Few fossil‐based environmental and climate records in northern Europe are dated to Marine Isotope Stage (MIS) 5a around 80 ka BP. We here present multiple environmental and climate proxies obtained from a lake sequence of MIS 5a age in the Sokli basin (northern Finland). Pollen/spores, plant macrofossils, NPPs (e.g. green algae), bryozoa, diatoms and chironomids allowed an exceptionally detailed reconstruction of aquatic and telmatic ecosystem successions related to the development of the Sokli Ice Lake and subsequent infilling of a relatively small and shallow lake confined to the Sokli basin. A regional vegetation development typical for the early half of an interglacial is recorded by the pollen, stomata and plant macrofossil data. Reconstructions of July temperatures based on pollen assemblages suffer from a large contribution of local pollen from the lake's littoral zone. Summer temperatures reaching present‐day values, inferred for the upper part of the lake sequence, however, agree with the establishment of pine‐dominated boreal forest indicated by the plant fossil data. Habitat preferences also influence the climate record based on chironomids. Nevertheless, the climate optima of the predominant intermediate‐ to warm‐water chironomid taxa suggest July temperatures exceeding present‐day values by up to several degrees, in line with climate inferences from a variety of aquatic and wetland plant indicator species. The disequilibrium between regional vegetation development and warm, insolation‐forced summers is also reported for Early Holocene records from northern Fennoscandia. The MIS 5a sequence is the last remaining fossil‐bearing deposit in the late Quaternary basin infill at Sokli to be studied using multi‐proxy evidence. A unique detailed climate record for MIS 5 is now available for formerly glaciated northern Europe. Our studies indicate that interglacial conditions persisted into MIS 5a, in agreement with data for large parts of the European mainland, shortening the Last Glacial by some 50 ka to MIS 4‐2.

中文翻译：

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北欧“最后一次冰河期”期间长时间的冰期间温暖

北欧很少有基于化石的环境和气候记录可追溯到约80 ka BP的海洋同位素阶段（MIS）5a。我们在这里介绍了从索格里盆地（芬兰北部）MIS 5a年龄的湖泊序列中获得的多种环境和气候代理。花粉/孢子，植物大化石，NPP（例如绿藻），苔藓虫，硅藻和尺虫可以对与索克里冰湖发展有关的水生和遥感生态系统演替进行非常详细的重建，并随后填充相对较小和较浅的密闭湖到索克里盆地。花粉，气孔和植物大型化石数据记录了间冰期前半期典型的区域植被发育。基于花粉组合的7月份温度重建受湖滨带局部花粉的影响很大。根据湖泊序列的上部推断，夏季温度达到今天的值，这与植物化石数据表明的以松树为主的北方森林的建立是一致的。栖息地的偏爱也影响了基于天文学的气候记录。不过，主要的中温水手足类分类群的气候最佳状态表明，7月的温度比当前值高出几度，这与来自各种水生和湿地植物指示物种的气候推断相符。区域植被发展与温暖之间的不平衡，据报道，北部芬诺斯坎迪亚地区有全新世早期的早期暴晒记录。MIS 5a序列是索克里第四纪盆地晚期充填物中剩余的最后一个含化石沉积物，将使用多代理证据进行研究。MIS 5的独特详细气候记录现在可用于前冰川北部的欧洲。我们的研究表明，与欧洲大陆大部分地区的数据一致，冰间条件一直存在于MIS 5a中，从而使最后一次冰期缩短了约50 ka至MIS 4-2。