Lithofacies relations and palaeoecology of a Late Jurassic to Early Cretaceous fan delta to shelf depositional system in the Sierra Madre Oriental of north‐east Mexico

Abstract

The La Casita Formation in north‐eastern Mexico represents a period of increased terrigenous clastic supply that is characteristic for the entire northern and western margins of the Gulf of Mexico Basin during latest Jurassic and earliest Cretaceous time. A prograding delta complex developed at the south‐eastern margin of the Coahuila Peninsula. Delta plain, delta front, prodelta and shelf areas show distinct lithofacies associations. Some of the most characteristic elements are fining upward and coarsening upward grain size trends, syndepositional deformational features, storm layers, phosphorites, fossiliferous carbonate concretions and an anaerobic biofacies. A possible break in sedimentation is inferred for parts of the Valanginian. This may be interpreted as a sequence boundary between second order cycles. The Kimmeridgian ‐ Berriasian cycle appears to correlate with the Cotton Valley cycle of the Texas Gulf Coast.

The bivalve Anopaea (Inoceramidae) from the Upper Jurassic–lowermost Cretaceous of Mexico

“…This interpretation coincides with facies interpretations of the La Caja and La Pimienta formations, which are considered to represent hemipelagic depositional environments (e.g., Michalzik, 1988;Michalzik and Schumann, 1994;Adatte et al, 1994;Goldhammer and Johnson, 2001). In the Southern Hemisphere, the occurrence of Anopaea is linked to deepwater facies associated with the circum-Pacific volcanic arcs, along with buchiids, M A N U S C R I P T…”

“…The latter were likely the result of upwelling of nutrient-rich cold bottom waters (Michalzik, 1988;Michalzik and Schumann, 1994;Zell et al, 2014b). The presence of Anopaea in the La Caja and La Pimienta formations therefore supports the occurrence of cold bottom-water intervals in the subtropical Gulf of Mexico region.…”

Mollusks of the Upper Jurassic (upper Oxfordian-lower Kimmeridgian) shallow marine Minas Viejas Formation, northeastern Mexico

“…During the early Kimmeridgian, a fan delta system developed along the northern and northeastern margins of the Central Mexican Basin and led to a region-wide deposition of sandstones, shales and marls of the lower Kimmeridgian to lowermost Berriasian La Casita Formation (e.g., Michalzik, 1988;Michalzik and Schumann, 1994;Adatte et al, 1994;Eguiluz de Antuñano, 2001;Cross, 2012).…”

“…The upper part of the Minas Viejas succession at this locality was later considered to be a lateral time-equivalent of the Zuloaga and La Gloria formations by Longoria (1984), G€ otte (1990), Michalzik and Schumann (1994) and Vega and Lawton (2011). Stratigraphic relationships with the Olvido Gypsum with an unnamed anhydrite unit located in the state of Tamaulipas, as well as with approximately coeval evaporitic strata in the subsurface of eastern Mexico remain unclear to date (Longoria, 1984;G€ otte, 1990).…”

“…The Minas Viejas Formation underlies the Zuloaga Formation with a gradual contact. The latter is represented by shallow water carbonates and was considered to be of middle or late Oxfordian to early Kimmeridgian age by Ovanki (1974), Michalzik and Schumann (1994) and Ol oriz et al (2003).…”