Abstract: We have measured δD, δ¹⁸O and ³H of surface water, spring water and drip water in Shihua cave area.The average values with the standard deviation of δD and δ¹⁸O are (-65.4±3.5)‰, (SMOW) and (-9.4±0.3)‰(SMOW), respectively.The average tritium content is (30.8± 4.5)TU.These data demonstrate that the drip water in Shihua cave represents fast penetration of surface water above the cave, and the mixing effect of old groundwater is negligible.Therefore, the variations in isotopic composition of cave drip water can reflect changes in isotopic composition of surface water which represent weighted mean annual isotopic composition of precipitation in the locality.The major factors that influence isotopic composition of cave drip water are mean annual air temperature, mean annual rainfall and change in moisture source.This research work forms the basis of using high-resolution δ¹⁸O record in speleothem to reconstruct paleoclimatic record in the region, especially for paleomonsoon variability.

Key words: Isotopic age dating, Limestone, Karst water

摘要： 北京石花洞地区水系的δD平均值为(-65.4±3.0)‰(SMOW),δ¹⁸O平均值为(-9.4±0.3)‰(SMOW),氚含量平均值为(30.8±4.5)TU.石花洞洞内滴水是由地表水很快下渗得来,受古老地下水的混合作用很小。因此,洞内滴水的稳定同位素组成能够灵敏地反映地表水同位素组成(即重量加权的年平均雨水的同位素组成)的变化。影响洞内滴水的稳定同位素组成的因素主要是年平均气温、年降雨量以及降水气团的来源的变化。利用高分辨率的洞穴碳酸盐的稳定同位素记录。可以建立以湿度变化为主的古气候信息。尤其是我国季风气候的变化历史。

关键词: 同位素年龄, 石灰岩, 岩溶水