Mass movement deposits in the 3.6 Ma sediment record of Lake El'gygytgyn, Far East Russian Arctic
Mass movement deposits in the 3.6 Ma sediment record of Lake El'gygytgyn, Far East Russian Arctic
复制标题
DOI：
10.5194/cp-9-1949-2013
复制
发表时间：
2013-01
影响因子：
4.3
通讯作者：
M. Sauerbrey;O. Juschus;A. Gebhardt;V. Wennrich;N. Nowaczyk;M. Melles
中科院分区：
文献类型：
--
作者：
M. Sauerbrey;O. Juschus;A. Gebhardt;V. Wennrich;N. Nowaczyk;M. Melles
摘要。本文研究了俄罗斯远东地区El'gygytgyn湖第四纪和上新世沉积物中的块体运动沉积（MMDs）特征及其成因。在国际大陆科学钻探计划（ICDP） 5011-1站点的320 m长沉积物记录中，钻了3个部分重叠的孔，几乎完全恢复了第四纪，上新世至3.6 Ma，恢复了52%。根据宏观岩心描述、x射线图像、高分辨率磁化率和伽马射线密度，在所有三个岩心中研究了块体运动矿床。确定了五种不同类型的MMDs：浊积岩、颗粒流沉积、碎屑、滑塌和滑动。这些都是由过渡的质量运动过程形成的，因此可以是共属的。最初的边坡破坏被认为转变成泥石流，使前缘沉积物变形，部分解体并稀释成浊流。浊积岩是目前湖中心最常见的MMD类型。它们出现在整个记录的所有远洋沉积相中，但它们在寒冷气候条件下形成的相中较薄。相比之下，所有其他MMDs都只切割了在温暖气候下沉积的远洋相。在123 m厚的第四纪复合沉积记录中，确定了230个质量运动事件，占沉积物长度的33%。浊积岩占第四纪MMDs总数的93%，但厚度仅占其35%。在123 ~ 320 m的上新世沉积物中，新增体块运动沉积181个，占回收沉积物的约33%。第四纪和上新世MMDs的平均复发间隔分别为11 ka和5 ka。
Abstract. This paper focuses on the characterization and genesis of mass movement deposits (MMDs) in the Quaternary and Pliocene sediments of Lake El'gygytgyn, Far East Russian Arctic. Three partly overlapping holes were drilled into the 320 m long sediment record at International Continental Scientific Drilling Program (ICDP) Site 5011-1 in the lake basin, recovering the Quaternary almost completely, and the Pliocene down to 3.6 Ma with 52% recovery. Mass movement deposits were investigated in all three cores, based on macroscopical core descriptions, radiographic images, high-resolution magnetic susceptibility and gamma-ray density. Five different types of MMDs were identified: turbidites, grain-flow deposits, debrites, slumps and slides. These are formed by transitional mass movement processes, and thus can be co-generic. An initial slope failure is thought to transform into a debris flow that deforms frontal sediments, partly disintegrates and dilutes into a turbidity flow. Turbidites are by far the most frequent MMD type in the lake center. They occur throughout the record in all pelagic sedimentary facies, but they are thinner in facies formed during cold climate conditions. All other MMDs, by contrast, incise exclusively the pelagic facies deposited during warm climates. In the 123 m thick Quaternary composite sediment record 230 mass movement events are identified, comprising 33% of the sediment length. Turbidites contribute 93% of the number of Quaternary MMDs, but only 35% of their thickness. In the Pliocene sediments between 123 and 320 m, 181 additional mass movement deposits are identified, which constitute ~33% of the recovered sediments. The mean recurrence interval for MMDs is 11 and 5 ka in the Quaternary and Pliocene, respectively.