Carbon isotope signatures of latest Permian marine successions of the Southern Alps suggest a continental runoff pulse enriched in land plant material

Abstract

The latest Permian mass extinction, the most severe Phanerozoic biotic crisis, is marked by dramatic changes in palaeoenvironments. These changes significantly disrupted the global carbon cycle, reflected by a prominent and well known negative carbon isotope excursion recorded in marine and continental sediments. Carbon isotope trends of bulk carbonate and bulk organic matter in marine deposits of the European Southern Alps near the low-latitude marine event horizon deviate from each other. A positive excursion of several permil in d 13 C org starts earlier and is much more pronounced than the short-term positive d 13 C carb excursion; both excursions interrupt the general negative trend. Throughout the entire period investigated, d 13 C org values become lighter with increasing distance from the palaeocoastline. Changing d 13 C org values may be due to the influx of comparatively isotopically heavy land plant material. The stronger influence of land plant material on the d 13 C org during the positive isotope excursion indicates a temporarily enhanced continental runoff that may either reflect increased precipitation, possibly triggered by aerosols originating from Siberian Trap volcanism, or indicate higher erosion rate in the face of reduced land vegetation cover.

Carbon isotope perturbations and faunal changeovers during the Guadalupian mass extinction in the middle Yangtze Platform, South China

“…The heavier values of δ 13 C org occurring in the coastal environments instead of the open shallow-marine environments at Tianfengping indicates that the input of terrestrial organic matter controls the δ 13 C org changes (e.g. Siegert et al 2011; Kraus et al 2013) because marine organic carbon older than Oligocene age is isotopically lighter than the land-derived carbon (Galimov, 2006) and Permian wood shows heavier δ 13 C values than coeval marine-sourced organic matter (Foster et al 1997; Krull, 1999; Korte et al 2001; Ward et al 2005; Hermann et al 2010). The negative correlation between δ 13 C carb and δ 13 C org (R 2 = 0.62, Fig.…”

Episodic euxinia in the Changhsingian (late Permian) of South China: Evidence from framboidal pyrite and geochemical data

“…Interestingly, the organic-carbon isotope profile also shows two positive excursions at the same positions (Fig. 9), which may reflect the influx of isotopically heavy land plant debris during episodes of intensified subaerial weathering (cf., Kraus et al, 2013). On the basis of ΣREE, Al 2 O 3 , Hf and Nb, and organic-carbon isotope data, we infer that both Interval I cherts and Interval III limestones contain only limited clays, but that the upper Interval II and lower Interval IV contain significantly higher clay concentrations (Fig.…”

Terrestrial acidification during the end-Permian biosphere crisis?

“…In the Bulla reference section, the first appearance of Hindeodus parvus marks the Permian-Triassic boundary at 1.30 m above the base of the Lower Tesero Member. The globally recognized end-Permian negative excursion in the carbon-isotopic composition of marine carbonates (d 13 C carb ) straddles the boundary between the Bulla and Lower Tesero Members (e.g., Kraus et al, 2013).…”