Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, CA 94709, USA.
Science. 2013 Feb 8;339(6120):684-7. doi: 10.1126/science.1230492.
Mass extinctions manifest in Earth's geologic record were turning points in biotic evolution. We present (40)Ar/(39)Ar data that establish synchrony between the Cretaceous-Paleogene boundary and associated mass extinctions with the Chicxulub bolide impact to within 32,000 years. Perturbation of the atmospheric carbon cycle at the boundary likely lasted less than 5000 years, exhibiting a recovery time scale two to three orders of magnitude shorter than that of the major ocean basins. Low-diversity mammalian fauna in the western Williston Basin persisted for as little as 20,000 years after the impact. The Chicxulub impact likely triggered a state shift of ecosystems already under near-critical stress.
大规模灭绝在地球的地质记录中表现为生物进化的转折点。我们提出的 (40)Ar/(39)Ar 数据表明，白垩纪-古近纪界线与希克苏鲁伯撞击事件及其相关的大规模灭绝具有同步性，误差在 32000 年以内。边界处大气碳循环的扰动可能持续不到 5000 年，其恢复时间尺度比主要海洋盆地短两个到三个数量级。希克苏鲁伯撞击事件发生后，西威利斯顿盆地的低多样性哺乳动物群仅持续了不到 20000 年。希克苏鲁伯撞击事件可能引发了已经处于近临界压力下的生态系统的状态转变。
