Weathering of organic carbon contained in sedimentary rocks (petrogenic OC, OC_petro) is an important control on the concentrations of carbon dioxide (CO₂) and oxygen in the atmosphere. Of particular significance are steep mountainous catchments, where high rates of physical erosion introduce OC_petro to the surface, where oxygen in air and water can help drive oxidative weathering reactions, yet measurements of CO₂ emissions from OC_petro oxidation are still scarce. Here, we use in situ gas accumulation chambers and show that CO₂ fluxes, and their environmental controls, can be determined during a stand-alone, short-term (8 days) field campaign, applied to a remote setting. In the rapidly eroding Waiapu River catchment, New Zealand, dominated by mudstones, we measured high rates of CO₂ release (222–1590 mgC m⁻² d⁻¹) in five accumulation chambers in the near-surface of naturally fractured and bedded rock outcrops. The corresponding CO₂ concentrations are very high (pCO₂ ~4700–27,100 ppmv), and such values could influence acid-hydrolysis reactions during chemical weathering of co-occurring silicate minerals. The CO₂ is radiocarbon depleted (fraction modern, F¹⁴C = 0.0122–0.0547), confirming it is petrogenic in origin. Stable carbon isotopes suggest a source from OC_petro, but δ¹³C values of the CO₂ are lower by ~3.5–3.7 ± 0.1 ‰ from those of OC_petro (−25.9 ± 0.1 ‰), consistent with isotope fractionation associated with microbial respiration of OC_petro. Over 6 days of measurement, we find that CO₂ fluxes respond quickly to changes in temperature and humidity, indicating an environmental regulation that is captured by our short-term installation. The approaches applied here mean that future research can now seek to constrain the climatic, lithological and biological controls on OC_petro oxidation across regional to global scales.

沉积岩中所含有机碳（成岩OC、OC _petro）的风化作用是对大气中二氧化碳（CO ₂）和氧气浓度的重要控制。特别重要的是陡峭的山区集水区，高速率的物理侵蚀将 OC _petro引入地表，空气和水中的氧气可以帮助驱动氧化风化反应，但对OC _{petro氧化产生的 CO 2}排放的测量仍然很少。在这里，我们使用原位气体聚集室并表明 CO ₂通量及其环境控制可以在独立的短期（8 天）野外活动中确定，并应用于远程设置。在快速侵蚀的新西兰怀阿普河流域，以泥岩为主，我们测量了天然裂缝和层状岩石近地表的五个聚集室中的高 CO ₂释放率（222-1590 mgC m ^-2 d ^-1 ）露头。相应的 CO ₂浓度非常高（p CO ₂  ~4700–27,100 ppmv），这些值可能会影响共生硅酸盐矿物化学风化过程中的酸水解反应。CO ₂是放射性碳耗尽的（现代馏分，F¹⁴ C = 0.0122–0.0547)，证实它是成岩性的。稳定的碳同位素表明来自 OC _{petro ，但 CO 2}的δ ¹³ C 值比OC petro ( _-25.9 ± 0.1 ‰)低约 3.5–3.7 ± 0.1 ‰，这与与微生物呼吸相关的同位素分馏一致OC_石油。经过 6 天的测量，我们发现 CO ₂通量对温度和湿度的变化反应迅速，这表明我们的短期安装已经捕捉到了环境调节。这里应用的方法意味着未来的研究现在可以寻求限制对 OC _{petro的气候、岩性和生物控制}跨区域到全球范围的氧化。