Reijmer, John J. G., Bauch, Thorsten and Schäfer, Priska (2012) Carbonate facies patterns in surface sediments of upwelling and non-upwelling shelf environments (Panama, East Pacific). Sedimentology, 59 (1). pp. 32-56. DOI 10.1111/j.1365-3091.2010.01214.x.

Text Reijmer et al 2012.pdf - Published Version Restricted to Registered users only Download (2MB) | Contact

Abstract

In this study two carbonate environments are compared and contrasted; the
Gulf of Panama and the Gulf of Chiriquı´ on the Pacific side of Panama. These
two embayments are in close geographic proximity at latitudes between 7° N
and 9° N. The Gulf of Panama and the Gulf of Chiriquı´ are characterized by
contrasting oceanographic conditions with year-round stable non-upwelling
conditions in the Gulf of Chiriquı´ and strong seasonal upwelling in the dry
season (December to April) in the Gulf of Panama. The upwelling variations
only have a limited influence on the amount of carbonate produced; however,
they do have a major impact on the occurrence of specific carbonate producing
biota. In addition, carbonate production and distribution is influenced in both
gulfs by the occurrence of islands and by terrigenous input. Terrigenous
material is found mainly in the smaller grain sizes (<63 to 250 lm) that can be
transported easily by currents and waves. Carbonate dominant sediments
(carbonate sands and mixed carbonate–siliciclastic sands) mainly occur
around the islands and are dominated by larger grain-sizes (>500 lm).
The Gulf of Panama and the Gulf of Chiriquı´ both show warm and
temperate carbonate-producing biota, with carbonate producers from tropical
(corals) to mixed tropical to cool-water (coralline red algae) and cold-water
(balanids) environments. The Gulf of Chiriquı´ is characterized by oligotrophic
to mesotrophic conditions resulting in a photozoan (coral) and/or rhodolith-
facies in shallow-water areas surrounding the islands and a molluscdominated
facies in deeper waters towards the shelf edge. Seasonal upwelling
causes temporary eutrophic conditions in the Gulf of Panama, which results in
a heterozoan facies around the islands dominated by balanids, echinoderms
and molluscs. Thus a ‘cool-water’ carbonate fauna and eutrophic conditions
can exist in the tropics within an area prone to seasonal upwelling. The
distinct facies differences found on the Pacific shelf of Panama stress the
importance of variations in oceanographic conditions, upwelling versus nonupwelling,
in determining carbonate production and associated facies patterns
in the tropics.

Actions (login required)

View Item