U.S. Geological Survey, Menlo Park, CA, 94025, USA.
Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
Sci Rep. 2017 Nov 30;7(1):16620. doi: 10.1038/s41598-017-16958-2.
Large quantities of impact-related microspherules have been found in fine-grained sediments retained within seven out of nine, radiocarbon-dated, Late Pleistocene mammoth (Mammuthus primigenius) and bison (Bison priscus) skull fragments. The well-preserved fossils were recovered from frozen "muck" deposits (organic-rich silt) exposed within the Fairbanks and Klondike mining districts of Alaska, USA, and the Yukon Territory, Canada. In addition, elevated platinum abundances were found in sediment analysed from three out of four fossil skulls. In view of this new evidence, the mucks and their well-preserved but highly disrupted and damaged vertebrate and botanical remains are reinterpreted in part as blast deposits that resulted from several episodes of airbursts and ground/ice impacts within the northern hemisphere during Late Pleistocene time (~46-11 ka B.P.). Such a scenario might be explained by encounters with cometary debris in Earth-crossing orbits (Taurid Complex) that was generated by fragmentation of a large short-period comet within the inner Solar System.
大量与撞击有关的微球体已在九个放射性碳定年的晚更新世猛犸象（Mammuthus primigenius）和野牛（Bison priscus）头骨碎片中保留的细颗粒沉积物中发现。这些保存完好的化石是从美国阿拉斯加的费尔班克斯和克朗代克矿区以及加拿大育空地区暴露的冷冻“淤泥”（富含有机质的淤泥）沉积物中回收的。此外，在对四个化石头骨中的三个头骨进行的沉积物分析中发现了铂含量升高。鉴于这一新证据，部分重新解释了淤泥及其保存完好但高度破碎和损坏的脊椎动物和植物残骸，它们是在晚更新世（约公元前 46-11 年）北半球发生的几次爆炸和地面/冰撞击事件产生的爆炸沉积物。这种情况可能是由穿越地球轨道（金牛座复合体）的彗星碎片与内太阳系中一颗大型短周期彗星的碎片相互作用而产生的。
