Occurrence of the ichnogenus Teredolites in a megablock of the Peñalver Formation, Cretaceous–Paleogene boundary (K/Pg), Western Cuba.

Abstract

The presence of wood borings in Cuba is herein for the first time documented. They are present in a megablocks made up by sandstones and lutites included in the Cretaceous–Paleogene boundary (K/Pg) deposits of the Peñalver Formation. Two types of borings have been identified, which are attributed to the icnoespecies Teredolites clavatus and Teredolites longissimus. Both ichnotaxa were created by mechanic bioerosion and by the action of xylophagous bivalves. Shells of bivalves are abundant in the sample, but they do not correspond to the tracemaker of Teredolites. Megabloks as the one with the borings range in size from a few to dozens of meters, and were emplaced in the basin as olistolithes. The siliclastic sequence containing the wood with Teredolites and the mollusc body fossils can be interpreted as tempestite deposits formed in an open basin. Some fossil elements seem to come from the inner platform as rocks in the same sequencial and facial situation bear abundant orbitoidid macroforams. Vegetal remains strongly indicate the presence of nearby emerged lands. This last hypothesis is supported by the presence in the same outcrop of conglomerates of volcanomitic composition. The origin of these olistostromic deposits can be related with the collapse of the Cuban platform edge during the origin of K/Pg deposits, as result of the seismic impact derived from the Chicxulub site (Yucatan).