The chemical weathering of carbonate rocks is the main form of interaction between earth spheres in the karst critical zone. The karst weathering cover, which is composed by residua from carbonate rocks weathering, contains important information about the climate environment and material cycle. We present the chemical composition of weathering covers in karst area of Guilin, Guangxi province, analyze their weathering process and strength, and compare them with the other weathering covers in other karst area in China, including Yunnan, Guizhou, Hunan, and Qinghai Tibet Plateau. The results showed: (1) the chemical composition of Guilin weathering covers were similar to that of carbonate weathering covers in other areas of China, and had the common characteristics of uniform distribution of chemical composition in the profile and obvious enrichment of Fe, Al and trace elements. During the formation of carbonate weathering cover and the residua, the rapid dissolution of Ca and Mg had an important impact on the migration and enrichment of other elements. (2) The chemical index of alteration (CIA) of carbonate weathering covers in Guilin and other karst areas of China was much larger than that in the upper crust (UCC) (60.13), which showed strong chemical weathering characteristics of the humid and hot climate. (3) The weathering process of carbonate rock was different from that of silicate and loess. In the early stage of carbonate rock weathering, soluble components (calcite and dolomite) had been rapidly dissolved and leached. All the carbonate weathering residua was measured to be in the stage of K₂O weathering and Al₂O₃ increasing. Therefore, the weathering degree of carbonate weathering cover was mainly determined by the leaching of K₂O and the increase of Al₂O₃. As a result, there was no correlation between CIA and Na/K (molar ratio), but was a significant negative correlation between CIA and K/Al (molar ratio) in the carbonate weathering cover. (4) The CIA values of weathering residua and carbonate weathering cover in southern China were negatively correlated with latitude, reflecting the influence of climate factors. From the influence of lithology, the chemical compositions of parent rock can affect the CIA of weathering cover, and the content of insoluble matter in carbonate rock was negatively correlated with CIA. From the influence of topography, the CIA value of weathering residua decreased from the high to the low position and from the shallow to the deep part of the profile.

The Shangri-La area lies within the Yunnan-Tibet geothermal belt, characterized by intense tectonic activity and abundant geothermal resource potential. However, existing studies have largely focused on individual hot springs, and a regional scale understanding of geothermal geology and fluid circulation mechanisms remains lacking. This study systematically elucidates the geological setting, hydrogeological characteristics, circulation mechanisms, and resource potential of the geothermal systems by integrating hydrogeological surveys with hydro chemical and isotopic analyses. The results indicate that the Zhongxiao Fault Zone and its associated secondary structures are the primary controllers of geothermal water distribution, serving as both thermal conduits and hydrogeological boundaries. The primary heat source is attributed to the natural geothermal gradient, supplemented by additional contributions from magmatic activity. The geothermal waters are classified as Na-HCO₃ or Ca-HCO₃ types and are notably rich in fluoride. The mean values of δD and δ¹⁸O for geothermal water were −127.86‰ and −15.53‰, respectively, exhibiting isotopic depletion compared with non-thermal water. The geothermal water samples plot near both the Global and Local Meteoric Water Lines while exhibiting a distinct mean ¹⁸O shift of +1.24‰, indicating that the systems are recharged by atmospheric precipitation and have subsequently undergone intense water–rock interaction. Analysis using the Na-K-Mg triangle diagram reveals that most geothermal water samples are immature waters. Thus, the quartz geothermometer provides more reliable estimates of reservoir temperatures. Calculations yield reservoir temperatures ranging from 70 °C to 123 °C, characterizing the system as a medium-to-low temperature resource. With an annual exploitable energy of 5.9 × 10¹⁴ J and high fluoride content, these resources can offer substantial potential for clean energy and balneotherapy.