Fig. 4: Sedimentary deposits forming the substrates of seasonally flooded environments in lowland Amazonia.

The general sedimentary architecture is represented by underlying sandy bar (SD) deposits covered by muddy bar top and floodplain (BT/F) deposits. Pictures were taken during the dry season (September to November). Sedimentary facies are shown in Fig. 6. a Right margin of the Solimões River, upstream the Tefé River mouth near sampling site ALC29. b Left margin of the Solimões River, near the Purus River mouth. c Right margin of the Solimões River, upstream the Negro River mouth near sampling site NSM20. d Right margin of Amazon River upstream of the Tapajós River mouth, near sampling site TAP27. e Island of the Xingu River, near the city of Altamira. Scale is approximate. Geographic coordinates of sampling sites are presented in Supplementary Data 1.