Annually-laminated lake sediments and the study of Quaternary environmental changes — a review
Annually-laminated lake sediments and the study of Quaternary environmental changes — a review
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DOI：
10.1016/0277-3791(83)90008-2
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发表时间：
1983
影响因子：
4
通讯作者：
P. O'sullivan
中科院分区：
文献类型：
--
作者：
P. O'sullivan
近年来，特别是自原位冷冻取样器的发展以来，发现了越来越多的年度层状湖泊沉积物（非冰川纹层）。到目前为止，大多数例子出现在三个主要地区（北美东部、北方和中欧以及东非和中非）。然而，一个更广泛的分布似乎是极有可能的。淡水湖泊中年度层状的形成受许多因素的影响，其中最重要的似乎是形态测量学。沉积物供应的季节性可能受湖泊或其集水区的物理、生物或甚至文化过程的控制，这一点也很明显。迄今为止，已记录了四种主要类型的层积（这里称之为铁成因层积、钙质层积、生物成因层积和碎屑层积），尽管很明显还存在其他类型的层积。为了充分利用纹层沉积物的特殊性质，需要特殊的野外和实验室技术。迄今为止，年积层沉积物已被应用于第四纪许多方面的研究。这些研究包括：（a）地质年代学;（B）气候变化;（c）植被历史，特别是火在森林生态系统中的作用;（d）计算沉积物流入湖泊的速度和湖泊集水区的侵蚀速度;（e）监测现代环境中的各种过程，如重金属污染、富营养化、年积层湖泊沉积物结合了联合收割机的内部，独立的年表与保存离散的，可见的季节性和年度沉积增量。考虑到这种独特的性质，以及可能会发现更多的例子，这些沉积物的研究进一步应用于第四纪调查的前景似乎非常好。
Annually-laminated lake sediments (non-glacial varves) have in recent years been discovered in increasing abundance, especially since the development ofin situfreezer samplers. So far, the majority of examples have been found in three main areas (Eastern North America, Northern and Central Europe, and East and Central Africa). A much more widespread distribution seems highly probable however.The formation of annual laminations in freshwater lakes is governed by a number of factors, the most important of which appears to be morphometry. Seasonality of sediment supply, which may be controlled by physical, biological or even cultural processes in the lake, or in its catchment, is also clearly significant.Four main types of laminations (here termedferrogenic, calcareous, biogenicandclastic) have so far been recorded, although it is quite clear that others exist. Special field and laboratory techniques are needed in order that the particular properties of varved sediments may be fully exploited.Annually-laminated sediments have so far been applied to the investigation of a number of aspects of the Quaternary. These include the study of (a) geochronology (b) climatic change, (c) vegetation history, especially the role of fire in forest ecosystems, (d) the calculation of rates of sediment influx to lakes, and of rates of erosion from their catchments, and (e) the monitoring of processes in the modern environment such as heavy metal pollution, eutrophication, and ‘acid rain’.Annually-laminated lake sediments combine an internal, independent chronology with the preservation of discrete, visible increments of seasonal and annual sedimentation. Given this unique property, and the likelihood that many more examples will be discovered, the prospects for further applications of studies of these sediments to the investigation of the Quaternary seem very good indeed.