晚中新世以来亚洲季风阶段性演化的海陆记录

本文在综合对比晚新生代以来中国黄土高原黄土一红粘土沉积、西北太平洋粉尘沉积、南海有孔虫、阿拉伯海有孔虫记录的基础上，探讨了大约8Ma以来亚洲季风的阶段性演化历史。结果发现，黄土高原粉尘沉积在8Ma前后大规模出现，在3．5Ma前后大幅增加；印度季风在8Ma前后形成(或显著加强)；南海ODP1146站位浮游有孔虫Neoglcboquadrina丰度也有两次明显增加，表明海水表面温度不断降低和海洋生产力的增加，指示东亚冬季风作用增强。北太平洋()DP885／886钻孔风成粉尘通量也有增加，指示亚洲内陆进一步的干旱化和冬季风作用的增强。印度洋沉积通量在11Ma前后开始增加。在9～8Ma时出现峰值，表明喜马拉雅山和青藏高原南部逐渐隆起。当隆起达到足够高度时，导致亚洲内陆干旱气候带扩大，同时提供大量粉尘并向东传输到中国北方和北太平洋地区。青藏高原北缘山前盆地的沉积记录显示，在3．6Ma时，高原北部的进一步快速隆升过程可能影响到整个高原，从而导致亚洲内陆更加干旱化，东亚季风增强，粉尘沉积加快，南海及印度洋陆源沉积作用加剧。

The Evolution of the Asian Monsoon Since Late Miocene: Evidence from the Continental and Oceanic Sediments

An evolutionary history of the Asian monsoon since Late Miocene has been discussed based on the comprehensive comparison of the loess-red clay deposits in the Chinese Loess Plateau, eolian flux in the north-west Pacific Ocean, foraminifera fossils in the South China Sea and Arabian Sea. It shows that the wind-blown sediments were accumulated over a wide area in the Chinese Loess Plateau around 8 Ma, when the Indian Monsoon was formed (or obviously enhanced), and around 3. 5 Ma respectively. The low abundance of planktonic foraminifera Globigermoides sacculifer, G. ruber and high abundance of Neogloboquad-rma approximately 8 Ma at ODP site 1146 in the South China Sea indicate that the oceanic surface temperature was decreased and the oceanic productivity was increased, which indicate the enhancement of the East Asian winter monsoon winds. The high abundance of eolian dusts in the North Pacific Ocean revealed by ODP site 885/886 indicates enhancement of the widespread aridity in the Asian interior.The sediment flux had been increased in the Indian Ocean since 11 Ma with peak flux at ,9 ?8 Ma, which is responsible to the rising process of the Himalayas. When the rise reached sufficient height, the aridity area was expended in central Asia and a large amount of dusts was transported eastwards to the north China and the North Pacific. Further rapid uplift of the entire Tibetan Plateau at 3. 6 Ma, indicated by a thick gravel bed on the north flank of th< Plateau, resulted in further aridity in the basins of central and eastern Asia, enhancement of the East Asian monsoon, and strong terrigenous sedimentation in both the South China Sea and the Indian Ocean in late Pliocene.