There have been few studies of Cenozoic continental climate in tropical South America. By early Albian time, South America had begun its westward drift away from Africa, always remaining at nearly the same latitude. The increasing expansion of the Atlantic Ocean moisture source in the east and plate convergence with development of a high mountain range in the west helped enhance South American monsoonal circulation and increased the intensity of tropical South American precipitation in climate modelling studies (e.g., Lenters and Cook, 1995; Insel et al., 2010; Poulsen et al., 2010; Garreaud et al., 2010). Likewise, increased Pacific Walker circulation, proposed to have taken place in the Pliocene (Wara et al., 2005; Ford et al., 2015), likely was associated with increased precipitation in the Amazon center of convection (Garreaud et al., 2010). All three posited controls work in the same direction, to increase precipitation, perhaps fitfully, through the Cenozoic. However, we have no long-term Cenozoic record of precipitation or runoff for Amazon for hypothesis testing.