Gohn G S, Koeberl C, Miller K G, Reimold W U, Browning J V, Cockell C S, Horton J W, Kenkmann T, Kulpecz A A, Powars D S, Sanford W E, Voytek M A
U.S. Geological Survey, Reston, VA 20192, USA.
Science. 2008 Jun 27;320(5884):1740-5. doi: 10.1126/science.1158708.
Samples from a 1.76-kilometer-deep corehole drilled near the center of the late Eocene Chesapeake Bay impact structure (Virginia, USA) reveal its geologic, hydrologic, and biologic history. We conducted stratigraphic and petrologic analyses of the cores to elucidate the timing and results of impact-melt creation and distribution, transient-cavity collapse, and ocean-water resurge. Comparison of post-impact sedimentary sequences inside and outside the structure indicates that compaction of the crater fill influenced long-term sedimentation patterns in the mid-Atlantic region. Salty connate water of the target remains in the crater fill today, where it poses a potential threat to the regional groundwater resource. Observed depth variations in microbial abundance indicate a complex history of impact-related thermal sterilization and habitat modification, and subsequent post-impact repopulation.
在美国弗吉尼亚州始新世晚期切萨皮克湾撞击构造中心附近钻取的一个深度达1.76千米的岩芯样本，揭示了其地质、水文和生物历史。我们对这些岩芯进行了地层学和岩石学分析，以阐明撞击熔体的形成、分布、瞬态空洞坍塌以及海水回涌的时间和结果。对撞击构造内外撞击后沉积层序的比较表明，火山口填充物的压实作用影响了大西洋中部地区的长期沉积模式。目标体的含盐原生水如今仍保留在火山口填充物中，对区域地下水资源构成潜在威胁。观察到的微生物丰度随深度的变化表明，撞击相关的热灭菌和栖息地改变以及撞击后的重新定殖过程十分复杂。
