Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Science. 2013 May 24;340(6135):941-5. doi: 10.1126/science.1234204. Epub 2013 Mar 21.
The end-Triassic extinction is characterized by major losses in both terrestrial and marine diversity, setting the stage for dinosaurs to dominate Earth for the next 136 million years. Despite the approximate coincidence between this extinction and flood basalt volcanism, existing geochronologic dates have insufficient resolution to confirm eruptive rates required to induce major climate perturbations. Here, we present new zircon uranium-lead (U-Pb) geochronologic constraints on the age and duration of flood basalt volcanism within the Central Atlantic Magmatic Province. This chronology demonstrates synchroneity between the earliest volcanism and extinction, tests and corroborates the existing astrochronologic time scale, and shows that the release of magma and associated atmospheric flux occurred in four pulses over about 600,000 years, indicating expansive volcanism even as the biologic recovery was under way.
晚三叠世灭绝的特点是陆地和海洋生物多样性的大量丧失，为恐龙在接下来的 1.36 亿年里统治地球铺平了道路。尽管这次灭绝与洪水玄武岩火山活动大致同时发生，但现有的地质年代学数据分辨率不足以确定引发重大气候扰动所需的喷发率。在这里，我们提供了关于中大西洋岩浆省洪水玄武岩火山活动的年龄和持续时间的新的锆石铀铅（U-Pb）年代学约束。这一年代学表明最早的火山活动与灭绝是同时发生的，检验并证实了现有的天文年代学时间尺度，并表明岩浆的释放和相关的大气通量在大约 60 万年的时间里以四个脉冲的形式发生，这表明即使在生物恢复的过程中，火山活动仍在扩张。
