Camel Lake : a 40 000-yr record of vegetational and forest history from Northwest Florida
Camel Lake : a 40 000-yr record of vegetational and forest history from Northwest Florida
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骆驼湖：佛罗里达州西北部 4 万年的植被和森林历史记录
作者：
W. Watts;B. C. Hansen;E. Grimm
抽象的。骆驼湖记录了佛罗里达西北部从距今4万年到现在的植被历史。威斯康星州中部（距今40 000 ~ 29 000年）是一个以松树、橡树和多种梅西奇树种为主的森林时代。板栗（Castanea）是31000 yr BP前植被的重要组成部分。晚威斯康星州森林（29 000 ~ 14 000 yr BP）是一个物种贫乏的松林。威斯康星时代的森林在物种组成上不时变化很大，可能是因为气候变化。从14000年到12000年BP，云杉（云杉）出现在北方水生森林中，森林中有丰富的山核桃（山核桃）和其他落叶树木。这被认为是骆驼湖记录的最冷阶段，1月平均气温为-5 °C，类似于今天的魁北克南部。在12 000年BP之后，森林以橡树为主，落叶阔叶树种类繁多，不像佛罗里达东北部，那里当时的中温带植物群较少，有一些草原发育，湖泊水位较低，有许多干涸的湖泊盆地。在浅水沉积是连续的骆驼湖在全新世早期，但沉积物类型和花粉组成的突然变化表明10 020年和7760年BP之间的间隙。之后，现代土耳其橡树/长叶松树森林出现。在全新世晚期，地下水位上升了约4米，柏树沼泽和海湾发展起来。花粉资料所显示的气候与已发表的威斯康星州晚期和全新世大气环流模式（GCM）的模拟结果相冲突。差异可能是由模型中使用的特定边界条件解释的，特别是假设佛罗里达纬度的海洋温度变化很小。
Abstract. Camel Lake records the vegetation history of northwest Florida from ""40 000 yr BP to the present. The Middle Wisconsin, from 40 000 to 29 000 yr BP, was a time of forests with abundant pine, oak, and diverse mesic tree species. Chestnut (Castanea) was an important element in the vegetation before 31 000 yr BP. The Late Wisconsin forest (29 000 yr BP to 14 000 yr BP) was a species-poor pine forest. The Wisconsin-age forests varied greatly in species composition from time to time, probably because of climatic variation. From 14 000 to 12 000 yr BP Picea (spruce) was present with northern aquatics in forest with abundant Carya (hickory) and other deciduous trees. This is believed to be the coldest phase recorded at Camel Lake, with a suggested climate of-5°C January mean temperatures, similar to southern Quebec today. After 12 000 yr BP the forest was oakdominated with diverse deciduous hardwoods, unlike northeast Florida, which at that time had a less mesic flora with some prairie development and low lake levels with many driedout lake basins. Sedimentation in shallow water was continuous at Camel Lake in the early Holocene, but a sudden change in sediment type and pollen composition indicates a hiatus between 10 020 and 7760 yr BP. After the hiatus modern turkey oak/long-leaf pine forests were present. There was a rise of some 4 m in the water table in the later Holocene, and cypress swamps and bayheads developed. The climates indicated by pollen data are in conflict with the simulations of published general circulation models (GCMs) for both the Late Wisconsin and the Holocene. Discrepancies may be explained by the particular boundary conditions used for the models, especially an assumption of little change in ocean temperatures at the latitude of Florida.