Triassic (Anisian and Rhaetian) palaeomagnetic poles from the Germanic Basin (Winterswijk, the Netherlands)

Abstract

In this paper, we provide two new Triassic palaeomagnetic poles from Winterswijk, the Netherlands, in the stable interior of the Eurasian plate. They were respectively collected from the Anisian (~ 247–242 Ma) red marly limestones of the sedimentary transition of the Buntsandstein Formation to the dark grey limestones of the basal Muschelkalk Formation, and from the Rhaetian (~ 208–201 Ma) shallow marine claystones that unconformably overlie the Muschelkalk Formation. The magnetization is carried by hematite or magnetite in the Anisian limestones, and iron sulfides and magnetite in the Rhaetian sedimentary rocks, revealing for both a large normal polarity overprint with a recent (geocentric axial dipole field) direction at the present latitude of the locality. Alternating field and thermal demagnetization occasionally reveal a stable magnetization decaying towards the origin, interpreted as the Characteristic Remanent Magnetization. Where we find a pervasive (normal polarity) overprint, we can often still determine well-defined great-circle solutions. Our interpreted palaeomagnetic poles include the great-circle solutions. The Anisian magnetic pole has declination D ± ∆Dx = 210.8 ± 3.0°, inclination I ± ∆Ix = − 26.7 ± 4.9°, with a latitude, longitude of 45.0°, 142.0° respectively, K = 43.9, A95 = 2.9°, N = 56. The Rhaetian magnetic pole has declination D ± ∆Dx = 32.0 ± 8.7°, inclination I ± ∆Ix = 50.9 ± 8.1°, with a latitude, longitude of 60.6°, 123.9° respectively, K = 19.3, A95 = 7.4°, N = 21. The poles plot close to the predicted location of global apparent polar wander paths (GAPWaPs) in Eurasian coordinates and are feasible for future apparent polar wander path construction. They confirm that the intracontinental, shallow-marine Germanic Basin, in which the Muschelkalk Formation was deposited, existed at a palaeolatitude of 14.1° [11.3, 17.1] N, in a palaeo-environment reminding of the Persian Gulf today. In Rhaetian times, palaeolatitudes of 31.6° [24.8, 39.8] N were reached, on its way to the modern latitude of 52°N.