Sedimentation during Marine Isotope Stage 3 at the eastern margins of the Glacial Lake Humber basin, England
Sedimentation during Marine Isotope Stage 3 at the eastern margins of the Glacial Lake Humber basin, England
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DOI：
10.1002/jqs.3066
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发表时间：
2018-09
影响因子：
2.3
通讯作者：
D. Evans;D. Roberts;M. Bateman;A. Medialdea;J. Ely;S. Moreton;C. Clark;D. Fabel
中科院分区：
文献类型：
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作者：
D. Evans;D. Roberts;M. Bateman;A. Medialdea;J. Ely;S. Moreton;C. Clark;D. Fabel
位于亨伯湖盆地东缘的北洞地层层序记录了河流冰缘扇(LFS1-4)的沉积，早期沉积(LF1)可追溯到海洋同位素阶段(MIS3)(光激发发光年龄范围为41.8-38.6ka，14C年龄为41.6-49ka BP)。在MIS3期间，冻土和冰楔发育的三个阶段是明显的，这表明可能的扇被遗弃，从而减少了冰川径流。LF4b中11.1ka的卷曲构造具有大的巨石和细粒的分选圆圈，被解释为冰冻扰动的滨海沉积，巨石来自锚冰，最初在MIS2期间沉积在亨伯湖的边缘，海拔高达8m OD。北洞穴的河流冰缘扇沉积的样式和时代与英国德文斯中期的几个地点相一致，其特征是显著的冰川融化和从永久冻结的Cuesta地貌中陡峭的陡峭山谷中流失。在冰川湖、Humber和Fenland盆地周围记录到冰河-冰缘扇堆积到接近或低于0m OD的阶段，表明当时不存在冰川湖泊。
The stratigraphic sequence at North Cave, on the eastern margins of the Lake Humber basin, records the deposition of a fluvioperiglacial fan (LFs 1–4), with early sedimentation (LF1) dating to Marine Isotope Stage (MIS) 3 (optically stimulated luminescence date range 41.8–38.6 ka and 14C dates 41.6–49 ka BP). Three phases of permafrost and ice wedge development during MIS 3 are evident and indicate possible fan abandonment and hence periods of reduced nival runoff. Involution structures dated to 11.1 ka with large boulders and fine‐grained sorted circles in LF4b are interpreted as periglacially cryoturbated littoral deposits with boulders derived from anchor ice, initially deposited at the margins of Lake Humber up to an altitude of 8 m OD during MIS 2. The style and age of fluvioperiglacial fan deposition at North Cave is compatible with several mid‐Devensian sites around Britain characterized by significant nival melt and run‐off from steeply incised valleys in permafrozen cuesta landscapes. This phase of fluvioperiglacial fan aggradation to near or below 0 m OD is recorded around the glacial lakes Humber and Fenland basins and indicates that no glacial lakes existed at that time.