A combined imaging and modelling approach to understand magmatic systems across the SE Asia-Australia collision zone

结合成像和建模方法来了解东南亚-澳大利亚碰撞带的岩浆系统

• 批准号: 449466527
• 负责人: Professor Dr. Boris J.P. Kaus
• 金额: --
• 依托单位: Department of Earth Sciences
• 依托单位国家: 德国
• 项目类别: Research Grants
• 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/449466527?language=en
• 关键词: combined; imaging; modelling; approach; understand

The zone of collision between the southern region of the Eurasian plate and Australia is a complex aggregate of Gondwana-derived terranes, subducting plates, and a colliding lithospheric block. Recently we have achieved significant resolution on the deep regional subduction for both P- and S-waves, especially across the Banda Sea. Seismic arrays recently deployed across the region now allow to increase resolution across the entire collision zone. Still, attenuation remains an important obstacle for a reliable lithospheric-scale, full-waveform-inversion of the area. Attenuation tomography can both fill this gap and offer improved sensitivity and illumination on lithospheric processes, especially those leading to magmatism. The first objective of this proposal is to image the lithospheric-scale attenuation structures leading to volcanism across the SE Asia – Australia collision zone, providing (1) a regional-scale benchmark to improve full-waveform imaging at regional scale and (2) improved imaging of the lithospheric structures connecting mantle structures to magmatic centres. To do so, the project will adapt an existent machine-learning framework for velocity tomography to waveform analysis, and will join 3D direct-wave-attenuation imaging with crustal absorption and scattering mapping. The end-results will be used together with existent tomographic models and available data from partners for the second objective: performing regional-scale visco(elasto)plastic modelling for (1) the entire collision zone and (2) the magmatic systems feeding Agung volcano, once combined to an adjoint-based inversion scheme. Using the derived high-resolution and mechanically-consistent structural models, the final deliverables will allow a better quantitative evaluation of the mechanisms in play in the zone of collision, giving insight into magma and fluid migration from subduction to surface.

欧亚板块南部地区和澳大利亚之间的碰撞带是冈瓦那派生的地体、俯冲板块和碰撞的岩石圈块体的复杂集合体。最近，我们在纵波和S波的深区域俯冲，特别是横跨班达海的区域俯冲问题上取得了重大成果。最近在该地区部署的地震阵列现在可以提高整个碰撞带的分辨率。尽管如此，衰减仍然是该地区可靠的岩石圈规模、全波形反演的重要障碍。衰减层析成像既可以填补这一空白，又可以提高对岩石圈过程的灵敏度和照度，特别是那些导致岩浆作用的过程。这一提议的第一个目标是成像导致整个东南亚-澳大利亚碰撞带火山活动的岩石圈尺度的衰减结构，从而提供(1)区域尺度的基准，以改进区域尺度上的全波形成像，(2)改进连接地幔结构和岩浆中心的岩石圈结构的成像。为此，该项目将把现有的速度层析成像机器学习框架应用于波形分析，并将3D直接波衰减成像与地壳吸收和散射测绘结合起来。最终结果将与现有的层析模型和合作伙伴提供的现有数据一起用于第二个目标：对(1)整个碰撞带和(2)为阿贡火山提供燃料的岩浆系统进行区域尺度的粘性(弹塑性)塑性模拟，一旦结合到一个基于伴随的反演方案中。使用导出的高分辨率和力学上一致的结构模型，最终交付成果将允许更好地定量评估碰撞带中发挥作用的机制，从而深入了解岩浆和流体从俯冲到地表的迁移。