ORGANIC-MATTER ASSEMBLAGES FROM RECENT SEDIMENTS OF THE TACARIGUA COASTAL LAGOON (NORTHERN VENEZUELA)

Sediments of the Tacarigua coastal lagoon in northern Venezuela are ri ch in organic material. The lagoon and its sediments are therefore imp ortant as a modern-day analog for the interpretation of palynofacies a ssemblages in elastic sediments that formed in tropical coastal enviro nments. Samples representative of the most important subenvironments o f the lagoon were collected and prepared with standard palynological m ethods. The organic materials were analyzed in terms of biological ori gin, source area and textural characteristics. The analytical results were evaluated with standard statistical techniques. Based on Principa l Components Analysis (PCA) six sample groups are differentiated. Samp le groups A and B are very rich in humic gels and they represent the w estern part of the lagoon in which sedimentation largely reflects the influence of the River Guapo. Sample group C contains both humic gels and degraded plant material. Group C represents the central part of th e lagoon where sedimentation is influenced both by the River Guapo and the lagoon mouth. Sample group F contains sub-equal percentages of de graded algal and/or bacterial material, humic gels and degraded plant material. Group F is representative of the eastern part of the lagoon where autochthonous sedimentation is important. Sample groups D and E which have a high percentage of degraded algal and/or bacterial materi al, are representative of sediments that were laid down in close proxi mity to mangrove vegetation. In view of the varied character of the or ganic assemblages in these modern lagoonal deposits, the interpretatio n in environmental terms of similar fossil assemblages is complex and requires a careful consideration of all the evidence.