Advanced Micro-XRF Method to Separate Sedimentary Rhythms and Event Layers in Sediments: Its Application to Lacustrine Sediment from Lake Suigetsu, Japan
Advanced Micro-XRF Method to Separate Sedimentary Rhythms and Event Layers in Sediments: Its Application to Lacustrine Sediment from Lake Suigetsu, Japan
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DOI：
10.1007/s10933-006-9028-3
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发表时间：
2007-01
影响因子：
2.1
通讯作者：
N. Katsuta;M. Takano;S. Kawakami;Shoji Togami;H. Fukusawa;M. Kumazawa;Y. Yasuda
中科院分区：
文献类型：
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作者：
N. Katsuta;M. Takano;S. Kawakami;Shoji Togami;H. Fukusawa;M. Kumazawa;Y. Yasuda
与事件相关的沉积层是由于火山爆发、地震或暴雨偶尔沉积的，通常包含在湖泊和海洋沉积物的有节奏序列中。利用扫描x射线分析显微镜（SXAM），建立了一种分离沉积节律和事件层的分析方法，并获得了日本水越湖湖泊沉积物中Al、Si、K、Ca、Ti、Mn和Fe 7种元素的序列剖面。从33层沉积物的元素组成可以检测到两种类型的事件层：3个已知的火山灰层和30个含有12种浊积岩的粘土层。利用基于自回归（AR）模型的Sompi事件分析（SEA）估计，后者的重复周期平均为640±160年，可能由局部重要地震引发并存档。在元素剖面中去除代表事件层的部分后，我们根据三个火山灰层的温度年代学获得了事件去除（ER）时间剖面。锰和铁的ER时间剖面可能代表了菱铁矿的含量，显示了全新世千年尺度的变化，与北大西洋的漂流事件相吻合。
Event-related sedimentary layers, which are deposited occasionally due to volcanic eruptions, earthquakes or heavy rains, are often contained in the rhythmical sequences of lacustrine and marine sediments. We have developed an analytical method for separating the sedimentary rhythms and the event layers identified using the scanning X-ray analytical microscope (SXAM) and obtained sequential profiles of seven elements Al, Si, K, Ca, Ti, Mn, and Fe in the lacustrine sediment from Lake Suigetsu, Japan. Two types of event layers could be detected from the elemental composition of 33 layers of sediment: three known volcanic ash layers and 30 clay layers containing 12 turbidites. The recurrence interval of the latter, which may potentially be initiated and archived by locally important earthquakes, is estimated to be an average of 640 ± 160 years by using Sompi event analysis (SEA) based on an autoregressive (AR) model. After removing those portions that represented event layers from the elemental profiles, we obtained event-removed (ER) temporal profiles based on the tephrochronology of the three volcanic ash layers. The ER temporal profiles of manganese and iron, probably representing the siderite content, showed a millennial-scale variation in the Holocene that corresponded well with ice-rafting events in the North Atlantic.