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岩溶洞穴次生沉积物——石笋因其独有的高精度测年和高分辨率记录的优势已越来越成为过去全球变化研究中重要的支柱。进行洞穴碳酸盐沉积机理研究对于理解石笋沉积速率,结晶形态、准确解译气候替代指标和现代洞穴合理保护具有重要意义。以我国南北交汇带亚洲季风敏感区河南鸡冠洞为例,通过对2010—2015年连续6个水文年对鸡冠洞滴水和碳酸盐沉积的监测发现:1洞内滴水水化学指标与沉积速率表现出很好的一致性,雨季大气降水增加,气温升高,生物活动加强,土壤CO_2含量增加,滴水滴速、Ca~(2+)、HCO_3~-、电导率(EC)和沉积速率同时增加,旱季反之;洞内CO_2对方解石沉积的抑制作用被滴水饱和度掩盖。2受2012—2013年年降雨量显著减少的影响,水岩作用减弱,2014年滴水饱和度降至最低,出现为期一年的沉积间断,直至2014年下半年降水增加,于11月重新接收到方解石沉积。3自2013年下半年开始,受人为淋滤洞穴影响,滴水NO_3~-上升数十倍,模拟实验显示其对CaCO_3溶解的能力较之前提高约60%,表明NO_3~-对方解石沉积存在抑制作用,这可能是个别月份滴水饱和度高却没有回收到CaCO_3沉积的原因,建议景区在进行补水的同时要考虑水质对岩溶作用的影响。
Karst Cave Secondary Sediments - Stalagmites have increasingly become an important pillar of past global change research because of their unique high-precision dating and high-resolution recording. It is of great significance to study the sedimentation mechanism of cave carbonate sediments for the understanding of sedimentary deposition rate, crystal morphology, accurate interpretation of climate change indicators and the reasonable protection of modern caves. Taking Jijiang Cave, an Asian monsoon sensitive area, as an example, we monitored the drip and carbonate deposition of Jiguan Cave in six consecutive hydrological years from 2010 to 2015 and found that the chemical indicators and deposition rate of drip water in 1 hole There was a good consistency between the rainy season, the precipitation increased, the temperature increased, the biological activities strengthened, the soil CO_2 content increased, drip drip rate, Ca 2 +, HCO 3 -, EC and deposition rate increased at the same time On the contrary, the inhibitory effect of CO2 on calcite deposition in the cave was obscured by drip water saturation. 2 Affected by a significant decrease in annual rainfall in 2012-2013, water and rock action weakened and drip water saturation was reduced to a minimum in 2014 with a one-year sedimentary discontinuity until precipitation increased in the second half of 2014 and was re-received in November Calcite deposition. 3 Since the second half of 2013, due to the influence of leaching caverns, the NO_3 ~ - in water drip rose tens of times, and the simulation experiment showed that its ability to dissolve CaCO_3 was about 60% higher than before, indicating that NO_3 ~ - inhibited calcite deposition. This may be the reason why the drip water saturation is high in some months but the CaCO_3 is not recovered. It is suggested that the impact of water quality on karst should be considered in the scenic area when water is replenished.