Abstract

ZEA, Sven et al. Sandstone reefs in the Gulf of Salamanca, continental shelf of the Colombian Caribbean. Bol. Invest. Mar. Cost. [online]. 2019, vol.48, n.1, pp.153-158.  Epub Sep 16, 2019. ISSN 0122-9761.  https://doi.org/10.25268/bimc.invemar.2019.48.1.762.

In tropical seas there are submerged hard bottoms that harbor corals but that are not coralline in origin. This is the case for the "Banco de las Ánimas" sector in the continental shelf of the Gulf of Salamanca, Colombian Caribbean. In its upper portion (14-16 m in depth), there are low mounds of sandstone blocks and slabs, conforming reefs, colonized by coralline biota and sparse corals. To confirm their lithology an initial petrographic analysis was carried out, which showed the rocks are made up of fine-grained sands, mature in texture, cemented by dolomite. It is proposed that these reefs were formed in a beach-dune-lagoon system during an ancient sea level, similar to the recent coastal bar of Salamanca. In these high-evaporation, supratidal saline environments, they could have been formed as beach rocks or as eolianites, by aragonite cementation, modified later into dolomite. Whether the foundation of the deeper coral formations of the bank is also sandstone or in fact coralline, remains to be determined.

Keywords : Beach rock; Sandstone reef; Sea level changes; Banco de las Ánimas; Southwestern Caribbean.

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