Editing Rio Grande (section)

===Ancestral Rio Grande===
[[File:Rio Grande White Rock Overlook Park View 2006 09 05.jpg|thumb|left|View of the Rio Grande from Overlook Park, [[White Rock, New Mexico]]]]The [[sedimentary basin]]s forming the modern [[Rio Grande Valley (New Mexico)|Rio Grande Valley]] were not integrated into a single river system draining into the Gulf of Mexico until relatively recent geologic time. Instead, the basins formed by the opening of the [[Rio Grande rift]] were initially [[bolson]]s, with no external drainage and a central [[Dry lake|playa]].<ref name="repasch-etal-2017">{{cite journal |last1 = Repasch |first1 = Marisa |last2 = Karlstrom |first2 = Karl |last3 = Heizler |first3 = Matt |last4 = Pecha |first4 = Mark |title = Birth and evolution of the Rio Grande fluvial system in the past 8 Ma: Progressive downward integration and the influence of tectonics, volcanism, and climate |journal = Earth-Science Reviews |date = May 2017 |volume = 168 |pages = 113–164 |doi = 10.1016/j.earscirev.2017.03.003 |bibcode = 2017ESRv..168..113R |doi-access = }}</ref> An axial river existed in the Espanola Basin as early as 13 million years ago, reaching the Santo Domingo Basin by 6.9 million years ago. However, at this time, the river drained into a playa in the southern [[Albuquerque Basin]] where it deposited the [[Popotosa Formation]].<ref name="koning-etal-2018">{{cite journal |last1 = Koning |first1 = Daniel J. |last2 = Jochems |first2 = Andy P. |last3 = Heizler |first3 = Matthew T. |title = Early Pliocene paleovalley incision during early Rio Grande evolution in southern New Mesico |journal = New Mexico Geological Society Field Conference Series |date = 2018 |volume = 69 |pages = 93–108 |url = https://nmgs.nmt.edu/publications/guidebooks/downloads/69/69_p0093_p0108.pdf |archive-url = https://ghostarchive.org/archive/20221009/https://nmgs.nmt.edu/publications/guidebooks/downloads/69/69_p0093_p0108.pdf |archive-date = October 9, 2022 |url-status = live |access-date = May 20, 2020 }}</ref> The upper reach of this river corresponded to the modern [[Rio Chama]], but by 5 million years ago, an ancestral Rio Grande draining the eastern [[San Juan Mountains]] had joined the ancestral Rio Chama.<ref name="repasch-etal-2017"/>

The ancestral Rio Grande progressively integrated basins to the south, reaching the [[Mesilla Basin]] by 4.5 million years and the Palomas basin by 3.1 million years ago, forming [[Lake Palomas]]. [[River capture]] by a tributary of the Pecos River then occurred, with the Rio Grande flowing to Texas by 2.06 million years, and finally joining the Pecos River 800,000 years ago, which drained into the Gulf of Mexico. Volcanism in the Taos Plateau reduced drainage from the San Luis Basin until a spillover event 440,000 years ago that drained [[Lake Alamosa]], forming the [[Rio Grande Gorge]], and fully reintegrated the San Luis Basin into the Rio Grande watershed.<ref name="repasch-etal-2017"/>