Catastrophic emplacement and depositional processes during large asteroid impacts: lithofacies analysis and applied volcanology, Manicouagan (Canada)

大型小行星撞击期间的灾难性侵位和沉积过程：岩相分析和应用火山学，马尼瓜根（加拿大）

• 批准号: 2609781
• 金额: --
• 依托单位: University of Leicester
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2609781
• 关键词: Catastrophic; emplacement; depositional; processes; during

When asteroids or comets collide with Earth they cause catastrophic shock, vaporisation, melting, fragmentation and ejection, significantly modifying the crust and devastating environments and biota. Such 'hypervelocity collisions' are a fundamental process of planetary evolution and arguably the greatest natural hazard. Significant advances in shock metamorphism, petrology and modelling have been made, but several geological aspects of what happens remain poorly understood. We need to better understand the processes of molten ejecta emplacement in order to account for the wider effects. A principle source of information lies in Earth's geological record, but accessible, well-preserved large impact craters filled with clastic and melted products are rare.This project will help decipher the fragmentation and emplacement processes of crater-fill material in very large impact craters on Earth, focussing on Manicouagan (Canada) and Chicxulub (Mexico). Both impacted continental crust, one on land the other at sea, and both have been drilled. The investigation will document, analyse and interpret the crater fills to shed new light on the physical processes of their formation. The student will draw upon state-of-the-art geological and physical volcanological techniques and understanding about how hot magma is fragmented, emplaced, and then deposited and agglutinated back together to form thick rock bodies that subsequently cool, and variously devitrify and crystallise. An objective is to develop a new facies scheme for large impact crater fills in order to help reconstruct the events by which they form.

当小行星或彗星与地球相撞时，它们会引起灾难性的冲击、蒸发、熔化、破碎和喷射，显着改变地壳并破坏环境和生物群。这种“超高速碰撞”是行星演化的基本过程，也可以说是最大的自然灾害。冲击变质作用、岩石学和建模方面已经取得了重大进展，但对所发生的情况的几个地质方面仍然知之甚少。我们需要更好地了解熔融喷射物的注入过程，以解释更广泛的影响。信息的主要来源在于地球的地质记录，但是可接近的、保存完好的充满碎屑和熔化产物的大型撞击坑非常罕见。该项目将有助于破译地球上非常大的撞击坑中撞击坑填充材料的破碎和就位过程。地球，重点关注马尼瓜根（加拿大）和希克苏鲁伯（墨西哥）。两者都撞击了大陆地壳，一个在陆地上，另一个在海上，并且都已被钻探。这项调查将记录、分析和解释陨石坑的填充物，为了解其形成的物理过程提供新的线索。学生将利用最先进的地质和物理火山学技术，并了解热岩浆如何破碎、安置，然后沉积并凝结在一起，形成厚厚的岩体，随后冷却，并以各种方式失透和结晶。一个目标是为大型撞击坑填充开发一种新的相方案，以帮助重建它们形成的事件。