Loc. 6-10B [Esmeraldas Fm] (Pliocene of Ecuador)

Where: Ecuador (1.0° N, 79.8° W: paleocoordinates 0.8° N, 79.0° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Esmeraldas Formation, Zanclean (5.3 - 3.6 Ma)

• 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.

• bed-level stratigraphic resolution

Environment/lithology: deep-water; unlithified, tuffaceous, green mudstone

• 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.
• 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.

Size classes: mesofossils, microfossils

Collection methods: bulk, chemical, hydrochloric, sieve,

• 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.

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

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 90840: authorized by Austin Hendy, entered by Austin Hendy on 18.08.2009

Creative Commons license: CC BY (attribution)

Taxonomic list

• COVERAGE: Exhaustive for foraminifera, nannofossils, and radiolarians. NOMENCLATURE: Not an authoritative publication, but with modern nomenclature and species-resolution identifications.
Coccolithophyceae
 Prymnesiophycidae - Prymnesiophycidae
  -
Sphenolithus abies Deflandre 1954
  - Ceratolithaceae
Helicosphaera
  -
"Helicopontosphaera kamptneri" = Helicosphaera, "Helicopontosphaera sellii" = Helicosphaera
"Helicopontosphaera kamptneri" = Helicosphaera
"Helicopontosphaera sellii" = Helicosphaera
Foraminifera
 Buliminoidea - Buliminidae
Globothalamea
 Rotaliida - Discorbidae
 Rotaliida - Cibicididae
 Rotaliida - Gavelinellidae
Foraminifera
  - Chilostomellidae
 Globigerinoidea - Globorotaliidae
Globorotalia ungulata Bermudez 1961
"Globorotalia humerosa" = Neogloboquadrina humerosa Takayanagi and Saito 1962
 Globigerinoidea - Globigerinidae
Globigerinoides ruber d'Orbigny 1839
"Globigerina decoraperta" = Globoturborotalita decoraperta Takayanagi and Saito 1962
 Rotaliina - Cassidulinidae
 Buliminacea - Uvigerinidae
 Nodosariacea - Glandulinidae
Glandulina laevigata d'Orbigny 1826
 Rotaliina - Bolivinidae
Protozoa
 Entactinaria - Saturnalidae
 Nassellaria -