Paleomagnetism in Extremadura (Central Iberian zone, Spain) Paleozoic rocks: extensive remagnetizations and further constraints on the extent of the Cantabrian orocline
Paleomagnetism in Extremadura (Central Iberian zone, Spain) Paleozoic rocks: extensive remagnetizations and further constraints on the extent of the Cantabrian orocline
复制标题
埃斯特雷马杜拉（西班牙伊比利亚中部地区）古生代岩石的古地磁作用：广泛的重磁化和对坎塔布里亚山斜范围的进一步限制
DOI：
10.1007/s41513-017-0039-x
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发表时间：
2017
影响因子：
1.3
通讯作者：
Langereis Cor G.
中科院分区：
文献类型：
--
作者：
Pastor-Galan Daniel;Gutierrez-Alonso Gabriel;Dekkers Mark J.;Langereis Cor G.
在伊比利亚半岛的蜿蜒华力西带，具有坎塔布连造山带（伊比利亚西北部）和中央伊比利亚曲线，是最重要的表现，晚石炭世合并的盘古大陆，产生重磁化几乎跨越整个地球仪settingsAlso在伊比利亚半岛，晚石炭世重磁化是普遍的，往往阻碍古地磁解释方面的前盘古地质历史。与此相反，这种重磁化促进了坎塔布里亚造山带的运动学研究。紧挨着它的南面是中伊比利亚曲线，其几何学和运动学正在争论中。最近的研究表明，这种假定的结构不能形成在同一过程中的坎塔布连orocline.ResultsHere，我们提出了一个古地磁和岩石磁性研究埃斯特雷马杜拉，在最西部的南部肢体的中部伊比利亚曲线的区域。我们的新研究结果表明，在埃斯特雷马杜拉的古生代岩石两个不同的重磁化事件：（1）中生代或新生代重磁化发生在石化石灰岩和（2）晚石炭世重磁化石灰岩，其特点是一致的浅倾角，但很大程度上分散的磁偏角指示逆时针（CCW）垂直轴旋转。磁黄铁矿被证明是石灰岩中的磁性载体，证明了在准变质条件下，即在华力西或古地磁期间的再磁化。InterpretationWe解释decentralscattering作为一个再磁化coeval垂直轴旋转。所描述的CCW旋转是那些预期的坎塔布连造山带的南翼，并在晚石炭世的伊比利亚中部弯曲的第二个起源不一致，延长坎塔布连造山带至少大部分伊比利亚半岛。
IntroductionThe winding Variscan belt in Iberia, featuring the Cantabrian orocline (NW Iberia) and the Central Iberian curve, is a foremost expression of the late Carboniferous amalgamation of Pangea, which produced remagnetizations spanning almost the entire globe.Geological settingsAlso in Iberia, late Carboniferous remagnetizations are widespread often hindering paleomagnetic interpretations in terms of pre-Pangean geologic history. In contrast, such remagnetizations facilitated the kinematic study of the Cantabrian orocline. Immediately to its south is located the Central Iberian curve whose geometry and kinematics are under debate. Recent studies suggest that this putative structure cannot have formed in the same process as the Cantabrian orocline.ResultsHere we present a paleomagnetic and rock magnetic study from Extremadura, a region in the utmost west of the southern limb of the Central Iberian curve. Our new results show two distinct remagnetization events in Paleozoic rocks in Extremadura: (1) Mesozoic or Cenozoic remagnetization occurring in dolomitized limestones and (2) late Carboniferous remagnetization in limestones, characterized by consistent shallow inclinations, but largely scattered declinations indicating a counter clockwise (CCW) vertical axis rotation. Pyrrhotite is documented as magnetic carrier in the limestones which testifies a remagnetization under anchimetamorphic conditions, i.e. during the Variscan orogeny.InterpretationWe interpret the declination scattering as a remagnetization coeval to the vertical axis rotation. The described CCW rotations are those expected for the southern limb of the Cantabrian orocline and are in disagreement with a late Carboniferous secondary origin for the Central Iberian bend, extending the Cantabrian orocline to at least most of the Iberian peninsula.