| 世界自然遗产-四川黄龙钙华景观的形成与演化 |
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| 引用本文：刘再华,田友萍,安德军,王海静,唐淑,张金流,孙海龙,刘彦,张清明.2009.世界自然遗产-四川黄龙钙华景观的形成与演化[J].地球学报,30(6):841-847. |
| DOI：10.3975/cagsb.2009.06.16 |
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| 基金项目:中国科学院百人计划项目和国家自然科学基金项目(编号40572107、40872168) |
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| 中文摘要:本文对作者十余年来在四川黄龙(世界遗产地)的钙华研究成果和最新的一些监测发现进行了综述, 目的是为公众更好地了解黄龙、保护黄龙提供科学基础。主要结果和结论是: (1)黄龙钙华的形成是由于地球深部高分压的CO2在碳酸盐岩补给区产生富含碳酸氢钙的地下水, 当其以泉的形式出露地表时, 由于泉水的CO2分压远远高于空气, 泉水中的CO2大量逸出, 结果导致碳酸钙过饱和而发生沉积; (2)黄龙钙华的颜色以黄色为主色调, 主要是在雨季因雨水冲刷土壤向水中混入泥沙的缘故; 而在旱季, 钙华主要形成于清亮干净的泉水, 因此, 钙华的颜色呈现出纯净碳酸钙沉积的本色-白色。这也是黄龙洞钙华剖面年层中出现黄-白相间亚层的原因; (3)高精度的铀-钍同位素测年表明, 黄龙钙华主体是全新世以来形成的; (4)地表水向地下河的漏失是黄龙地表水日益减少, 导致钙华体表面干涸, 从而气生蓝藻大量滋生, 致使某些钙华变黑的主要原因, 因此, 有必要尽早采取防渗补水措施; (5)旅游活动已对黄龙钙华景观产生影响, 包括上游人为践踏使下游钙华池淤塞, 以及磷酸盐污染使硅藻等过度繁殖和钙华沉积速率可能降低等, 因此, 必须尽早采取相应防控措施。 |
| 中文关键词:钙华 成因 颜色 形成年代 地表水渗漏 人为污染 |
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| Formation and Evolution of the Travertine Landscape at Huanglong, Sichuan, One of the World Natural Heritages |
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| Abstract:To make people know more about the Huanglong Ravine of Sichuan (one of the world natural heritage sites) and provide scientific basis for protecting it, this paper summarized the authors’ research achievements on the travertine deposits reached during the past decades along with the latest monitoring findings in the Huanglong Ravine. The major results and conclusions are: (1) The formation of travertine was because firstly dissolution of carbonate rock in the recharge area produced groundwater rich in calcium and bicarbonate ions under higher par-tial pressure of deep-seated CO2, and then calcite deposited on the ground surface due to CO2 degassing from the groundwater-fed spring with much higher pCO2 than that in the atmosphere, which made water to be supersaturated with calcium carbonate; (2) The dominant color of Huanglong travertine was yellow, which was mainly related to the interfusion of soil impurities in the rainy season due to soil erosion after rainfall. However, travertine was formed mainly in the clean and clear spring water in the dry season, so, the color of travertine was white, i.e., the native color of pure calcium carbonate. This was also the reason why the travertine section in the Huanglong Cave shows the lamination structure of yellow alternating with white; (3) High resolution uranium-thorium dating indi-cated that the main body of Huanglong travertine has formed since Holocene; (4) the main reason for the decrease in surface flow rate was leakage to the underground river, which results in the dryness and propagation of aerial algae communities on the travertine surface, the latter was the reason for the black color of travertine. Therefore, it is necessary to take measures to prevent leakage and replenish surface water as early as possible; (5) The tourism activity has shown its influences on the Huanglong travertine landscape. These include the filling up of some tra-vertine rimstone pools downstream due to human trampling on the travertine landscapes upstream, and the propa-gation of diatom and possible decrease in travertine deposition rate due to the pollution of the phosphate in the tourism midseason. Therefore, relevant preventing and controlling measures must be taken as soon as possible. |
| keywords:travertine origin color forming times surface water leakage anthropogenic pollution |
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