Organic matter from the Chicxulub crater exacerbated the K–Pg impact winter
Organic matter from the Chicxulub crater exacerbated the K–Pg impact winter
复制标题
来自希克苏鲁伯陨石坑的有机物加剧了 KâPg 撞击冬季
DOI：
10.1073/pnas.2004596117
复制
发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Freeman, Katherine H.
中科院分区：
文献类型：
--
作者：
Lyons, Shelby L.;Karp, Allison T.;Bralower, Timothy J.;Grice, Kliti;Schaefer, Bettina;Gulick, Sean P. S.;Morgan, Joanna V.;Freeman, Katherine H.
一颗小行星撞击尤卡坦半岛，引发了一系列事件，导致76%的物种在白垩纪-古近纪（K-Pg）大规模灭绝，包括非鸟类恐龙。这次撞击击中了一个碳酸盐平台，并将硫酸盐气溶胶和尘埃释放到地球的高层大气中，使地球变冷并变暗-这就是所谓的撞击冬天。在全球K-Pg边界记录中观察到有机燃烧标记，但其来源存在争议。如果有些来自沉积碳，而不仅仅是野火，这意味着目标岩石的烟灰也有助于影响冬季。希克苏鲁布陨石坑沉积物和两个深海地点的多环芳烃（PAHs）特征表明，经历了快速加热的化石碳源，与陨石坑形成过程中喷出的有机物一致。此外，PAH的大小分布近端和远端的火山口表明喷出的碳分散在全球的大气过程。分子和木炭证据表明，野火也存在，但更延迟和持久，可能在生物防御中发挥的作用不如以前所建议的那么严重。根据陨石坑附近的地层学，有7.5 × 1014至2.5 × 1015克的黑碳从靶中释放出来，并喷射到大气中，在几个小时内在地球仪中循环。这些碳，加上硫酸盐气溶胶和尘埃，引发了一个影响冬季和全球变暗，减少了光合作用，并被广泛认为是导致K-Pg大灭绝的原因。
An asteroid impact in the Yucatán Peninsula set off a sequence of events that led to the Cretaceous–Paleogene (K–Pg) mass extinction of 76% species, including the nonavian dinosaurs. The impact hit a carbonate platform and released sulfate aerosols and dust into Earth’s upper atmosphere, which cooled and darkened the planet—a scenario known as an impact winter. Organic burn markers are observed in K–Pg boundary records globally, but their source is debated. If some were derived from sedimentary carbon, and not solely wildfires, it implies soot from the target rock also contributed to the impact winter. Characteristics of polycyclic aromatic hydrocarbons (PAHs) in the Chicxulub crater sediments and at two deep ocean sites indicate a fossil carbon source that experienced rapid heating, consistent with organic matter ejected during the formation of the crater. Furthermore, PAH size distributions proximal and distal to the crater indicate the ejected carbon was dispersed globally by atmospheric processes. Molecular and charcoal evidence indicates wildfires were also present but more delayed and protracted and likely played a less acute role in biotic extinctions than previously suggested. Based on stratigraphy near the crater, between 7.5 × 1014and 2.5 × 1015g of black carbon was released from the target and ejected into the atmosphere, where it circulated the globe within a few hours. This carbon, together with sulfate aerosols and dust, initiated an impact winter and global darkening that curtailed photosynthesis and is widely considered to have caused the K–Pg mass extinction.
登录
查看更多内容
白垩纪-第三纪边界地层中的化石木炭：灾难性火灾和巨波的证据
DOI：
--
发表时间：
1994
期刊：
影响因子：
--
作者：
M. Kruge;B. Stankiewicz;J. Crelling;A. Montanari;D. Bensley
通讯作者：
D. Bensley
影响因子：
56.9
作者：
ALVAREZ, LW;ALVAREZ, W;MICHEL, HV
通讯作者：
MICHEL, HV
DOI：
--
发表时间：
1989
期刊：
影响因子：
--
作者：
S. Clube
通讯作者：
S. Clube
回复 T.P. Jones 关于“白垩纪-第三纪边界地层中的化石木炭：灾难性风暴和巨浪的证据”的评论
DOI：
--
发表时间：
1996
期刊：
影响因子：
--
作者：
M. Kruge;B. Stankiewicz;J. Crelling;A. Montanari;D. Bensley
通讯作者：
D. Bensley
影响因子：
4.4
作者：
Rui Wang;P. Cadman
通讯作者：
Rui Wang;P. Cadman