美国科尔比学院Ian J. Glasspool和Robert A. Gastaldo对泥盆纪野火进行了再评估。相关论文于2024年8月27日发表于国际顶尖学术期刊《地质学》杂志上。

据介绍，在上泥盆纪较低的至下部最低的岩石记录中，几乎没有野火代用物大化石木炭的证据。这个时代的煤很少，岩石学数据表明，木炭的体积很低(<10%的矿物质游离)。这种数据的缺乏构成了“炭间断”的基础，这种间断被用于暗示大气氧含量(pO₂)异常低的延长间隔。

研究人员使用来自缅因州(美国东北部)鳟鱼谷和圣弗罗伊德湖地层的Emsian-Eifelian期的木炭，重新评估了这种间断的现有证据，研究还整合了分散有机质的微观木炭记录。本研究得出结论，在中泥盆世有充足的火的证据。这个时间间隔并不具有天生的低pO₂。更确切的说，这是一种对现有数据的解释不足导致人们认为木炭缺乏的情况。

这种调和表明，显生宙野火的记录基本上是不间断的。因此，研究人员认为，从志留纪开始，通过植物群和动物群在陆地上的定居，pO₂达到了>16%并一直保持在这样的水平，从目前的估计来看，直到现在都保持在这样的水平。

附：英文原文

Title: Don’t mind the “charcoal gap”: A reassessment of Devonian wildfire

Author: Ian J. Glasspool, Robert A. Gastaldo

Issue&Volume: 2024-08-27

Abstract: Little evidence of macrofossil charcoal, a wildfire proxy, is recorded from upper Lower to lowermost Upper Devonian rocks. Coals of this age are few, and petrographic data indicate low volumes (<10% mineral-matter free) of charcoal. This paucity of data forms the basis of the “charcoal gap,” which is used to suggest an extended interval of abnormally low atmospheric oxygen (pO₂). We reassess the current evidence for this hiatus using Emsian-Eifelian charcoal from the Trout Valley and St. Froid Lake Formations, Maine (northeastern United States), and integrate the microscopic charcoal record of dispersed organic matter. We conclude there is ample evidence of fire in the Middle Devonian. This interval is not innately of low pO₂. Rather, it is one in which under-interpretation of available data has led to a perceived paucity of charcoal. This reconciliation indicates the Phanerozoic record of wildfire was substantially uninterrupted. Hence, we propose that pO₂ achieved levels >16% and remained at such levels from the Silurian through the floral and faunal colonization of land and, from our current estimates, stayed as such until the present.

DOI: 10.1130/G52648.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G52648.1/647389/Don-t-mind-the-charcoal-gap-A-reassessment-ofredirectedFrom=fulltext