Fig. 7: Schematic diagram of two-stage oxidation of OCpetro.
From: Two-stage oxidation of petrogenic organic carbon in a rapidly exhuming small mountainous catchment
The pie charts depict the schematic proportions of disordered (orange) vs. ordered (gray) OCpetro. The oxidation proceeds with transforming highly mature OCpetro into disordered form with concomitant CO2 production (20–35 tC km−2 yr−1) in rock-soil profiles and talus deposits during soil development. The resulting OCpetro with a spectrum of maturity is eroded and entrained into river systems, and experiences limited microbial degradation. The second stage of OCpetro oxidation occurs during submarine transport by degrading more disordered OCpetro, thereby enhancing the preservation of highly mature OCpetro in the distal abyssal plain. Across the river and marine realms, mica underperforms quartz/rutile in protecting OCpetro from physical abrasion and pulverization.
