Isolation basins, sea-level changes and the Holocene history of the Greenland Ice Sheet
Isolation basins, sea-level changes and the Holocene history of the Greenland Ice Sheet
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DOI：
10.1016/j.quascirev.2011.10.013
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发表时间：
2011-12
影响因子：
4
通讯作者：
A. Long;S. Woodroffe;D. Roberts;S. Dawson
中科院分区：
文献类型：
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作者：
A. Long;S. Woodroffe;D. Roberts;S. Dawson
隔离盆地是天然的地形洼地，在其历史的不同时期，可能由于相对海平面的变化而与海洋相连或与海洋隔绝。它们为跟踪数千年来RSL的大尺度（数十米）变化提供了宝贵的数据来源，也为记录海啸、冰山翻滚或风暴引起的突变的静水沉积环境提供了宝贵的数据来源。在本文中，我们回顾了隔离盆地作为RSL数据的来源，并特别关注了它们在格陵兰岛的应用，以限制冰盖的全新世历史。本文给出了西格陵兰岛Disko Fjord的一条新的RSL曲线，该曲线表明在约11k calyr BP时建立了局部无冰条件，此后RSL从约80m的海洋极限迅速下降到约14k calyr BP时接近现在的海平面。我们将这一记录与Disko Bugt其他六个地点的隔离盆地RSL数据进行了比较，发现在全新世早期和中期，该地区出现了强烈的西北/东南差异反弹，反映了冰负荷历史的变化。我们将Disko Bugt数据与先前发表的Sisimiut（西格陵兰中部）、Nanortalik（南格陵兰）和Ammassalik（东南格陵兰）的隔离盆地RSL记录进行了比较。在Nanortalik（约10 k calyr BP）的早全新世和其他地方的中、晚全新世期间，RSL低于现在，然后上升到现在。这些差异反映了自末次盛冰期以来格陵兰冰负荷变化的时间和数量的变化，以及非格陵兰过程，特别是劳伦泰德前隆起的崩塌，以及冰等效海平面的变化。与其他RSL指标相比，隔离盆地数据具有相对较小的年龄和高度不确定性，使其能够在不同的地球和冰盖模式之间进行分辨，特别是在大冰负荷和RSL变化期间。
Isolation basins are natural topographic depressions that at various times in their history may be connected to or isolated from the sea by changes in relative sea-level (RSL). They provide a valuable source of data for tracking large scale (tens of meters) changes in RSL over millennia, as well as quiet-water depositional environments where abrupt changes caused by tsunami, iceberg roll or storms may be recorded. In this paper we review isolation basins as sources of RSL data with a particular focus on their use in Greenland to constrain the Holocene history of the ice sheet. A new RSL curve from Disko Fjord, West Greenland is presented, which shows that local ice free conditions were established at c. 11 k cal yr BP, after which RSL fell rapidly from a marine limit at c. 80 m to reach close to present sea level by c. 4 k cal yr BP. We compare this record with other isolation basin RSL data from six other sites in Disko Bugt and note a strong northwest/southeast differential rebound across the area during the early and mid-Holocene that reflects variations in ice load history. We compare the Disko Bugt data with other previously published isolation basin RSL records from Sisimiut (central West Greenland), Nanortalik (south Greenland) and Ammassalik (southeast Greenland). RSL fell below present during the early-Holocene at Nanortalik (c. 10 k cal yr BP) and during the mid to late Holocene elsewhere before rising to present. These differences reflect variations in the timing and amount of Greenland ice load change since the last glacial maximum, as well as non-Greenland processes, notably the collapse of the Laurentide forebulge and also changes in ice equivalent sea-level. Isolation basin data have relatively small age and height uncertainties compared with other RSL indicators, enabling them to resolve between different earth and ice sheet models, especially during periods of large ice load and RSL change.