DOI: 10.5061/dryad.15dv41p5r
title: Data from: Constraining soil hydrothermal CO2 degassing across the Changbaishan volcanic area: insights from 13C-14C perspective

description: Volcanic degassing releases large amounts of hydrothermal CO2, which
 influences long-term global climate. Soil hydrothermal CO2 is an important
 form of volcanic degassing, making the corresponding output crucial for
 understanding the solid Earth degassing and climate change. We
 investigated the soil gases from the Changbaishan volcanic area, the most
 active volcano in China, focusing on their gas compositions and carbon
 isotopic compositions, and soil CO2 fluxes. Our results showed that the
 soil gases from diffuse degassing structures had higher CO2 concentrations
 and isotopic compositions closer to hydrothermal CO2 compared to gases
 from volcano-affected structures. We developed an isotopic mixing model to
 determine the fractions of atmospheric CO2, biogenic CO2, and hydrothermal
 CO2 in soil gases, providing a more accurate constraint of carbon sources.
 Our findings revealed that hydrothermal CO2 was the primary carbon source
 for soil CO2 in diffuse degassing structures, whereas biogenic CO2
 predominated in volcano-affected structures. We integrated the reported
 data to calculate the local carbon budget for the Changbaishan volcanic
 area, demonstrating that the study area acts as a carbon source.
 Additionally, we collected soil hydrothermal CO2 data from 80-degassing
 volcanoes and estimated the soil hydrothermal CO2 output from global
 volcanic areas to be approximately 150 Mt yr−1. Our study highlighted the
 effectiveness of using δ13C-CO2 and Δ14C-CO2 to identify hydrothermal CO2
 and emphasized the importance of accurately estimating soil hydrothermal
 CO2 emissions.
description: We collected 31 soil gas samples following
 CO<sub>2</sub> flux measurements in October 2023 in the
 Changbaishan volcanic area. Gas chromatography-quadrupole time-of-flight
 mass spectrometry (GC/Q-TOF) was used to measure gas components. The ratio
 of <sup>13</sup>C/<sup>12</sup>C was analyzed by
 GC combined with isotope ratio mass spectrometer (IRMS). The ratio of
 <sup>14</sup>C/<sup>12</sup>C was analyzed by a
 0.5 MV accelerator mass spectrometer (AMS). The soil CO2 fluxes was
 measured  by accumulation chamber method in 85 sites in the Changbaishan
 volcanic area. 
description: # Data from: Constraining Soil Hydrothermal CO2 Degassing across the
 Changbaishan Volcanic Area: Insights from 13C-14C Perspective
 [https://doi.org/10.5061/dryad.15dv41p5r](https://doi.org/10.5061/dryad.15dv41p5r) ## Description of the data and file structure This data set is about the soil CO2 fluxes and soil gas components, carbon isotopic compositions of soil CO2 in the Changbaishan volcanic area. Gas chromatography-quadrupole time-of-flight mass spectrometry (GC/Q-TOF) was used to measure gas components. The ratio of C/C was analyzed by GC combined with isotope ratio mass spectrometer (IRMS). The ratio of C/C was analyzed by a 0.5 MV accelerator mass spectrometer. Table 1 is Soil CO2 fluxes in the Changbaishan volcanic area. Table 2 is Component and carbon isotopic compositions of soil gas. Table 3 is Hydrothermal CO2 output in soil degassing. Table S1 is Characteristic values of different carbon sources in soil CO2. Table S2 is Fractional contributions of different carbon sources in soil CO2. Table S3 is Soil CO2 output in global volcanic areas. Table S4 is Fractional contributions of hydrothermal CO2 on soil CO2 in global volcanic areas.