Exploring controls of the early and stepped deglaciation on the western margin of the British Irish Ice Sheet
Exploring controls of the early and stepped deglaciation on the western margin of the British Irish Ice Sheet
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DOI：
10.1002/jqs.3315
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发表时间：
2021-06
影响因子：
2.3
通讯作者：
S. Benetti;R. Chiverrell;C. Ó. Cofaigh;M. Burke;A. Medialdea;D. Small;C. Ballantyne;M. Bateman;S. L. Callard;P. Wilson;D. Fabel;C. Clark;R. Arosio;S. Bradley;P. Dunlop;J. Ely;Jenny G. Gales;S. Livingstone;S. Moreton;Catriona Purcell;M. Saher;K. Schiele;K. V. van Landeghem;Kasper Weilbach
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文献类型：
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作者：
S. Benetti;R. Chiverrell;C. Ó. Cofaigh;M. Burke;A. Medialdea;D. Small;C. Ballantyne;M. Bateman;S. L. Callard;P. Wilson;D. Fabel;C. Clark;R. Arosio;S. Bradley;P. Dunlop;J. Ely;Jenny G. Gales;S. Livingstone;S. Moreton;Catriona Purcell;M. Saher;K. Schiele;K. V. van Landeghem;Kasper Weilbach
新的光释光测年和贝叶斯模型集成了所有传统和BRITICE-CHRONO地质年代学，促进了对英国-爱尔兰冰盖两个前部分（多尼加尔湾（DBIS）和马林海冰流（MSIS））冰川消退控制的探索。陆架边缘冰川作用发生在全球末次盛冰期之前约27 ka，陆架范围的退缩开始于26-26.5 ka，速率约为18.7-20.7 m a-1。MSIS接地带楔形体和DBIS退缩冰碛显示出间歇性退缩，并伴有长时间的静止。到23-22 ka，外陆架（约25 000 km 2）已无冰。在此之后，MSIS后退更快（~20 m a-1 vs. ~2-6 m a-1的DBIS）。爱尔兰和苏格兰冰源的分离发生在~20-19.5 ka，留下一个独立的多尼加尔冰丘。内Malin陆架冰消期跟随海底槽到达赫布里底海岸~19 ka。20.5 ~ 19 ka，DBIS退缩形成了多尼加尔湾外广泛的冰碛复合体。DBIS在陆地上消退约17-16 ka。苏格兰和爱尔兰的孤立冰帽持续到~14.5 ka。这种海洋终止边缘的早期退缩最好解释为局部冰负荷增加水深和促进崩解冰损失，而不是全球温度的变化。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。
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.