Within-region replication of late Holocene relative sea-level change: An example from southern New England, United States
Within-region replication of late Holocene relative sea-level change: An example from southern New England, United States
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DOI：
10.1016/j.quascirev.2022.107868
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发表时间：
2023-01
影响因子：
4
通讯作者：
Rachel B. Stearns;S. Engelhart;A. Kemp;T. Hill;M. Brain;D. Corbett
中科院分区：
文献类型：
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作者：
Rachel B. Stearns;S. Engelhart;A. Kemp;T. Hill;M. Brain;D. Corbett
北大西洋西部的验潮仪测量显示出跨多个空间尺度的连续的、多年代际相对海平面（RSL）趋势。盐沼沉积物的替代重建可以扩展这一仪器记录。然而，通过区域内复制，代理重建的一致性程度未得到充分检查。为了探索区域内的复制，我们从罗德岛的福克斯山沼泽开发了一个新的RSL重建，以补充附近站点的类似记录。我们利用贝叶斯传递函数从有孔虫组合和块状沉积物δ13C值中确定了前海平面的高度。我们采用放射性碳定年和污染水平识别来构建一个核心年表。自公元前约1200年以来，福克斯山沼泽的RSL上升了约3.7米。在对冰川均衡调整进行校正后，应用旨在量化（多）世纪尺度趋势的统计模型表明，至少在过去3000年中，最快的上升速度在2020年为1.71±0.84 mm/yr（95%可信区间）。这一结果与区域测潮仪测量结果和其他代理重建结果相吻合。利用另一种用于确定次百年海平面变化的统计模型，我们研究了美国东北部是否存在18世纪海平面上升的热点，但没有发现空间上一致的趋势（即在所有或大多数地点发生）。这种缺乏复制的现象表明，18世纪的加速上升很可能是局部（特定地点）的规模，或者是个别重建的产物。继续努力复制RSL重建将增加对记录准确性及其后续解释的信心。
Tide-gauge measurements in the western North Atlantic Ocean show coherent, multi-decadal relative sea-level (RSL) trends across multiple spatial scales. Proxy reconstructions developed from salt-marsh sediment can extend this instrumental record. However, the degree of coherence in proxy reconstructions is underexamined through within-region replication. To explore within-region replication, we developed a new RSL reconstruction from Fox Hill Marsh, Rhode Island to complement similar records at nearby sites. We established the elevation of former sea level from assemblages of foraminifera and bulk-sediment δ13C values using a Bayesian transfer function. We employed radiocarbon dating and recognition of pollution horizons to construct a core chronology. Since ∼1200 BCE, RSL rose by ∼3.7 m at Fox Hill Marsh. After correction for glacial isostatic adjustment, application of a statistical model intended to quantify (multi-) century-scale trends showed that the fastest rate of rise in at least the past 3000 years was 1.71 ± 0.84 mm/yr (95% credible interval) in 2020 CE. This result replicates regional tide-gauge measurements and other proxy reconstructions. Using an alternative statistical model constructed to identify sub-centennial sea-level changes, we examined if there was a hotspot of 18th century rise in the northeastern United States and found no spatially-coherent trend (i.e., occurring at all or most sites). This lack of replication indicates that accelerated rise during the 18th century is likely local (site-specific) in scale, or an artifact of individual reconstructions. Continued efforts to replicate RSL reconstructions will increase confidence in the accuracy of records and their subsequent interpretation.