Rock-slope failure at Baosbheinn, Wester Ross, NW Scotland: age and interpretation
Rock-slope failure at Baosbheinn, Wester Ross, NW Scotland: age and interpretation
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苏格兰西北部韦斯特罗斯 Bausbheinn 的岩石斜坡破坏：年龄和解释
DOI：
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发表时间：
2009
影响因子：
0.7
通讯作者：
J. Stone
中科院分区：
文献类型：
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作者：
C. Ballantyne;J. Stone
概要 包斯拜因西北端的断裂疤痕下方有一个由大型板状巨石组成的巨大弓形山脊，此前被解释为洛蒙德湖斯塔迪尔湖（约 12.9–11.5ka）年龄的前缘壁垒或距骨岩石冰川。山脊位于岩石滑坡破坏区的下坡，两侧是陡峭的岩石支撑，在这里被重新解释为由背坡上 0.5-0.6 吨岩石破坏产生的岩石滑坡碎片组成。据推断，流出的碎片在撞击斜坡的底折时失去了动量，因此积累成一个陡峭的山脊，并有一个平缓的背衬凹陷，部分埋藏了约 1000 年 Wester Ross Readvance (WRR) 造成的侧碛石。 14.0–13.5 ka。岩崩径流碎片上大圆石的宇宙成因 10Be 暴露年龄表明，岩崩发生在晚冰期间期冷温带条件下的 14.0 ± 1.6 ka 和 13.3 ± 1.2 ka 之间。破坏可能发生在被覆盖的WRR冰碛沉积后的几个世纪内，并归因于由于冰消卸载和随后的冰川应力释放而导致的岩石坡弱化，可能由于基岩节理内的冰融化而增强。
Synopsis A massive arcuate ridge composed of large tabular boulders below a failure scar at the NW extremity of Baosbheinn has previously been interpreted as a protalus rampart or talus rock glacier of Loch Lomond Stadial (c. 12.9–11.5 ka) age. The ridge occurs downslope of a rockslide failure zone flanked by steep rock buttresses, and is here reinterpreted as consisting of rockslide debris produced by failure of 0.5–0.6 Mt of rock from the backing slope. The runout debris is inferred to have lost momentum as it impacted the basal break of slope and consequently accumulated as a steep-fronted ridge with a gentle backing depression, partly burying a lateral moraine attributed to the Wester Ross Readvance (WRR) of c. 14.0–13.5 ka. Cosmogenic 10Be exposure ages for large boulders on the rockslide runout debris indicate that the rockslide occurred between 14.0 ± 1.6 ka and 13.3 ± 1.2 ka under cool temperate conditions during the Lateglacial Interstade. Failure probably occurred within a few centuries after deposition of the over-ridden WRR moraine, and is attributed to rock-slope weakening due to deglacial unloading and consequent paraglacial stress release, possibly enhanced by thaw of ice within bedrock joints.