Latest Permian to Middle Triassic cyclo-magnetostratigraphy from the Central European Basin, Germany: Implications for the geomagnetic polarity timescale

Abstract

In Central Germany, the about 1 km thick mainly clastic Germanic Lower Triassic (Buntsandstein) consists of about 60 sedimentary cycles, which are considered to reflect variability in precipitation within the epicontinental Central European Basin, most probably due to solar-induced short eccentricity cycles. They provide a high-resolution cyclostratigraphic framework that constitutes the base for creating a composite geomagnetic polarity record, in which this paper presents a Middle Buntsandstein to lowermost Muschelkalk magnetostratigraphy obtained from 6 outcrops and 2 wells where a total of 471 samples was collected. Combined with recently established records, a well-documented magnetostratigraphy for the upper Zechstein to lowermost Muschelkalk (latest Permian to Middle Triassic) of Central Germany has been constructed, encompassing an overall stratigraphic thickness of about 1.3 km and 22 magnetozones derived from about 2050 paleomagnetic samples. Along with available biostratigraphy, this multi-disciplinary study facilitates detailed links to the marine realm, in order to directly refer biostratigraphically calibrated Triassic stage boundaries as well as radioisotopic ages to the Buntsandstein cyclostratigraphy and, conversely, to contribute to calibrating the geologic timescale.

Sedimentary evolution of the continental Early–Middle Triassic Cañizar Formation (Central Spain): Implications for life recovery after the Permian–Triassic crisis

“…However, it is also important to stress that in NW Europe, the early-middle Spathian was a more humid interval (Szurlies, 2007) with some paleosoils and tetrapod footprints in the rocks of the German Basin, (Detfurth and Hardegsen formations, Haubold, 1983;Fichter and Kunz, 20(4), or only paleosoils in the Paris Basin ("Zone limite violette", Gall et al, 1977). These data allow speculation about some climate variations during the early-middle Spathian from Central-N to SW Europe, from approximately latitude 20c to 10c• Different sedimentary and biotic indicators show that this period of arid to very arid conditions suddenly changed during the sedimen tation of the upper part of the Cafiizar Fm., probably in the middle- late Spathian.…”

“…F-fluvial Ae-aeolian 4:7' transverse dunes (Olenekian, Early Triassic) except in central German Basin, where there is a continuous sedimentary record from the Induan (Szurlies, 2007). Late Paleozoic-Late Triassic construction and dismemberment of Pangea and the possible associated volcanism are thought to have profoundly altered atmospheric circulation over tropical regions (e.g.…”

Keuper magnetostratigraphy in the southern Mesozoic margin of the Holy Cross Mts. (southeastern edge of the German Basin)

“…This is es pe cially vis i ble in the Buntsandstein de pos its in the Ger man Ba sin (Nawrocki, 1997;Szurlies 2004Szurlies , 2007 and in the Mid dle Tri as sic from Spain (Rey et al, 1996). In the Keuper de pos its from Po land, the pri mary Tri as sic mag ne ti za tion was de scribed as car ried by haematite (Nawrocki et al, 2015).…”

“…5A-C). This is typ i cal in sam ples dom i nated by haematite, like in the Tri as sic Buntsandstein de pos its in the Ger man Ba sin (Nawrocki, 1997;Szurlies, 2004Szurlies, , 2007. The ex am ples il lus trated in Fig ure 5A and C are sim i lar with a slow in crease of mag ne ti za tion between 0 and 0.2 T, unachieved sat u ra tion, sta ble de crease of MS, and com plete re moval of IRM at ~600-650°C.…”

“…On the con trary, the ex am ple il lus trated in Fig ure 5B char acter izes a rapid in crease of mag ne ti za tion be tween 0 and 0.2 T, unachieved sat u ra tion, rapid de crease of MS be tween 450 and 500°C, in crease of MS be tween 650 and 700°C, and complete re moval of IRM at ~700°C. The in crease of mag ne ti zation can be in ter preted as a re sult of ad mix ture of mag ne tite in the sam ple dom i nated by haematite, like in the Mid dle Tri as sic from the Ibe rian Ranges (Rey et al, 1996) and in the Buntsandstein de pos its from the Ger man Ba sin (Szurlies, 2004(Szurlies, , 2007; see also ex per i ments with mix ture of haematite and mag ne tite pro vided by Frank and Nowaczyk, 2008). The pres ence of low-coercivity min eral can be clearly in ter preted from the three-axes ther mal de mag ne ti za tion curves (Fig.…”