Radiocarbon dating pedogenic carbonates Adult chat no emails
We conclude that carbonate precipitation stopped ca.
Radiocarbon dating of SOM provides minimum ages of SOM for the length of soil formation [10,11,12,13,14,15].
Radiocarbon ages of the SOM are controlled by the rate of carbon cycling in soils, reflecting the input rates and mean residence time (MRT) of gradually accumulating SOC (the carbon of soil humus) rather than the age of the soils [4,16,17].
An increase in the activity of carbon exchange processes, and, hence, the rejuvenation of radiocarbon dates, indicate the input of young SOM to the soils, while more ancient dates indicate a decrease in recent SOM.
The presence of soil carbonates (disseminated and concretions) can also impact the C ages of carbonates that were younger than the ages of deposits in which they formed .
The proportion of pedogenic carbonates was highly variable: in the native grassland, it was 27% (C-horizon); in the continuous fallow, it varied from 53% (Bk1-horizon) to 72% (C2-horizon); and in the cropland, it varied from 85% (A-horizon) to 10% (Ck-horizon).