Departamento de Estratigrafía y Paleontología, Universidad de Granada, Granada, Spain.
Research Unit: Analytical, Environmental and Geo-Chemistry, Department of Chemistry, Vrije Universiteit Brussel, AMGC-WE-VUB, Pleinlaan 2, 1050, Brussels, Belgium.
Sci Rep. 2022 Jul 5;12(1):11376. doi: 10.1038/s41598-022-15566-z.
To fully assess the resilience and recovery of life in response to the Cretaceous-Paleogene (K-Pg) boundary mass extinction ~ 66 million years ago, it is paramount to understand biodiversity prior to the Chicxulub impact event. The peak ring of the Chicxulub impact structure offshore the Yucatán Peninsula (México) was recently drilled and extracted a ~ 100 m thick impact-generated, melt-bearing, polymict breccia (crater suevite), which preserved carbonate clasts with common biogenic structures. We pieced this information to reproduce for the first time the macrobenthic tracemaker community and marine paleoenvironment prior to a large impact event at the crater area by combining paleoichnology with micropaleontology. A variable macrobenthic tracemaker community was present prior to the impact (Cenomanian-Maastrichtian), which included soft bodied organisms such as annelids, crustaceans and bivalves, mainly colonizing softgrounds in marine oxygenated, nutrient rich, conditions. Trace fossil assemblage from these upper Cretaceous core lithologies, with dominant Planolites and frequent Chondrites, corresponds well with that in the overlying post-impact Paleogene sediments. This reveals that the K-Pg impact event had no significant effects (i.e., extinction) on the composition of the macroinvertebrate tracemaker community in the Chicxulub region.
为了全面评估生命对白垩纪-古近纪（K-Pg）之交大规模灭绝事件的恢复能力，了解希克苏鲁伯撞击事件之前的生物多样性至关重要。最近在墨西哥尤卡坦半岛近海的希克苏鲁伯撞击构造的顶峰环进行了钻探，并提取了约 100 米厚的撞击产生的、含熔融物的、混杂角砾岩（撞击浮岩），其中保存了具有常见生物成因结构的碳酸盐角砾。我们将这些信息拼凑起来，首次通过古遗迹学与微体古生物学相结合，重现了撞击前该撞击坑地区的大型撞击事件前的大型底栖生物痕迹制造者群落和海洋古环境。在撞击前（晚白垩世-古近纪）存在着可变的大型底栖生物痕迹制造者群落，其中包括环节动物、甲壳类动物和双壳类动物等软体动物，主要在海洋含氧、富营养的条件下殖民于软底。这些上白垩统岩心岩性中的遗迹化石组合，以 Planolites 和 Chondrites 为主，与上覆的古近纪后撞击沉积物中的组合非常吻合。这表明，K-Pg 撞击事件对希克苏鲁伯地区大型无脊椎动物痕迹制造者群落的组成没有显著影响（即灭绝）。
