Ice marginal dynamics of the last British-Irish Ice Sheet in the southern North Sea: Ice limits, timing and the influence of the Dogger Bank
Ice marginal dynamics of the last British-Irish Ice Sheet in the southern North Sea: Ice limits, timing and the influence of the Dogger Bank
复制标题
北海南部最后一个英国-爱尔兰冰盖的冰边缘动态：冰的限制、时间和多格浅滩的影响
DOI：
10.1016/j.quascirev.2018.08.010
复制
发表时间：
2018
影响因子：
4
通讯作者：
Roberts D
中科院分区：
文献类型：
--
作者：
Roberts D
北海南部是了解英国-爱尔兰冰盖（BIIS）在末次冰期循环期间行为的一个特别重要的地区。它保存了BIIS东部最大范围的记录，以及多个不同冰流阶段和BIIS动态重组的证据。然而，迄今为止，该地区已知的冰盖历史和地质年代学主要来自陆上地质证据，最后一个冰盖的离岸印记和动力学历史在很大程度上仍然未知。利用英国-克罗诺项目收集的新数据，本文探讨了多格滩的起源和年龄，重新评估了多格滩和北诺福克海岸之间北海浅水区的冰川沉积物的范围和年龄;重新表示本文研究了31.6 ~ 21.5ka北海南部BIIS的动力学行为，表明Dogger浅滩的核心是由冰湖相沉积时间为31.6 ~ 25.8ka。形成后，多格湖的西端被覆盖着冰，达到北纬154度，冰缘与之前被绘制为Bolders Bank Fm的冰下冰碛的南部范围一致。这最初的冰覆盖和撤退北回整个Dogger湖完成了23.1 ka，但导致了广泛的压缩冰川构造的湖泊沉积物和逆冲冰碛复合体的形成。沿着北方边缘的岸碛是上重叠的晚期冰川湖泊和海洋沉积物，但没有显示出证据的后续冰override。浅海底的西部和西南部的多格银行记录了几个后期阶段的冰前进和后退的北海凸角之间的多格银行和约克郡/林肯郡海岸流动，并达到北诺福克。新的光释光（OSL）年龄从加勒特山的冰水限制到达的BIIS在诺福克海岸到22.8-21.5 ka。诺福克北部海底的多个冰碛层和冰碛链标志着北海叶缘向北撤退时的动态振荡。这种行为模式与冰下沉积的陆地记录大致同步，沿约克郡海岸沿着的冰川河流和冰川湖泊沉积物与21.5 ka后的丁灵顿体育场冰缘振荡有关（0.30 - 23 ka），BIIS南缘与Dogger湖的相互作用对流动不稳定性和冰的快速进退起着关键作用。然而，在最后一次盛冰期（22-21 ka）的后期，在北海南部的晚期冰前进成为限制到西部的多格银行，这是一个重大的地形特征，由这个时候。这种地形限制，加上BIIS和芬诺斯堪的纳维亚冰盖（FIS）进一步向北分离，使冰到达北诺福克海岸，在海床上覆盖了Bolders Bank Fm的晚期冰碛。
The southern North Sea is a particularly important area for understanding the behaviour of the British-Irish Ice Sheet (BIIS) during the last glacial cycle. It preserves a record of the maximum extent of the eastern sector of the BIIS as well as evidence for multiple different ice flow phases and the dynamic re-organisation of the BIIS. However, to date, the known ice sheet history and geochronology of this region is predominantly derived from onshore geological evidence, and the offshore imprint and dynamic history of the last ice sheet remain largely unknown. Using new data collected by the BRITICE-CHRONO project this paper explores the origin and age of the Dogger Bank; re-assesses the extent and age of the glaciogenic deposits across the shallow areas of the North Sea between the Dogger Bank and the north Norfolk coast and; re-examines the dynamic behaviour of the BIIS in the southern North Sea between 31.6 and 21.5 ka.This paper shows the core of the Dogger Bank to be composed glaciolacustrine sediment deposited between 31.6 and 25.8 ka. Following its formation the western end of the Dogger lake was overridden with ice reaching ∼54°N where the ice margin is co-incident with the southerly extent of subglacial tills previously mapped as Bolders Bank Fm. This initial ice override and retreat northwards back across the Dogger lake was complete by 23.1 ka, but resulted in widespread compressive glaciotectonism of the lake sediments and the formation of thrust moraine complexes. Along the northern edge of the bank moraines are on-lapped by later phase glaciolacustrine and marine sediments but do not show evidence of subsequent ice override.The shallow seafloor to the west and southwest of the Dogger Bank records several later phases of ice advance and retreat as the North Sea Lobe flowed between the Dogger Bank and the Yorkshire/Lincolnshire coasts and reached North Norfolk. New optically stimulated luminescence (OSL) ages from Garrett Hill on outwash limit the arrival of the BIIS on the Norfolk coast to 22.8–21.5 ka. Multiple till sheets and chains of moraines on the seafloor north of Norfolk mark dynamic oscillation of the North Sea Lobe margin as it retreated northwards. This pattern of behaviour is broadly synchronous with the terrestrial record of deposition of subglacial, glaciofluvial and glaciolacustrine sediments along the Yorkshire coast which relate to post Dimlington Stadial ice marginal oscillations after 21.5 ka.With respect to forcing mechanisms it is likely that during the early phases of the last glacial maximum (∼30-23ka) the interaction between the southern margin of the BIIS and the Dogger Lake was critical in influencing flow instability and rapid ice advance and retreat. However, during the latter part of the last glacial maximum (22–21 ka) late-phase ice advance in the southern North Sea became restricted to the western side of the Dogger Bank which was a substantial topographic feature by this time. This topographic confinement, in addition to decoupling of the BIIS and the Fennoscandian Ice Sheet (FIS) further north, enabled ice to reach the north Norfolk coast, overprinting the seabed with late-phase tills of the Bolders Bank Fm.
登录
查看更多内容
欧洲西北部陆架海古潮汐模型对末次盛冰期以来冰川均衡调整的敏感性
影响因子：
4
作者：
S. Ward;S. Neill;J. Scourse;S. Bradley;Katsuto Uehara
通讯作者：
Katsuto Uehara
英国东北安格利亚分层耕作组合的变形床特征：调查沉积物流变学和应变特征的控制
影响因子：
4
作者：
D. Roberts;J. Hart
通讯作者：
J. Hart
最后一个英国-爱尔兰冰盖消退期间前冰川亨伯湖的新多阶段衰退模型
影响因子：
2.2
作者：
W. A. Fairburn;M. Bateman
通讯作者：
M. Bateman
更新世至东约克郡的起源：重建英国北海波瓣的冰流
影响因子：
12.1
作者：
M. Busfield;Jonathan R. Lee;J. Riding;J. Zalasiewicz;Sarah Lee
通讯作者：
Sarah Lee
末次冰期期间爱尔兰东南部爱尔兰海冰流边缘振荡的沉积证据
影响因子：
2.2
作者：
D. Evans;C. Ó. Cofaigh
通讯作者：
C. Ó. Cofaigh