Guiaco-Tamana Trinidad (Eocene to of Trinidad and Tobago)

Where: Trinidad and Tobago (10.6° N, 61.1° W: paleocoordinates 8.1° N, 51.4° W)

• coordinate estimated from map

When: Brasso Formation, Early/Lower Eocene to Early/Lower Eocene (55.8 - 37.2 Ma)

Environment/lithology: marine; lithified, massive, silty, sandy claystone

• The sedimentological log records two poorly-lithified sand and silt-rich sections the lowest 5 m and uppermost 5 m, respectively separated by an interval of claystones with thinner sands and variable quantities of mollusc (bivalve + gastropod) debris. The large masses of samples JBW-97 and JBW-116 are due to the large amounts of sand in the residues. Neither primary sedimentary structures nor trace fossils are found within the sandstones,but 2.5 m above the base of the study section one horizon within a bed of silt is conspicuously burrowed. The sand at the base of the section contains stringers of lignite. The soles of the sandstone beds are sharp and erosional, and two sand beds, both with hematite cement, occupy channels. The lower of these, 10 m above the study section base, commences within a lag deposit of mollusc fragments.

Size class: microfossils

Collection methods: The section studied was sampled in May 2003, samples JBW-97 through JBW-117 being taken at 1 m intervals. Their positions were recorded on a sedimentological log (Fig. 2). Due to vegetation growth in the interim, it was not possible in May 2003 to sample the whole of the upper subsection with sand-filled channels as described by Wilson (2003, 2004a).

Primary reference: B. Wilson. 2010. A lagoonal interlude with occasional hypersalinity in the deposition of the Early-Middle Miocene Brasso Formation of Trinidad. Journal of South American Earth Sciences 29:254-261 [M. Uhen/R. McClees-Funinan]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 140160: authorized by Mark Uhen, entered by Ricardo McClees-Funinan on 04.03.2013

Creative Commons license: CC BY (attribution)

Taxonomic list

 Chilostomellacea - Heterolepidae
 Chilostomellacea - Gavelinellidae
 Rotaliina - Fursenkoinidae
Fursenkoina sp. d'Orbigny 1846
 Rotaliina - Cassidulinidae
 Rotaliina - Siphoninidae
 Planorbulinacea - Cibicididae
 Planorbulinacea - Planorbulinidae
 Buliminacea - Uvigerinidae
 Buliminacea - Buliminidae
 Buliminacea - Reusselidae
 Discorbacea - Bagginidae
 Discorbacea - Discorbidae
 Discorbacea - Rosalinidae
 Discorbacea - Eponididae
Eponides parantillarum McCulloch 1977
 Rotaliacea - Rotaliidae
 Rotaliacea - Elphidiidae
Elphidium sagrum d'Orbigny 1839
Elphidium advenum Cushman 1922
 Rotaliina -
 Nonionacea - Nonionidae
 Asterigerinacea - Amphisteginidae
Amphistegina gibbosa d'Orbigny 1839
 Rotaliina - Bolivinidae
Brizalina compacta
Brizalina alazanensis venezuelana, Brizalina marginata multicostata
 Ammodiscoidea - Ammodiscidae
 Textulariacea - Textulariidae
 Nodosariacea - Nodosariidae
 Miliolida - Miliolidae
 Miliolida - Hauerinidae
Triloculina sp. d'Orbigny 1826