Carbon-isotope variability of Triassic amber, as compared with wood and leaves (Southern Alps, Italy)

The carbon-isotope signatures of Carnian (Late Triassic) amber drops from Rifugio Dibona (Southern Alps, Italy) were studied and compared with that of other Middle-early Late Triassic fossil plant remains, namely wood and leaves. Amber, wood and leaf carbon-isotope data are highly variable within the same beds. δ13Camber values vary by up to 5.4‰ and are enriched by ~ 2.5‰ with respect to associated wood. δ13Cwood and δ13Cleaf ranges are narrower than that of amber (~ 2–3‰) and the isotopic offset within each bed is similar over time. The high Triassic amber carbon-isotope variability is similar to that of recent resin. Despite the high variability, δ13Cwood and δ13Cleaf illustrate a Middle-early Late Triassic secular positive trend that is similar to that of marine δ13Cinorg data and must record the carbon-isotope evolution of the ocean–atmosphere system.

Research Highlights
► Modern plant δ13C signature is highly variable between different taxa and tissues.
► We studied the δ13C variability of Triassic plant remains (wood, leaves and resin).
► Wood, leaf and amber δ13C is highly variable within the same stratigraphic level.
► Amber is more variable than other analyzed tissues.
► Wood and leaves register a Mid-Late Triassic δ13C positive secular shift.