青藏高原南部第四纪花粉植物群及古气候

Quaternary palynoflora and palaeoclimate in the southern Qinghai-Xizang Plateau

本文选择了青藏高原南部具有代表性的６个花粉剖面，应用主成分分析处理这些剖面的花粉数据，重建了这些地区的古植被和古气候。研究表明，在青藏高原南部，早、中更新世的植被类型主要是松林、云杉林、铁杉林、桦林、桤木林和栎林，晚更新世和全新世的植被类型主要是高山灌丛草原、小半灌木草原、杂类草草甸、亚高山灌丛和落叶阔叶灌丛；在早、中更新世气候条件良好，有森林生长，晚更新世以后气候明显恶化，基本无森林生长。

This paper gives a qualitatively and quantitatively study of Quaternary palynoflora and palaeoclimate in the southern part of the Qinghai-Xizang Plateau. 4 Pleistocene sections and 2 Holocene sections in Xizang are selected for palaeoeco logical interpretation by principal component analysis (Shcn et. al. 1992), 11 vege tation types are reconstructed, namely spruce forest, birch forest, hemlock forest and pine forest in the early Pleistocene, pine forest, hemlock forest, alder forest and oak forest in the middle Pleistocene, alpine meadow, subalpine shrub and pine forest in the late Pleistocene and deciduous broad-leaf shrub, pine forest, subalpine shurb, small semifrutex steppe and genuina herbosa meadow in the Holocene. Based on the results of principal components of palaeovegetation types, palaeoclimate of Quaternary including mean annual temperature, coldest mouth temperature and warmesttemperature are respectively indicated as follows: 1.7°C-6. 4°C,-7.2°C- -3.4°C and9. 8°C-14. 4°C in the early Pleistocene at Maerguochaka, 5. 7°C - 9. 1 °C, -4.1°C- -0.1°Cand 13. 0°C-15. 1°C in the middle Pleistocene at Hamencuo-Ximencuo ,-2.1°C- -0. 2°C,-11.6°C- -9.7°C and 6.0°C- -7.8°C in the late Pleistocene at Hamencuo-Ximencuo, and -2.2°C- -2.7°C, -11.6°C- -7.1°C and 5.9°C-9.9°C in Holocene at Nariyon gcuo.