Structural characteristics of the halite fabric type ‘Kristallbrocken’ from the Zechstein Basin with regard to its development
Structural characteristics of the halite fabric type ‘Kristallbrocken’ from the Zechstein Basin with regard to its development
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DOI：
10.1007/s00531-008-0399-8
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发表时间：
2010-04
影响因子：
2.3
通讯作者：
Y. Küster;B. Leiss;M. Schramm
中科院分区：
文献类型：
--
作者：
Y. Küster;B. Leiss;M. Schramm
水晶布洛克是一种典型的厘米到厘米大小的层状岩盐织物类型，产于泽赫施泰因盆地的Stassfurt组。到目前为止，从文献中还不清楚kristallbrocken的性质，即它们是细晶多晶岩盐层的遗迹还是“单晶层”的碎屑，以及这种岩盐类型的变形机制。从泽希施泰因盆地南缘的Teutschenthal盐矿中钻取岩心材料，现在首次可以研究变形程度较低的样品。这些晶石的变形行为范围从脆性到延性不等，这可以通过一方面断裂的晶石和另一方面弱弯曲甚至折叠的晶石来证明。局部的x射线纹理测量表明，kristallbrocken绝对是单晶，它们可以被认为是以前更大的“单晶层”的遗迹，大小可达几微米。褶皱晶块的单粒织构特征清楚地表明，其晶格是弯曲的，这很可能是由一种弯曲剪切折叠形成的，而不是由细粒聚集体经过再结晶变形而形成的。由于晶晶的单晶性和原本较大的尺寸，以及内部形成层状的固体包裹体，使得晶晶具有明显强于周围细粒至粗粒多晶岩盐的流变性能，因此也会发生断裂变形。
TheKristallbrockenare a characteristic centimetre- to decimetre-sized, laminated halite fabric type occurring in the Stassfurt Formation in the Zechstein Basin. Up to now, the nature of theKristallbrocken, i.e. if they are relics of fine-grained, polycrystalline halite beds or clasts of ‘single crystal-layers’, as well as the deformation mechanisms of this halite type, were not clear from the literature. Drill core material from the salt deposit Teutschenthal at the southern rim of the Zechstein Basin now allowed investigating less intensely deformed samples for the first time. The deformational behaviour of theseKristallbrockenranges from brittle to ductile, which is evidenced by fracturedKristallbrockenon the one hand and weakly bent or even foldedKristallbrockenon the other hand. Local X-ray texture measurements demonstrated that theKristallbrockenare definitely single crystals and that they can be regarded as relics of formerly larger ‘single crystal-layers’ of up to several dm2in size. The foldedKristallbrockenclearly display by their single grain texture characteristics that their crystal lattice is bent, which was most likely enabled by a kind of flexural-shear folding, and did not develop after deformation from a fine-grained aggregate by recrystallisation. Due to their monocrystallinity, their originally large size, and the solid inclusions forming the internal lamination, theKristallbrockenhave clearly stronger rheological properties than the surrounding fine- to coarse-grained polycrystalline rock salt, and thus also deform by fracturing.