THE CARBONIFEROUS-PERMIAN TRANSITION IN CAÑON DEL COBRE, NORTHERN NEW MEXICO

The Cañon del Cobre is a large box canyon in southeastern Rio Arriba County, New Mexico, along the southeastern border of the Colorado Plateau. Within the canyon are significant exposures of the El Cobre Canyon and Arroyo del Agua formations of the Carboniferous-Permian Cutler Group. These deposits have been extensively collected and studied over the last 150 years, beginning with J.S. Newberry in 1859. These strata contain significant collections relevant to paleobotany, palynology, vertebrate paleontology, and vertebrate and invertebrate ichnology. The paleoflora of the El Cobre Canyon Formation include: Alethopteris zeilleri, Macroneuropteris scheuchzeri, Danaeites emersonii, Sphenophyllum verticillatum, S. oblongifolium, S. angustifolium, Annulariai carinata, Asterophyllites equisetiformis, Sigillaria bardii, Pseudomariopteris cordato-ovata, Taeniopteris and walchian conifers. Palynological samples from the El Cobre Canyon Formation include monosaccate, taeniate, bisaccate and non-taeniate bisaccate pollen. The ichnotaxa from the El Cobre Canyon Formation include arthropod trackways (Diplichnites gouldi, Diplopodichnus, cf. Paleohelcura tridactyla, Protichnites isp.), invertebrate grazing and feeding traces (Gordia indianensis and Helminthoidichnites tenuis), tetrapod footprints (Batrachichnus salamandroides and aff. Amphisauropus isp.) and fish swimming trails (Undichna britannica). Vertebrate fossils are known from both the El Cobre Canyon and Arroyo del Agua formations and represent the Seymouran, Coyotean and Cobrean land-vertebrate faunachrons. Notable tetrapod taxa include the eryopid amphibian Eryops, the diadectomorph Limnoscelis paludis, and various eupelycosaurs (e.g., Ophiacodon navajovicus, Ruthiromia elcobrensis, Sphenacodon ferox). Cañon del Cobre provides rare and important documentation fo the Carboniferous-Permian transition, especially of tetrapods, in a nonmarine red-bed succession.