Data for: Distribution of pyrolytic polycyclic aromatic hydrocarbons across Triassic-Jurassic boundary in the Sichuan Basin, southwestern China: Evidence of wildfire occurrence outside the Central Atlantic Magmatic Province

Published: 07-12-2019| Version 1 | DOI: 10.17632/572tbr9y59.1
Contributors:
shucheng xie,
Genming Luo,
Thomas Algeo,
Liqin Li,
Yi Song,
Yongdong Wang,
Wenjun Wu

Description

1. The elevated concentration of pyrolytic polycyclic aromatic hydrocarbons (PAHs) in Sichuan Basin during Triassic-Jurassic shows multistage wildfire events(TJB, R1,R2 events), including Phenanthrene (Phe), fluoranthene (Fl), pyrene (Py), chrysene (Chry), benzofluoranthene (BFl), benzo[e]pyrene (BPy), indeno[1,2,3-cd] pyrene (InPy), benzo[ghi]perylene (Bpery), and coronene (Cor). 2.We calculated the parent-PAH-to-(parent-PAH+alkyl-PAH) index (PPAHI) to test variation in PAH sources, including methylnaphthalene (MeN), methylphenanthrene (MePh), methylfluoranthene (MeFl), methylpyrene (MePy), and other alkyl-PAH homologues present in the aromatic fraction. PPAHI increased during wildfire events. 3. Ratios of fluoranthene to fluoranthene plus pyrene Fl/(Fl+Py) and indenopyrene to indenopyrene plus benzoperylene InPy/(InPy+Bpery) implies a combustion source. 4.The high content of total oxygenated PAHs, dibenzofuran (DBFs) and its derivatives, occur during wildfire events that indicate soil erosion, possibly due to a loss of rooted vegetation. 5.The vertical distributions of ratios of total alkanes with carbon numbers <21 to alkanes with carbon numbers >22 (ΣC21-/ΣC22+) reflect a large increase in inputs of organic matter from higher plants during wildfire events. 6.Three episodes of enhanced wildfire frequency in the Sichuan Basin were as a result of regional climate aridification. Also, wildfire events would be a main factor of terrestrial plant change during TJB.

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