3-D Inversion of MT Data for Imaging Deformation Fronts in NW Poland
3-D Inversion of MT Data for Imaging Deformation Fronts in NW Poland
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DOI：
10.1007/s00024-016-1275-2
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发表时间：
2016-04
影响因子：
2
通讯作者：
K. Slezak;W. Jóźwiak;K. Nowożyński;H. Brasse
中科院分区：
文献类型：
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作者：
K. Slezak;W. Jóźwiak;K. Nowożyński;H. Brasse
波美拉尼亚地区（波兰西北部）占据重要位置，是欧洲最大的构造边界所在。这是东欧克拉通（EEC）与古生代地台（PP）接触的区域，被称为跨欧洲缝合带（TESZ）。TESZ形成于古生代，是几个地壳单元碰撞的结果，它从东南部的黑海延伸到西北部的不列颠群岛。这是一个对我们了解欧洲构造史至关重要的地区。基于二维反演的大地电磁（MT）结果表明，接触带具有岩石圈不连续特征，前寒武纪EEC、过渡带TESZ和新PP的地电结构存在明显差异，中下地壳深处也存在明显的导体。因此，本文研究的主要目的是获得波兰西北部TESZ以下地壳和上地幔电导率的详细三维图像及其区域分布。为了完成这项任务，我们应用了最新的3-D反演代码，这使我们能够获得更真实的模型几何形状。此外，为了证实和补充研究，实现了水平磁张量（HMT）分析。这种方法使我们有机会有效地定位导电结构的位置。因此，我们获得了一个更清晰的三维电导率分布模型，其中出现了高导电性的岩石复合体，我们暂时将其与变形前沿联系起来。
The Pomerania region (northwest part of Poland) occupies a significant position, where the largest European tectonic boundary is situated. This is the area of the contact between the East European Craton (EEC) and the Paleozoic Platform (PP) and it is known as the Trans-European Suture Zone (TESZ). The TESZ was formed during Paleozoic time as a consequence of the collision of several crustal units and it extends from the Black Sea in the southeast to the British Isles in the northwest. It is a region of key importance for our understanding of the tectonic history of Europe. Previous magnetotelluric (MT) results, based on 2-D inverse modeling, show that the contact zone is of lithospheric discontinuity character and there are distinct differences in geoelectric structures between the Precambrian EEC, transitional zone (TESZ), and the younger PP. The presence of a significant conductor at mid and lower crustal depths was also shown. Thus, the main aim of the research presented here was to obtain detailed, 3-D images of electrical conductivity in the crust and upper mantle and its regional distribution below the TESZ in the northwest part of Poland. To accomplish this task we applied the latest 3-D inversion codes, which allowed us to get more realistic model geometries. Additionally, to confirm and complement the study, the Horizontal Magnetic Tensor (HMT) analysis was realized. This method gives us an opportunity to efficiently locate the position of well-conducting structures. As a result we obtain a clearer, three-dimensional model of conductivity distribution, where highly conductive rock complexes appear which we tentatively connected to deformation fronts.