Abstract The Permian remagnetization belt that affects the southwestern margin of Gondwana has an important geographic extension reaching several South American cratons and terranes. A paleomagnetic pole for the Early Cambrian Guachos Formation in the Eastern Cordillera of Argentina was computed (LG: Lat: 58.1°S, Long: 20.2°E, A95: 6.4°, n: 30), that likely corresponds to a Permian remagnetization and suggests that such belt might extend further north than previously envisaged. We performed several rock-magnetic studies on this succession of laminated fine grain sandstones and siltstones in order to determine the magnetic phases that carry the remanence. Thermomagnetic (k vs. T) curves, field and frequency dependence of bulk susceptibility, hysteresis loops, isothermal remanent magnetization acquisition and back-field curves, three-axis IRM thermal demagnetization, among others, permitted to establish magnetite as the main mineral carrying the remanence. Microscopic observations confirmed a secondary chemical origin for magnetite. Magnetic fabric studies indicate a tectonic fabric, consistent with cleavage developed on these rocks together with low-grade metamorphism. However, a Permian remagnetization, as suggested by the paleomagnetic pole position, cannot be related to Cambrian deformation and metamorphism and might be related to hydrothermal processes.

中文翻译：

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阿根廷东科迪勒拉早寒武世 Guachos 地层二叠纪再磁化

摘要 影响冈瓦纳大陆西南边缘的二叠纪再磁化带具有重要的地理延伸，可到达几个南美克拉通和地体。计算了阿根廷东科迪勒拉早寒武纪 Guachos 组的古地磁极（LG：纬度：58.1°S，经度：20.2°E，A95：6.4°，n：30），这可能对应于二叠纪再磁化和表明该带可能比先前设想的更向北延伸。我们对这一系列层状细粒砂岩和粉砂岩进行了几项岩磁研究，以确定携带剩磁的磁相。热磁 (k vs. T) 曲线、体磁化率的场和频率依赖性、磁滞回线、等温剩磁采集和背场曲线，除其他外，三轴 IRM 热退磁允许将磁铁矿确立为携带剩磁的主要矿物。显微镜观察证实了磁铁矿的次要化学来源。磁性织物研究表明构造织物与这些岩石上发育的解理以及低级变质作用一致。然而，古地磁极位置表明的二叠纪再磁化与寒武纪变形和变质作用无关，可能与热液过程有关。与这些岩石上发育的解理以及低品位变质作用一致。然而，古地磁极位置表明的二叠纪再磁化与寒武纪变形和变质作用无关，可能与热液过程有关。与这些岩石上发育的解理以及低品位变质作用一致。然而，古地磁极位置表明的二叠纪再磁化与寒武纪变形和变质作用无关，可能与热液过程有关。