Marks (1951) IPC# 1134 (Basal Calcareous Mbr, Daule Fm) (Miocene of Ecuador)

Where: Guayas, Ecuador (1.7° S, 80.3° W: paleocoordinates 2.5° S, 77.3° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Basal Calcareous Member (Daule Formation), Middle Miocene (16.0 - 11.6 Ma)

• From Daule Fm, which is of Middle Miocene age comprises three members, a "basal calcareous" member, a middle "blue siltstone" member, and an "upper calcareous" member. The exact thickness of the unit has not been measured accurately in this section because of structural complications. The basal member, from which this collecion is derived is 1840 ft thick. Basal strata overlie igneous and metamorphic rocks of Cretaceous age. Faunal compositions suggests a Middle Miocene age, with affinities to the Progreso Fm, and Middle Miocene formations of Peru. Taxa are share with the Gatun fm, the Tubera Fm, the Cucurrupi Fm of Colombia.

• bed-level stratigraphic resolution

Environment/lithology: transition zone or lower shoreface; lithified, calcareous sandstone

• Shallow to moderately deep-water siliciclastic environment, with normal salinity conditions, although some brackish water taxa are present. Probably upper neritic zone, a few km from the shoreline, deposited during transgressive onlap.
• Mainly calcareous indurated sandstone.

Size class: macrofossils

Reposited in the PRI

Collection methods: quarrying,

• Fossil material derived from the International Ecuadorian Petroleum Company (subsidiary of Standard Oil Co.) and was collected by the author (then employed by oil company) during field exploration and drilling operations. All type and voucher material reposited in PRI collections.

Primary reference: J. G. Marks. 1951. Miocene stratigraphy and paleontology of Southwestern Ecuador. Bulletins of American Paleontology 33(139):1-448 [A. Miller/A. Hendy]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 61077: authorized by Austin Hendy, entered by Austin Hendy on 29.05.2006

Creative Commons license: CC BY (attribution)

Taxonomic list

• Exhaustive for gastropoda and bivalvia.
unclassified
  -
Bivalvia
 Arcida - Glycymerididae
Glycymeris sp. Da Costa 1778 clam
 Arcida - Arcidae
 Arcida - Noetiidae
Noetia dauleana Marks 1951 clam
Gastropoda
 Neogastropoda - Buccinidae
Phos haughti Marks 1951 true whelk
 Cerithioidea - Potamididae