特征进行了详细研究.隆起山地型地热资源受断裂构造控制,地下水通过深循环加热,沿深大断裂呈温泉形式出露地表.按水化学类型,温泉热水可划分为重碳酸盐型、硫酸盐型、硫酸盐氯化物型、硫酸重碳酸盐型及重碳酸硫酸盐型.  相似文献   

Synoptic sampling reveals spatial stability in flow and chemistry patterns despite large seasonal variability in a subarctic mountain catchment     

Arsh Grewal  Sean K. Carey 《水文研究》2024,38(2):e15080

Seasonality plays a critical role in cold mountain regions as variation in air temperature, ground thermal status, and precipitation phase alter the rate, timing and magnitude of hydrological and chemical transport. Additionally, cold mountain catchments can have highly variable topography, geology, permafrost, and landcover, which intrinsically add to this irregularity. Understanding how external and internal variability act to control mass fluxes requires sampling at a high spatial resolution over time, which rarely occurs in cold remote regions. In this work, we conduct five snapshot sampling surveys across 34 subcatchments during the ice-free period in Wolf Creek Research Basin (a mesoscale montane subarctic catchment) and two additional winter surveys across a subset of sites to assess the drivers of variability in stream chemistry and discharge. We sampled for specific conductance (SpC), major ions, and dissolved organic carbon (DOC) and used statistical metrics and Bayesian mixing analysis to quantify patterns of flow and chemistry across space and time. Our results indicate patterns in both flow and chemistry remain largely consistent across seasons for all solutes. However, there was weaker correlation of chemistry between sites, suggesting asynchronous behaviour within the catchment. There was evidence of increasing production of ions and DOC along the stream network during high spring flows but not during low flows. Although concentrations and flows exhibit high seasonality in subarctic mountains, this seasonal variability does not alter spatial patterns that arise from highly variable catchment characteristics.  相似文献   

哀牢山北段蛇绿岩中构造蚀变岩型金矿床特征     

田农  杨岳清 《地质与资源》1993,2(2):81-89

哀牢山北段蛇绿岩中构造蚀变岩型金矿床主要产于蛇绿岩上部的玄武岩和火山碎屑岩中,并受北西向断裂构造控制。区内分布有喜玛拉雅期煌斑岩和花岗闪长斑岩等脉岩,其与成矿作用密切相关。围岩蚀变以碳酸盐化为主,其次是绢云母化和黄铁矿化。矿石主要金属矿物为黄铁矿、毒砂、辉锑矿;包裹体成分以Na⁺、Zn²⁺、Cl^-、SO₄^2-、H₂O和CO₂为主;主要微量元素是As、Sb、W;稀土元素表现出轻稀土降低和重稀土相对增加的演化特征。硫、氧同位素研究表明,该矿床属于以岩浆热液为主,伴有部分地下水加入的中低温热液矿床。  相似文献   

浙江诸暨璜山地区韧性剪切带中金（银）矿床流体包体特征     

叶桂顺  叶有钟  赵关连  柏庆如 《现代地质》1994,8(3):291

矿物流体包裹体研究表明,浙江诸暨璜山地区赋存于韧性剪切带中的金（银）矿为大气降水浅成低温热液矿床。成矿流体主要为下渗的被加热了的大气降水,并有一定量的岩浆或火山热液加入;成矿溶液为中等盐度的中性偏碱性水;成矿作用是在低温、低压、弱氧化或弱还原条件下进行的。  相似文献   

多普勒天气雷达在扑灭"7.29"井冈山火警中的应用     

董家祥  王华军  吕作范 《气象与减灾研究》2005,28(1):50-52

从多普勒天气雷达产品和天气形势分析入手,对利用人工增雨手段扑灭"7·29"井冈山火警过程进行了技术总结,得到了一些有益的结论一是井冈山区处副热带高压西南象限时,有利于人工增雨;二是中低空弱的冷平流有利于井冈山局部对流的发展;三是井冈山区对流单体在初始阶段的移向移速与700hPa风向风速对应较好;四是罗霄山脉中部的低空平均径向速度入流区的演变,与井冈山局部对流单体关系密切;五是应按山脉走向来布设人工增雨作业炮点.  相似文献   

Origin of a bouldery diamicton,Kunlun Pass,Qinghai-Xizang Plateau,People's Republic of China: gelifluction deposit or rock glacier?     

Stuart A. Harris  Cui Zhijiu  Cheng Guodong 《地球表面变化过程与地形》1998,23(10):943-952

On the west side of the military road to Tibet in the Kunlun Shan, a major body of diamicton is moving slowly downslope from the ridge crest at 4800 m in a northerly and easterly direction. The material is derived from Middle Pleistocene till deposits and the underlying Pliocene alluvial gravels. More than 10 per cent of the material is composed of boulders longer than 2 m, 45 per cent has long axes between 0·5 and 2 m, while the matrix is a poorly sorted sandy loam. The mean annual air temperature is −7°C to −5°C and the mean annual precipitation is under 300 mm a⁻¹. The diamicton lacks a vegetation cover, in contrast to meadow tundra on the surrounding slopes. The diamicton mantles the north slope of the ridge, but splits into at least 16 separate tongues which are moving down fluvially graded valleys. The average slope of the landform is about 19°, while the mean slope of the fronts of the tongues is 21°. With one exception, the slope of the fronts does not exceed 25°, unlike true rock glaciers. The diamicton is up to 40 m thick in valley 4. The active layer was 12 to 30 cm deep in July at 4780 m, increasing to 1·5 to 2 m at about 4650 m. Ice contents in the permafrost may reach 57 per cent but 30 per cent is more usual The larger boulders act as braking blocks on the upper slopes of the landform and are frozen into the permafrost. The lower parts of the landform move at under 3 cm a⁻¹, whereas the fine-grained material in the active layer moves past the braking blocks on the upper slopes at up to 30 cm a ⁻¹. There is no direct evidence for flowage of the icy diamicton forming the deposit. It is therefore best referred to as a gelifluction slope deposit, and is the longest and most spectacular of such deposits described so far in the world. © 1998 John Wiley & Sons, Ltd.  相似文献   

Coarse bedload transport in a mountain river     

P. A. Carling  J. J. Williams  A. Kelsey  M. S. Glaister  H. G. Orr 《地球表面变化过程与地形》1998,23(2):141-157

Coarse bedload transport dynamics are investigated utilizing hydrodynamic and sediment transport data obtained in an extensively instrumented study reach located in Squaw Creek, Montana, USA. During 1991 and 1992, a number of discrete bedload transport events associated with the daily rise and fall in stream discharge were investigated. Data show that initiation of sediment transport was accompanied by a reduction in bed roughness and by changes in bulk hydraulic parameters. For larger discharges, coarser fractions of the bed material mobilized, and bedload transport rates and average hydraulic parameters stabilized. As discharge reduced, mobile coarse particles became less frequent and deposited fine particles were removed, resulting in an increase in bed roughness. These observations are attributed to the downstream translation of bar sediments during the passage of a hydrograph. Bedload pulses were aperiodic but spatially variable. Flow turbulence and velocity profile data obtained during low flows allowed comparison between average bed shear stress and apparent bed roughness estimates obtained using different approaches. © 1998 John Wiley & Sons, Ltd.  相似文献   

“上山”找金铜, “下山”找钨锡及其理由   总被引：5，自引：0，他引：5  

张旗  金惟俊  李承东  王元龙 《地球科学》2009,34(4):547-568

金铜和钨锡是两种不同类型的矿产资源, 金铜经常伴生, 钨锡经常伴生, 金铜和钨锡通常不在一起.研究表明, 金铜主要与埃达克岩和喜马拉雅型花岗岩有关, 产于加厚的地壳底部, 地表相应的出现高原或山脉; 钨锡主要与南岭型花岗岩有关, 代表减薄的陆壳, 产于平原区, 地势较低.因此, 从找矿的角度来说, 应当“上山”找金铜, “下山”找钨锡.文中识别出中国三叠纪以来可能存在过的7个山脉(华北北部山脉、西秦岭-东昆仑山脉、额尔古纳山脉、松潘-中甸山脉、湘赣山脉、浙闽山脉和哀牢山-羌塘山脉) 和2个高原(中国东部高原和湖南山地) 以及现存的青藏高原, 建议在上述高原和山脉上去找金铜矿, 指出喜马拉雅型花岗岩与金矿的密切关系, 是今后找金矿的一个重要目标.认为钨锡成矿目前仍然以华南为最佳, 但应注意在其他地块寻找钨锡的问题.   相似文献