Santa Rosa Formation, New Mexico

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Santa Rosa Formation
Stratigraphic range: Carnian
Santa Rosa Formation along I-25 in Glorieta Pass.
TypeFormation
Sub-unitsTecolotito Member, Los Esteros Member, Tres Lagunas Member
UnderliesGarita Creek Formation
OverliesAnton Chico Formation
Thickness32 meters (105 ft)
Lithology
PrimarySandstone, mudstone
OtherConglomerate
Location
Coordinates34°57′43″N 104°41′25″W / 34.9620°N 104.6902°W / 34.9620; -104.6902
RegionNew Mexico, Texas
CountryUnited States
Type section
Named forSanta Rosa, New Mexico
Named byN.H. Dalton
Year defined1919
Santa Rosa Formation, New Mexico is located in the United States
Santa Rosa Formation, New Mexico
Santa Rosa Formation, New Mexico (the United States)
Santa Rosa Formation, New Mexico is located in New Mexico
Santa Rosa Formation, New Mexico
Santa Rosa Formation, New Mexico (New Mexico)

The Santa Rosa Formation is a geologic

Period.[1]

Description

The formation consists mostly of white to brown sandstone and mudstone with some interbedded conglomerate. The formation lies on the Anton Chico Formation[1] and is overlain by the Garita Creek Formation.[2] The total thickness of the formation is 32 meters (105 ft).[1]

The formation is divided into (in ascending stratigraphic order) the Tecolotito

Member, which is primarily sandstone; the Los Esteros Member, which is primarily mudstone; and the Tres Lagunas Member, which is primarily sandstone.[1]

The sandstone members are interpreted as

lacustrine deposit in lakes that formed due to local subsidence from dissolution of underlying Permian salt beds. Paleocurrents were primarily to the south in the Tecolotito Member and northeast in the Tres Lagunas Member but are indeterminate in the Los Esteros Member.[3]

Fossils

The Los Esteros Member has yielded fossils of the

Zamites powelli, the conifer Pelourdea pleoensis, the gymnosperm Dinophyton spinusos, and seeds (Samaropsis).[4]

This member also includes a microvertebrate site in

In east-central New Mexico, the Los Esteros Member has also yielded a

Otischalkian dinosauromorph assemblage that includes specimens of Silesauridae and Lagerpetidae, including Dromomeron, the latter of unusually large size.[7]

History of investigation

The formation was first named as the Santa Rosa Sandstone by N.H. Darton in July 1919 but the report was not published until 1922.[8] By then the name had already appeared in other publications.[9][10] A type locality was not formally designated until 1972.[11] In 1987, Spencer G. Lucas and Adrian Hunt removed the lower sandstone beds into the Anton Chico Formation and divided the remaining beds into members.[1] W.I. Finch and coinvestigators redesignated the unit as the Santa Rosa Formation in 1988.[12]

References

Bibliography