ASPECTS OF MICRO- AND MACROBORINGS FROM THE WHITE LIMESTONE GROUP, JAMAICA, WEST INDIES

The Middle Eocene to Middle Miocene White Limestone Group contains uncommon but relatively diverse, moderately to well-preserved macroborings and common, diverse, well-preserved microborings along with relatively diverse, poor to moderately preserved soft-sediment ichnotaxa. The Troy, Somerset, Moneague and Montpelier formations have yielded macroborings while the Somerset Formation, and to a lesser extent the Moneague and Montpelier formations, have yielded microborings.

Nine ichnogenera represented by 29 ichnospecies of macroborings along with 15 ichnogenera represented by 24 ichnospecies of microborings have been identified. These ichnogenera are:- macroborings - Caulostrepsis, Clionolithes, Conchotrema, Entobia, Gastrochaenolites, Maeandropolydora, Oichnus, Trypanites, and Uniglobites; microborings - Catellocaula, Caulostrepsis, Centrichnus, Conchotrema, Curvichnus, Dipalulichnus, Entobia, Maeandropolydora, Oichnus, Penetrantia, Podichnus, Reticulina, Scolecia, Stellalichnus, Trypanites.

The majority of macroborings identified are preserved in scleractinian corals. Crab carapaces, mollusks and hardgrounds are the other substrates that have yielded these structures. However, the majority of microborings show affinity for foraminifers and to a far lesser extent scleractinian corals.

The distribution of the bioerosional structures reflects, in part, the taphonomic history of the bored substrates. The fossiliferous Moneague, Somerset and Montpelier formations exhibit the highest diversity of these structures.