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Ongoing River Capture in the Amazon
Author(s) -
Stokes Maya F.,
Goldberg Samuel L.,
Perron J. Taylor
Publication year - 2018
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2018gl078129
Subject(s) - amazon rainforest , tributary , drainage basin , hydrology (agriculture) , geology , channel (broadcasting) , discharge , drainage , sedimentation , geography , geomorphology , sediment , cartography , ecology , geotechnical engineering , engineering , electrical engineering , biology
River capture is thought to trigger abrupt changes in evolving continental drainage systems, but it is almost always inferred rather than observed, and the mechanisms that lead to capture are unclear. We shed light on these mechanisms by documenting an ongoing capture involving major South American rivers. The Rio Casiquiare is a distributary of the Rio Orinoco and a tributary of the Rio Negro; it forms a perennial water connection between the drainage basins of the Amazon and Orinoco, the largest and fourth‐largest rivers on Earth by discharge. This unusual configuration is the result of an incomplete and ongoing river capture, in which the Rio Negro is capturing the upper Rio Orinoco. We describe a positive feedback between diversion of water into the capturing channel and sedimentation within the channel being captured, a mechanism that could drive river capture in the Amazon and elsewhere.