Holocene coastal evolution and evidence for paleotsunami from a tectonically stable region, Tasmania, Australia
Holocene coastal evolution and evidence for paleotsunami from a tectonically stable region, Tasmania, Australia
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澳大利亚塔斯马尼亚构造稳定地区的全新世海岸演化和古海啸证据
DOI：
10.1177/0959683610391317
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
C. Mazengarb
中科院分区：
文献类型：
--
作者：
K. Clark;U. Cochran;C. Mazengarb
对塔斯马尼亚东南部三个沿海水体的地层调查揭示了与海平面变化有关的主要古环境阶段和与海啸淹没相一致的异常沉积物。研究了22个短沉积岩心的沉积学特征和硅藻、有孔虫和大化石组合；获得了9个放射性碳年龄。尽管每个遗址的全新世历史不同，但可以区分出全新世古环境演化的四个共同阶段。在第一阶段（距今8000年以前），陆地环境已经存在。在第二阶段（距今8000-6500年），在海侵海岸屏障后面形成了池塘淡水环境。在第三阶段（距今6500-2000年），这些地点受到不同程度的海洋影响，导致环境从水流冲刷的潮汐入口到受庇护的咸淡咸海泻湖。在第四阶段（距今2000年至今），海洋的影响有所减少，一个地点变成了淡水湿地环境，而另外两个地点变成了短暂的盐田。该研究表明，塔斯马尼亚东南部的冰川后海平面上升在约7300 calyr BP之后达到顶峰，海平面可能在全新世晚期下降。这些古环境史提供了一个框架，在其中识别异常矿床并评估其可能的原因。发现了5个异常矿床，其中3个被认为可能是由大约4000 cal. yr BP、2000 cal. yr BP和<2000 cal. yr BP发生的海啸沉积的，尽管不能排除大风暴沉积的可能性。
Stratigraphic investigations of three coastal waterbodies in southeastern Tasmania reveal major paleoenvironmental phases related to sea level change and anomalous deposits consistent with tsunami inundation. Twenty-two short sediment cores were examined for their sedimentology and fossil diatom, foraminifera and macrofossil assemblages; nine radiocarbon ages were obtained. Despite diverse Holocene histories at each site, four common phases of Holocene paleoenvironmental evolution can be distinguished. In Phase I (pre-8000 yr BP) terrestrial environments existed. During Phase II (8000–6500 yr BP) ponded freshwater environments formed behind transgressive coastal barriers. In Phase III (6500–2000 yr BP) the sites were subject to varying degrees of marine influence, resulting in environments ranging from current-swept tidal inlets to sheltered brackish-marine lagoons. In Phase IV (2000 yr BP to present) there was a decrease in marine influence, one site changed to a freshwater wetland environment while the other two changed to ephemeral salt pans. This study suggests that postglacial sea level rise culminated after c. 7300 cal. yr BP in southeastern Tasmania and that there was probably a late-Holocene fall in sea level. These paleoenvironmental histories provide a framework within which to identify anomalous deposits and assess them for likely causes. Five anomalous deposits are identified, three of which are considered likely to have been deposited by tsunami occurring at c. 4000 cal. yr BP, c. 2000 cal. yr BP and <2000 cal. yr BP, although deposition by large storms cannot be ruled out.
影响因子：
8.3
作者：
Hughen, KA;Baillie, MGL;Weyhenmeyer, CE
通讯作者：
Weyhenmeyer, CE