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Exploring controls of the early and stepped deglaciation on the western margin of the British Irish Ice Sheet
Journal of Quaternary Science ( IF 1.9 ) Pub Date : 2021-06-02 , DOI: 10.1002/jqs.3315
Sara Benetti 1 , Richard C. Chiverrell 2 , Colm Ó Cofaigh 3 , Matt Burke 2 , Alicia Medialdea 4 , David Small 3 , Colin Ballantyne 5 , Mark D. Bateman 4 , S. Louise Callard 6 , Peter Wilson 1 , Derek Fabel 7 , Chris D. Clark 4 , Riccardo Arosio 8 , Sarah Bradley 4 , Paul Dunlop 1 , Jeremy C. Ely 4 , Jenny Gales 9 , Stephen J. Livingstone 4 , Steven G. Moreton 10 , Catriona Purcell 11 , Margot Saher 11 , Kevin Schiele 1 , Katrien Van Landeghem 11 , Kasper Weilbach 3
Affiliation  

New optically stimulated luminescence dating and Bayesian models integrating all legacy and BRITICE-CHRONO geochronology facilitated exploration of the controls on the deglaciation of two former sectors of the British–Irish Ice Sheet, the Donegal Bay (DBIS) and Malin Sea ice-streams (MSIS). Shelf-edge glaciation occurred ~27 ka, before the global Last Glacial Maximum, and shelf-wide retreat began 26–26.5 ka at a rate of ~18.7–20.7 m a–1. MSIS grounding zone wedges and DBIS recessional moraines show episodic retreat punctuated by prolonged still-stands. By ~23–22 ka the outer shelf (~25 000 km2) was free of grounded ice. After this time, MSIS retreat was faster (~20 m a–1 vs. ~2–6 m a–1 of DBIS). Separation of Irish and Scottish ice sources occurred ~20–19.5 ka, leaving an autonomous Donegal ice dome. Inner Malin shelf deglaciation followed the submarine troughs reaching the Hebridean coast ~19 ka. DBIS retreat formed the extensive complex of moraines in outer Donegal Bay at 20.5–19 ka. DBIS retreated on land by ~17–16 ka. Isolated ice caps in Scotland and Ireland persisted until ~14.5 ka. Early retreat of this marine-terminating margin is best explained by local ice loading increasing water depths and promoting calving ice losses rather than by changes in global temperatures. Topographical controls governed the differences between the ice-stream retreat from mid-shelf to the coast.

中文翻译:

探索对英属爱尔兰冰盖西缘早期和阶梯式冰消的控制

新的光学受激发光测年和贝叶斯模型整合了所有传统和 BRITICE-CHRONO 地质年代学,促进了对英国-爱尔兰冰盖前两个部分多尼戈尔湾 (DBIS) 和马林海冰流 (MSIS) 冰川消退控制的探索)。在全球末次盛冰期之前,大陆架边缘冰川作用发生了约 27 ka,并且大陆架范围的退缩开始于 26-26.5 ka,速度为约 18.7-20.7 ma –1。MSIS 接地区楔形和 DBIS 后退碛显示偶发性后退被长时间的静止不动打断。到大约 23-22 ka,外大陆架(大约 25 000 公里2)没有接地冰。在此之后,MSIS 撤退速度更快(~20 ma –1 vs. ~2-6 ma –1DBIS)。爱尔兰和苏格兰冰源的分离发生了大约 20-19.5 ka,留下了一个自治的多尼戈尔冰穹。内马林架冰消随着海底槽到达赫布里底群岛海岸~19 ka。DBIS 撤退在 20.5-19 ka 时在多尼戈尔湾外形成了广泛的冰碛复合体。DBIS 在陆地上撤退约 17-16 ka。苏格兰和爱尔兰的孤立冰帽一直持续到~14.5 ka。这种海洋终止边缘的早期退缩最好用局部冰负荷增加水深和促进产冰损失来解释,而不是用全球温度的变化来解释。地形控制控制了冰流从大陆架中部撤退到海岸之间的差异。
更新日期:2021-06-22
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