摘要
程海是位于云南省西北部的一个较为特殊的湖泊 ,其矿化度已接近盐湖下限。湖泊沉积物无机碳、氧同位素组成敏感地记录了流域内环境变化的信息 ,其相关性有效地揭示了湖泊的封闭条件。组成的变化受到温度高低、降水大小、光合作用强弱、碳酸盐体系溶解平衡及水文条件等因素的控制。通过对该湖沉积物无机碳酸盐碳、氧同位素组成的研究 ,追溯了该流域内自采样深度以来的数十年内的环境变化情况 ,研究表明 :程海流域气候变化有呈现出 11～ 12a的小周期变化的趋势 ,但是在孔柱底部的信号噪声较大 ;沉积物碳酸盐δ1 3C δ1 8O的良好相关性指示了程海近几十年内的水文封闭条件 ;并将碳、氧同位素这一环境敏感指标推广到了高矿化度的“准”咸湖的环境中。
As a special one of the Yunnan Guizhou plateau lakes, Chenghai Lake, which is a typical closed lake with precipitation occupying one third more of annual water input, is high in total salinity (equivalent to a saline lake).The inorganic C,O isotopic composition of lake sediments recorded the information about environmental changes in the catchment sensitively, while their co variance can indicate the close hydrological condition of the lake effectively. Their changes are controlled by temperature, precipitation, photosynthesis, dissolving equilibrium of carbonate system and hydrological condition. According to our research on the inorganic C, O isotopic compositions of the lake sediments, we traced back to several decades pertaining to environmental changes in this catchment. The results showed that Chenghai Lake has kept good hydrological close condition for several decades, as indicated by the good co variance of inorganic C, O isotopic composition of lake sediments; and that environmental changes in this catchment tend to evolve with a period of about 11～12 years, although the noise is relatively high at the bottom of the sediment core. And we also can extend C, O isotopes, this sensitive environmental information indicator to nearly saline lake conditions of high degree mineralization.
出处
《矿物学报》
CAS
CSCD
北大核心
2002年第2期184-188,共5页
Acta Mineralogica Sinica
