Retrodictions of Mid Paleogene mantle flow and dynamic topography in the Atlantic region from compressible high resolution adjoint mantle convection models: Sensitivity to deep mantle viscosity and tomographic input model
Retrodictions of Mid Paleogene mantle flow and dynamic topography in the Atlantic region from compressible high resolution adjoint mantle convection models: Sensitivity to deep mantle viscosity and tomographic input model
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DOI：
10.1016/j.gr.2017.04.027
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发表时间：
2018-01-01
影响因子：
6.1
通讯作者：
Oeser, J.
中科院分区：
文献类型：
--
作者：
Colli, L.;Ghelichkhan, S.;Oeser, J.
虽然地幔对流在地球一样的活力是一个混乱的过程，它已被概念研究表明，可以限制其流动历史的时间相当于地幔翻转，大约1亿年，如果切向表面速度场的知识和估计的现代非均匀性状态。这种追溯，通过计算要求伴随方法，是一个很有前途的工具，以提高我们的理解地球深部过程，并链接到地质观测的不确定的地球动力学建模参数。在这里，我们提出了第一个地幔流追溯地球动力学合理的，可压缩的，高分辨率的地球模型与近似6.7亿有限元，可以追溯到中古近纪。我们的追溯涉及从低粘度区（LVZ）在上地幔的动力学效应，同化过去的板块运动模型的切向表面速度场，并探讨不确定的建模参数的影响，通过使用两个不同的估计现今地幔的非均匀性状态的成像由两个最近的地震层析成像研究，和两个不同的深地幔粘度值。专注于非洲半球，我们发现，我们的追溯产生一个空间和时间上高度可变的软流圈流快于板块的速度，和历史的动态地形特征的局部隆起事件，在考虑板块驱动力，和区域尺度隆起的地质文献报道。我们的研究结果表明，改进的约束地球表面的非均衡垂直运动提供的，例如，盆地分析，地震地层学，地形研究，或沉积记录将发挥重要作用，在我们了解最近的地幔流动的历史。(C)2017年国际冈瓦纳研究协会。Elsevier B.V.出版，保留所有权利。
Although mantle convection at Earth-like vigor is a chaotic process, it has been shown by conceptual studies that one can constrain its flow history back in time for periods comparable to a mantle overturn, approximate to 100 million years, if knowledge of the tangential surface velocity field and estimates on the present-day heterogeneity state are available. Such retrodictions, enabled through computationally demanding adjoint methods, are a promising tool to improve our understanding of deep Earth processes, and to link uncertain geodynamic modeling parameters to geologic observables. Here we present the first mantle flow retrodictions for geodynamically plausible, compressible, high resolution Earth models with approximate to 670 million finite elements, going back in time to the Mid Paleogene. Our retrodictions involve the dynamic effects from a low viscosity zone (LVZ) in the upper mantle, assimilate a past plate motion model for the tangential surface velocity field, and probe the influence from uncertain modeling parameters by using two different estimates for the present-day heterogeneity state of the mantle as imaged by two recent seismic tomographic studies, and two different values for deep mantle viscosity. Focusing on the African hemisphere, we find that our retrodictions produce a spatially and temporally highly variable asthenosphere flow with faster-than-plate velocities, and a history of dynamic topography characterized by local doming events, in agreement with considerations on plate driving forces, and regional scale uplifts reported in the geologic literature. Our results suggest that improved constraints on non-isostatic vertical motion of Earth's surface provided, for instance, by basin analysis, seismic stratigraphy, landform studies, or the sedimentation record will play an important role in our understanding of the recent mantle flow history. (C) 2017 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.