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

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.

在侏罗纪-三叠纪时期，四川盆地中多环芳烃（PAHs）的浓度显著升高，反映了多阶段森林火灾事件（TJB、R1、R2事件），包括芘（Phe）、荧蒽（Fl）、芴（Py）、苯并荧蒽（Chry）、苯并氟荧蒽（BFl）、苯并[e]芴（BPy）、苯并[1,2,3-cd]芴（InPy）、苯并[ghi]芘（Bpery）和芘环（Cor）。我们计算了母体-PAH与（母体-PAH+烷基-PAH）指数（PPAHI），以检验PAH来源的变异，包括甲基萘（MeN）、甲基芘（MePh）、甲基荧蒽（MeFl）、甲基芴（MePy）以及其他存在于芳香族组分中的烷基-PAH同系物。在森林火灾事件期间，PPAHI呈现上升趋势。荧蒽与荧蒽加芴的比率（Fl/(Fl+Py)）以及 indenopyrene与indenopyrene加苯并芘的比率（InPy/(InPy+Bpery)）暗示了燃烧源。在森林火灾事件期间，总氧化性PAHs、二苯并呋喃（DBFs）及其衍生物的高含量出现，这表明了土壤侵蚀，可能是由于根系植被的损失。碳原子数小于21的总烷烃与碳原子数大于22的烷烃的垂直分布比率（ΣC21-/ΣC22+）反映了在森林火灾事件期间，来自高等植物的有机物输入的大幅增加。四川盆地三次火灾频率的增强是由于区域气候的干旱化。此外，森林火灾事件将是TJB期间陆地植物变化的主要因素。