Middle-Upper Triassic carbonate platforms in Minorca (Balearic islands): Implications for Western Tethys correlations

Abstract

In order to progress in the knowledge of the Middle to Upper Triassic evolution of the western Tethys realm, an integrated approach which includes new sedimentological, sequence stratigraphic and biostratigraphic data, has been accomplished in the carbonate marine successions (Muschelkalk facies) of that age in Minorca (Balearic Islands, Spain). The new biostratigraphy, which includes six successive ammonoid biozones, allowed to assign these carbonate successions to the uppermost Anisian–lower Carnian interval. The integration of the new chronostratigraphic framework with the sedimentological analysis allowed to recognize five main successive stages of carbonate platform evolution: 1) Initial marine transgression and shallow ramp development (uppermost Anisian); 2) Carbonate ramp drowning (Anisian–Ladinian boundary); 3) Prevalence of open sea conditions (Ladinian–early Carnian); 4) Abrupt sea-level drop (intra-lower Carnian) and; 5) Shallow carbonate ramp and transition to sabkha systems (Keuper facies). Furthermore, the sequence stratigraphic analysis allowed to divide some of these stages into depositional sequences.Minorca was located in the westernmost Tethys area during the Triassic, in a key paleogeographic location close to the present-day Iberia, Sardinia and the Cottian and Southern Alps. The new data have allowed an interregional comparative analysis among these areas, with recognition of major suprarregional events and episodes in the framework of the western Tethys evolution.