Polar gravel beach-ridge systems: Sedimentary architecture, genesis, and implications for climate reconstructions (South Shetland Islands/Western Antarctic Peninsula)
Polar gravel beach-ridge systems: Sedimentary architecture, genesis, and implications for climate reconstructions (South Shetland Islands/Western Antarctic Peninsula)
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极地砾石滩-山脊系统：沉积结构、成因以及对气候重建的影响（南设得兰群岛/南极半岛西部）
DOI：
10.1016/j.geomorph.2014.06.013
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发表时间：
2014
期刊：
影响因子：
3.9
通讯作者：
Ilona Schutter
中科院分区：
文献类型：
--
作者：
S. Lindhorst;Ilona Schutter
极地砾石滩脊的沉积结构，它表明，脊内部的几何形状反映了过去的波气候条件。沿着波特半岛（乔治王岛）海岸获得的探地雷达（GPR）数据显示，海滩山脊不整合地覆盖在海岸线平原上。个别海脊的发展被认为是在风暴波对海岸的影响增加的时期多个风暴的结果。相比之下，滨岸-平原沉积作用是在持续平静的条件下，在海滩表面的冲刷沉积的结果。在海岸隐蔽部分的海滩脊的沉积结构的特点是向海倾斜的沉积层，是在风暴条件下的冲刷沉积的结果，或由波浪越顶形成的加积床。相比之下，暴露于高能波的海脊则由向海和向陆倾斜的地层组成，并被许多侵蚀不整合面捆绑在一起。这些侵蚀不整合面是沉积物缺乏或异常强风暴期间山脊物质部分改造的结果。在一定时间间隔内保存下来的个别海脊的数量沿海岸沿着变化，这取决于地貌动力学环境：有遮蔽的海岸的特点是有许多小海脊，而裸露的海滩上则形成较少但较大的海脊。洋脊形成的频率从低能量环境下的几十年到高能量条件下的1600年不等。研究区域的海滩脊集中在现今风暴海滩上方9.5、7.5、5.5和3.5 m以下。根据放射性碳数据，这被解释为反映了不同时期的风暴增加和/或缩短每年的海冰覆盖率在南设得兰群岛地区的时间约4.3，c。3.1、1.9 ka cal BP和0.65 ka cal BP之后。年龄进一步表明，即使是海拔较高的山脊，也可能在较晚的时候被重新激活和改造。因此，在取样测年之前，对地层结构进行仔细调查是必不可少的。
The sedimentary architecture of polar gravel-beach ridges is presented and it is shown that ridge internal geometries reflect past wave-climate conditions. Ground-penetrating radar (GPR) data obtained along the coasts of Potter Peninsula (King George Island) show that beach ridges unconformably overlie the prograding strand plain. Development of individual ridges is seen to result from multiple storms in periods of increased storm-wave impact on the coast. Strand-plain progradation, by contrast, is the result of swash sedimentation at the beach-face under persistent calm conditions. The sedimentary architecture of beach ridges in sheltered parts of the coast is characterized by seaward-dipping prograding beds, being the result of swash deposition under stormy conditions, or aggrading beds formed by wave overtopping. By contrast, ridges exposed to high-energy waves are composed of seaward- as well as landward-dipping strata, bundled by numerous erosional unconformities. These erosional unconformities are the result of sediment starvation or partial reworking of ridge material during exceptional strong storms. The number of individual ridges which are preserved from a given time interval varies along the coast depending on the morphodynamic setting: sheltered coasts are characterized by numerous small ridges, whereas fewer but larger ridges develop on exposed beaches. The frequency of ridge building ranges from decades in the low-energy settings up to 1600 years under high-energy conditions. Beach ridges in the study area cluster at 9.5, 7.5, 5.5, and below 3.5 m above the present-day storm beach. Based on radiocarbon data, this is interpreted to reflect distinct periods of increased storminess and/or shortened annual sea-ice coverage in the area of the South Shetland Islands for the times around 4.3, c. 3.1, 1.9 ka cal BP, and after 0.65 ka cal BP. Ages further indicate that even ridges at higher elevations can be subject to later reactivation and reworking. A careful investigation of the stratigraphic architecture is therefore essential prior to sampling for dating purposes.
影响因子：
4.4
作者：
A. Matias;J. Williams;G. Masselink;Ó. Ferreira
通讯作者：
A. Matias;J. Williams;G. Masselink;Ó. Ferreira