Where did the sediment come from that froms the Rio Grande aquifer?

Question

in new mexico

Answer 1

The Middle Rio Grande Basin lies in the Rio Grande rift valley, a zone of faults and basins that stretches from Mexico north to approximately Leadville, Colorado (about 150 miles north of the New Mexico border)—the modern Rio Grande follows this rift valley. The rift formed more than 25 million years ago and initially consisted of a succession of topographically closed basins. These closed basins filled with sediment from the adjacent mountain ranges, dune deposits from windblown sand, and volcanic deposits from local volcanic areas such as the Jemez Mountains. Flowing southward into and through the successive basins in the rift, the Rio Grande deposited river-borne sediment and established the through-flowing river seen today. About 3 million years ago the Rio Grande began to erode into sediment that it had deposited previously, suggesting that the river drained all the way to the Gulf of Mexico. Basin-fill deposits derived from all these sources (deposited in both open- and closed-basin conditions) are known as the Santa Fe Group and range from about 1,400 feet thick at the basin margins to approximately 14,000 feet in the deepest parts of the Middle Rio Grande Basin. The Santa Fe Group, in addition to younger alluvial deposits along the Rio Grande, makes up the Santa Fe Group aquifer system.