【摘要】 《西洱河图》为唐时南诏国人所绘制的一幅洱海地图,其中保存了洱海湖水南流的珍贵信息。文章采用第四纪地质学、地貌学、历史学和考古学等方面的材料、成果与研究方法,证明该图所显示的古洱海湖水南流的情况是真实可信的,古洱海湖水可以循波罗江道、定西岭裂隙南流,并由此复原了全新世中期以来洱海湖水南流通道的变迁过程:第1阶段(约8465~6950 cal.aB.P.),洱海湖水南流时间较短;第2阶段(约6950~2560 cal.aB.P.),洱海湖水绝大部分时间南流,流量较大;第3阶段(约2560 cal.aB.P.~1111A.D.),洱海湖水南流,流量变小;第4阶段(约1111A.D.至今),洱海湖水南流水道完全阻塞。最后指出,全新世中期以来,洱海出现的高水面主要与洱海的另一出水口———西洱河断裂带裂隙的堵塞有关,而洱海水面出现的快速下降现象,亦主要与西洱河断裂带裂隙的通畅有关。研究结论不但为长期不得其解的全新世中期以来洱海湖面的大幅度升降之谜提供了较好的解释,而且也可以纠正学术界在汉代“叶榆河”、“仆水”、“劳水”问题上出现的错误认识。更多还原

【Abstract】 The Xi′erhe Lake Map is an ancient map of the Erhai Lake in Northwest Yunnan Province of China protracted by officers of the Nanzhao Kingdom(649～902A.D.)during the Tang Dynasty(618～907A.D.),which shows the southward flowing of lake water.Based on a synthetic research of stratigraphic analysis of the south bank of the lake,physiognomic materials from the Mt.Dingxiling cranny of the Honghe River(a river flowing into the South China Sea) fault belt,historic documents from the Western Han Dynasty(206BC～24A.D.) to the Republic of China(1912～1949A.D.),and archaeological results of some ancient city walls built at the lake bank during the Nanzhao Kingdom,this paper confirms the southward flowing of lake water shown on the map.Furthermore,the change history of water system of the Erhai Lake since the mid-Holocene is drawn from the stratigraphic analysis of the south bank section which chiefly displays alternatedly arranged snail layers and spore and pollen layers chiefly.It can be divided into the following 4 stages:(1)From about 8465cal.aB.P.to 6950cal.aB.P.,the lake water flowed southward through the channel of the Boluojiang River,the Mt.Dingxiling cranny for a short time,and westward through the(Xi′erhe) River cranny for a longer time;(2)From about 6950cal.aB.P.to 2560cal.aB.P.,the lake water flowed southward with a high water flow for most of the time;(3)From about 2560cal.aB.P.to 1111A.D.,the lake water flowed southward with a lower water flow,and to the west with an increasing flow;(4)From about 1111A.D.to present,the watercourse to the south was entirely blocked,with all water flowed westward through the Xi′erhe River.Evidence shows that since the mid-Holocene a high water surface level of the Erhai Lake appeared once might be caused by the jam of the Xi′erhe River cranny,and a dropped level appeared shortly at another time might be related to the open of the cranny,a notion different from the previous one which believed that the level change was mainly due to the dry and wet alternation of climatic.更多还原