Stratigraphy and age of Upper Jurassic strata in north-central Sonora, Mexico: Southwestern Laurentian record of crustal extension and tectonic transition
Por:
Mauel, DJ, Lawton, TF, Gonzalez-Leon, C, Iriondo, A, Amato, JM
Publicada:
1 abr 2011
Resumen:
Stratigraphy, sedimentology, and geochronology of the Upper Jurassic Cucurpe Formation in north-central Sonora, Mexico, provide new insights into Late Jurassic rifting along the southwestern margin of Laurentia. The Cucurpe Formation is the fill of the Altar-Cucurpe Basin. This basin developed upon attenuated crust of the Triassic-Middle Jurassic continental arc and was part of the Arivechi-Cucurpe seaway; a narrow marine embayment oriented parallel to and located west of the Chihuahua trough. The Cucurpe Formation unconformably overlies Middle Jurassic arc assemblages and represents upward-coarsening marine prodeltaic deposits. New U-Pb zircon geochronology and a Kimmeridgian ammonite (Idoceras cf. I. densicostatum) constrain its age to between ca. 158 and 149 Ma. Detrital zircon ages from the unconformably overlying Lower Cretaceous Bisbee Group indicate a maximum depositional age of 139 +/- 2 Ma (2 sigma error), demonstrating a hiatus of at least 10 m.y. between Jurassic and Cretace
Filiaciones:
Gonzalez-Leon, C:
Univ Nacl Autonoma Mexico, Estn Reg Noroeste, Inst Geol, Hermosillo 83000, Sonora, Mexico
Iriondo, A:
Univ Nacl Autonoma Mexico, Ctr Geociencias, Mexico City 76230, DF, Mexico
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