| 利用石笋δ13C重建岩溶石漠化研究进展 |
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| 引用本文： | 徐玉珍,李廷勇,李俊云,杨琰.利用石笋δ13C重建岩溶石漠化研究进展[J].中国岩溶,2022,41(4):660-674. |
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| 作者姓名： | 徐玉珍 李廷勇 李俊云 杨琰 |
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| 作者单位： | 1.岩溶环境重庆市重点实验室, 西南大学地理科学学院, 重庆 400715 |
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| 基金项目： | 云南省基础研究计划重点项目(202101AS070070)；国家自然科学基金项目(42172204)；广西喀斯特动力学重点科技创新开放项目(KDL & Guangxi 202003) |
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| 摘 要： | 岩溶石漠化的形成演化机制是被关注的科学问题，对脆弱的岩溶区生态环境恢复具有重要的现实意义。洞穴石笋δ13C受到多种因素影响，能敏感响应地表生态环境以及岩溶水文条件的变化。因此，利用石笋δ13C研究岩溶地区生态环境演变历史成为一个重要方向。本文从地表环境和洞穴沉积两个方面梳理了影响石笋δ13C的主要因素。结合现代洞穴监测及模型模拟研究，分析整理了影响洞穴滴水和沉积物中δ13C的主要因素和机理。在多重因素的影响下，石笋δ13C的环境意义具有多解性，文章从时间尺度、空间分布、沉积环境三方面归纳了石笋δ13C的指示意义。为了准确解释石笋δ13C环境意义，提出了综合分析、现代监测以及模型模拟的解决方案。通过对岩溶石漠化概念、成因、发展过程、以及环境效应的讨论，分析了地表石漠化与石笋δ13C记录的密切联系。总结了已经发表的利用石笋δ13C重建区域石漠化的研究成果，讨论了目前研究中面临的主要问题:(1) 如何正确解译石笋δ13C的指示意义？这是石笋δ13C能够用于重建区域石漠化历史的前提；(2) 在空间上，石笋δ13C记录反映上覆地表的面积是有限的，需考虑石笋能否代表目标研究区域的环境变迁；(3) 石漠化可在年—十年际时间尺度上快速发展，而石笋测年存在一定的年龄误差，石笋δ13C是否能够敏感记录地表的石漠化过程？为了准确重建区域岩溶环境以及石漠化演变历史，提出以下主要建议:(1) 为了避免石笋δ13C重建古环境的不确定性，可加强石笋δ13C与δ18O、微量元素、矿物结构等指标的综合对比分析，与现代监测以及模型模拟的解决方案综合集成，能更加准确重建研究区岩溶水文变化过程，判定石漠化的演化历史；(2) 通过区域和同一洞穴的多根石笋记录对比，减少单一石笋记录的区域代表性问题；(3) 高精度年代控制的高分辨率多指标石笋记录，有助于捕捉快速发生的石漠化过程。
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| 关 键 词： | 岩溶石漠化 洞穴石笋 石笋δ13C 古环境重建 |
| 收稿时间： | 2022-01-20 |
Progress in reconstruction of karst rocky desertification by stalagmite δ13C |
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| Institution: | 1.Chongqing Key Laboratory of Karst Environment/School of Geographical Sciences, Southwest University, Chongqing 400715, China2.Yunnan Key Laboratory of Plateau Geographical Processes & Environmental Changes/Faculty of Geography, Yunnan Normal University, Kunming, Yunnan 650500, China |
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| Abstract: | The formation and evolution mechanism of karst rocky desertification is a scientific problem that has been paid increasing attention, and the ecological environment in karst areas is not only fragile, but also unstable. Therefore, the study of karst rocky desertification is of practical significance for the restoration of ecological environment in karst areas. Cave stalagmite δ13C is affected by many factors and can respond sensitively to the changes of surface ecological environment and karst hydrological conditions. Hence, the use of stalagmites δ13C on the study of evolution history of ecological environment in karst areas has become an important direction. In this paper, we discuss the main factors affecting stalagmite δ13C from two aspects, i.e., the overlying surface environment and cave deposition. Combining the results of modern cave monitoring with model simulation, we analyze the main factors and mechanisms affecting δ13C in cave drop water and sediment. Under the influence of multiple factors, the environmental significance of stalagmites δ13C has multiple implications. According to the published research results, in this paper, we summarize the indicative significance of stalagmite δ13C from three aspects, different time scales, different regional distribution, and different cave sedimentary environments. In order to accurately interpret the environmental significance of stalagmite δ13C, we put forward the solutions-comprehensive analysis, modern monitoring and model simulation. In this paper, we discuss the concept, genesis, development process and environmental effects of karst rocky desertification, and analyze the close relationship between surface rocky desertification and stalagmite δ13C records in caves. We also summarize published research results about the application of stalagmites δ13C to the reconstruction of regional rocky desertification. Meanwhile, we discuss main problems faced in the current research, (1) How to interpret the indicative meaning of stalagmite δ13C correctly? This problem is the premise that stalagmite δ13C can be used to reconstruct the history of regional rocky desertification. (2) Spatially, the area of the overlying surface reflected by stalagmites δ13C records is limited, so it is necessary for us to carefully consider whether the selected stalagmite region reflects the same spatial distribution as that of the study area, and whether it represents the environmental changes of the target study area, when using stalagmite δ13C to reconstruct the evolution history of rocky desertification in a certain region. (3) Karst rocky desertification can develop rapidly on the decadal time scale, while a certain age error may occur in stalagmite dating. Can stalagmite δ13C record sensitively record the changes of surface environment in such a short period and reconstruct the process of regional rocky desertification? In order to accurately reconstruct the regional karst environment and the evolution history of rocky desertification, we put forward the following suggestions, (1) In order to avoid the uncertainty of stalagmite δ13C in paleo-environment reconstruction, the comparative analysis of stalagmite δ13C and δ18O, trace elements and mineral structure can be integrated with modern monitoring and model simulation to correctly interpret the indicative significance of stalagmite δ13C. On this basis, the karst hydrological process can be reconstructed more accurately and the evolution history of rocky desertification can be determined. (2) By comparing the evolution process of rocky desertification recorded by stalagmites from multiple caves in the study area and multiple stalagmites from the same cave, the regional representativeness of single stalagmite record can be reduced. (3) Multi-index stalagmite records with high resolution and high precision chronological control can accurately record the changes of the land surface environment during the rapid occurrence and development of the rocky desertification process. |
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