Combining global and lithospheric-scale thermomechanical models of continental break-up in South Atlantic

结合南大西洋大陆破裂的全球和岩石圈尺度热机械模型

• 批准号: 79419035
• 负责人: Professor Dr. Stephan V. Sobolev, Ph.D.
• 金额: --
• 依托单位: Sektion 2.5: Geodynamische Modellierung
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2012-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/79419035?language=en
• 关键词: Combining; global; lithospheric; scale; thermomechanical

In this project we will use thermomechanic models at both lithospheric and global scales as well as analog modeling to define possible driving forces and mechanical weakening factors that resulted in break-up at western margin of South Africa and formation of South Atlantics. In the global numerical models (GFZ+Munich) we will investigate possible role of subduction zones around Gondwana as well as effect of global mantle convection, including arrival of large plumes in generation of tensile stresses in the continental lithosphere. However, even if tensile stresses are there, the normal continental lithosphere is likely too strong to be broken by the available plate-tectonic forces. Therefore additional, still poorly understood, processes/factors leading either to the weakening of the lithosphere or to the stress concentration or to both, must be involved in the break-up. The possible candidates are: (i) thermal and chemical effect of mantle plume, (ii) sub-lithospheric melting and magma transport, (iii) inherited lithospheric weak zones, (iv) strain weakening, (v) stress concentration at the tip of propagating rift and (vi) extensive strike-slip deformation accompanied extension. The possible role of all those factors in break-up will be investigated using both lithospheric-scale numerical (GFZ) and analog (VU Amsterdam) 3D modeling techniques. Finally we will combine lithospheric and global scale models and will verify model scenarios using observations from other SAMPLE projects.

在这个项目中，我们将使用在岩石圈和全球尺度的热力学模型以及模拟建模，以确定可能的驱动力和机械弱化因素，导致在南非西部边缘的分裂和南南极洲的形成。在全球数值模式（GFZ+慕尼黑）中，我们将研究冈瓦纳大陆周围俯冲带的可能作用以及全球地幔对流的影响，包括大陆岩石圈张应力产生的大羽流的到来。然而，即使存在张应力，正常的大陆岩石圈也可能过于强大，无法被可用的板块构造力破坏。因此，额外的，仍然知之甚少，过程/因素，导致岩石圈的弱化或应力集中或两者兼而有之，必须涉及在破碎。可能的候选人是：（i）地幔柱的热化学效应;（ii）岩石圈下熔融和岩浆运移;（iii）继承性岩石圈软弱带;（iv）应变弱化;（v）扩张裂谷尖端的应力集中;（vi）伴随伸展的广泛走滑变形。将使用岩石圈尺度数值（GFZ）和模拟（VU阿姆斯特丹）三维建模技术来研究所有这些因素在破裂中的可能作用。最后，我们将结合联合收割机岩石圈和全球尺度的模式，并将验证模型的情况下，使用从其他SAMPLE项目的观测。