Magnetostratigraphy of the Punta Grohmann section (Dolomites, Italy): improving the chronology of the Ladinian/Carnian boundary

Abstract

We provide the magnetostratigraphy of the Ladinian/Carnian Punta Grohmann stratigraphic section (Dolomites, Italy), calibrated with UPb ages from the literature (237.58 ± 0.04 Ma; 237.68 ± 0.05 Ma). The FO of ammonoid Zestoceras lorigae, the base of the vigens-densus palynomorphs Zone, and sequence stratigraphy suggest a Carnian age for the upper part of the section, which has been confirmed by the magnetostratigraphic correlation between Punta Grohmann and Prati di Stuores (Carnian GSSP). Additional magnetostratigraphic correlation between Punta Grohmann and key time-calibrated Ladinian–Carnian sections from the literature (e.g., Mayerling, Seceda, Rio Nigra) lead to a more precise age of the Carnian base (∼236.5 Ma) and to a better definition of the Middle–Late Triassic Geomagnetic Polarity Time Scale.