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Spatial and temporal distribution of landslide-dammed lakes in Purlung Tsangpo
Engineering Geology ( IF 6.9 ) Pub Date : 2022-08-04 , DOI: 10.1016/j.enggeo.2022.106802
Hao Wang , Peng Cui , Liqin Zhou , Weiming Liu , Anna Yang , Shunyu Yao , Zhenni Jiang

Reconstructing the ages and magnitudes of prehistoric extreme events that are recorded in landforms and sediments allows us to capture the full range of frequency-magnitudes and estimate the expected time for the repetition of a catastrophic event. The Eastern Himalayan Syntaxis and its surrounding areas are highly prone to the occurrence of river blocking. Previous studies have re-established three glacier-dammed lakes in the valley of Yurlung Tsangpo, namely, Gaga Lake, Dazhuka–Yueju Lake and Jiedexiu Lake. Here, we identified a series of sedimentary evidence containing offshore clay or silt varve, nearshore vaguely stratified silty sand and subaqueous foresets, which are associated with five landslide-dammed lakes in the lower reach of Purlung Tsangpo, including Lulang (LLDL), Dongjiu (DJDL), 102 (102DL), Jialong (JLDL) and Zedang (ZDDL). By assuming an initial catastrophic drainage, the highest elevation of exposures and original dam heights derived from dam morphology were used to represent the minimum and maximum estimates of lake levels of individual lakes. The maximum estimate of lake volume ranges from 4.3 × 109 m3 (LLDL) to 1.1 × 108 m3 (ZDDL). The 14C dating results provide the chronology of the LLDL from 24.2 ka BP to 15.4 ka BP. DJDL from 11.5 ka cal. BP to 7.0 ka cal. BP, JLDL from 4.9 ka cal. BP to 2.7 ka cal. BP. ZDDL from early Holocene to 5.8 cal. BP. Most of them occurred during deglaciation. We further used low-temperature thermochronological data to illustrate the spatial pattern of fluvial incision rates. Overall, climate-driving factors, such as rainfall intensity along with enhanced river incision post LLGM, preconditioned the occurrence of the abovementioned landslides.



中文翻译:

蒲隆藏布滑坡堰塞湖时空分布

重建在地貌和沉积物中记录的史前极端事件的年龄和幅度,使我们能够捕捉到所有频率幅度,并估计灾难性事件重复的预期时间。东喜马拉雅山脉及其周边地区极易发生河流阻塞。已有研究在玉龙藏布谷重新建立了三个冰川堰塞湖,即嘎嘎湖、大竹卡-越居湖和介德秀湖。在这里,我们确定了一系列沉积证据,包括近岸粘土或粉砂岩、近岸模糊分层的粉砂和水下森林,它们与普鲁藏布江下游的五个滑坡堰塞湖有关,包括鲁朗(LLDL)、东久( DJDL)、102(102DL)、嘉隆(JLDL)和泽当(ZDDL)。通过假设最初的灾难性排水,从大坝形态得出的最高暴露高度和原始大坝高度用于代表各个湖泊的湖泊水位的最小和最大估计值。湖泊体积的最大估计范围为 4.3 × 109  m 3 (LLDL) 至 1.1 × 10 8  m 3 (ZDDL)。14 C 测年结果提供了从 24.2 ka BP 到 15.4 ka BP 的 LLDL 年表。DJDL 从 11.5 大卡。BP 至 7.0 大卡。BP,JLDL 从 4.9 大卡。BP 至 2.7 大卡。英国石油公司。ZDDL 从全新世早期到 5.8 cal。英国石油公司。其中大部分发生在冰川消融期间。我们进一步使用低温热年代数据来说明河流切开率的空间格局。总体而言,气候驱动因素,如降雨强度以及 LLGM 后河流切口的增加,是上述滑坡发生的先决条件。

更新日期:2022-08-04
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