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Relationship between magnetic fabrics and deformation of the Miocene Pohorje intrusions and surrounding sediments (Eastern Alps)
International Journal of Earth Sciences ( IF 1.8 ) Pub Date : 2020-03-30 , DOI: 10.1007/s00531-020-01846-4
László I. Fodor , Emő Márton , Marko Vrabec , Balázs Koroknai , Mirka Trajanova , Mirijam Vrabec

The Miocene deformation history of magmatic and host metamorphic rocks and surrounding sediments was reconstructed by measuring meso- and microscale structures and anisotropy of magnetic susceptibility (AMS) data in order to constrain the structural evolution of the Pohorje pluton during the onset of lithospheric extension at the Eastern Alps–Pannonian Basin transition. Principal AMS axes, lineation and foliation are very similar to mesoscopic lineation and foliation data from the main intrusive body and from some dykes. Although contribution from syn-magmatic texture is possible, these structures were formed during the cooling of the pluton and associated subvolcanic dykes just shortly after the 18.64 Ma pluton intrusion. Dykes emplaced during progressively younger episodes reflect decreasing amount of ductile strain, while firstly mesoscopic foliation and lineation, and then the tectonic AMS signal gradually disappears. In the structurally highest N–S trending dacite dykes, the AMS fabric only reflects the magmatic flow. The Miocene sediments underwent the same, NE–SW to E–W extension as the magmatic and host metamorphic rocks as indicated by both AMS and fault-slip data. All these events occurred prior to ~ 15 Ma, i.e., during the main syn-rift extension of the Pannonian Basin and during the fastest exhumation of the Tauern and Rechnitz windows, both demonstrating considerable extension of diverse crustal segments of the Alpine nappe pile. After a counterclockwise rotation around ~ 15 Ma, the maximum stress axis changed to a SE–NW orientation, but it was only registered by brittle faulting. During this time, the overprinting of a syn-rift extensional AMS texture was not possible in the cooled or cemented magmatic, metamorphic and sedimentary rocks.



中文翻译:

磁性纤维与中新世Pohorje侵入体及周围沉积物(东阿尔卑斯山)的变形之间的关系

通过测量中微尺度结构和磁化率(AMS)数据的各向异性,重建了岩浆和宿主变质岩及周围沉积物的中新世变形历史,以限制Pohorje岩体在岩石圈伸展开始时的结构演化。东阿尔卑斯山-潘诺尼盆地过渡期。AMS的主要轴,线条和叶面与主要侵入体和某些堤坝的介观线条和叶面数据非常相似。尽管可能由同岩浆质地引起,但是这些结构是在18.64 Ma岩体侵入后不久就在岩体和相关的次火山岩冷却期间形成的。在逐渐年轻化的时期中放置的堤坝反映出延展性应变的数量减少,首先是介观叶状和线状,然后构造的AMS信号逐渐消失。在结构上最高的N–S趋势达克石堤中,AMS织物仅反映岩浆流动。中新世沉积物经历了与岩浆和主体变质岩相同的NE-SW至E-W延伸,如AMS和断层滑动数据所表明的。所有这些事件都发生在〜15 Ma之前,即在Pannonian盆地的主要同裂谷伸展期间以及在Tauern和Rechnitz窗的最快掘出期间,都表明了高山推覆带不同地壳段的相当大的伸展。在逆时针旋转约15 Ma后,最大应力轴变为SE–NW方向,但仅由脆性断层记录。在这段时间,

更新日期:2020-04-21
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