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1.
长白山二道白河源区倒石堆发育特征 总被引：1，自引：0，他引：1
1987—1988年,笔者先后四次到长白山地区进行野外考察,对倒石堆这一重要的山地地貌类型的形态,沉积特征及发育过程进行一定程度的研究。通过进一步的室内分析和整理得出若干结论。 相似文献
2.
青河县三道海子石堆墓初探 总被引：1，自引：0，他引：1
本文在实地考察与分析历史资料的基础上,对青河县三道海子石堆墓做了详细考证,认为三道海子石堆墓是一座蒙古族的皇陵,是蒙古帝国第三代大汗──贵由汗的陵墓。 相似文献
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青海县三道海子石堆墓初探 总被引：3，自引：2，他引：1
本文在实地考察与分析历史资料的基础上,对青河县三道海子石堆墓做了详细考证,认为三道海子石堆墓是一座蒙古族的皇陵,是蒙古帝国第三大代大汗－贵由汗的陵墓。 相似文献
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天山山区公路山地灾害主要出现于海拔>3000米的现代冰缘区,遭山地灾害威胁较严重的是独山子—库车公路和乌鲁木齐—库尔勒公路。较突出的山地灾害是雪崩、风吹雪、自然积雪、泥石流与石冰川,其次是倒石堆、热融滑塌和热融掏蚀。该区公路山地灾害防治应采取预防为主、防治结合的原则,此外应加强灾害预报。 相似文献
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通过多波束水深资料,研究了南海西沙海域甘泉海台地形特征。甘泉海台顶面平坦,坡度通常＜1°,但存在3级阶梯状地形,水深范围介于550~700 m,这3级阶梯状地形总体向南西倾斜。在600~850 m水深范围内,甘泉海台普遍发育水下阶地,识别出的水下阶地多达5级,其中西侧阶地发育程度优于东侧。初步认为：甘泉海台顶部和周缘阶梯状地形是冰期―间冰期旋回尺度上全球海平面变化和南海地壳沉降共同作用的结果,这２个因素可能也控制着南海其他珊瑚礁的发育演化。在850~1 300 m水深范围内,甘泉海台周缘存在倒石堆状地形,推测主要是珊瑚礁碎屑从礁顶搬运沉积的产物,甘泉海台西北侧比东南侧倒石堆地形更加发育的现象估计与甘泉海台顶面向南西倾斜直接相关。 相似文献
8.
鳞毛蕨天山云杉林粗死木质残体贮量及其分解动态 总被引：6，自引：0，他引：6
为了丰富我国森林粗死木质残体研究的对象类型,并为探讨粗死木质残体在天山云杉天然更新中的生态作用奠定基础,借助粗死木质残体5级分类系统,采用临时标准调查法对西天山国家级自然保护区原始鳞毛蕨天山云杉纯林粗死木质残体的贮量、养分含量及其分解动态进行了研究.结果表明:(1)鳞毛蕨天山云杉林粗死木质残体体积贮量为337.61 m3/hm2,生物量为87.98mg/hm2;倒木树干是粗死木质残体的主体组成部分,占总体积的98.09%;(2)以基本密度(比重)为衡量指标,倒木腐朽等级越高,其密度越小,倒木分解符合单项指数衰减模型,分解常数为0.01174.5个不同腐朽等级倒木的平均滞留时间依次为4年、18年、38年、68年和92年.在自然状态下,倒木分解50%、90%和95%所需时间分别为59年、196年和255年;(3)倒木有机碳、全N、全P、全K、Na+的平均含量依次为55.93%±1.42%、0.34%±0.07%、0.12%±0.01%、0.06%±0.01%和0.03%±0.002%,Ca2+、Mg2+的平均含量分别为56.74±4.87 g/kg和34.89±3.66 g/kg,不同养分的变化趋势不同,但同一养分在不同腐朽等级倒木之间的差异不显著. 相似文献
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天山乌鲁木齐河源区冰缘地貌的分布和演变过程 总被引：9，自引：1，他引：9
根据1985—1989年度的野外考察和定位重复测量、坑探、物探、砾向组构及地肮衣测年、室内分析等,总结出本区各类冰缘地貌空间分布特点和在发生学卜的联系与转化;分析了基岩寒冻风化速率、倒石堆、岩屑坡、石冰川的分布、运动特点和发育年代;讨论了冻疱和烛状冰型冻胀丘、泥流舌、石环和热喀斯特沉陷的分布、演变及成因;概述了沉积物室内分析得出的结果。 相似文献
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《山地学报》2016,(6)
冰-草生态交错带是陆地生态交错带的重要组成部分,在全球气候变暖背景下,研究其环境特征对于保护该带脆弱的生态环境具有重要意义。以提孜那甫河流域山区特有的冰-草生态交错带为研究对象,利用MODIS产品,基于遥感技术对其环境特征进行定性、定量分析。结果表明:交错带常年低温,年平均温度为-4.79℃,5—9月气温0℃,是主要的融雪期,融雪水量为5.4×108m~3,占提孜那甫河总径流量的70.03%,是叶尔羌绿洲重要的水源补给来源,当年9月到次年5月气温均在0℃以下为主要的积雪期;处在发育初级阶段的寒冻土和寒漠土广泛分布于交错带内,冻融荒漠化普遍且严重,植被分布极为稀疏;交错带主要包含高山流石坡、高山倒石堆、高山稀疏垫状植被等三种极干旱的内陆高原荒漠景观类型。 相似文献
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OLIVER SASS 《Geografiska Annaler: Series A, Physical Geography》2010,92(3):375-391
Lichenometric measurements using Rhizocarpon ssp. were carried out on 20 talus slopes in the cirques of the Finstertal valley (Austria) at an elevation of 2300–3000 m a.s.l. The aim was to assess activity patterns on selected slopes and between the slopes of the study area, to find evidence of rockfall pulses in the last centuries and to calculate rockwall retreat rates. A calibration curve was derived from five sites of known age and adapted to the prevailing size of talus boulders. We measured the five largest lichens on more than 300 boulders and the percentage coverage of Rhizocarpon‐free clasts on more than 1000 test fields. Most of the investigated talus cones are characterized by moderate rockfall supply, with the apex being more active than the talus foot and moderate redistribution by avalanche and debris flows. Considerably enhanced activity was found under rockwalls influenced by permafrost, particularly on the north faces at an elevation of >2600 m a.s.l. At currently moderately active sites, boulder falls seem to have been slightly more frequent in the late nineteenth and first half of the twentieth century. In positions where permafrost is expected in the rockwalls, a weak maximum in the late nineteenth century and highly active present‐day conditions were found, the latter being assigned to current permafrost melt. Rockwall retreat rates derived from lichen coverage are between 400 and 1500 mm/ka which is in good concurrence with talus volume assessments, but higher than the rates derived from direct rockfall measurements. The rates derived from lichen coverage have to be taken with caution as the effects of debris redistribution are hard to quantify. 相似文献
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表碛覆盖型冰川是中国西部较为常见的冰川类型。表碛层存在于大气—冰川冰界面,强烈影响大气圈与冰冻圈之间的热交换。表碛厚度的空间异质性可极大地改变冰川的消融率和物质平衡过程,进而影响冰川径流过程和下游水资源。基于Landsat TM/TIRS数据,运用能量平衡方程反演了贡嘎山地区冰川表碛厚度,研究了贡嘎山地区冰川在1990—2019年间表碛覆盖范围及厚度变化情况,同时对比了东西坡差异。结果表明：① 贡嘎山地区冰川表碛扩张总面积达43.824 km2。其中,海螺沟冰川扩张2.606 km2、磨子沟冰川1.959 km2、燕子沟冰川1.243 km2、大贡巴冰川0.896 km2、小贡巴冰川0.509 km2、南门关沟冰川2.264 km2,年均扩张率分别为3.2%、11.1%、1.5%、0.9%、1.0%和6.5%;② 海螺沟冰川、磨子沟冰川、燕子沟冰川、大贡巴冰川、小贡巴冰川、南门关沟冰川表碛平均增厚分别为5.2 cm、3.1 cm、3.7 cm、6.8 cm、7.3 cm和13.1 cm;③ 西坡冰川表碛覆盖度高,表碛覆盖年均扩张率低,冰川末端退缩量小;东坡冰川表碛覆盖年均扩张率高,但表碛覆盖度总体低于西坡,冰川末端退缩量大。 相似文献
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资勒沟泥石流灾害及特征 总被引：1，自引：1，他引：0
1987年6月5日晨,资勒沟暴发了一场灾害性泥石流,沟口的公路桥和凉红道班被摧毁,致使5名道班工人死亡。该沟是一条暴发频率很低的泥石流沟。这场泥石流是由局地暴雨激发而引起的,雨强为55.2毫米/小时。泥石流为粘性,容重2.18吨/立方米,最大流量352.1立方米/秒,最大流速10—12米/秒,总冲出物方量约8万—9万立方米。 相似文献
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HIROYUKI OBANAWA YUICHI S. HAYAKAWA YUKINORI MATSUKURA 《Geografiska Annaler: Series A, Physical Geography》2009,91(4):269-278
On the basis of a space–time substitution, rates of cliff retreat and talus development overthe pasttens ofthousands of years were quantified for valley‐side slopes along the Shomyo River with a known rate of waterfall recession. Detailed profiles of the valley‐side slopes were obtained at 19 sites along the river by map reading and field survey, and the morphologic characteristics of the slopes were then measured. By combining the locations of the slopes with the recession rate of Shomyo Falls, it is estimated that the growth rate of the talus slope is 3.9–7.2 mm/yr, the rate of decline of the cliff is 2.0–4.0 × 10?4 deg/yr, and the retreat rate of the cliff top is 6.2–11.6 mm/yr. 相似文献
15.
Lateglacial and Holocene talus slope development and rockwall retreat on Mynydd Du, UK 总被引：1，自引：0，他引：1
Modification of Lateglacial and Holocene talus sheets by debris flows and gully incision on Mynydd Du, Wales, has resulted in a convergence of upper slope form characterised by an upper rectilinear slope gradient of 36°±3° and a range of concavities of c. 0.1–0.2. In most cases, gully incision and accumulation of debris cones have led to an increase in slope concavity. Evidence for talus erosion, reworking and redeposition on the upper slope emphasises secondary reworking processes, as well as primary talus accumulation on the upper slope, and permits construction of a model of talus development at Mynydd Du. On the basis of talus volume, calculation of the first rockwall retreat data set for southern Britain suggests that c. 7.1 m (84%) of overall rockwall retreat (8.5 m) took place during the Lateglacial, and only c. 1.4 m (16%) occurred during the Holocene. These figures imply that Lateglacial retreat rates ranged from 1.01 to 2.44 m ka−1, with an overall mean rate of 1.23 m ka−1. In contrast, Holocene rockwall retreat rates range from 0.10 to 0.17 m ka−1, with a mean rate of 0.12 m ka−1. Approximately 27% of cliff retreat is attributed to microgelivation. While similar to Holocene and present-day alpine environments, these Lateglacial retreat rates are one order of magnitude higher than most equivalent values for arctic sites. This reflects both ‘alpine-style’ diurnal freeze–thaw activity on Mynydd Du during the Younger Dryas and paraglacial rock-mass instability following deglaciation. Assuming an exponential decline in rockwall sediment release, it is estimated that approximately half the talus had accumulated within c. 1 ka of deglaciation. At one site, paraglacial talus accumulation appears to have contributed significantly to the glacial sediment transport system of a subsequent ice advance. Present-day rates of rockwall retreat and talus accumulation by rockfall are estimated to be 0.014 and 0.022 mm yr−1 (m ka−1), respectively, similar to values for other British sites and markedly lower than Holocene rates of cliff recession due to microgelivation. By implication, the geomorphic significance of microgelivation may have been greatly underestimated in studies of inland rock-slope evolution in temperate, mid-latitude environments. 相似文献
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Depending on thickness, debris‐cover can enhance or reduce ablation, compared to bare‐ice conditions. In the geological record, hummocky moraines often represent the final product of the melt‐out of ice‐cored moraines, and the presence or absence of such moraine deposits can have paleoclimatic implications. To evaluate the effects of varying debris‐cover and climate on ice‐melt in a maritime mid‐latitude setting, an 11‐day ablation stake study was undertaken on ice‐cored moraine at Fox Glacier, on the western flank of the New Zealand Southern Alps. Ablation rates varied from 1.3 to 6.7 cm d?1, with enhancement of melt‐rate under thin debris‐covers. Highest melt‐rates (effective thickness) occurred under debris‐cover of c. 2 cm, with ～3 cm being the debris thickness at which melt‐rates are equal to adjacent bare‐ice (critical thickness). Air temperature from nearby Franz Josef Glacier allowed for a simple degree‐day approach to ablation calculations, with regression relationships indicating air temperature is the key climatic control on melt. Digital elevation models produced from topographic surveys of the ice‐cored moraine over the following 19 months indicated that ablation rates progressively decreased over time, probably due to melt‐out of englacial debris increasing debris‐cover thickness. The morphology of the sandur appears to be strongly determined by episodic high‐magnitude fluvial flows (jökulhlaups), in conjunction with surface melt. Thus, ‘hummocky’ moraine appears to be a transient landform in this climatic setting. 相似文献
17.
S.A. Harris G. Cheng X. Zhao & D. Yongqin 《Geografiska Annaler: Series A, Physical Geography》1998,80(2):123-133
Active block streams are common on the slopes of mountains on the northern, drier portion of the Qinghai-Xizang (Tibetan) Plateau. Between 1990 and 1995, the authors studied a block stream northeast of the crest of the Kunlun Pass at latitude 35°50’N, longitude 94°05’ E. It occurs on a 31° slope facing southwest at 4800 m altitude and consists of a 15 cm layer of blocks moving downslope over a sandy loam of lacustrine origin. The blocks are derived from both frost shattering of exposed bedrock and by ejection of blocks from the till capping the hill. No water flows in the block stream and its surface is level with the surrounding slope. Mean annual air temperature is –6°C and mean annual precipitation is about 320 mm. The few plants growing between the blocks exhibit elongated stems and/or roots, indicating movement of the upper layers of blocks relative to the underlying materials. Average mean annual downslope movement of the surface blocks ranges up to 95 cm but varies both across the block stream and also along its long axis. The blocks are gradually extending further downslope. Comparison of movement of lines painted on stones in summer and winter shows that most of the movement occurs in winter. The stones usually rotate randomly as they move, probably by sliding on ice. There is no obvious sorting or rounding of the blocks during movement downslope. The deposits produced differ from talus/scree sediments as they have a dip of less than the maximum angle of rest of dry sediment (c. 33°) and also show no sorting downslope. The movement of material takes place predominantly in winter, rather than in summer and the deposits occur in areas of negligible snow cover. Ground temperatures suggest exceptionally rapid temperature changes under the blocks, indicating air exchange in the voids. Mean ground temperatures in the loams beneath the blocks are about 7°C colder than in the adjacent soils. Winter snow covers are noticeably absent, and summer precipitation is often in the form of snow, which soon melts. Permafrost is present beneath the block stream but is absent in the sandy loam soils. The ground is also moister beneath the blocks. It appears that the surface blocks tend to slide downslope on the icy surface of the underlying blocks, perhaps aided by water from melting snow. This and the lack of sorting by clast size clearly differentiates them from talus slopes or avalanche deposits. 相似文献
18.
重庆万州的长江岸坡发育剥蚀基岩平台与陡崖,我们采用三角坡面法估计了陡崖的后退速率。采用该方法的依据是,铺垭口的陡崖下存在形成时代不同的坡面,同时该地点的地层近水平,所以我们假定陡崖的后退过程类似干旱-半干旱环境中的平顶岩屑堆地貌的形成过程。通过对前一阶段残留坡面的函数拟合,可以估计陡崖的后退距离。如将残留坡面上T3阶地的年龄近似为崩坡积的形成年龄,则计算出的陡崖后退速率大约是0.51 m/ka。这个数据表明,该地区最高的450 m的剥蚀基岩平台大约在2.3 M a前左右被长江切穿,推测2.3 M a可能是三峡贯通年龄的上限。 相似文献
19.
首先论述了四种沙石体运动模式,还通过理论推导,求解沙石体运动的加速度、末速度和平均速度的计算公式,最后分析了沙石体在多级变坡斜面上加速运动的速度计算方法。 相似文献
20.
Povl Frich Erik Brandt 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(1):32-43
Frich, Povl and Brandt, Erik: Holocene talus accumulation rates,—and their influence on rock glacier growth. A case study from Igpik, Disko—West Greenland. Geografisk Tidsskrift 85: 32–44 Copenhagen, October 1985. The Igpik area is located ten km east of Godhavn on the south-coast of the island Disko. Geologically the area is dominated by Tertiary basalt formations. A general geomorphological classification of this area, which covers approximately three square kms, has been made. Based on radiocarbon ages of former marine levels in the Disko Bugt area, the beginning of talus accumulation has been determined for two talus cones situated on raised beaches. They have ages of 5800 and 7900 14C y. B.P. Using theodolite readings, the volumes of three different talus cones have been determined and two average talus accumulation rates have been calculated for the cones located on raised beaches. These values are transformed into an average Holocene rockwall retreat rate of 0.0005 and 0.0015 m/year, respectively. The total volume of two lobate rock glaciers is calculated to be 2.2 mill, cu.m and as they are located inside 9000 years old local moraines, the average Holocene mass-transfer through the third talus cone has been estimated to 1.4 106 tons×m/sq.km/y. Finally the results are discussed, with reference to other areas, and as a possible threshhold for the initiation of rock glaciers. 相似文献