Magnetostratigraphy and biostratigraphy of the Middle Triassic Margon section (Southern Alps, Italy)

A magnetostratigraphic study has been performed on the paleontologically we ll constrained pelagic Middle Triassic (Lower/Upper Ladinian boundary) sect ion at Margon (Trento, Southern Alps, Italy). Rock magnetic investigations indicate the presence of both, high and low coercivity minerals. Specimens subjected to progressive thermal demagnetization procedures show that nearl y all of them exhibit a low temperature magnetization component, parallel t o the present-day field before bedding correction, and a high temperature o ne, characterized by either positive or negative and opposite polarity, con sidered as the characteristic Triassic magnetization. The comparison of the Margon magnetic polarity zonation with those of two coeval sections poses some problems when ammonoid- and conodont-based stratigraphies have to be c orrelated. However, good correlation has been obtained for the recognized M iddle Triassic ammonoid biozones in the Tethyan realm. Valuable data to the construction of a standard magnetostratigraphic and paleontological scale are contributed by the results from the Margon section. (C) 2001 Elsevier S cience B.V. All rights reserved.