White Ridge Quartzite

The White Ridge Quartzite is a geologic formation in central New Mexico. It has a maximum age of 1650 million years (Ma), corresponding to the Statherian period.

White Ridge Quartzite
Stratigraphic range: Statherian Pha. Proterozoic Archean Had.
Type	Formation
Unit of	Manzano Group
Underlies	Estadio Schist
Overlies	Abajo Formation
Thickness	4,500 ft (1,400 m)
Lithology
Primary	Quartzite
Other	Schist
Location
Coordinates	34.383°N 106.540°W / 34.383; -106.540
Region	Los Pinos Mountains, New Mexico
Country	United States
Type section
Named for	White Ridge
Named by	Stark and Dapples
Year defined	1946
White Ridge Quartzite (the United States) Show map of the United States White Ridge Quartzite (New Mexico) Show map of New Mexico

History of investigation

The unit was first defined by Stark and Dapples in 1946, during their mapping of the Los Pinos Mountains, and named for White Ridge, a prominent ridge in the northeastern part of the mountains.^[1]

Geology

The unit is a thick sequence of massive quartzite beds, white to reddish or tan in color, 2 to 7 feet (0.6 to 2 m) thick. There are also scattered beds of sericite schist that become more numerous in the uppermost part of the formation, where the quartzite beds thin to 1 to 2 feet (0.3 to 0.6 m) in thickness and the beds are reddened by hematite. The quartzite often contains significant sericite, biotite, and hematite. The total thickness of the formation is up to 3,700 feet (1,100 m). The beds dip steeply to the west, at a dip angle of 32 to 70 degrees.^[1] The formation overlies the Abajo Formation and in turn is overlain by the Estadio Schist.^[2]

Detrital zircon grains in the formation are almost identical in age and isotope composition to the underlying Sevilleta metarhyolite, suggesting that the sediments of the quartzite were weathered almost exclusively from local sources. The minimum zircon age is about 1650 Ma,^[2] and radiometric dating of underlying and overlying formations place the age of the White Ridge Quarzite between 1650 and 1588 Ma.^[3]

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. S2CID 225308346.
3. Medaris, L. Gordon; Singer, Brad S.; Jicha, Brian R.; Malone, David H.; Schwartz, Joshua J.; Stewart, Esther K.; Van Lankvelt, Amanda; Williams, Michael L.; Reiners, Peter W. (September 2021). "Early Mesoproterozoic evolution of midcontinental Laurentia: Defining the geon 14 Baraboo orogeny". Geoscience Frontiers. 12 (5): 101174. doi:10.1016/j.gsf.2021.101174.