La Boca Formation

La Boca Formation
Stratigraphic range: Lower Pliensbachian-Latest Aalenian, 189–171 Ma [1][2]
TypeGeological formation
Unit ofHuizachal Group
Sub-units
  • Upper Part with Epiclastic Sedimentation
  • Lower Part with Pyroclastic sedimentation
UnderliesLa Joya Formation
OverliesHuizachal Formation
Thickness<10 m
Lithology
PrimaryRed sandstones, mudstones, and siltstones
OtherPyroclastic volcanic rocks
Location
RegionTamaulipas
Country Mexico

The La Boca Formation is a geological formation in Tamaulipas state, northeast Mexico. It was originally thought to date back to the Early Jurassic, concretely the Pliensbachian stage epoch of 193-184 Ma.[3] Later studies found that while the unit itself was likely deposited during the earliest Pliensbachian, as proven by zircon dating 189.0 ± 0.2 Ma, the local vulcanism (related to the aperture of the Atlantic Ocean and the several Rift Events) continued until the Bajocian.

However, the lower section of the fossil taxa deposited on the rocks above the La Boca Formation is likely of Late Pliensbachian-Lower Toarcian age, and the upper section of Late Toarcian-Late Aalenian age.[4]

Due to successions of Aalenian depositional systems on the upper layers of the Huizachal Canyon, has been delimited the formation to the Toarcian stage, being the regional equivalent of the Moroccan Azilal Formation.[2] Deposits of Late Triassic Age referred to this unit have been reclassified in a new formation, El Alamar Formation.[5] In North America, La Boca Formation was found to be a regional equivalent of the Eagle Mills redbeds of southern United States, the Todos Santos Formation of southern Mexico and the Barracas Group of the Sonora desert region.[6]

  1. ^ Rubio-Cisneros, I. I.; Lawton, T. F. (2011). "Detrital zircon U-Pb ages of sandstones in continental red beds at Valle de Huizachal, Tamaulipas, NE Mexico: Record of Early-Middle Jurassic arc volcanism and transition to crustal extension". Geosphere. 7 (1): 159–170. Bibcode:2011Geosp...7..159R. doi:10.1130/GES00567.1.
  2. ^ a b Martini, M.; Ortega-Gutiérrez, F. (2018). "Tectono-stratigraphic evolution of eastern Mexico during the break-up of Pangea: A review". Earth-Science Reviews. 183 (3): 38–55. Bibcode:2018ESRv..183...38M. doi:10.1016/j.earscirev.2016.06.013. S2CID 132691866. Retrieved 2 April 2022.
  3. ^ Bartolini, Claudio; Wilson, James Lee; Lawton, Timothy Frost (1999). Mesozoic Sedimentary and Tectonic History of North-central Mexico (2 ed.). Texas: Geological Society of America. p. 221. ISBN 9780813723402. Retrieved 2 April 2022.
  4. ^ Boschman, L.; Van Hinsbergen, D. J.; Langereis, C. G.; Molina-Garza, R. S.; Kimbrough, D. L. (2017). "Paleomagnetic Constraints on the Tectonic History of the Mesozoic Ophiolite and Arc Terranes of Western Mexico". AGU Fall Meeting Abstracts. 2 (2): 345. Bibcode:2017AGUFM.T22B..05B. Retrieved 2 April 2022.
  5. ^ Barboza-Gudiño, J. R; Zavala-Monsiváis, A.; Venegas-Rodríguez, G.; Barajas-Nigoche, L. D. (2010). "Late Triassic stratigraphy and facies from northeastern Mexico: Tectonic setting and provenance". Geosphere. 6 (5): 621–640. doi:10.1130/GES00545.1.
  6. ^ Mixon, R. B.; Murray, G. E.; Teodoro, D. G. (1959). "Age and Correlation of Huizachal Group (Mesozoic), State of Tamaulipas, Mexico". ADDENDUM. AAPG Bulletin. 43 (4): 757–771. Retrieved 2 April 2022.