Dataset of the soil CO2 degassing measurements and carbon isotopic composition of the interstitial gas in the Larderello geothermal system area, Italy

This dataset presents the identification number, geographic coordinates, soil temperature, CO2 flux and δ13C-CO2 values of the interstitial gas for each sampling site related to hot and cold degassing areas of the Larderello geothermal field (Tuscany, Italy). A total amount of 648 flux measurements were carried out in nine different degassing areas. In specific degassing sites, 77 interstitial gas samples, for the determination of the δ13C-CO2 values, were also collected. The flux measurements and isotopic composition of C are used to compute a first quantification of the diffuse CO2 flux emitted from the Larderello geothermal field by incorporating measurements from both thermally active and cold degassing soils located near the core and at the periphery of the system, respectively, and to bring further elements for defining the role of the transfer zones in controlling the geothermal fluid pathways. Moreover, CO2 fluxes and C isotopic composition of the interstitial soil CO2 were used to identify the origin of the CO2 and its link with the geothermal reservoir(s).

本数据集收录了意大利托斯卡纳大区拉德里莱洛（Larderello）地热田冷热脱气区域各采样点的标识编号、地理坐标、土壤温度、二氧化碳（CO₂）通量以及孔隙气体（interstitial gas）的δ¹³C-CO₂值。本次研究共在9处不同脱气区域完成了648次通量测定。针对δ¹³C-CO₂值的测定需求，研究人员还在特定脱气点位采集了77份孔隙气体样品。本研究结合分别位于地热系统核心区附近的热活跃土壤与系统外围的冷脱气土壤的实测数据，依托通量测定结果与碳同位素组成，首次量化了拉德里莱洛地热田的弥散性CO₂排放通量，并为阐释输导带在调控地热流体运移路径中的作用提供了新的佐证依据。此外，本研究还借助土壤孔隙CO₂的通量数据与碳同位素组成，甄别了CO₂的来源及其与地热储层的关联。