Blue Springs Formation

Blue Springs Formation
Stratigraphic range: Calymmian Pha. Proterozoic Archean Had.
Type	Formation
Unit of	Manzano Group
Overlies	Sais Quartzite
Thickness	4,000 feet (1,200 m)
Lithology
Primary	Schist
Other	Slate, siltstone
Location
Coordinates	34°25′23″N106°31′05″W / 34.423°N 106.518°W / 34.423; -106.518
Region	New Mexico
Country	United States
Type section
Named for	Blue Springs
Named by	J.T. Stark and E.C. Dapples
Year defined	1946
Blue Springs Formation (the United States) Show map of the United States Blue Springs Formation (New Mexico) Show map of New Mexico

The Blue Springs Formation is a geologic formation exposed in the Los Pinos Mountains of central New Mexico.

Description

The formation consists of almost 4,000 feet (1,200 m) of metasedimentary rock. The lower beds are massive gray to red slate and siltstone, while the central portion mostly is greenish sericite schist with occasional slate and siltstone beds. The uppermost beds are again red to gray slate. ^[1] The formation is underlain by the Sais Quartzite and overlain by Phanerozoic units. The middle schist is interpreted as a metarhyolite (a metamorphosed rhyolite). ^[2]

The crystallization age of the formation is placed at 1588 ± 7 million years (Ma), corresponding to the earliest Calymmian period of the Mesoproterozoic. ^[2]

History of investigation

The formation was originally described as the Blue Springs schist by J.T. Stark and E.C. Dapples in 1946 and named for Blue Springs, a seepage area just north of Highway 60. ^[1] The formation was first assigned to the Manzano Group in 2006. ^[3]

See also

• Earth sciences portal
• Paleontology portal

• List of fossiliferous stratigraphic units in New Mexico
• Paleontology in New Mexico

References

1. Stark, J. T.; Dapples, E. C. (1946). "Geology of the Los Pinos Mountains, New Mexico". Geological Society of America Bulletin. 57 (12): 1121. doi:10.1130/0016-7606(1946)57[1121:GOTLPM]2.0.CO;2.
2. Holland, Mark E.; Grambling, Tyler A.; Karlstrom, Karl E.; Jones, James V.; Nagotko, Kimberly N.; Daniel, Christopher G. (September 2020). "Geochronologic and Hf-isotope framework of Proterozoic rocks from central New Mexico, USA: Formation of the Mazatzal crustal province in an extended continental margin arc". Precambrian Research. 347: 105820. doi:10.1016/j.precamres.2020.105820.
3. Luther, Amy (2006). History and timing of polyphase Proterozoic deformation in the Manzano thrust belt, central New Mexico [master's thesis] . Retrieved 27 August 2020.