根据孢粉分析论青藏高原西部和北部全新世环境变化

通过对青藏高原西部班公湖钻孔和北部中昆仑山３个湖相剖面的孢粉研究，揭示青藏高原西部和北部地区全新世１万年期间植被的演替和气候变化，西部在全新世早期９９００－７８００ｙｒ．Ｂ．Ｐ．植被由荒漠转为草原，气候好转；中期７８００－３５００ｙｒ．Ｂ．Ｐ．，草原发展，气候较适宜，以７２００－６３００ｙｒ．Ｂ．Ｐ．为高温湿期，５５００ｙｒ．Ｂ．Ｐ．和３５００ｙｒ．Ｂ．Ｐ．出现干旱，晚期从３５００ｙｒ．Ｂ．Ｐ．至今植被为荒漠，气候干旱，其中７００ｙｒ．Ｂ．Ｐ．气候恶化。北部地区全新世时期为荒漠植被，当气候温湿时，蒿和禾本科，莎草科成份增加，藜科减少，气候干旱时则相反，北部全新世的气候分期和干湿波动与西部相近，两地在晚期气候朝干旱化发展。

HOLOCENE ENVIRONMENTAL CHANGES OF WESTERN AND NORTHERN QINGHAI-XIZANG PLATEAU BASED ON POLLEN ANALYSIS

Studies on the pollen from cores of Bangong Lake in westem Xizang and three lacustrine sections in middle North Kunlun mountains show climatic changes and the evolution of vegetation during the Holocene ( 10 000yr.B.P).In early Holocene(10000-7800yr.B.P.),the westem Plateau changed from desert to grassland with the climate becoming better;in middle Holocene(7800-3 500yr.B.P.),grassland was developed and the climate became temperate.The climate was highly temperate and moist during 7200-6300yr.B.P.,but it was dry during 500yr.B.P.and 3500yr.B.P.It was dry in late Holocene(3500yr.B.P.Present),especially since 700yr.B.P.,and the plateau became desert.On the northem plateau,there were desert-type vegetations during the Holocene,when the climate was temperate and moist,with an increase in the plants of Artemisia,Gramineae and Cyperaceae and a decrease in the plant of Chenopodiaceae. But that was opposite when the climate became dry.The climatic change and dry-moist fluctuations on the northern plateau were the same as on the western plateau during Holocene.The climates in both regions showed a tendency toward becoming dry in Late Holocene.