概括
美国西南部的沙漠在8000年前因冬季降水量减少而从林地转变为沙漠. 这种气候变化落后于全球趋势,因为冰川融化影响了天气模式.
科学领域:
- 古气候学 古气候学
- 四年纪地质学四年纪地质学
- 生态生态学 生态生态学
背景情况:
- 包装老鼠的中间提供了有价值的古生态记录.
- 美国西南部的沙漠在四年纪末期经历了显著的气候变化.
研究的目的:
- 在美国西南部沙漠重建过去的林地社区.
- 为了确定植被变化的时间和原因.
主要方法:
- 通过放射性碳测年法测年29个包装大鼠的中间体.
- 分析中间的化石植物材料,以推断过去的植被.
主要成果:
- 在不到1万年前,在西南沙漠记录了森林社区.
- 大约8000年前,在奇瓦胡安,索诺兰和莫哈维沙漠中发生了同步过渡到沙漠或草原.
- 推断原因:阿勒低和冬季风暴轨道向北移动,降水量减少.
结论:
- 与北半球相比,西南地区的气候转变为非雨天气候的时间延迟了.
- 大陆冰川的融化影响了大气循环模式,影响了西南部的气候.
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