云南西部羊邑和龙陵地区晚上新世植被和古气候

LATE PLIOCENE VEGETATION AND PALAEOCLIMATE OF YANGYI AND LONGLING OF WESTERN YUNNAN PROVINCE

云南西部羊邑和龙陵地区晚上新世孢粉组合均以被子植物占优势 ,蕨类和裸子植物次之 ,藻类类群少。龙陵孢粉组合比羊邑孢粉组合含有更丰富的亚热带被子植物成分 ;裸子植物类群相对较少 ;蕨类类群较多 ,但孢子含量低。与研究地区现生植被对比研究的结果显示羊邑孢粉组合的大部分类群来自常绿针阔叶混交林 ,现在分布于羊邑地区海拔 2 80 0～3 1 0 0m的地带 ,其余部分来自海拔 3 2 0 0m以上的云冷杉林 ;而龙陵孢粉组合的大部分类群来自山地湿润常绿阔叶林 ,分布于今日龙陵地区海拔 1 60 0～ 2 50 0m的地带 ,其余部分来自海拔 2 30 0～2 90 0m的常绿针阔叶混交林。这些云南西部晚上新世植被反映了湿润的亚热带山地气候。

Late Pliocene palynofloras of both Yangyi and Longling are dominated by angiosperms, along with a moderate number of ferns and gymnosperms, and a few algae. Compared with Yangyi playnoflora, Longling palynoflora contains more abundant subtropical elements of angiosperms, more ferns and less gymnosperms. Based on comparison with the vertical zones of modern vegetations, most elements of Longling palynoflora derived from the montane humid evergreen broad-leaved forest at elevation of 1 600～2 500 m, with less contributions of the evergreen coniferous and broad-leaved mixed forest from 2 300 to 2 900 m, whereas most of Yangyi palynoflora derived from the evergreen coniferous and broad-leafed mixed forest at elevation of 2 800～3 100 m, with less contributions of evergreen coniferous forest above 3 200 m. Both Late Pliocene vegetation reflect humid subtropical,mountain climate with humidity.