Updated evidence and discussion of the Triassic palaeomagnetic age of the Kupferschiefer Cu-Ag ore deposits in Poland

Abstract

In the 1987 palaeomagnetic study of the Kupferschiefer ore deposits in Poland by Jowett, Pearce, and Rydzewski, the reversed palaeomagnetic pole obtained for the ore-stage Rote Fäule oxide zone of 49.0°N, 157.2°E corresponded to a mid-Triassic age on the apparent polar wander path (APWP) calculated from contemporary databases. A late diagenetic origin for the Rote Fäule oxide zone, and thus the economic sulphides, was supported by geological evidence and by subsequent dating methods of palaeomagnetism, sulphides, and clays. In response to these results being challenged in a 2011 critical analysis, updated evidence from palaeomagnetic laboratories in Kiev and Utrecht/Milano showed that the 1987 Rote Fäule palaeopole lies directly on the newest APWPs. However, its actual age depends on applying ‘inclination shallowing corrections’ to the palaeopole and to the APWP. Although accurate shallowing corrections cannot be calculated retroactively, the corrected Rote Fäule palaeopole matches a Triassic age on corrected APWPs, just as the uncorrected pole does on the uncorrected 1987 APWP. The Rote Fäule palaeopole also closely matches palaeopoles from the Triassic Buntsandstein rocks in subsequent studies in Germany and Poland, supporting an ore genesis timing of Triassic or later.