MagmaCourse: Fluid pathways below the Eger Rift constrained by numerical and analog simulations.

MagmaCourse：埃格尔裂谷下方的流体路径受到数值和模拟模拟的约束。

• 批准号: 344745229
• 负责人: Professorin Dr. Eleonora Rivalta, Ph.D.
• 金额: --
• 依托单位: Lehrstuhl für Mineralogie und Petrologie
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/344745229?language=en
• 关键词: MagmaCourse; Fluid; pathways; below; Eger

The aim of this proposal is to obtain a conceptual model of deep fluid pathways consistent with observations, especially seismic and magnetotelluric (MT) observations that are sensitive to fluids, mineralization and presence of magma (Q1 and Q2). We plan for the first time to combine mechanical models (numerical simulations and complementary laboratory analog models) with constrained MT inversions and geochemical models in a loop process where the output of one model is used as input for the next step.The Vogtland/West Bohemia seismic swarms are a prominent example of crustal seismicity where fluids are playing a primary role, and relate to one of the few intra-plate seismically active regions of Europe. Many debates and unanswered questions revolve around these seismic swarms, here we list a selection: Q1) The role played by the intra-continental tectonics of the area. The area is a Paleozoic suture that was reactivated by Cenozoic post-orogenic extension, creating the 300km long and 50km wide Eger Graben and the Cheb-Domazlice Graben. Abundant, spatially distributed alkaline volcanism is associated with this area. What controls the spatial distribution of the volcanism and its geochemistry? How are seismicity and volcanism linked?Q2) Deep fluid pathways. Isotope ratios reveal that the high CO2 flux, reaching the surface in the form of CO2 rich mofettes and hydrothermal activity, originates directly from the upper mantle. What are the pathways followed by the magma and by the other fluids, and what factors are controlling them? What are the composition and the physicochemical properties of the fluids while they are migrating?Q3) Channeling of the fluids into pre-existing faults and the triggering factors for the seismicity. In the last 30 years multiple swarms have occurred in the area. What is the mechanics of the pressurized fluids entering into the pre-existing fault zone? What are the mechanisms supporting fluid movement? What is the composition of the crustal fluids reaching the seismogenic volume? What are their physical properties, and how do they evolve with time? How is the fluid-rock coupling converting fluid pressurization into rock stressing?These interconnected questions represent key questions for the ICDP Eger Rift project. We will develop new numerical and analog mechanical and geochemical models, and use them to constrain the model space of existing 2D inversion models, that are now non-unique. We will use available deep crustal seismic data and MT data acquired along 2 perpendicular profiles (autumn 2015) and on a dense grid (spring 2016) in the area of earthquake swarms and mofettes. A close cooperation with the MT group aimed at directly countercheck individual assumptions is novel and pioneering. The generation of the seismicity in the seismogenic zone will be addressed in a follow-up proposal.

该提案的目的是获得与观测结果一致的深层流体路径概念模型，特别是对流体、矿化和岩浆存在敏感的地震和大地电磁 (MT) 观测结果（Q1 和 Q2）。我们计划首次将力学模型（数值模拟和互补的实验室模拟模型）与受约束的大地电磁反演和地球化学模型结合在一个循环过程中，其中一个模型的输出用作下一步的输入。沃格特兰/西波希米亚地震群是地壳地震活动的一个突出例子，其中流体发挥着主要作用，并且与少数几个板内地震之一有关。 欧洲活跃地区。许多争论和悬而未决的问题都围绕着这些地震群，这里我们列出了一个选择：Q1）该地区的大陆构造所发挥的作用。该地区是一个古生代缝合带，由于新生代后造山运动的延伸而重新激活，形成了长 300 公里、宽 50 公里的埃格尔地堑和 Cheb-Domazlice 地堑。丰富的、空间分布的碱性火山活动与该地区有关。是什么控制着火山活动的空间分布及其地球化学？地震活动和火山活动有何联系？Q2) 深层流体通道。同位素比表明，高二氧化碳通量以富含二氧化碳的微晶和热液活动的形式到达地表，直接源自上地幔。岩浆和其他流体的路径是什么？控制它们的因素是什么？流体在运移时的成分和物理化学性质是什么？Q3) 流体引导到预先存在的断层中以及地震活动的触发因素。在过去的30年里，该地区发生了多次蝗群。加压流体进入预先存在的断层带的机制是什么？支持流体运动的机制是什么？达到发震体积的地壳流体的成分是什么？它们的物理特性是什么？它们如何随时间演变？流体-岩石耦合如何将流体加压转化为岩石应力？这些相互关联的问题代表了 ICDP Eger Rift 项目的关键问题。 我们将开发新的数值和模拟机械和地球化学模型，并使用它们来约束现有的二维反演模型的模型空间，这些模型现在不是唯一的。我们将使用在地震群和微动区域沿 2 个垂直剖面（2015 年秋季）和密集网格（2016 年春季）采集的可用深地壳地震数据和 MT 数据。与 MT 小组的密切合作旨在直接反核个人假设，这是新颖且具有开创性的。震源区地震活动的产生将在后续提案中解决。