Interpreting alluvial archives: sedimentological factors in the British Holocene fluvial record
Interpreting alluvial archives: sedimentological factors in the British Holocene fluvial record
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解释冲积档案：英国全新世河流记录中的沉积学因素
DOI：
10.1016/j.quascirev.2005.01.009
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发表时间：
2005
影响因子：
4
通讯作者：
E. Johnstone
中科院分区：
文献类型：
--
作者：
J. Lewin;M. Macklin;E. Johnstone
根据所涉及的沉积风格分析了英国506个测年单位的全新世冲积档案。该数据库按沉积单元（河道沉积物、古河道充填物、河漫滩表层沉积物、洪泛盆地和崩积沉积物）和冲积物集合（扇和锥、高地冲沟和溪流、辫状系统和活跃/非活跃曲流和冲积系统）分类。洪泛平原，古河道和洪泛盆地沉积物占主导地位的记录，主要来自曲流/沉积系统。不同的沉积物单元显示出不同的记录环境变化的潜力：有些是相对较差的日期相对于所涉及的材料的体积，而许多日期'浮动'在沉积活动的时期，持续了很长的时间。许多过时的活动是自生的，在解释外部环境影响方面价值相对较小。集合体和单元体的年龄模式在某些方面相似（通常它们在沉积活动中表现出一系列短期高峰），但在其他方面不同。洪泛盆地，并在一定程度上，辫状体系的功能在全新世早期，而过时的扇沉积是在全新世晚期更为明显。有一个一般的偏见，晚全新世时代的沉积物单位，这可能反映了保存因素。以前的英国全新世冲积层模型进行了审查：它建议，大多数早期的模型反映了有限的区域覆盖范围和可用的测年施加的部分意见。
A Holocene alluvial archive of 506 dated units for Great Britain is analysed in terms of the sedimentation styles involved. The database is classified by sedimentation unit (channel sediments, palaeochannel fills, floodplain surface sediments, floodbasins and colluvial deposits) and alluvial ensemble (fans and cones, upland gullies and streams, braided systems and active/inactive meandering and anastomosing systems). Floodplain, palaeochannel and floodbasin sediments dominate the record, mostly from meandering/anastomosing systems. Different sediment units show varied potential for recording environmental change: some are relatively poorly dated with respect to the volumes of material involved, whilst many dates ‘float’ in periods of depositional activity which lasted for extended time periods. Much dated activity is autogenic and of relatively little value in interpreting external environmental influence. Ensembles and units are similar in age patterns in some respects (commonly they exhibit sets of short-term peaks in sedimentation activity) but differ in others. Floodbasins and, to an extent, braided systems feature in the earlier Holocene, whilst dated fan deposition is more evident in the late Holocene. There is a general bias towards sediment units of late Holocene age, which probably reflects preservation factors. Previous British Holocene alluviation models are reviewed: it is suggested that the majority of earlier models reflect partial views imposed by limited regional coverage and available dating.