Middle Miocene (Serravallian) wetland development on the northwest edge of Europe based on palynological analysis of the uppermost Brassington Formation of Derbyshire, United Kingdom
Middle Miocene (Serravallian) wetland development on the northwest edge of Europe based on palynological analysis of the uppermost Brassington Formation of Derbyshire, United Kingdom
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DOI：
10.1016/j.palaeo.2022.111180
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发表时间：
2022-08
期刊：
影响因子：
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通讯作者：
J. Mccoy;Tabitha Barrass-Barker;Emma P. Hocking;J. O'Keefe;J. Riding;M. Pound
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文献类型：
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作者：
J. Mccoy;Tabitha Barrass-Barker;Emma P. Hocking;J. O'Keefe;J. Riding;M. Pound
本文描述了英国德比郡贝灵顿附近Bees Nest Pit的贝灵顿组中中新世（Serravallian）Kenslow段的孢粉组合，推断植被类型及其古气候意义。有限的横向范围的1.33米厚的粘土和褐煤的继承，其位置周围的一个大树干的碎片，表明继承可能已经积累在一个树扔洞或可能在一个浅的停滞的池塘，虽然水生湖泊palynomorphs尚未被确定，以确认后一种假设。根据58个样品的孢粉组合的地层分布，可以重建湿地演替。利用CONISS聚类分析，确定了两个花粉带，并确定了一个以暖温带和中生混交林为主的生物群系，两个花粉带中以Tsuconifer花粉类型为主（<42%）。这片森林湿地的组成变化是对当地环境变化的反应，而不是主要的气候变化。湿地的发展最终形成了一个相对开放的灌木和芦苇为主的沼泽，产生了褐煤前体泥炭。应用共存方法，平均年温度为15.6-21.7 °C，平均年降水量为703-1682 mm，表明古气候为暖温带至亚热带，两个参数在剖面上没有显着变化。研究结果表明，在中新世中期气候最适期之后，欧洲西北边缘的塞拉瓦利气候仍然比中欧湿润得多，中欧的干旱气候已经重建，这种差异可能是由于原始北大西洋洋流的影响。
In this paper, we describe palynological assemblages in the Middle Miocene (Serravallian) Kenslow Member of the Brassington Formation at Bees Nest Pit, near Brassington, Derbyshire, U.K., and infer vegetation types and their palaeoclimate implications. The limited lateral extent of the 1.33 m-thick succession of clay and lignite, and its position surrounding fragments of a large tree trunk, suggests that the succession may have accumulated within a tree throw hole or possibly within a shallow stagnant pond, although aquatic lacustrine palynomorphs have not been identified to confirm this latter hypothesis. The stratigraphical distribution of palynological assemblages, based on 58 samples allows reconstruction of a wetland succession. Two pollen zones were identified using CONISS cluster analysis, and a predominantly warm-temperate and mixed mesophytic forest biome was recognised withTsugaconifer pollen-types being dominant (<42%) in both pollen zones. Changes in the make-up of this forested wetland were in response to local environmental changes rather than major climatic shifts. Wetland development culminated in the formation of a relatively open shrub and reed-dominated mire which produced the lignite-precursor peat. Applying the Co-existence Approach, Mean Annual Temperature was 15.6–21.7 °C and Mean Annual Precipitation was 703–1682 mm indicating a warm-temperate to subtropical palaeoclimate, and both parameters show no significant change through the section. Findings suggest that, following the Middle Miocene Climatic Optimum, the Serravallian climate of the northwestern margin of Europe remained much wetter than Central Europe, where more arid climates have been reconstructed, and this difference may have been due to the influence of the proto-North Atlantic Current.