Discriminating between subglacial and proglacial lake sediments: an example from the Dänischer Wohld Peninsula, northern Germany
Discriminating between subglacial and proglacial lake sediments: an example from the Dänischer Wohld Peninsula, northern Germany
复制标题
区分冰下和冰前湖泊沉积物：德国北部丹尼斯沃尔德半岛的一个例子
DOI：
10.1016/j.quascirev.2015.01.030
复制
发表时间：
2015
影响因子：
4
通讯作者：
Livingstone S
中科院分区：
文献类型：
--
作者：
Livingstone S
冰下湖泊是现代冰体的共同特征。然而，它们在地质记录中很少被发现。这是由于冰下和冰前湖沉积物之间的区分困难;冰前起源通常被认为是“最简单”的解释。我们假设，目前解释为记录冰前期湖泊沉积的许多沉积物实际上可能起源于冰下。在这里，我们试图通过调查北方德国半岛的三个沿着地点，找到区分冰前和冰下湖泊沉积物的方法。我们确定了两个主要阶段的冰活动和相关的湖泊形成在晚Weichselian冰川。(1)在波罗的海冰流前进的前方，20023 ka冰前湖的形成。这个湖随后被覆盖，随着冰继续前进到最大程度，沉积物被冰川构造化。(2)在1900万年，冰退回到波罗的海盆地，并形成了持续了1400万年的冰前湖。我们认为，冰下湖泊活动可能发生在两个网站之间的23和19万年。这是基于存在的加积沉积物矿床的特点是分层/层压diamictons和夹层板状渠道化分选沉积物，并置相对未变形的waterlain沉积物和冰下直到，没有glaciotectonic冲断和折叠或细化/粗化继承和地貌协会隧道山谷南部的研究领域。沉积和变形的风格提供了最大的洞察力的前冰与冰下沉积的冰湖沉积物的歧视。发光信号古剂量分布也提供了一个潜在的强大的手段指纹沉积物运输途径的年轻冰川系统。
Subglacial lakes are common features of contemporary ice masses. However, they are rarely identified in the geological record. This is due to the difficulty in discriminating between subglacial and proglacial lake sediments; a proglacial origin is typically preferred as the ‘simplest’ explanation. We hypothesise that numerous deposits currently interpreted to record proglacial lake sedimentation may actually have a subglacial origin. Here we try and find ways of distinguishing proglacial from subglacial lake sediments by investigating three sites along the Dänischer Wohld Peninsula, northern Germany, which have been interpreted to record both proglacial and subglacial sedimentation. We identify two major phases of ice activity and associated lake formation during the Late Weichselian glaciation. (1) Proglacial lake formation at ∼23 ka in front of the advancing Baltic Ice Stream. This lake was subsequently overridden and the sediments glaciotectonised as ice continued to advance to its maximum extent. (2) Retreat of ice back into the Baltic Basin at ∼19 ka and formation of a proglacial lake that persisted for ∼4 ka. We suggest that subglacial lake activity may have occurred at two of the sites between 23 and 19 ka. This is based on the presence of aggrading sediment deposits characterised by stratified/laminated diamictons and interbedded tabular to channelized sorted sediments, the juxtaposition of relatively undeformed waterlain sediment and subglacial till, absence of glaciotectonic thrusting and folding or of fining/coarsening successions and the geomorphic association with tunnel valleys to the south of the study area. The style of sedimentation and deformation provided the greatest insight into the discrimination of proglacially vs subglacially deposited glaciolacustrine sediments. The luminescence signal palaeodose distributions also offers a potentially powerful means of fingerprinting sediment transport pathways of young glacial systems.
登录
查看更多内容
冰/床界面马赛克：波兰桑普瓦瓦斯堪的纳维亚冰盖边缘下稳定区域的变形点
DOI：
--
发表时间：
2013
期刊：
影响因子：
--
作者：
Karol Tylmann;J. Piotrowski;W. Wysota
通讯作者：
W. Wysota
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
泥沙流沉积物和冰下沉积物的微观结构：比较
DOI：
--
发表时间：
2001
期刊：
影响因子：
--
作者：
M. Lachniet;G. Larson;D. Lawson;E. Evenson;R. Alley
通讯作者：
R. Alley
影响因子：
2.8
作者：
M. Bateman;Claire Boulter;A. Carr;C. Frederick;D. Peter;M. Wilder
通讯作者：
M. Bateman;Claire Boulter;A. Carr;C. Frederick;D. Peter;M. Wilder
基底融化造成的分层鲶鱼溪耕地的起源
DOI：
--
发表时间：
2008
期刊：
影响因子：
--
作者：
P. Gibbard
通讯作者：
P. Gibbard