Deglacial climate variability in central Florida, USA
Deglacial climate variability in central Florida, USA
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美国佛罗里达州中部冰消期气候变化
DOI：
10.1016/j.palaeo.2007.04.016
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
R. Larson
中科院分区：
文献类型：
--
作者：
D. Willard;C. Bernhardt;G. Brooks;T. Cronin;T. Edgar;R. Larson
现代佛罗里达坦帕湾湖泊沉积物中的花粉和介形虫证据记录了亚热带地区频繁和突然的气候和水文事件叠加在冰消期变暖上。放射性碳年代学保存完好的软体动物壳和花粉残留物从核心MD02 - 2579文件连续沉积在各种非海洋栖息地在岩溶控制的盆地从20 ka到11.5 ka。在末次盛冰期（LGM），花粉组合中富含藜科和山核桃属植物，松属植物（<10%）稀少，表明当时的气候条件比现代干燥和凉爽。松花粉在最初的冰川消退期（约17.2 ka）的变暖期间增加到20 - 40%，在Bølling/Allerød间隔（14.7 - 12.9 ka）的温暖，潮湿的气候中达到接近现代的丰度（60 - 80%）。在Bølling/Allerød地区，百年尺度的干旱事件对应于Older Dryas和Intra-Allerød寒冷期，表明植被对气候变率的快速反应（<50年）。新仙女木（12.9 - 11.6 ka）的特征是两个不同的阶段：12.9 - 12.3 ka之间比Bølling/Allerød峰稍干燥，12.3 - 11.5 ka之间更干燥。坦帕湾记录的冰消期大气温度和湿度可以与其他古气候记录在北大西洋地区和气候强迫冰盖波动，温盐环流和大气环流的影响。
Pollen and ostracode evidence from lacustrine sediments underlying modern Tampa Bay, Florida, document frequent and abrupt climatic and hydrological events superimposed on deglacial warming in the subtropics. Radiocarbon chronology on well-preserved mollusk shells and pollen residue from core MD02-2579 documents continuous sedimentation in a variety of non-marine habitats in a karst-controlled basin from 20 ka to 11.5 ka. During the last glacial maximum (LGM), much drier and cooler-than-modern conditions are indicated by pollen assemblages enriched in Chenopodiaceae and Carya, with rare Pinus (<10%). Pinus pollen increased to 20–40% during the warming of the initial deglaciation (∼17.2 ka), reaching near modern abundance (60–80%) during warmer, moister climates of the Bølling/Allerød interval (14.7–12.9 ka). Within the Bølling/Allerød, centennial-scale dry events corresponding to the Older Dryas and Intra-Allerød Cold Period indicate rapid vegetation response (<50 years) to climate variability. The Younger Dryas (12.9–11.6 ka) was characterized by two distinct phases: slightly drier than the peak Bølling/Allerød between 12.9 and 12.3 ka and much drier from 12.3 to 11.5 ka. The Tampa Bay record of deglacial atmospheric temperature and moisture can be correlated with other paleoclimate records in the North Atlantic region and has implications for climate-forcing by ice-sheet fluctuation, thermohaline circulation, and atmospheric circulation.