Mid-latitude continental temperatures through the early Eocene in western Europe
Mid-latitude continental temperatures through the early Eocene in western Europe
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DOI：
10.1016/j.epsl.2016.12.009
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发表时间：
2017-02-15
影响因子：
5.3
通讯作者：
Pancost, Richard D.
中科院分区：
文献类型：
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作者：
Inglis, Gordon N.;Collinson, Margaret E.;Pancost, Richard D.
支链甘油二烷基甘油四醚(BrGDGTS)越来越多地被用于重建古近纪早期的年平均气温(MAAT)。然而，这种替代品在煤矿中的应用有限，而且只在未成熟的煤(即褐煤)中检测到brGDGT。利用从德国Schoningen(类似于北纬48度)采集的样品，我们首次通过一系列早始新世褐煤及其伴生夹层详细研究了brGDGT的产状和分布。BrGDGT含量丰富，存在于每个样品中。与现代研究相比，植被类型的变化似乎不会对brGDGT分布产生重大影响；然而，代表泥炭形成环境的褐煤与硅屑近岸海相层间沉积环境之间存在着细微的差异。利用最近为土壤开发的brGDGT温度校准(MAT(MR))，我们生成了欧洲中西部大陆到始新世早期的第一个大陆温度记录。来自褐煤的MAAT估计在23至26摄氏度之间，而来自近岸海洋夹层的MAAT估计超过20摄氏度。这些估计与其他中纬度环境和模型模拟一致，表明中纬度、始新世早期的温暖程度增强。在所研究的剖面的底部，褐煤(类似于2摄氏度)和近岸海洋夹层(类似于2-3摄氏度)都记录到了变暖。这最终导致了一个长期的最高温度，可能包括始新世早期气候最佳时期(EECO)。尽管这一长期变暖趋势在海洋领域已经确立，但在陆地环境中很少表现出来。利用一套模型模拟，我们表明，舒宁根变暖的幅度与二氧化碳增加一倍大体一致，这与古新世晚期和始新世早期PCO(2)的估计一致。(C)2016年，作者(S)。爱思唯尔出版公司(Elsevier B.V.)
Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are increasingly used to reconstruct mean annual air temperature (MAAT) during the early Paleogene. However, the application of this proxy in coal deposits is limited and brGDGTs have only been detected in immature coals (i.e. lignites). Using samples recovered from Schoningen, Germany (similar to 48 degrees N palaeolatitude), we provide the first detailed study into the occurrence and distribution of brGDGTs through a sequence of early Eocene lignites and associated interbeds. BrGDGTs are abundant and present in every sample. In comparison to modern studies, changes in vegetation type do not appear to significantly impact brGDGT distributions; however, there are subtle differences between lignites - representing peat-forming environments - and siliciclastic nearshore marine interbed depositional environments. Using the most recent brGDGT temperature calibration (MAT(mr)) developed for soils, we generate the first continental temperature record from central-western continental Europe through the early Eocene. Lignite-derived MAAT estimates range from 23 to 26 degrees C while those derived from the nearshore marine interbeds exceed 20 degrees C. These estimates are consistent with other mid-latitude environments and model simulations, indicating enhanced mid-latitude, early Eocene warmth. In the basal part of the section studied, warming is recorded in both the lignites (similar to 2 degrees C) and nearshore marine interbeds (similar to 2-3 degrees C). This culminates in a long-term temperature maximum, likely including the Early Eocene Climatic Optimum (EECO). Although this long-term warming trend is relatively well established in the marine realm, it has rarely been shown in terrestrial settings. Using a suite of model simulations we show that the magnitude of warming at Schoningen is broadly consistent with a doubling of CO2, in agreement with late Paleocene and early Eocene pCO(2) estimates. (C) 2016 The,Author(s). Published by Elsevier B.V.