Development History of Landslide-Related Sagging Geomorphology in Orogenic Belts: Examples in Central Japan
Development History of Landslide-Related Sagging Geomorphology in Orogenic Belts: Examples in Central Japan
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DOI：
10.1007/978-3-319-09057-3_91
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
S. Kojima;H. Kaneda;Hidehisa Nagata;Ryota Niwa;N. Iwamoto;Koichiro Kayamoto;T. Ohtani
中科院分区：
文献类型：
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作者：
S. Kojima;H. Kaneda;Hidehisa Nagata;Ryota Niwa;N. Iwamoto;Koichiro Kayamoto;T. Ohtani
通过对激光雷达数据制作的高分辨率地图图像的分析，已知日本山区存在小规模下垂地貌特征。通过 GIS 分析、野外测绘、机器和手钻钻孔、AMS14C 测年以及火山灰地质年代学，对 Kanmuriyama、Tsuenomine 和 Nogo-Hakusan 地区的下垂地貌的发育历史进行了分析。冠村山地区山脊顶部凹陷处堆积的沉积物产生了年龄为 1,234–1060、6,191–5,996 和 7,931–7,731 cal BP 的木材碎片，还包括约 7.3 ka 的 K-Ah 火山灰。这些年龄表明洼地是在末次冰期之后气候温暖湿润之初开始形成的。另一方面，Tsuenomine 地区的双山脊形成时间早于 Kikai-Tozurahara 碎石沉积，距今约 95ka。野后白山地区下陷的GIS分析表明，大部分下陷分布在缺口线（侵蚀锋）正上方的平坦或平缓的表面上；这意味着缺口线通过凹陷地貌的重复形成和破坏而后退。
Small-scale geomorphic features of sagging have been known to occur in mountainous areas in Japan by the analyses of high resolution map images made from the LiDAR data. Development histories of the sagging landforms were analyzed by the GIS analyses, field mapping, machine and hand auger boring, AMS14C dating, and tephra geochronology in the Mt. Kanmuriyama, Tsuenomine and Nogo-Hakusan areas. Sediments accumulated in the ridge-top depression in the Mt. Kanmuriyama area yield wood fragments with the ages of 1,234–1060, 6,191–5,996 and 7,931–7,731 cal BP, and also include the K-Ah tephra of ca 7.3 ka. These ages indicate that the depression started to form at the beginning of warm and humid climate after the last glacial period. On the other hand, the double ridges in the Mt. Tsuenomine area formed much earlier before the deposition of the Kikai-Tozurahara tephra about 95 ka. The GIS analyses of sagging in the Mt. Nogo-Hakusan area indicate that most of them are distributed on the flat or gentle surface just above the knick line (erosion front); it means that the knick lines retreat through the repetitive formation and destruction of the sagging landforms.