Paleomagnetism of the Guanyang Devonian sedimentary successions in Guangxi province, South China

Abstract The Devonian position of the South China Block (SCB) remains debated because apparently contradictory Devonian paleopoles have been documented. Here we report two characteristic remanent magnetization components from the mildly deformed Guanyang Devonian successions (Lochkovian-Famennian) within the cratonic interior of the SCB. Both components pass reversal tests and occur in different samples across the successions. Component A and associated paleopole DA (228.9°E, 37.7°N, A95 = 3.7°) are comparable with published Devonian data and were likely acquired before Permian-Triassic folding and likely reflect syn-depositional magnetization. Component B and its associated paleopole DB (204.6°E, 4.5°N, A95 = 5.5°) are distinct from published results and were probably acquired during minor tilting associated with the Late Devonian Liujiang orogeny. If paleopole DA was acquired prior to the Late Devonian Liujiang orogeny, the paleolatitude of the Guanyang successions varied little throughout the Devonian, but the azimuthal orientation of recorded declinations exhibits a 40° difference. The distinct positions of the two paleopoles are broadly consistent with existing enigmatic Devonian field records. Alternatively, given the uncertainty in the acquisition ages of both components in the Guanyang successions, a case can be made for component A being a secondary magnetization acquired during the Permian-Triassic Indosinian orogeny. Nonetheless, the similar distribution of Devonian paleopoles from Gondwana to those of cratonic interior of the SCB suggests a Devonian connection between the two continents, and adds further support for a non-uniformitarian geomagnetic field during this enigmatic time interval.