Pickerill, Ron K.; Donovan, S. K.; Mitchell, Simon F.; Keighley, David G.
Author Affiliation, Ana.
Department of Geography and Geology
Late cenozoic trace fossils from southeast coastal Jamaica
Jackson, Trevor A.
Caribbean geology into the third millennium: Transactions of the fifteenth Caribbean Geological Conference
Place of Publication
The University of the West Indies Press
Date of Publication
Series Editor Role
Series Volume Identification
Series Issue Identification
Late Cenzoic strata of the Port Morant area, southeast coastal Jamaica, comprise the Bowden Formation (Pliocene), the Old Pera Beds (early Pleistocene) and the Port Morant Formation (ate Pleistocene). The Bowden Formation consists of a basal? 5 m of conglomerate and coarse-grained sandstone layers (the Bowden shell bed) overlain by at least 145 m of bioturbated marlstones with rare and thin micritic limestone and pebbly sandstone horizons. The highly fossil-iferous Bowden shell bed contains at least forty-five mollusc species exhibiting the borings Oichnus paraboloides and Oichnus simplex, produced respectively by naticid and muricid gastropods, as well as rare examples of Gastrochaenolites and Teredolites. Marlstones of the Bowden Formation are dominated by ichofabrics comprising the ichnotaxa Planolites, Chondrites, Phycosiphon and Teichichnus, produced by annelids and supporting its deposition in a relatively deep-water setting. Strata of the Old Pera Beds are approximately 28 m thick and interpreted as a storm-influenced, interlayered sandstone and sandy siltstone sequence deposited on a shallow water shelf above storm wave base, but below fair-weather wave base; they contain abundant and spectacularly preserved examples of Bichordites monastiriensis. This ichnotaxon, produced by spatangoid echinoids, is a rarely reported form and to date this occurrence is its only record in the western hemisphere. Lagoonal strata of the Port Morant Formation, essentially sandstone-dominated and 10 m thick, are pervasively bioturbated by the crustacean-produced ichnotaxa Thalassinoides and Ophiomorpha. More importantly, they contain the most abundant and diverse assemblage of bioerosional ichnotaxta reported to date from the Caribbean. These include ichnotaxa produced by bivalves (Gastrochaenolites ispp.), gastropods (Oichnus ispp.), sponges (Entobia ispp.) and polychaete annelids (Caulostrepsis ispp., Clionoides thomasi, Meandropolydora cf. sulcans).....