UPPER ANISIAN TO LOWER CARNIAN MAGNETOSTRATIGRAPHY FROM THE NORTHERN CALCAREOUS ALPS (AUSTRIA)

We present a magnetostratigraphic study of three pelagic limestone sec tions (Gamsstein, Mendlingbach and Mayerling) from the eastern part of the Northern Calcareous Alps. Together these sections, which contain a rich conodont fauna, yield a sedimentary record encompassing the upp ermost Anisian, the Ladinian and the Lower Carnian. Thermal demagnetiz ation and isothermal remanent magnetization experiments indicate that the magnetization is essentially carried by a mineral of the magnetite family. The high unblocking temperature components isolated from the three sections provide clear magnetic polarity zonations. Correlations between these results, based on the biostratigraphic data and tephroc hronology, allow the construction of a composite magnetic polarity seq uence from the Illyrian substage (Upper Anisian) to the Julian 2 zone (Lower Carnian). This sequence contains 17 well-defined polarity rever sals, and eight more poorly defined intervals. Correlations can be sug gested between the new data and other magnetostratigraphic results pre viously obtained from marine sections. We estimate that the magnetic r eversal frequency was 2.5 to 3.6 reversals per million years during th e Ladinian.