Bathymetry, Salinity, Temperature, and Distribution of Recent Sediments in the Laguna de Terminos, Campeche, Mexico

Abstract

This work presents a study of recent sediments from an environmental perspective. Although a marginal lagoon environment or a classic backwater, such as that of Laguna de Términos, tends towards the formation of a specific type of deposit, it has been found that the characteristics of the sediments vary locally according to changes in environmental conditions.
Due to the diversity of environmental conditions in Laguna de Términos, the current sedimentary process constitutes a very complex unit. It is very difficult to analyze it by considering each of the distinct factors separately, which is why it was necessary to obtain as much information as possible about the geological agents, ecological factors, and both organic and inorganic processes, and to make a complete interrelation of these to analyze and more accurately understand the sedimentary process.
Particularly, it seems that the main factors controlling sediment deposition are the currents produced by the tides that move large volumes of water in and out through the channels or passages, from open sea to the lagoon, the river discharge that has a selective effect on the sedimentary materials of the bottom, the direction and intensity of the prevailing winds that reclassify sedimentary materials by transporting them from the sandbar or Isla del Carmen into the interior of the lagoon, and the morphology and geographical location of the area that favor the interaction of a complex system of geological transport and sedimentation agents.
The source of the sediments currently being deposited, listed in decreasing order of quantitative importance, consists of the rivers (in the same order: Candelaria, Palizada, Chompín, and the Río del Este), the Paso Real channel, the volume resulting from the organic process, and finally the inorganic process. The intensity and interaction of the factors controlling the sedimentary process in specific areas of the lagoon are mainly manifested by the variation in particle size, their degree of classification, the variation in CaCO3 content, and the relative abundance with which the main constituents of the sediments are distributed.
As a result of this study, a limitation of the classic marginal lagoon environment is proposed, divided into three deposition environments. Additionally, the specific deposition conditions within the lagoon are outlined.
This work discusses only the characteristics of the surface sediments, leaving the discussion of the three-dimensional phase for a future study, from which sufficient information is expected to be obtained to make an accurate interpretation of the result of the current sedimentation process through the study of the stratigraphy of partially or unconsolidated sediments. At the same time, further information will be sought to base the discussion of the formation and development of the coast or geological history of the study area.