Pickerill, Ron K.; Donovan, S. K.; Mitchell, Simon F.
Author Affiliation, Ana.
Department of Geography and Geology
Ichnology and biotic interactions on a Pliestocene gastropod from south-east Jamaica
Caribbean Journal of Science
Date of Publication
Late Pleistocene lagoonal siliciclastic strata (approximately 10 m thick) of the Port Morant Formation, exposed on the southeastern side and east of Port Morant Harbour, southeast coastal Jamaica, contain a relatively abundant and moderately diverse ichnofauna that is described herein in detail. The sequence contains soft-sediment ichnotaxa (Ophiomorpha nodosa Lundgren, 1891; Palaeophycus tubularis Hall, 1847; Thalassinoides paradoxicus (Woodward, 1830)) and those formed as a consequence of bioerosion Caulostrepsis cf. contorta Bromley and DŽAlessandro, 1983, C. cretacea (Voight, 1971), C. taeniola Clarke, 1908; Clionoides thomasi Fenton and Fenton, 1932; Entobia ovula Bromley and DŽAlessandro, 1984, Entobia isp. or ispp.; Gastrochaenolites cf. cluniformis Kelly and Bromley, 1984, G. cf. torpedo Kelly and Bromley, 1984; Meandropolydora cf. sulcans Voight, 1965; Oichnus paraboloides Bromley, 1981, O. simplex Bromley, 1981). Only P. tubularis, O. paraboloides and O. simplex have previously been described from the Jamaican rock record; the remainder are therefore formally documented for the first time. The sequence can be subdivided into three units. In ascending stratigraphic order, unit 1 comprises an erosionally-based boulder conglomerate, and units 2 and 3 of clay-rich, calcareous, fine- to coarse-grained sandstones. Small scleractinian coral patch reefs and isolated heads occur at the base of unit 2, and laterally discontinuous (southwards) pebble conglomer- ates are present at the base of unit 3. Soft-sediment ichnotaxa occur in units 2 and 3, whereas bioerosional ich- notaxa occur in association with unit 1, the patch reefs of unit 2, and two abundantly fossiliferous horizons near the top of unit 3.....