This is the headline at https://phys.org/print413031282.html … the earth sank twice flooding eastern Amazonia – according to a team that found a shark tooth in the NW part of the Amazon basin, deep inland. They are suggesting its presence, and that of other marine organisms, show that when the Andes rose in an uplift event, eastern Amazonia sank – on two separate occasions. Further, each event lasted for around a million years (according to uniformitarian geochronology). Water from the Caribbean flooded the region from Venezuela to NW Brazil.
The research is published in Science Advances (May 2017). Pollen seeds from oil wells in Columbia and rocks in NW Brazil show two short lived transgression events in which ocean water flooded the upper Amazon basin. Geologists appear to disagree about the origin of the sediments it would seem but the researchers in this instance appear to be quite confident they are of marine origin. In fact, some geologists have suggested, in an alternative view, that a shallow sea covered the Amazon region for a much longer period – millions of years. This view itself is divided as some visualise a sort of vast inland lake and others consider there was a massive marine transgression over the same lengthy episode. Both ideas may tie in with an adjustment of global sea levels during axial movements – and the uplift in the Andes may have occurred at the same time as a result of seismic pressure after such an axial movement – but this is not mentioned. In their view the land sank and then rose up again and Andes uplift is nothing much out of the ordinary as earthquakes are quite common in the region.