浙江瑶琳洞风化碳酸钙景观复生试验

目前,世界上80%以上的风景旅游洞穴,开放后,大量游客涌入和高能景观灯的应用,洞穴环境及能量埸和化学埸发生了巨大变化,洞穴碳酸钙景观遭受严重破坏,其景观的美学价值大大降低。文中论述了在已遭风化破坏的碳酸钙景观上滴喷高Ca⁺²碱液,吸收洞穴空气CO₂,形成CaCO₃沉积层的试验。试验结果表明,Ca⁺²碱液滴喷技术可以恢复风化碳酸钙景观的美学度,同时又降低洞穴空气中的浓度,改善洞穴环境。

Experiment of recovering weathered speleothem in Yaolin cave, Tonglu, Zhejiang, China

The speleothem stability is threatened because it is seriously weathered and broken down as the cave environment is seriously effected by the tourism activities.The speleothem weathering is quite often in the show caves.Based on the laboratory experiments,the calcareous alkaline solution is the best one for the recovering experments.The field experiment work lasted one year.The calcareous alkaline solution was employed for the experiments to be dropped on the strong weathered stalagmite and flowstone with the slope of 45° and sprayed on the vertical column.The changes of conductivity, pH, Ca⁺² contents and alkalinity in the solution were monitored during the experiments.The results demonstrate that 98.9% of Ca⁺² was deposited in the distance of 1.5 m from the dropping point.pH values droped from 12.2 down to 8.5, OH-content decreased from 17.76 mg/l to 0 and the conductivity from 2 160 us/cm to 98.9 us/cm.After the experiments lasting for 3 month, the front side of the stalagmite was completely covered.The new stalactites, leaf pools and stone ears developed like the natural one.The scanning electronic microscope (SEM)is used to observe the crystal of calcite.The natural calcite performs the well trigonal crystals larger than 0.3 mm with perfect rhembohedral cleavage.The crystal of CaCO₃ deposited by the spaying solution is very similar to the natural one.The deposits by dropping are not so good as the spraying one, however, they have developed the trigonal crystals with the size of 15 μ-20μm even 35μm with good rhembohedral cleavage.The CaCO₃ deposit on the stalagmite has been changed to be hard to well protect the weathered speleothem.