Collisional Magmatism during the Amalgamation of Pangea: Implications for Crustal Growth Processes

盘古大陆合并过程中的碰撞岩浆作用：对地壳生长过程的影响

• 批准号: RGPIN-2018-05484
• 负责人: Braid, James
• 金额: $ 3.64万
• 依托单位: St. Francis Xavier University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=751122
• 关键词: Collisional; Magmatism; during; Amalgamation; Pangea

Continental crust covers almost 40% of the earth's surface and it is generally accepted that crustal growth has lasted from the early Archean to present-day. Traditionally, crustal growth was considered as accomplished primarily through island arc and continental arc magmatism with collisional orogenesis responsible for reworking of the continental crust. However, recent investigations of modern collisional orogens suggest that many magmatic rocks record depleted mantle isotopic signatures. This relationship suggests that continental subduction and collision zones may be key sites for the interaction and mass transfer between the crust and the mantle, the generation of juvenile magmas and the growth of continental crust. Magmatism occurs at different stages during the collisional process from continental subduction, exhumation to orogenic collapse, and much controversy still exists surrounding the (i) genesis of this magmatism, (ii) processes associated with crust and the mantle interaction, (iii) relationship of this magmatism to continental growth, and (iv) detailed evolution of the continental crust throughout earth's history.In order to investigate these relationships, I will focus on the late Paleozoic Variscan orogen of Western Europe, which formed during the assembly, and amalgamation of the most recent supercontinent, Pangea. This well-documented collisional orogen provides exposure of a wide range of magmatic rocks, which formed at different stages of the continental collision and, therefore, provides an excellent framework to investigate crust-mantle processes and crustal growth during supercontinent amalgamation and, in turn, assess the role of late Paleozoic collisional magmatism to the global crustal evolution. The proposed research will focus on key locations around the Variscan orogen that each contains exposed magmatic rocks that formed at different times during the continental collision. My students and I will study the field relationships, age (U/Pb geochronology) and structural evolution of magmatic rocks to provide a space-time framework for the regional tectonic evolution. These observations and data will then be used to help interpret the geochemistry and isotopic signatures to assess how the interaction between the crust and mantle potentially changes with the evolving collision process.This research is based solidly on my existing research strengths, and represents many undergraduate, graduate student and other HQP opportunities. The overall goal of my proposed program is to contribute to the understanding of the collisional magmatism during the Variscan Orogen, providing insight into the understanding of the genesis of orogenic magmatism, potential late Paleozoic crustal growth and the complex tectonics associated with supercontinent amalgamation.

大陆地壳覆盖了地球表面的近40％，通常认为，从早期的大将到当今的地壳生长持续了。传统上，地壳生长被认为主要是通过岛屿弧和大陆弧岩浆作用，其碰撞造山学负责重新加工大陆地壳。 然而，最近对现代碰撞烤口的调查表明，许多岩浆岩石记录了枯竭的地幔同位素特征。 这种关系表明，大陆俯冲和碰撞带可能是地壳与地幔之间相互作用和传质的关键部位，少年岩浆的产生以及大陆壳的生长。 在碰撞过程中，山地坡发生从大陆俯冲，灌输到造影症的崩溃，以及许多争议仍然存在于这种粘膜的（i）岩浆的生成（II）过程中，与地幔相互作用相关的（II）过程，（ii）磁岩的关系与磁岩相关的关系，并将其与（III）进行了研究，并将其与（III）进行了序言，并在这些过程中进行了研究，并在这些层面上进行了（II），这是cormatismiss的关系，并在这些过程中进行了井层的关系。着重于在组装过程中形成的西欧的晚古生代瓦里斯山造成，并将最近的超大型庞吉（Pangea）合并。这种有据可查的碰撞造山基因可暴露于各种岩浆岩石，它们在大陆碰撞的不同阶段形成，因此提供了一个很好的框架，以研究超大型合并期间的地壳掩体过程和地壳生长，然后评估后期古生代碰撞型魔法的作用。拟议的研究将集中在瓦里斯卡造山带周围的关键位置，每种造山基因造成的位置都包含在大陆碰撞期间在不同时间形成的裸露岩石岩石。我和我的学生将研究岩浆岩石的现场关系，年龄（U/PB地质学）和结构性演变，以为区域构造进化提供时空框架。 然后，这些观察结果和数据将用于帮助解释地球化学和同位素特征，以评估地壳和地幔之间的相互作用如何随着不断发展的碰撞过程的可能变化。这项研究牢固地基于我现有的研究优势，并代表许多本科生，研究生，研究生，研究生和其他HQP机会。我提议的计划的总体目标是为对瓦里斯卡造山机期间碰撞岩浆的理解做出贡献，从而深入了解造山学岩浆作用，潜在的晚古生代地壳生长以及与超官方合并相关的复杂构造。