The post-last glacial maximum transgression in the de la Plata River and adjacent inner continental shelf, Argentina

摘要

Deposits resulting from the last glacial maximum transgression have been studied in the lowermost regions of the del Plata fluvial basin in eastern Argentina, which include the de la Plata River and adjacent inner shelf and coastal plains. After applying the concepts of sequence stratigraphy, those deposits were considered as a unit and defined as a depositional sequence composed of two systems tracts, respectively, representing the transgressive event and the highstand of sea-level. The sequence was deposited in different but genetically linked depositional environments such as high and low energy coasts with coastal barriers, beach ridges, coastal plains, estuaries and deltas as well as inner shelf. The boundary between the sequence and the underlying pre-transgressive units is represented by the transgressive surface or unconformity (modeled by the ravinement process) which extends from the outer edge of the shelf to the coast. This surface is time-transgressive and can be recognized by distinct physical characteristics above and below it depending on the successive sedimentary environments developed in deep, shallow or coastal waters as sea-level fluctuated.