Magnetic polarity of Upper Triassic sediments of the Germanic Basin in Poland

Abstract

Palaeomagnetic results are presented for 205 samples of cores from the Ksi¹¿ Wielkopolski IG-2, WoŸniki K1 and Patoka 1 wells, drilled in the Polish part of Germanic Basin. The magnetic polarity stratigraphy is based on the inclination of the characteristic remanent magnetization, isolated in 60% of the total samples and found to be in general agreement with the expected Late Triassic inclination at the sampling sites. A total of 22 magnetozones from the integration of the three records correspond to about 25% of the published polarity zones for the Upper Triassic sediments that were combined in the worldwide composite polarity-time scale. The magnetic polarity pattern, defined for the Schilfsanstein, fits very well with the one defined in the Tethys area for the upper part of the Julian sub-stage. According to the magnetostratigraphic data, the uppermost part of the Upper Gypsum Beds (equivalent to the Ozimek Member of the redefined Grabowa Formation) and the lowermost part of the Patoka Member, containing the Krasiejów bone-breccia horizon, can be correlated with the latest Tuvalian (~228.5 Ma) or with the middle part of Lacian (~225 Ma). However, if the "Long-Tuvalian" option for the Late Triassic Time Scale is taken into consideration, the parts of these substages mentioned above should be correlated with ~221.5 Ma and ~218.5 Ma, respectively.

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

“…More over, poor biostratigraphic doc umen ta tion, strati graphic gaps, and in for mal lithostratigraphical sub di vi sion, do not fa vour the HCM sec tions as prom is ing ones for world wide magnetostratigraphic cor re la tion. How ever, the suc ces sion con tains red beds usu ally pro vid ing a re li able primary palaeomagnetic sig nal, which en ables at least the cor re lation with the Silesian suc ces sions de scribed in de tails by Szulc and Racki (2015), Szulc et al (2015a, b) and dated magnetostratigraphically by Nawrocki et al (2015). This cor re la tion is es pe cially im por tant since ver te brate re mains were dis cov ered in the Opole re gion (Dzik et al, 2000;see also Dzik and Sulej, 2007) and sev eral other bone-bear ing sec tions were also found in Up per Silesia (Dzik et al, 2008;NiedŸwiedzki et al, 2014).…”

“…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). Only in few cases, the mag ne tite or a mix ture of mag ne tite and haematite bring the pri mary mag ne ti za tion.…”

“…The magnetostratigraphic scale com piled by Nawrocki et al (2015) for the Keuper of Po land in cludes 22 mag netic po lar ity zones, in which six were dis tin guished in the Patoka Mem ber of the Grabowa For ma tion. Nawrocki et al (2015: fig.…”

“…Nawrocki et al (2015: fig. 9) pro posed two op tions of their cor re la tion with the Late Tri as sic Com posite.…”

“…2). Nawrocki et al (2015) used magnetostratigraphy as a tool for the com po sition of the mag netic po lar ity time scale for the Pol ish Keuper suc ces sion, which was cor re lated with the stan dard Com pos ite Late Tri as sic Mag netic Po lar ity Time Scale (Kent and Olsen, 1999;Hounslow and Muttoni, 2010;Hüsing et al, 2011;Ogg, 2012). This was the only pub lished work ded i cated to Keuper magnetostratigraphy in Po land, so far.…”