A novel design for continuous measurement of CO2 from deep remineralization of petrogenic organic carbon
Journal
Vadose Zone Journal
Journal Volume
24
Journal Issue
3
ISSN
1539-1663
1539-1663
Date Issued
2025-04-29
Author(s)
Abstract
The oxidation of petrogenic organic carbon contributes a large CO2 flux to the atmosphere, regulating the geological carbon cycle. While few in situ fluxes have been measured in near-surface sedimentary rocks, deep fracture-controlled metamorphic terranes remain unexplored. Here, we present a novel design for continuous in situ measurements of subsurface CO2 flux feasible for metamorphic rocks. The accumulative CO2 measurements were performed by either the passive mode or active recirculation on an 80-m deep borehole in eastern Taiwan. Measurements in the passive mode yielded stepwise CO2 releases in the fractured zone and steady accumulation in the pulverized zone at rates (18.9–132 mgC m−2 day−1) resembling those for other active orogens. By contrast, the active recirculation produced an overestimation of CO2 flux. The high flux combined with variation patterns highlights heterogeneous metamorphic terranes as an important CO2 source and the necessities of extended monitoring using the passive mode.
Subjects
Taiwan
Carbon cycles
Continuous measurements
Measurements of
Near surfaces
Novel design
Organics
Passive mode
Petrogenic
Recirculations
Remineralization
borehole
carbon dioxide
carbon flux
metamorphic rock
organic carbon
petrogenesis
remineralization
Publisher
Wiley
Type
journal article