Coastal peats from northwest Ireland: implications for late‐Holocene relative sea‐level change and shoreline evolution
Coastal peats from northwest Ireland: implications for late‐Holocene relative sea‐level change and shoreline evolution
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爱尔兰西北部沿海泥炭：对全新世晚期相对海平面变化和海岸线演化的影响
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
R. Carter
中科院分区：
文献类型：
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作者：
J. Shaw;R. Carter
在爱尔兰最西北部的沿海地区，泥炭和富含有机物质的沉积物在各种各样的环境中堆积，往往受到晚全新世相对海平面变化和地貌过程的强烈影响。阿兰莫尔岛海岸的深层泥炭层序最初在一个湖泊中聚集，随后在淡水沼泽环境中聚集。漫长的花粉记录是地区性活动的模板。它延伸到全新世的大部分地区，并显示出相对较高的松属花粉水平，直到该分类群在约3600BP消失之前。其他地方的沿海泥炭产状要薄得多，并在较短的时间内积累；它们包含了进一步的证据，表明沿海地区与今天相比林木茂盛，在公元前4000年左右之前，松树是重要的林地成分。在格威巴拉湾的遗址，潮间带泥炭记录了过去5000年来由于地貌事件而关闭的小河口。巴利尼斯、克隆马斯和特拉文纳的海岸遗址显示了退化的地层学˜成矿的海洋沉积物被高度有机的淡水泥炭覆盖在粉质泥炭上。基础放射性碳测年的范围从4500到3300BP。粉质泥炭被解释为形成于盐沼环境，含有独特的花粉光谱，以高水平的松树和木本植物花粉为标志。数据表明，到全新世中期，该地区的相对海平面接近今天的水平。相对海平面变化的模式与地球物理模型预测的模式很好地吻合。
Peat and organic rich sediments at coastal sites in extreme northwest Ireland have accumulated in a wide variety of environments, often strongly influenced by late Holocene changes in relative sea level and by geomorphic processes. A deep peat sequence on the coast of Aranmore Island accumulated initially in a lake and subsequently in a freshwater marsh environment. The long pollen record serves as a template for regional events. It extends over much of the Holocene and shows relatively high levels of Pinus pollen up to just before the disappearance of this taxon at c. 3600 BP. Coastal peat occurrences elsewhere are much thinner and have accumulated over shorter periods; they contain further evidence to show that coastal areas were well-wooded compared with today, and that Pinus was an important woodland component prior to c. 4000 BP. At sites in Gweebarra Bay intertidal peats record the closure of small estuaries by geomorphological events during the past 5000 years. Coastal sites at Ballyness, Clonmass, and Trawenagh display regressive stratigraphies ˜ minerogenic marine sediments are overlain by silty peats capped by highly organic freshwater peats. Basal radiocarbon dates range from 4500 to 3300 BP. The silty peats are interpreted as having formed in salt-marsh environments and contain distinctive pollen spectra, marked by high levels of Pinus and Compositae Liguliflorae pollen. The data suggest that relative sea level attained levels close to that of today by the mid-Holocene in this region. The pattern of relative sea-level change agrees well with that predicted by geophysical modelling.