Late Quaternary Glaciation in the Esaoman-Tottabetsu Valley, Hidaka Range, Hokkaido, Japan
Late Quaternary Glaciation in the Esaoman-Tottabetsu Valley, Hidaka Range, Hokkaido, Japan
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日本北海道日高山脉 Esaoman-Tottabetsu 山谷的晚第四纪冰川
DOI：
10.5026/jgeography.109.37
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发表时间：
2000
影响因子：
3.1
通讯作者：
T. Sawagaki
中科院分区：
文献类型：
--
作者：
Shogo Iwasaki;K. Hirakawa;T. Sawagaki
根据冰川地貌和沉积物地层学资料，重建了北海道中部Hidaka山脉北部Esaoman-Tottabetsu山谷晚第四纪冰川波动。通过温度年代学的方法，对末次冰期的两个已知的台阶，Poroshiri和Tottabetsu台阶进行了重新评估。在850m a. s. l的河床上，被Poroshiri Stadial终末冰碛覆盖的Shikotsu 1 tephra表明该冰川在40ka左右达到最大值（氧同位素阶段3:OIS-3）。这一推进应该在之前的寒期01S-4开始。前冰期外冲沉积物中的Kuttara 6 tephra （86 ka）表明，即使在末次冰期早期（01S-5b）相对温暖的时期，冰川也在漩涡底部附近波动。与此相反，包括Eniwa a tephra （18ka）在内的冰期和前冰期沉积物表明，该地区在Tottabetsu冰期（LGM）期间的冰川推进被限制在圆环底部。第二次冰期为Esaoman冰期，该冰期是由沿流域可追溯的断续残层地形提示的。这些特征表明，这一阶段的冰川推进在750m a.s.l，低于末次冰期。
Late Quaternary glacial fluctuations in the Esaoman-Tottabetsu Valley, inthe northern Hidaka Range, central Hokkaido were reconstructed based on stratigraphy of glacial landforms and sediments. By mean of tephrochronology, the two previously known stadials of the Last Glacial Stage, the Poroshiri and Tottabetsu Stadials, were reassessed. Shikotsu 1 tephra overlain by the terminal moraine of the Poroshiri Stadial at the river bed of 850m a. s. l. indicates that the glacier reached its maximum at around 40ka (Oxygen Isotopic Stage 3: OIS-3). This advance should have been initiated in the preceding cold period of 01S-4. Kuttara 6 tephra (86 ka) in the proglacial outwash deposits indicates that a glacier fluctuated in the vicinity of the cirque bottom even in the relatively warm period of the early Last Glacial Stage (01S-5b). Contrary to this stadial, the glacial and proglacial deposits including Eniwa a tephra (18 ka) show that the glacial advance during the Tottabetsu Stadial (LGM) in this region was restricted within the cirque bottom. The penultimate glaciation, named the Esaoman Glaciation in this study, was suggested by the discontinuously traceable remnant bed topography along the river basin. These features recommend that the glacial advance of this stage reached at 750m a. s. l., lower than during the Last Glacial Stage.