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31.
Torgeir O. Rthe Jostein Bakke Eivind Wilhelm Nagel Stren 《Boreas: An International Journal of Quaternary Research》2019,48(3):616-634
A sudden release of large volumes of water during a glacier outburst flood (GLOF) is a major hazard worldwide. Here, we identify the sedimentary signature of glacial and non‐glacial processes, including GLOFs, based on lacustrine sediments from the distal glacier‐fed Lake Buarvatnet in western Norway. Historically documented GLOFs in 2002 CE and during the 1980s CE are identified in the 210Pb‐ and 14C‐dated sediments. These events have the same sedimentary signature as 12 earlier events throughout the Holocene interpreted to represent previous GLOFs in the catchment. The GLOFs are interpreted to have occurred during periods when the glacier extent was similar to the modern positions, and the events are thus used to pinpoint past positions of the glacier terminus and, hence, the equilibrium line altitudes (ELAs). The results indicate that the glacier Svartenutbreen, located at the eastern part of Folgefonna, had a similar size in 2002 CE as c. 8200–8300 cal. a BP, corresponding to the 8.2 ka event in the North Atlantic region. The regrowth of Sørfonna after the Holocene Thermal Optimum occurred at c. 6900 cal. a BP and Svartenutbreen was at modern size and extent in the periods c. 6400, c. 5450, c. 4850, c. 3850, c. 3550 and c. 1650 cal. a BP. Since 1650 cal. a BP, we infer that the glacier was larger than the 2002 CE glacier extent until 1910 CE when a GLOF occurred. Svartenutbreen has been retreating since 1910 CE, which led to the ice damming of the two historical GLOFs in the 1980s and 2002 CE separated by a glacier advance in the 1990s CE. The findings are discussed and compared to other regional glacier reconstructions in Norway, and emphasize the value of identifying and utilizing GLOFs as an indicator of past ELA variability. 相似文献
32.
LIU Yan DENG Jun LI Guowu SHI Guanghai State Key Laboratory of Geological Processes Mineral Resources China University of Geosciences Beijing Key Laboratory of Lithosphere Tectonics Lithoprobing Technology of the Ministry of Education China University of Geosciences Beijing Laboratory of Single-Crystal X-Ray Diffraction China University of Geosciences Beijing 《《地质学报》英文版》2007,81(1):61-67
1 Introduction Natural beryl is an accessory mineral mainly in pegmatite, partly in some highly diffractionated granite or metamorphic rocks, with the crystal shapes beingprismatic, or occasionally tabular. For tabular beryl found in pegmatite it is believed that the tabular configuration is connected with alkali metals (Bieus, 1960; Wang et al., 1981) and geneses of the tabular configuration have been reported before. In recent years, tabular beryl has been found in the Xuebaoding W-Sn-Be d… 相似文献
33.
阿尔金山羌塘高原水资源开发及罗布泊钾盐矿建设的设想 总被引:1,自引:1,他引:0
《阿尔金山及羌塘高原水资源开发利用与保护考察报告》编写组 《干旱区地理》2007,30(6):785-790
阿尔金山水资源相对丰富,是巴音郭楞蒙古自治州河川径流的主要形成区之一,巴音郭楞蒙古自治州若羌县罗布泊镇钾盐贮量很大,经济效益可观,但水资源成为了罗布泊钾盐矿发展的限制性因素。能否把阿尔金山的水资源作为罗布泊钾盐矿发展的支撑,是我们必须回答的一个问题。本文利用新疆维吾尔自治区水利厅阿尔金山野外考察资料,分析阿尔金山的水系与湖泊、自然地理和社会经济特点,以期为探讨阿尔金山能否作为罗布泊钾盐矿开发的水源条件提供理论依据。 相似文献
34.
35.
青藏高原东部新生代钾质碱性系列岩石地球化学特征:岩石成因及其地质意义 总被引:1,自引:0,他引:1
青藏高原东部新生代钾质碱性系列的岩石,包括深成岩、火山岩和煌斑岩,在时空上具有一致性,岩石化学成分均富碱、高钾、K2O/Na2O比值远大于1,高度富集Sr、Ba等大离子亲石元素(LILE)和轻稀土元素(LREE),亏损Nb、Ta等高场强元素(HFSE),及物质来源于富集地幔源区的Sr、Nd、Pb同位素组成等,均显示钾质碱性系列的岩石特有的特征,其形成与印度和欧亚两大陆碰撞,导致青藏高原北、东部在40Ma左右出现的大型走滑拉分带,致使地壳变薄以及地幔上拱的构造背景有关。 相似文献
36.
1 Introduction The Gaojiacun intrusive complex is one of the numerous ultramafic-mafic intrusions in Sichuan Province of China. It was mapped during the 1970s and studied mainly by Chinese scientists (e.g. Geological Team 106, 1975; Shen et al., 1986, 1989; CGGJC, 1986; Yang et al., 1993; Li et al., 1995; Shen et al., 2003; Zhu et al., 2004a). Since the year 2000, China has become one of the largest PGE consumers. While the country can produce only less than 1 ton PGE/year, the Chin… 相似文献
37.
Nicholas Dodd 《中国海洋工程》1995,(2)
A nonlinear short-wave-averaged (surf beat) model is presented. The model is based on that of Roelvink (1993), but the numerical techniques used in the solution are based on the so-called weighted-averaged flux (WAF) method (eg Watson et al., 1992), with time-operator splitting used for the treatment of some of the source terms. This method allows a small number of computational points to be used, and is particularly efficient in modelling breaking long waves. The short-wave (or primary-wave) energy equation is solved using a more traditional Lax-Wendroff technique. Results of validation indicate that the model performs satisfactorily in most respects. 相似文献
38.
Ahmet Ruhi Mermut 《山地科学学报》2009,(2):I0002-I0002
Soils, the Earth's Critical Zone, play a vital and fundamental role in the Earth's terrain eco- environment system and human life. Although the concepts of soil/quality and sustainable development have been introduced for decades, we are still failing to understand how well soils function and they need tobe cared and protected. We have been increasingly witnessing and becoming the victim of shrinking forests, 相似文献
39.
大同—阳高地震烈度宏观考察组 《山西地震》1991,(3):18-30
文中叙述了大同—阳高地震区的烈度划分原则、烈度分布范围、烈度异常情况,给出了宏观地震参数(h=11.2km,震级5.8M_L),指出宏观调查的烈度值与强震仪记录的强余震加速度基本一致。 相似文献
40.
本矿物为新发现的钇易解石族的端员矿物-钛钇易解石,产于江西省龙南县足洞燕山期中粒白云母花岗岩及其风化壳中。矿物属斜方晶系,常呈板状或短柱状,为天然晶质体,浅黄色,粒度为0.075mm,硬度4.7,比重4.73,二轴正晶,Ng=2.248,Nm=2.212,Np=2.194,Ng-Np=0.054,2V=70°。空间群为D^162h-Pmnb,a0=0.750nm,b0=1.092nm,C0=0.5 相似文献