Named. Type area is in Gardner Canyon and adjacent parts of Cave Creek in Santa Rita Mountains, Santa Cruz Co, AZ, Mount Wrightson quad. Crops out along major northwest striking fault zone, Santa Rita Mountains. A lower member is siltstone with lenses of pebble conglomerate and two beds of limestone. An upper member is red mudstone that contains beds of sandstone, conglomerate, and dacitic flows and tuff, and small dacite bodies probably intruded at shallow depths. Is at least 1,000 ft thick. A radiometric age of 192 Ma [Now considered Early Jurassic] was calculated for Zr from a dacite flow. Is assigned to the Triassic [Early Jurassic].

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

Sample collected from Gardner Canyon Formation in the Empire Mountains, AZ, Lat. 31 deg. 55 min. 50 sec. N., Long. 110 deg. 36 min. 40 sec. W. Age considered Triassic [now considered Jurassic]. Calculated Pb-alpha age on zircon 170 +/-35 Ma;
Sample from Gardner Canyon Formation(?), Lat. 31 deg. 51 min. 07 sec. N., Long. 110 deg. 44 min. 58 sec. W. Calculated Pb-alpha age on zircon 210 +/-30 Ma.

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

Zircon from one of the minor dacitic volcanics of the Gardner Canyon Formation yielded a nearly concordant U-Th-Pb age of 200 +/-5 Ma [Early Jurassic]. Though the formation is not in contact with the Mount Wrightson Formation, it is thought to be younger than the lower member of the Mount Wrightson because it contains clasts similar to andesites of lower member of Mount Wrightson. Study area in AZ is in the Basin-and-Range province.

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