Mountain permafrost in the Central Pyrenees: insights from the Devaux ice cave
Mountain permafrost in the Central Pyrenees: insights from the Devaux ice cave
复制标题
DOI：
10.5194/tc-17-477-2023
复制
发表时间：
2023-02
期刊：
影响因子：
--
通讯作者：
M. Bartolomé;Gérard Cazenave;M. Luetscher;C. Spötl;F. Gázquez;Á. Belmonte;A. Turchyn;J. López‐Moreno;Ana Moreno
中科院分区：
文献类型：
--
作者：
M. Bartolomé;Gérard Cazenave;M. Luetscher;C. Spötl;F. Gázquez;Á. Belmonte;A. Turchyn;J. López‐Moreno;Ana Moreno
抽象的。冰洞是冰冻圈中研究最少的部分之一，特别是那些位于高海拔或高纬度难以到达的永久冻土地区的冰洞。我们描述了德沃洞穴的气候动态和地貌特征，德沃洞穴是法国和西班牙边境中部比利牛斯山脉的一个著名冰洞。根据气温和地貌观察，确定了两个不同的洞穴区域。第一个由通风良好的画廊组成，温度波动很大，可能受到洞穴河流的影响。第二个区域对应于更孤立的房间，其中空气和岩石温度全年保持在 0 ∘C 以下。季节性层状冰和白霜占据第一部分，而透明的、巨大的常年冰存在于隔离室中。低温方解石和石膏主要存在于常年冰中。冬季，洞穴河在出水口结冰，导致洞穴筑坝和倒灌。我们认为，残冰的形成记录了过去的筑坝事件以及随后形成的凝冰。石膏的δ34S值表明硫酸盐来源于基岩中黄铁矿的氧化。空气和岩石温度、没有滴水、过去 7 年来冰的少量损失以及洞穴中冰体的位置等几个特征表明，洞穴永久冻土是通风过冷和周围永久冻土扩散传热共同作用的结果，厚度达到约 200 m。
Abstract. Ice caves are one of the least studied parts of the cryosphere, particularly those located in inaccessible permafrost areas at high altitudes or high latitudes. We characterize the climate dynamics and the geomorphological features of Devaux cave, an outstanding ice cave in the Central Pyrenees on the French–Spanish border. Two distinct cave sectors were identified based on air temperature and geomorphological observations. The first one comprises well-ventilated galleries with large temperature oscillations likely influenced by a cave river. The second sector corresponds to more isolated chambers, where air and rock temperatures stay below 0 ∘C throughout the year. Seasonal layered ice and hoarfrost occupy the first sector, while transparent, massive perennial ice is present in the isolated chambers. Cryogenic calcite and gypsum are mainly present within the perennial ice. During winter, the cave river freezes at the outlet, resulting in a damming and backflooding of the cave. We suggest that relict ice formations record past damming events with the subsequent formation of congelation ice. δ34S values of gypsum indicate that the sulfate originated from the oxidation of pyrite present in the bedrock. Several features including air and rock temperatures, the absence of drips, the small loss of ice in the past 7 decades, and the location of ice bodies in the cave indicate that the cave permafrost is the result of a combination of undercooling by ventilation and diffusive heat transfer from the surrounding permafrost, reaching a thickness of ∼ 200 m.