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对临夏盆地毛沟第三纪 (30 6～ 5 0Ma)红层剖面进行了系统而密集地孢粉样品采集与室内分析 ,获得丰富的孢粉化石 ,划分出 7个孢粉组合带和 4个植被与气候演化阶段 .阶段A(30 6～ 2 1 8Ma)为疏 (森 )林—草原植被 (带Ⅰ ) ,阶段B(2 1 8～ 8 5Ma)为森林 (带Ⅱ～Ⅴ ) ,阶段C(8 5～ 6 0Ma)为草原 (带Ⅵ ) ,阶段D(6 0～ 5 0Ma)为森林 (带Ⅶ ) .在此期间发生过几次重大气候事件 :1次降温期 (18 6～ 13 0Ma) ,3次温暖湿润期 (2 1 8～ 16 8Ma ,13.0～ 8 5Ma和 6 0～ 5 0Ma)和 1次旱化事件 (8 5～ 6 0Ma)
A systematical and intensive collection of sporopollen samples and laboratory analyzes of the third layer (30 6 ~ 50 Ma) red beds in the Moutou area of the Linxia Basin were conducted, and abundant sporopollen fossils were obtained. Seven sporopollen assemblages and four Vegetation and climate evolution stage. Stage A (30 6 ~ 2 1 8Ma) is sparse (forest) forest-steppe vegetation (zone Ⅰ), stage B (2 1 8 ~ 8 5Ma) is forest (zone Ⅱ ~ Ⅴ) C (85 ~ 60 Ma) was grassland (belt Ⅵ), and stage D (60 ~ 50 Ma) was forest (Ⅶ) .A few major climate events occurred during this period: 13 0Ma), 3 warm and humid periods (2 1 8 ~ 16 8Ma, 13.0 ~ 8 5Ma and 6 0 ~ 5 0Ma) and primary drought events (8 5 ~ 6 0Ma)