Loc. 6-11A [Esmeraldas Fm]: Zanclean, Ecuador

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Globigerinidae
Globorotaliidae
Pulleniatina primalis Banner and Blow 1967
Pulleniatina praecursor Banner and Blow 1967
Globorotalia limbata (Fornasini 1902)
Buliminidae
Buliminella curta Cushman 1925
Bulimina marginata d'Orbigny 1826
Globothalamea - Rotaliida - Gavelinellidae
Globothalamea - Rotaliida - Cibicididae
Globothalamea - Rotaliida - Discorbidae
unclassified
Nodosariata - Nodosariida - Nodosariidae
Nodosariata - Polymorphinida - Plectofrondiculariidae
Rotaliidae
Cassidulinidae
Uvigerinidae
Bolivinidae
Glandulinidae
Glandulina laevigata (d'Orbigny 1826)
Protozoa - Actinommidae
Sphaeropyle langii Dreyer 1889
Protozoa - Spumellaria - Spongodiscidae
Spongaster tetras Ehrenberg 1860
Protozoa - Nassellaria - Ultranaporidae
Protozoa - Nassellaria - Pterocorythidae
see common names

Geography
Country:Ecuador
Coordinates: 1.0° North, 79.8° West (view map)
Paleocoordinates:1.3° North, 78.7° West (Wright 2013)
Basis of coordinate:based on nearby landmark
Geographic resolution:outcrop
Time
Period: Neogene Epoch: Pliocene
Stage: Zanclean 10 m.y. bin: Cenozoic 6
Key time interval: Zanclean
Age range of interval: 5.333 - 3.6 m.y. ago
Stratigraphy
Formation:Esmeraldas
Stratigraphic resolution:bed
Stratigraphy comments: STRATIGRAPHIC RELATIONS: From the Esmeraldas Fm, which regionally overlies the Borbon Fm (Middle-Late Miocene). AGE: Zanclean, on the basis of microfossil biostratigraphy. STRATIGRAPHIC POSITION: From unknown position within formation.
Lithology and environment
Primary lithology:tuffaceous,green unlithified mudstone
Includes fossils?Y
Lithology description: SPECIFIC LITHOLOGY: Greenish tuffaceous mudstone, containing interbeds of white volcanic ash, graded sand, and in some places graded shell debris. LITHIFICATION: Unlithified, as stated in text.
Environment:deep-water indet.
Geology comments: ENVIRONMENT: Microplanktonic fauna is fairly diverse, which sug- gests water depths in excess of 200 m. The benthonic fora- minifera suggest depths in the 240 to 900-m range. The mol- luscan fauna contains many discrepancies, in the combined presence of shoal-water and deep-water forms. Olsson (1964), strongly influenced by the presence of the "unusual" deep- water species, estimated the depth at 200 fathoms or 365 m. Rosenberg (1981) plotted a histogram of depth distributions, which peaked at 64 m.
Taphonomy
Modes of preservation:body
Size of fossils:mesofossils,microfossils
Collection methods and comments
Collection methods:bulk,chemical,hydrochloric,sieve,field collection
Reason for describing collection:biostratigraphic analysis
Collection method comments: COLLECTOR: Presumably the authors. REPOSITORY: Not stated, but presumably Princeton University, New Jersey. PREPARATION: Eighty-five gram samples were crushed and boiled with Calgon, then washed through 420-,m, 177-Am, 74-,m and 63- ,m screens. A cut of the fines was saved for nannofossils. The two largest fractions and half of the 74-gm fraction were dried, floated on CC14 and picked for foraminifera. The re- maining half of the 74-um fraction and the 63-,um fraction were decalcified with HC1 and washed again, then dried and floated on CClI, before mounting on slides for study of ra- diolarians. The flotation in this case was found to enrich radiolaria by a factor of about 30, and to raise the proportion of unbroken specimens. Nannofossils were concentrated from the fines that passed the 63-um mesh, in two steps: settling for 1.5 minutes in a 1-liter beaker separated a coarser fraction, to be discarded. The poured-off liquid was then settled in a similar beaker for 30 minutes, which settled out such nannofossils as could be handled by optical microscopy, while the ultra-fine ma- terial was discarded. Radiolaria and nannofossils were pre- pared for study as strewn slides mounted in balsam. Nan- nofossils were identified by optical phase contrast and polarized microscopy, at 1200 x.
Taxonomic list comments:COVERAGE: Exhaustive for foraminifera, nannofossils, and radiolarians. NOMENCLATURE: Not an authoritative publication, but with modern nomenclature and species-resolution identifications.
Metadata
Database number:90839
Authorizer:A. Hendy Enterer:A. Hendy
Modifier:A. Hendy Research group:marine invertebrate,micropaleontology
Created:2009-08-18 20:22:32 Last modified:2025-02-22 15:12:02
Access level:the public Released:2009-08-18 20:22:32
Creative Commons license:CC0
Reference information

Primary reference:
30557. P. F. Hasson and A. G. Fischer. 1986. Observations on the Neogene of Northwestern Ecuador. Micropaleontology 32(1):32-42 [A. Hendy/A. Hendy]