Magnetostratigraphy and lithostratigraphy of the Lano vertebrate-site: Implications in the uppermost Cretaceous chronostratigraphy of the Basque-Cantabrian Region

Here we present the magnetostratigraphic dating of the Lafio locality (Condado de Trevino, northern Iberian Peninsula), one of the most noteworthy Campanian-Maastrichtian vertebrate sites of Europe. A composite section of 75 m thickness (Lano quarry) constructed from multiple, overlapping profiles and a continuous one (Faido) have been sampled for magnetostratigraphy. Thermal demagnetization techniques were systematically applied to 161 standard specimens and allowed characterizing the characteristic remanent magnetism, mostly carried out by magnetite. The palaeomagnetic signal is slightly scattered due to variety of lithologies, but the primary character can be guaranteed, since the normal and reverse directions are pseudo antiparallel; 346, 28 (alpha(95): 11.9 degrees, k: 5.3) and 175, 35 (alpha 95: 16.4 degrees, k: 4.6). Reliable samples allowed us to build the local polarity sequence made of eight magnetozones that has been used to correlate to the Global Polarity Time Scale. The age of the lower part of the Lano-village succession is basal late Campanian (Hoplitoplacenticeras marroti ammonite zone) and fits with the long reversed zone that must correlate to Chron C33r. The pattern of magnetozones allows tracking the section up to C30r at the upper part of the profile. In this correlation, the Laiio vertebrate site is regarded as latest Campanian in age as it falls within the C32n (approximate to 72-73.5 Ma). The combined lithostratigraphic and magnetostratigraphic analyses have yielded additional conclusions regarding the vertebrate assemblages that are representative of the Late Campanian of the Iberian Peninsula, in addition to highlight an older occurrence in Europe of some vertebrate groups such as salamandrid lissamphians and anguid lizards (or amphisbaenians). (C) 2015 Elsevier Ltd. All rights reserved.