In a section measured at Mogollon, Catron Co, NM, Basin-and-Range province, detailed magnetic studies reveal a simple pattern: Cooney Formation and Whitewater Formation [author is referring to Whitewater Creek Member of Cooney Tuff] are older than the other units (Bikerman, 1972), and they are consistently reversely magnetized. They are overlain by Pacific Quartz Latite, which correlates approximately with Apache Spring Quartz Latite. Pacific Quartz Latite is very stable magnetically, but it has an unusual direction of magnetization--therefore, it probably cooled rapidly during a time when the field was reversing. Both in its direction of magnetization and in its magnetic properties, Pacific bears a surprising similarity to Taylor Creek Rhyolite, but is distinctly older. Pacific underlies a sequence of basaltic andesite and rhyolite. Mineral Creek Andesite, Fanney flow-banded rhyolite [Fanney Rhyolite], and Last Chance Andesite are all normally magnetized. Magnetostratigraphic position of Taylor Creek unit within a preliminary model of the middle Tertiary paleomagnetic reversal pattern is depicted on fig. 4; Cooney, Whitewater, Apache Spring, Mineral Creek, Fanney, and Last Chance units depicted on fig. 5. Deadwood Gulch Rhyolite tuff overlies Last Chance Rhyolite; however, no useful magnetic information can be derived.

Source: GNU records (USGS DDS-6; Denver GNULEX).

Age changed from Miocene to Miocene and Oligocene based on dates of 25.0 +/-0.6 m.y. K-Ar whole rock age from flows north of Mineral Creek and of 23.2 +/-0.6 m.y. from flows west of Bearup Spring that are higher in the section. Map area is in the Basin-and-Range province.

Source: GNU records (USGS DDS-6; Denver GNULEX).

Lower part has a whole rock K-Ar age of 25.0 +/-0.8 m.y. Upper part has a whole rock K-Ar age of 23.2 +/-0.8 m.y. [These ages are generally regarded as Oligocene and Miocene.] Sample collected in Catron Co, NM in Basin-and-Range province.

Source: GNU records (USGS DDS-6; Denver GNULEX).