| 内蒙古苏尼特左旗中新世晚期孢粉记录干旱事件 |
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| 关键词:Late Miocene sporo-pollen dry event Sunitezuoqi Inner Mongolia |
| 基金项目:国家自然科学基金重点项目(编号90202017) |
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| 摘要: |
| A Study of the Late Miocene Dry Event Based on Sporo-Pollen Variations in Sunitezuoqi, Inner Mongolia |
| The sporo-pollen variations of Mid-Miocene Tonggur Formation and overlying Baogeda Ula Formation indicate that late Mid-Miocene was wetterand warmer than early Mid-Miocene in Sunitezuoqi,Inner Mongolia. A dry event occurred in the transitional period from Mid-Miocene to Late-Miocene at about 8.5 Ma, when grass and shrub pollens increased from 19.7% to 46%, tree pollens decreased from 69.5% to 34.7%, and the Pinus/Arlemisia ratio (A/C) decreased from 4 to 0.64 in this area. The paleomagnetism along Section PM-01 indicates a correlation between C5An and C4r in the standard polarity, with an age range of 12.5～12 Ma and a late stage of 8.5Ma. Widespread arid and semi-arid areas occurred in North China and Northwestern China since 8.5Ma of Late Miocene, and the dry event in North China at 8.5 Ma was related to the lift of the Himalayas and the red clay in the tableland. An extensive correlation of dry events in North China at 8.5 Ma is supported by sporo-pollen data. |
| DONG Ming-xing,LI Feng-lin,GAO De-zhen,GENG Ming-shan,LI Long-yin.2006.A Study of the Late Miocene Dry Event Based on Sporo-Pollen Variations in Sunitezuoqi, Inner Mongolia[J].Acta Geoscientica Sinica,27(3):207-212. |
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