Ramped PyrOx

Is Ramped PyrOx the right decision for your sample?

Ramped PyrOx X split run

This method uses increasing temperature to thermally break down organic carbon. The incremental pyrolysis is slow enough to allow for the separation of more thermochemically reactive constituents from more diagenetically stable ones. The typical Ramped PyrOx 5 Split run is used to separate a sample into 5 aliquots of CO₂. We have performed 3 split runs, we have processed 9 split runs. The amount of splits can depend on the scientific question and available funding. The CO₂ ampules are submitted to an AMS laboratory, where they are graphitized and analysed for ¹⁴C. We take the raw data and apply a blank correction based on standards with known ¹⁴C content.

Ramped PyrOx 5 split Animation credit: T.M. King

Subt et al., 2017 Composite and Isotope Dilution techniques

These methods are employed on highly detrital systems. When there is not enough autochthonous organic carbon present, even a Ramped PyrOx 5 split run may not produce a representative date of the youngest material. The first (youngest) split contains low proportions of contemporaneously deposited material, too low to fully separate from the detrital carbon component.

To generate enough autochthonous CO₂ from a sample for a ¹⁴C measurement, we apply multiple identical Ramped PyrOx analyses and combine ultra-small low-temperature aliquots of CO₂ of the same sample (Composite technique). In the other technique, we combine ultra-small low-temperature CO₂ aliquots with a surrogate of known age and quantity (Isotope Dilution technique).