Stratigraphy and paleontology of the early Cretaceous Cerro de Oro Formation, central Sonora
Por:
González-León C.M., Lucas S.G.
Publicada:
1 ene 1995
Resumen:
The Cerro de Oro Formation is proposed herein as a new lithostratigraphic unit in the Bisbee Group of Sonora. It forms the lowermost unit of that group in the Cerro de Oro area of central Sonora and unconformably overlies Upper Proterozoic strata of the Las Viboras Formation. It is disconformably overlain, by either the Morita Formation or the Upper Cretaceous La Palma Formation. The remainder of the Lower Cretaceous Bisbee Group of this area is composed of the Mural Limestone and the Cintura Formation. The 105-m-thick Cerro de Oro Formation is a yellowish to reddish succession of interbedded calcareous sandstone, siltstone, mudstone, and limestone, with a local fauna of ammonites, nautiloids, bivalves, gastropods, and brachiopods of shallowmarine origin. This unit is the first transgressive deposit of three transgressive-regressive events that are recorded in the Sonoran portion of the Bisbee basin. The Cerro de Oro Formation correlates with the El Aliso Formation of east-central Sonora.
Filiaciones:
González-León C.M.:
Estación Regional del Noroeste, Instituto de Geología, Universidad Nacional Autónoma de México, Apartado Postal 1039, 83000 Hermosillo, Sonora, Mexico
Lucas S.G.:
New Mexico Museum of Natural History and Science, 1801 Mountain Road N. W., Albuquerque, NM 87104, United States
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