Palm swamp forest sediments collected in French Guiana provide new data about late Holocene rainforest. Two cores were collected in 'Les Nouragues' ecological station (4 degrees 05'N, 52 degrees 40'W). The lithology shows two different types of sediment, organic peat in the upper part and oxidized clay with low organic content and lacking pollen in the lower part, both separated by a gravel horizon. Radiocarbon dates show that this gravel horizon could have been deposited between 4500 and 3000yrBP. Pollen analysis carried out on the organic sediments record rainforest disturbances between ca 1520-1380 and 1060-860cal yrBP suggested by the presence of the pioneer tree species Cecropia together with other shade intolerant genera. Cecropia is recorded for a period that lasts between 660 and 320 years. This abnormal duration for presence of a pioneer species in rainforest is explained by brief and repeated changes in the composition of the canopy asssociated to perturbations of the palm swamp.

中文翻译：

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法属圭亚那晚全新世雨林干扰

在法属圭亚那收集的棕榈沼泽森林沉积物提供了有关全新世晚期雨林的新数据。在“Les Nouragues”生态站（北纬 4 度 05 分，西经 52 度 40 分）收集了两个岩心。岩性显示两种不同类型的沉积物，上部为有机泥炭，下部为有机质含量低且缺乏花粉的氧化粘土，两者被砾石层隔开。放射性碳测年表明，该砾石层可能在 4500 至 3000yrBP 之间沉积。对有机沉积物进行的花粉分析记录了大约 1520-1380 年和 1060-860cal yrBP 之间的雨林干扰，这是由先锋树种 Cecropia 和其他不耐荫的属的存在所暗示的。Cecropia 的记录时间为 660 至 320 年。