Loc. 6-10B [Esmeraldas Fm]: Zanclean, Ecuador

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Chilostomellidae
Globigerinidae
Globorotaliidae
Buliminidae
Bulimina marginata d'Orbigny 1826
Globothalamea - Rotaliida - Gavelinellidae
Globothalamea - Rotaliida - Cibicididae
Globothalamea - Rotaliida - Discorbidae
Cassidulinidae
Uvigerinidae
Bolivinidae
Glandulinidae
Glandulina laevigata (d'Orbigny 1826)
unclassified
Coccolithophyceae
Discoaster brouweri Tan Sin Hok 1927
Coccolithus pelagicus (Wallich 1877)
Sphenolithus abies Deflandre 1954
Coccolithophyceae - Ceratolithaceae
Protozoa - Entactinaria - Saturnalidae
Protozoa - Nassellaria
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:90840
Authorizer:A. Hendy Enterer:A. Hendy
Modifier:A. Hendy Research group:marine invertebrate,micropaleontology
Created:2009-08-18 20:22:53 Last modified:2025-02-22 15:12:02
Access level:the public Released:2009-08-18 20:22:53
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]