摘要
文章报道了响水河河水的现场监测结果 ,得到响水河河水的Ca2 + 和HCO-3非常低 ,这明显与河床中大规模钙华的存在和景区内发育的茂密植被不匹配 ;并仔细观察发现 ,钙华表面有被侵蚀的痕迹 ,如溶蚀槽和溶蚀坑等 ,这说明目前所见钙华可能是过去环境条件下的产物。根据钙华碳氧稳定同位素组成特征的分析得出 :近 4 0 0 0年来 ,该地区总的气候环境变化趋势是 4 0 0 0～ 340 0aB .P .为相对温暖湿润期 ,植被生长好 ,为良性生态期 ;340 0～2 0 0 0aB .P .前期仍比较温暖但干燥 ,后期到 2 0 0 0aB .P .左右变得比较凉爽 ,从这一冷期到大致 90 0aB .P .前后 ,气候有些波动 ,但幅度较小 ,夹有冷暖干湿的交替 ;而 90 0aB .P .至今 ,钙华碳氧稳定同位素值的急剧增加 ,反映出气候的冷干和源区人类活动加剧造成的水土流失增加 ,岩溶石漠化加重 。
It was found by in-situ monitoring that the Xiangshui River has a very low concentration of calcium and bicarbonate, which does not match with the huge tufa deposits in the riverbed and the dense vegetation cover in surrounding area. In fact, there are some erosional features on the surface of the tufa, such as dissolutional notches and pits. It means that the tufa deposits may be remains of the past environment. Analyses on the stable carbon and oxygen isotopic compositions of the tufa revealed that for the past 4 000 years, the general trend in climatic and environmental change is: from 4 000aB.P. to 3 400aB.P., it was warm and humid, and the vegetation grew well, and the ecosystem was in benign cycle; from 3 400aB.P. to 2 000aB.P., in the early stage, it was warmer and drier, and in the later stage, it was getting cooler; from 2 000aB.P. to 900aB.P. the climate fluctuated gently, with alternation of cool and warm, dry and wet. However, from 900aB.P. till now, the value of the stable carbon and oxygen isotopic compositions increased steeply. It reflects that the climate was getting cooler and drier, soil erosion increased, and the ecosystem was in vicious cycle, the latter being intensified by human activity in the recharge area.
出处
《第四纪研究》
CAS
CSCD
北大核心
2004年第4期447-454,T005,共9页
Quaternary Sciences
基金
国家重大基础研究前期研究专项项目 (批准号 :2 0 0 2CCA0 5 2 0 0 )
国家自然科学基金项目 (批准号 :40 3 72 117)
国土资源部"百人计划"项目(批准号 :980 6)
广西自然科学基金项目 (批准号 :桂科回 0 14 40 10 )资助
关键词
水化学
钙华碳氧稳定同位素
古环境重建
岩溶石漠化
响水河
贵州荔波
hydrochemistry, tufa stable carbon and oxygen isotopes, paleoenvironmental reconstruction, karst rocky desertification, Xiangshui River, Libo County in Guizhou Province
