Four new fossil associations identified in the Cipit boulders from the St. Cassian Formation (Ladinian–Carnian; Dolomites, NE Italy)

Abstract

We describe four new fossil associations obtained from nine allochthonous blocks—the so-called Cipit boulders—on the basis of 23 thin sections. The samples were collected from the well-known Middle–Late Triassic St. Cassian Formation (NE Italy). These associations were determined by considering all biomorpha and microbialitic structures that were quantified and analyzed by performing Q-mode cluster analysis of the thin sections. Three algorithms and two indices were used for analysis. Additional identified materials include cementation and microsparite fabrics, as well as allochthonous components. The studied communities include the following: the Ceratoporella breviacanthostyl–Tubiphytes Association, the Cryptocoelia zitteli–Mesophylum Association, the Cladogirvanella–stromatolite Association, and the Amblysiphonella strobiliformis–Megalodon Association. The origins of the paleoenvironmental settings of the communities presented here are proposed based mainly on their fossil diversity, considering that many fossils are indicators of specific palaeoenvironmental conditions.