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Explosive interaction of impact melt and seawater following the Chicxulub impact event
Geology ( IF 4.8 ) Pub Date : 2020-02-01 , DOI: 10.1130/g46783.1
Gordon R. Osinski 1, 2 , Richard A.F. Grieve 1, 2 , Patrick J.A. Hill 1, 2 , Sarah L. Simpson 1, 2 , Charles Cockell 3 , Gail L. Christeson 4 , Matthias Ebert 5 , Sean Gulick 4, 6 , H. Jay Melosh 7 , Ulrich Riller 8 , Sonia M. Tikoo 9 , Axel Wittmann 10
Affiliation  

The impact of asteroids and comets with planetary surfaces is one of the most catastrophic, yet ubiquitous, geological processes in the solar system. The Chicxulub impact event, which has been linked to the Cretaceous-Paleogene (K-Pg) mass extinction marking the beginning of the Cenozoic Era, is arguably the most significant singular geological event in the past 100 million years of Earth’s history. The Chicxulub impact occurred in a marine setting. How quickly the seawater re-entered the newly formed basin after the impact, and its effects of it on the cratering process, remain debated. Here, we show that the explosive interaction of seawater with impact melt led to molten fuel–coolant interaction (MFCI), analogous to what occurs during phreatomagmatic volcanic eruptions. This process fractured and dispersed the melt, which was subsequently deposited subaqueously to form a series of well-sorted deposits. These deposits bear little resemblance to the products of impacts in a continental setting and are not accounted for in current classification schemes for impactites. The similarities between these Chicxulub deposits and the Onaping Formation at the Sudbury impact structure, Canada, are striking, and suggest that MFCI and the production of volcaniclastic-like deposits is to be expected for large impacts in shallow marine settings.

中文翻译:

Chicxulub撞击事件后撞击熔体和海水的爆炸性相互作用

小行星和彗星与行星表面的撞击是太阳系中最灾难性但最普遍的地质过程之一。Chicxulub撞击事件与白垩纪古生物大灭绝有关,标志着新生代时代的开始,这可以说是地球历史上一亿年以来最重要的单一地质事件。Chicxulub冲击发生在海洋环境中。撞击后海水重新进入新形成的盆地的速度及其对火山口形成过程的影响仍存在争议。在这里,我们证明了海水与冲击熔体的爆炸性相互作用导致了熔融的燃料-冷却剂相互作用(MFCI),这类似于发浆火山爆发期间发生的情况。这个过程使熔体破裂并分散,随后将其水下沉积以形成一系列分类良好的沉积物。这些矿床与大陆环境下的撞击产物几乎没有相似之处,并且在当前的撞击点分类方案中也没有考虑。这些Chicxulub矿床与加拿大萨德伯里冲击构造的Onaping组之间的相似性令人震惊,这表明MFCI和类火山碎屑矿床的生产有望在浅海环境中产生大冲击。
更新日期:2020-04-23
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