| 模拟不同气候条件下碳酸盐岩风化作用的淋溶实验研究 |
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| 引用本文： | 冯志刚,马强,李石朋,梁连东,王世杰.模拟不同气候条件下碳酸盐岩风化作用的淋溶实验研究[J].中国岩溶,2012,31(4):361-376. |
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| 作者姓名： | 冯志刚 马强 李石朋 梁连东 王世杰 |
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| 作者单位： | 1.南华大学核资源与核燃料工程学院 |
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| 基金项目： | 国家自然科学基金项目，国家基金委创新团队项目，中国科学院战略性先导科技专项 |
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| 摘 要： | 通过模拟干热、湿热与干冷3种气候条件,以饱和CO2水作为淋溶液,对黔中岩溶区3条碳酸盐岩风化壳岩-土界面的岩粉层试样进行了淋溶实验(其中干热、湿热条件下淋溶到残余酸不溶物阶段),对淋出液的pH值以及主要造岩元素的浓度进行了动态分析。结果表明,碳酸盐岩风化壳岩-土界面由岩到土的转变过程中,伴随碳酸盐的溶蚀,酸不溶物已表现出明显的风化倾向。碳酸盐的溶蚀强度表现为干冷>干热>湿热的变化趋势。温度低,碳酸盐的溶解速率大;排水条件好,碳酸盐溶解释放的Ca、Mg易随风化流体排出体系。对于酸不溶物组分,淋溶实验中有:(1)K、Na、Mg、Si、P的载体矿物风化强度在干热条件下最大(至于Ca,由于方解石与白云石均是其主要的载体矿物,酸不溶物相中的Ca难以在淋出液中有效识别)。在干冷与湿热之间,K、Na、Mg等盐基离子的溶出能力大多表现为湿热>干冷,指示了温度对盐基离子释放强度的重要制约作用;而Si和P未表现出一致的变化趋势,可能源于淋溶体系微环境的差异。(2)Fe与Mn表现出弱迁移性。其中,Fe在干冷环境下淋出强度最弱,说明温度是制约含Fe矿物分解速率的重要因素。而Fe在干热与湿热之间,以及Mn在3种淋溶条件下,未呈现出一致的变化趋势。(3)Al和Ti在碳酸盐岩风化过程中表现出强烈的惰性。
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| 关 键 词： | 碳酸盐岩风化壳 岩-土界面 岩粉层 风化作用 淋溶模拟 贵州 |
| 收稿时间： | 2012/7/13 0:00:00 |
Leaching experiment for the weathering of carbonate rocks by simulating different climates |
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| FENG Zhi-gang,MA Qiang,LI Shi-peng,LIANG Lian-dong and WANG Shi-jie.Leaching experiment for the weathering of carbonate rocks by simulating different climates[J].Carsologica Sinica,2012,31(4):361-376. |
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| Authors: | FENG Zhi-gang MA Qiang LI Shi-peng LIANG Lian-dong and WANG Shi-jie |
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| Institution: | 1.School of Nuclear Resource and Nuclear Fuel Engineering, University of South China2.The State Key Laboratory of Geochemistry, Institute of Geochemistry, CAS |
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| Abstract: | By simulating dry-hot, wet-hot and dry-cool climate respectively and taking water saturated with CO2 as leaching solution, a leaching experiment is carried out(of them, leaching experiment simulating dry hot and wet-hot climate reached acid-insoluble residue stage) on rock powder layer samples from rock-soilinterfacein3 weathering profiles in central Guizhou karst region. The results indicate that acid-insoluble residues have shown significant weathering tendency along with carbonate dissolution at rock-soil interface of weathering profiles. In three kinds of different leaching conditions, the dissolution intensity of carbonate displays the trend of dry-cool> dry-hot> wet-hot. When the temperature slow, the dissolution rate of carbonate is high, and as the drainage condition is good, Ca and Mg released by carbonate dissolution are easy to be discharged from the system. Concerning the acid-insoluble residues in carbonate rocks, firstly, the weathering intensity of carrier minerals of K, Na, Mg, Si and P is the strongest in dry-hot condition(as for Ca, for both calcite and dolomite are its major carrier minerals in carbonate rocks, it is different to effectively identify Ca deriving from acid-insoluble phase in leaching solution).Between dry-cool and wet-hot, the release ability of K, Na and Mg, i.e. base cations, from the system, in most cases, is for wet-hot> dry-cool, and it is indicated that the temperature severely constrains the release strength of base cations; the release ability of Si and P is not demonstrated a consistent trend in three samples, and it may be caused by the differences in microenvironment of the leaching system. Secondly, Fe and M n are weak migration elements. A among them, the leaching intensity of Fe in dry-cool condition is the weakest, and it indicates that the temperature is an important factor to constrain the decomposition rate of Fe-containing minerals. While leaching intensity of Fe between dry-hot and wet-hot and M n among three kinds of different leaching conditions, do not show a consistent trend in three samples. Thirdly, Al and Ti show strong inertness during weathering of carbonate rocks. |
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| Keywords: | weathering crust of carbonate rock rock-soil interface rock powder layer weathering leaching simulation Guizhou Province |
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