洞穴河流沉积物有机碳同位素特征及Ca、Mg、Sr含量的区域环境响应——以贵州省山王洞为例

Characteristics and regional environment response of organic carbon isotope and Ca,Mg and Sr content in cave river sediments:a case study on Shanwang Cave in Guizhou

洞穴河流沉积物因沉积环境稳定且保存较完好,蕴含着丰富的古环境信息。选取双河洞穴系统山王洞中河流沉积物为研究对象,分析沉积环境的水动力条件、沉积物有机碳同位素及Ca、Mg、Sr元素含量特征,以探讨其环境响应。结果表明:(1)在沉积过程中,地下河在该剖面位置长期处于静水水流状态,沉积环境稳定;(2)有机碳同位素特征显示沉积期分为C4植物为主、C3植物为主及过渡期3个时期,不同时期气候明显不同,随时间演变由冷转暖,沉积物来源于中新世以后的地表土壤;(3)洞穴河流沉积物Ca、Mg、Sr元素含量变化对炎热偏湿与湿冷环境的响应比较明显,气温和植被类型可能是影响其含量变化的因素。

Cave river sediments are stable and well preserved due to the stable environment,and contain rich information of paleoenvironment.In this study,the river sediments in Shanwang Cave in the Shuanghe Cave System were selected as the research object.The hydrodynamic conditions of the sedimentary environment and the characteristics of organic carbon isotope and Ca,Mg,Sr content in the sediments were analyzed to explore the environmental response.The results showed that:(1)during the sedimentation process,the underground river was in a state of static water flow for a long time around this section,and the sedimentary environment was stable;(2)the characteristics of organic carbon isotope indicated that the sedimentary period could be divided into C4 plants period,C3 plants period and transition period;the climate in this region was obviously different in the three periods,changing from cold to hot;the sediments came from the surface soil after the Miocene;(3)the content changes of Ca,Mg and Sr in the river sediments showed obvious response to wet-hot and wet-cold environments;temperature and vegetation types might be the factors influencing the content changes of Ca,Mg and Sr.