Translator Disclaimer
1 March 2011 TAPHONOMIC AND PALEOECOLOGICAL ANALYSES (MOLLUSKS AND FISHES) OF THE SÚA MEMBER CONDENSED SHELLBED, UPPER ONZOLE FORMATION (EARLY PLIOCENE, ECUADOR)
Author Affiliations +
Abstract

The early Pliocene sediments of the Súa Member (Onzole Formation) are spectacularly exposed along coastal cliffs in the surroundings of Súa (northwestern Ecuador). The shellbed at the base of these strata contains rich mollusk and fish assemblages and provides a rare opportunity to document the virtually unknown Pliocene shallow-water faunas of Ecuador. Stratigraphic context, faunal composition (both mollusks and fishes), biofabric trend, ichnological signatures, and taphonomic features presented here, all indicate that the shellbed is a stratigraphically condensed (hiatal) skeletal concentration generated primarily by low rates of net background sedimentation. Shellbeds of this type, immediately overlying a Glossifungites-demarcated ravinement surface, are regarded as onlap shellbeds and record landward stratal convergence and attenuation during the earliest phases of marine transgression. Although composed of largely autochthonous-parautochthonous specimens, the fossil assemblage contains mollusk species from a range of water depths and both soft- and hard-bottom habitats, implying in situ time averaging and admixture of different assemblages as transgression proceeded on a sediment-starved shoreline. The mollusk assemblage is composed of 54 taxa (26 bivalves, 26 gastropods, 2 scaphopods), and the fish assemblage of 31 taxa belonging to 16 families. Both are indicative of a well-oxygenated marine biotope swept by currents and waves, and devoid of a benthic macrophyte cover. With the exception of a few fish species and a single gastropod, the largest number of the mollusk and fish taxa are presently distributed throughout the Tropical Eastern Pacific Biogeographic Region.

GIORGIO CARNEVALE, WALTER LANDINI, LUCA RAGAINI, CLAUDIO DI CELMA, and GINO CANTALAMESSA "TAPHONOMIC AND PALEOECOLOGICAL ANALYSES (MOLLUSKS AND FISHES) OF THE SÚA MEMBER CONDENSED SHELLBED, UPPER ONZOLE FORMATION (EARLY PLIOCENE, ECUADOR)," Palaios 26(3), 160-172, (1 March 2011). https://doi.org/10.2110/palo.2010.p10-070r
Accepted: 5 December 2010; Published: 1 March 2011
JOURNAL ARTICLE
13 PAGES

This article is only available to subscribers.
It is not available for individual sale.
+ SAVE TO MY LIBRARY

SHARE
ARTICLE IMPACT
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top