High rates of rock organic carbon oxidation sustained as Andean sediment transits the Amazon foreland-floodplain.

The oxidation of organic carbon contained within sedimentary rocks ("petrogenic" carbon, or hereafter OC) emits nearly as much CO as is released by volcanism, thereby playing a key role in the long-term global C budget. High erosion rates in mountains have been shown to increase OC oxidation. However, these settings also export unweathered material that may continue to react in downstream floodplains.