Postglacial relative sea-level histories along the eastern Canadian coastline
Postglacial relative sea-level histories along the eastern Canadian coastline
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DOI：
10.1016/j.quascirev.2018.09.043
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发表时间：
2018-12
影响因子：
4
通讯作者：
M. Vacchi;S. Engelhart;D. Nikitina;Erica L. Ashe;W. Peltier;K. Roy;Robert E Kopp;B. Horton
中科院分区：
文献类型：
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作者：
M. Vacchi;S. Engelhart;D. Nikitina;Erica L. Ashe;W. Peltier;K. Roy;Robert E Kopp;B. Horton
我们已经收集了一个数据库的相对海平面（RSL）数据点从加拿大东海岸从哈德逊湾与美国的边界。在编制这个数据库，我们严格审查了1092放射性碳测年样品从提高海滩，隔离盆地，潮间带和海洋沉积物，考古指标，产生405海平面指数点和687海平面限制点。我们的全面，系统和质量控制的RSL数据库允许重建加拿大东部34个地区的冰后期演变提供了新的流域规模的见解，在过去的1.16万年驱动RSL变化的过程。海平面指数点的数据库与创新的地理-贝叶斯时空统计模型相结合，为空间可变的冰川均衡调整（GIA）的速率和幅度提供了新的见解，GIA主导了北美这一部门的冰后期RSL演变。在纬度≥ 1050 ° N的地区，观测到了冰后期RSL的持续下降，其中哈德逊湾东南部记录到的下降率更高（达35 mm a−1）。在低纬度地区，RSL的演变是非单调的，下降到一个空间可变的全新世早期低位，其次是全新世中期高位，并最终逐渐下降到目前的RSL。这种模式在圣劳伦斯走廊尤为明显。沿着纽芬兰、新玩法和新斯科舍省西部海岸的大部分地区，更新世晚期/全新世早期的RSL低水位之后是全新世的持续上升。在边缘的前冰盖（即东部新斯科舍省），我们的数据确定了一个连续的RSL上升，通过全新世。这些记录的特征是RSL上升速率随时间的推移而降低，从全新世早期的快速上升（高达1.17 mm a−1）开始，到全新世中期放缓（平均速率≤ 1.99 mm a−1），到全新世晚期进一步降低（平均速率< 2 mm a−1）。最后，我们的数据库允许识别的地区，包括拉布拉多海岸和圣劳伦斯走廊的一部分，需要进一步的调查，以更好地约束RSL的演变，提高我们的能力，以评估RSL的变化历史。
We have assembled a database of Relative Sea Level (RSL) data points from the eastern coast of Canada from Hudson Bay to the border with the USA. In compiling this database we have critically reviewed 1092 radiocarbon dated samples from raised beaches, isolation basins, intertidal and marine deposits, and archaeological indicators to produce 405 sea-level index points and 687 sea-level limiting points. Our comprehensive, systematic, and quality-controlled RSL database allowed for the reconstruction of the postglacial evolution of 34 regions of eastern Canada providing new basin-scale insights into the processes driving RSL changes in the last ∼16 ka. The combination of a database of sea-level index points with an innovative empirical-Bayesian spatio-temporal statistical model provided new insights into rates and magnitude of the spatially-variable glacial isostatic adjustment (GIA), which dominated the postglacial RSL evolution in this sector of North America. A continuous postglacial RSL fall is observed at latitudes ≥ ∼50° N with higher rates (up to 35 mm a−1) recorded in southeastern Hudson Bay. At lower latitudes, the evolution is non-monotonic with RSL that dropped to a spatially variable early-Holocene lowstand, followed by a mid-Holocene highstand and, eventually, a gradual drop to present RSL. This pattern is particularly evident in the St Lawrence corridor. Along the majority of the Newfoundland, New Brunswick and western Nova Scotia coasts, a late-Pleistocene/early-Holocene RSL lowstand was followed by a continuous rise through the Holocene. At the margin of the former ice-sheet (i.e. eastern Nova Scotia), our data identify a continuous RSL rise through the Holocene. These records are characterized by decreasing rates of RSL rise through time, commencing with a rapid rise during the early Holocene (up to ∼17 mm a−1), a slowdown in the mid-Holocene (average rates ≤ ∼9 mm a−1), and a further reduction in the late Holocene (average rates < 2 mm a−1). Finally, our database allowed the identification of regions, including the Labrador coast and part of the St Lawrence corridor, where further investigations are required to better constrain the RSL evolution and improve our ability to assess the variability of RSL histories.