Assertion: charcoal | /r/HasProperty | −25.7 ‰
Facets:
Source sentences:
text: The soils had been cropped with maize for at least 12 years which provided a continuous input of C with a C isotope signature (δ13C) −13.1, distinct from the δ13C of soil organic carbon (−27.4 ‰) and charcoal (−25.7 ‰) collected in the surrounding area.