三叠纪—侏罗纪之交准噶尔盆地南缘野火记录及全球对比

三叠纪—侏罗纪之交（距今约201 Ma）是地球历史上的关键时期，中大西洋火成岩省（Central Atlantic magmatic province，CAMP）快速地侵位和喷发，给全球的表生系统带来巨大的环境压力，其中之一是被广泛报道的同期野火事件。但此前的报道多集中在CAMP直接作用范围区内，对其是否具有全球性，以及是否是受CAMP的因果影响还存有争论。在新疆准噶尔盆地南缘的陆相三叠系—侏罗系界线的郝家沟剖面，进行系统地采样和测试分析发现:该剖面三叠系—侏罗系界线附近地层存在燃烧成因的多环芳烃（PAHs）含量的异常高值，并且与地层中指示CAMP侵位或喷发的Hg/TOC高峰值具有很好的对应关系，为全球首个对CAMP活动区外的高纬度陆相地层中三叠纪—侏罗纪之交野火记录的报道。通过与全球其他三叠系—侏罗系典型剖面的综合对比，推论CAMP活动与野火事件频率急剧地升高具有因果关系，但并非直接火源点燃的关系；推断野火频率激增可能是全球性事件，并预测在全球更广的范围内相应地层中也可观测到类似现象。

Wildfire Records Across the Triassic - Jurassic Boundary in the Southern Margin of the Junggar Basin,and Global Correlations

The Triassic-Jurassic transition （~201 Ma） was a critical period in the Earth’s history. The rapid emplacement and eruption of the Central Atlantic Magmatic Province （CAMP） put huge environmental pressure on the global surface ecosystem. One example was the synchronous wildfire events reported widely. However， previous reports have commonly focused on the area directly influenced by the CAMP. It is debatable whether the wildfire events were a global or a regional phenomenon. This study systematically collected samples across the Triassic?Jurassic boundary （TJB） in the Haojiagou section at the southern margin of the Junggar Basin， Xinjiang. Abnormally high values of combustive-derived polycyclic aromatic hydrocarbons （PAHs） were found around the TJB. The anomalies correspond well with the Hg/TOC peaks， indicating the CAMP emplacement or eruptions. This is the first report on wildfire records across the Triassic?Jurassic transition in high-latitude terrestrial strata outside the CAMP region. It is concluded from integrated global TJB correlations that the sharply rising wildfire frequency was triggered by the CAMP effect， but CAMP volcanism itself was not the direct igniting source. Increased wildfire frequency is inferred as a global event beyond the regions of CAMP activity， and similar wildfire records across the TJB could be observed on a global scale.