Deformation patterns in relation to the deep configuration of the lithosphere of the Alps and their forelands – DEFORM

与阿尔卑斯山及其前陆岩石圈深层构造相关的变形模式 – DEFORM

• 批准号: 442494818
• 负责人: Professor Dr. Hans-Jürgen Götze
• 金额: --
• 依托单位: Sektion 4.5: Sedimentbeckenmodellierung
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/442494818?language=en
• 关键词: Deformation; patterns; relation; deep; configuration

The present-day physical state of the Alps and their forelands is still a matter of debate due to observed variations of surface deformation and seismicity. Due to our limited knowledge of the internal structure of the lithosphere in relation to the present-day stress field, this leads to contradictory interpretations on which first order mechanisms are dominantly controlling present-day processes. In particular, the question of how the shallow domains of the crust are coupled or decoupled from deeper crustal levels and the mantle, is open. Results obtained in phase I of the SPP confirm that the internal structure of the lithosphere is characterized by a strong lateral and vertical variation in lithology from the orogen to the forelands indicated by the distribution of densities and seismic velocities. This variation in physical properties also results in a highly variable thermal field and a heterogeneous rheological zonation. The main objective of DEFORM is to test the hypothesis that different processes controlling recent deformation can be isolated and their relative contributions quantified if first-order characteristics of lithosphere configuration are considered together with physical processes. To test this hypothesis we aim to quantitatively assess how the data-derived internal lithospheric configuration deforms in response to plate boundary forces on the one hand and vertical loading or unloading over a glacial cycle on the other. In our project INTEGRATE running in phase I of the SPP we find a strong positive correlation between crustal density contrasts and present day deformation vectors from geodetic measurements as well as the distribution of large seismic events. To evaluate if there is a systematic and across scales relationship between the distribution of observed deformation and the rheological configuration of the lithosphere, we will use an updated rheological model as a base for simulations of coupled thermo-mechanical processes. Therefore, we propose to link thermomechanical models of large-scale deformation on geological timescales with regional thermomechanical approaches that can resolve the human time scale and account in a consistent way for the multi-physics coupling among the different deformation mechanisms controlling the bulk behavior of the lithosphere. In the simulations, the static rheological and thermal models are considered as initial conditions, the present-day deformation field at the surface as upper boundary condition and the deformation field of the uppermost asthenosphere derived from large-scale dynamic models will be extracted as lower boundary condition. The project contributes to Theme 2 of the current call for proposals: Surface and crustal responses to changes in mountain structure on different time scales. It links to many other partners in the SPP to ensure the integration of new results in the rheological model and to validate the simulation predictions.

由于观察到的地表变形和地震活动的变化，阿尔卑斯山及其前陆目前的物理状态仍然是一个有争议的问题。由于我们对与当今应力场相关的岩石圈内部结构的了解有限，这导致了关于一阶机制主要控制当今过程的矛盾解释。特别是，地壳浅层区域如何与地壳深层和地幔耦合或分离的问题仍然存在。 SPP第一阶段获得的结果证实，岩石圈内部结构的特点是从造山带到前陆的岩性存在强烈的横向和纵向变化，这可以从密度和地震速度的分布看出。这种物理性质的变化也会导致高度可变的热场和不均匀的流变分区。 DEFORM 的主要目标是检验以下假设：如果将岩石圈构型的一阶特征与物理过程一起考虑，则可以隔离控制近期变形的不同过程，并量化它们的相对贡献。为了检验这一假设，我们的目标是定量评估数据得出的内部岩石圈结构如何一方面响应板块边界力，另一方面响应冰川周期的垂直加载或卸载而变形。在 SPP 第一阶段运行的 INTEGRATE 项目中，我们发现地壳密度对比与大地测量的当今变形矢量以及大型地震事件的分布之间存在很强的正相关性。为了评估观测到的变形分布与岩石圈流变结构之间是否存在系统性和跨尺度的关系，我们将使用更新的流变模型作为模拟耦合热力过程的基础。因此，我们建议将地质时间尺度上大规模变形的热力模型与区域热力方法联系起来，这样可以解析人类时间尺度，并以一致的方式解释控制岩石圈整体行为的不同变形机制之间的多物理耦合。模拟中，以静态流变和热模型为初始条件，以现今地表变形场为上边界条件，提取大尺度动力模型推导的最上层软流圈变形场作为下边界条件。该项目对当前征集提案的主题 2 做出了贡献：地表和地壳对不同时间尺度上山体结构变化的响应。它与 SPP 中的许多其他合作伙伴联系，以确保将新结果集成到流变模型中并验证模拟预测。