Quaternary carbonates on the coast of the Yucatan Peninsula and the island of Cozumel, Mexico: Paleoenvironmental implications

• Published in: Journal of South American earth sciences 2020-10, Vol.102, p.102670, Article 102670
• Main Authors: Valera-Fernández, D., Solleiro-Rebolledo, E., López-Martínez, R.A., Pi-Puig, T., Salgado-Garrido, H., Cabadas-Báez, H.
• Format: Article
• Language: English
• ISSN: 0895-9811; 1873-0647
• DOI: 10.1016/j.jsames.2020.102670

Calcretes and palustrine carbonates are two types of continental carbonates that contain significant environmental information and can be found in nearshore environments. In three stratigraphic sections studied in the coastal area of the Yucatan Peninsula and the island of Cozumel, multiple levels of calcretes and palustrine carbonates were identified. The presence of these continental carbonates combined with calcarenites suggests a transition from a shallow marine deposit to a continental environment for paleosol development. This research analyzes the geochemical (δ13C and δ18O), mineralogical and micromorphological characteristics of the calcarenite, palustrine carbonate and calcretes to infer their paleoenvironmental formation conditions. The mineralogy of the samples consists entirely of aragonite and calcite. The micromorphology allowed us to identify α-calcretes and β-calcretes, as well as palustrine carbonates such as peloidal and mottled limestones. The isotopic signature of Palustrine carbonate has an intermediate isotopic signature (δ13C mean value of −5.24‰, δ18O mean value of −4.9‰), falling between that of calcarenites and calcretes. The δ13C (ranging from −10.10 to −7.50‰) and δ18O (−5.63 to −4.64‰) values of all calcretes analyzed in this work are similar to the values reported for the Pleistocene and Holocene calcretes exposed in the Caribbean Sea region. Isotopic values of δ13C in the studied sections are interpreted as the result of a change in vegetation from a predominant C3 vegetation associated with a cool-wet climate to a C3/C4 mixed vegetation, which is a plant cover that grows in a drier-hotter climate. •Continental carbonates (calcretes and palustrine) form in sections of the Yucatan Peninsula.•Continental carbonates were described by mineralogy, micromorphology, and geochemistry.•δ13C and δ18O calcretes data match with studies for the Caribbean area during the Quaternary.•Cycles of transitions between continental environments and shallow marine were identified.