Lower Cretaceous shallow-water carbonates and a new lituolid foraminifer (Bulbobaculites felixi n. sp.) from the Northern Apuseni Mountains (Romania)

Abstract

Shallow-water carbonates from the Lower Cretaceous (upper Aptian) of the Subpiatră Quarry (Apuseni Mountains, west Romania) contain a new species of lituolid foraminifera of the genus Bulbobaculites. The new foraminifer is characterized by a streptospiral initial part, followed by a rectilinear adult stage and a test-wall composed of agglutinated micritic grains. Within the Subpiatră limestones, three main facies can be distinguished: (a) coastal and littoral, (b) open-shelf/lagoon, and (c) shelf margin with bioconstructions and bioclastic shoals. The lower part of the succession contains facies typical for peritidal environments, with both low- and high-energy subtidal limestones, overlain by thinly bedded supratidal limestones. The middle part of the section contains dominantly subtidal limestones assigned to the open-shelf system, whereas the upper part consists of micro-reefs with corals and rudists interlayered with bioclastic shoals. In terms of microfacies, the new species of Bulbobaculites is most common in bioclastic grainstone/rudstone and floatstone/packstone assigned to the coastal/littoral and lagoonal facies.