Mesa Rica Sandstone
Stratigraphic range: Albian PreꞒ Ꞓ O S D C P T J K Pg N
Type	Formation
Unit of	Dakota Group
Underlies	Pajarito Formation
Overlies	Tucumcari Shale, Glencairn Formation
Thickness	33 meters (108 ft)
Lithology
Primary	Sandstone
Location
Coordinates	35°13′37″N 104°13′23″W / 35.227°N 104.223°W / 35.227; -104.223
Region	New Mexico, Oklahoma
Country	United States
Type section
Named for	Mesa Rica
Named by	Dobrovolny, Summerson, and Bates
Year defined	1947
Mesa Rica Sandstone (the United States) Show map of the United States Mesa Rica Sandstone (New Mexico) Show map of New Mexico

The Mesa Rica Sandstone is a geologic formation in Oklahoma and New Mexico. It preserves fossils dating back to the Cretaceous period.^[1]

The Mesa Rica Sandstone consists of crossbedded white to buff sandstone. The sandstone is massive and medium- to coarse-grained. It is a very mature sandstone, consisting of almost pure quartz and kaolin, which may reflect its provenance as reworked sediments of the Morrison Formation, or may be due to a slow rate of deposition that permitted meteoric water (water originating as rain or snow) to circulate through the sediments for an unusually long time.^[2] In some locations, there is minor quartz-pebble conglomerate at the base of the formation, which lies on the Tucumcari Shale^[3] or Glencairn Formation. It is overlain by the Pajarito Formation and has a thickness of up to 33 meters (108 ft).^[1]

The formation was laid down in a low-accommodation deltaic environment.^[2]

Dinosaur remains diagnostic to the genus level are among the fossils that have been recovered from the formation.^[4]

The upper part of the formation preserves dinosaur trackways and is part of the "dinosaur freeway" megatracksite of New Mexico, Colorado, and Oklahoma. Dinosaur tracks were discovered in the formation at the spillway of Clayton Lake State Park in 1982, at Mosquero Creek in 1986, and at Mills Canyon in 1995. The Mills Creek site shows twelve distinct trackways. The Clayton Lake trackways are unusual in showing trail dragging traces. The trackways here are accessible by a trail with interpretive signage but are rapidly eroding in the lake spillway. Most of the tracks at the three sites have been identified as Charirichnium leonardii.^[5]

The Mosquero Creek tracks represent 81 individual ornithopod dinosaurs, of two distinct species, and includes a rare limping track.^[5] The trackways also preserve evidence of movement as a group.^[6]

The lower part of the Mesa Rica Sandstone preserves marine invertebrate fossils, including the ammonite Mortoniceras equidistans (Cragin)^[7]

The unit was first named the Mesa Rica sandstone member of the Purgatoire Formation by Ernest Dobrovolny, Charles Summerson, and Robert Bates in 1947.^[3] It was raised to formation rank by Robert Griggs and Charles Read in 1959, who also abandoned the use of the Purgatoire Formation in northeastern New Mexico.^[8]

• List of fossiliferous stratigraphic units in Oklahoma

• Cotton, William D.; Cotton, Jennifer E.; Hunt, Adrian P. (December 1998). "Evidence for social behavior in ornithopod dinosaurs from the Dakota group of northeastern New Mexico, U.S.A.". Ichnos. 6 (3): 141–149. Bibcode:1998Ichno...6..141C. doi:10.1080/10420949809386445.
• Dobrovolny, Ernest; Summerson, Charles Henry; Bates, Robert Glenn (1947). "Geology of northwestern Quay County, New Mexico". USGS Oil and Gas Investigation Map. 62. doi:10.3133/om62. Retrieved 2 September 2020.
• Griggs, R.L.; Read, C.B. (1959). "Revisions in Stratigraphic Nomenclature in Tucumcari-Sabinoso Area, Northeastern New Mexico: GEOLOGICAL NOTES". AAPG Bulletin. 43. doi:10.1306/0BDA5E8E-16BD-11D7-8645000102C1865D.
• Hunt, Adrian P.; Lucas, Spencer G. (1998). "Tetrapod ichnofaunas from the lower Cretaceous of northeastern New Mexico,USA". New Mexico Museum of Natural History and Science Bulletin. 14: 163–168. Retrieved 3 September 2020.
• Lucas, Spencer G.; Hunt, Adrian P. (2000). "The lower Cretaceous ammonite Mortoniceras equidistans (Cragin) from the Mesa Rica Sandstone, Quay County, New Mexioco". New Mexico Museum of Natural History and Science Bulletin. 16: 97–100. Retrieved 3 September 2020.
• Van Yperen, Anna E.; Holbrook, John M.; Poyatos-Moré, Miquel; Midtkandal, Ivar (25 July 2019). "Coalesced Delta-front Sheet-like Sandstone Bodies from Highly Avulsive Distributary Channels: The Low-accommodation Mesa Rica Sandstone (Dakota Group, New Mexico, U.S.A.)". Journal of Sedimentary Research. 89 (7): 654–678. Bibcode:2019JSedR..89..654V. doi:10.2110/jsr.2019.27. hdl:10852/74350.
• Van Yperen, Anna E.; Line, Lina H.; Holbrook, John M.; Poyatos-Moré, Miquel; Midtkandal, Ivar (2019). "Revised Stratigraphic Relationships of the Dakota Group in the Tucumcari Basin, San Miguel County, New Mexico, USA" (PDF). New Mexico Geological Society Field Conference Series. 70: 89–100. Retrieved 8 September 2020.
• Weishampel, David B.; Dodson, Peter; Osmólska, Halszka, eds. (2004). The dinosauria (2nd ed.). Berkeley, Calif.: University of California Press. ISBN 0-520-24209-2.
• Ziegler, Kate E.; Ramos, Frank C.; Zimmerer, Matthew J. (2019). "Geology of Northeastern New Mexico, Union and Colfax Counties, New Mexico: A Geologic Summary" (PDF). New Mexico Geological Society Field Conference Series. 70 (4): 47–54. Retrieved 1 September 2020.