Collaborative Proposal: Chicxulub impact effects and the recovery of life using scientific drilling investigations at ground zero

地球上最新的一次？S五次最大的物种灭绝事件发生在一颗大约14公里的小行星撞击尤卡坦半岛(墨西哥)的同一时期，结束了中生代。2016年4月至5月，在国际大陆科学钻探计划(ICDP)的共同资助下，国际海洋发现计划(IODP)成功地从海底505-1337米处恢复了近100%的岩芯，进入了由此产生的200公里宽的希克苏鲁布撞击坑。这些岩心记录了一系列非同寻常的撞击和撞击后事件。该项目将进一步调查这些独特的核心，以了解与大灭绝事件有关的唯一撞击的局部和全球影响。这项研究是一个更大的国际努力的一部分，包括来自14个国家的约40名科学家，还支持本科生和研究生水平的教育和指导。项目研究人员将继续通过媒体采访、博物馆展览和其他活动进行外联和教育，向公众突出这项研究。IODP-ICDP最近在奇克苏鲁布进行的钻探探险首次发现了一个明确的峰环样本。峰环是在岩石行星上所有大型撞击坑的中央盆地内观察到的一个不连续的山脉环。CHICXULUB？S峰环主要由抬升约10公里的花岗岩地壳组成，这一发现校准了撞击模型，允许观察撞击过程，并对撞击的环境后果(杀死机制)进行了一级评估。新发现的岩心包括抬升的目标岩石：富含熔融影响的岩石类型、热液沉积、海啸床和沉降层，以及碳酸盐沉积的恢复。这些岩性记录了撞击后从几分钟到数百万年的过程。拟议的工作将：1.重建峰环的热历史和撞击引起的热液系统的持续时间，以确定这些过程如何影响生命返回陨石坑。将撞击岩石中的岩石碎片与撞击前的地层学进行比较，以量化释放的挥发物，并限制撞击引起的气候变化和灭绝的模型。3.发现陨石坑内存在小行星的第一个确凿证据，与全球K-PG边界记录相联系，并确定金属毒性的可能影响。结合沉积学、地层学和环境化学研究边界层序的化石记录，以阐明可能的杀戮机制，并确定从撞击后几周到古新世早期火山口内恢复的速度和时间。

The latest of Earth?s five largest mass extinction events occurred coeval with the impact of a ~14 km asteroid into the Yucatan Peninsula (Mexico), ending the Mesozoic Era. In April-May 2016, the International Ocean Discovery Program (IODP), with co-funding from the International Continental Scientific Drilling Program (ICDP), successfully cored with nearly 100% recovery from 505-1337 m below seafloor into the resulting 200 km-wide Chicxulub impact crater. These cores record an extraordinary sequence of impact and post-impact events. This project will investigate these unique cores further to understand the local and global effects of the only impact conclusively linked to a mass extinction event. This research is part of a larger international effort, including ~40 scientists from 14 countries, and also supports education and mentoring at the graduate and post-graduate level. Project researchers will continue to engage in outreach and education through media interviews, museum displays, and other activities to highlight the research to the general public. The recent IODP-ICDP drilling expedition at Chicxulub recovered the first-ever samples of an unequivocal peak ring. A peak ring is a discontinuous ring of mountains observed within the central basin of all large impact craters on rocky planets. The discovery that Chicxulub?s peak ring consists of largely granitic crust uplifted by ~10 km calibrates impact models, allows for observation of impact processes, and for a first-order assessment of the environmental consequences of the impact (?kill mechanisms?). Newly recovered cores include the uplifted target rocks: melt-rich impact generated rock types, hydrothermal deposits, a tsunami bed coupled with a settling layer, and the resumption of carbonate sedimentation. These lithologies record processes spanning from minutes to millions of years post-impact. The proposed work will: 1. Reconstruct thermal history of the peak ring and the duration of the impact-induced hydrothermal system to determine how these processes affected the return of life to the crater.2. Compare rock fragments in the impact rocks to pre-impact stratigraphy to quantify the volatiles released and constrain models of impact-induced climate change and extinction. 3. Find the first conclusive evidence of the asteroid within the crater to tie to global K-Pg boundary records and identify the possible influence of metal toxicity.4. Investigate the fossil record of the boundary sequence, in concert with the sedimentology, stratigraphy, and environmental chemistry, to illuminate possible killing mechanisms and determine the pace and timing of the recovery within the crater from the weeks after the impact through the early Paleocene.