Pre-evaporite onshore Mesozoic stratigraphic succession, western Gulf rim of Mexico

Abstract

Triassic(?)–Middle Jurassic marine and continental successions in northeastern and east-central Mexico indicate contrasting pre-salt depositional histories, but similar sediment sources, along the western rim of the Gulf of Mexico. Continental strata of early–middle Mesozoic age (Late Triassic–Middle Jurassic) assigned to the Huizachal Group crop out in northeastern Mexico in the Huizachal uplift and nearby Valle de Huizachal in the western part of the state of Tamaulipas. These strata are included in the El Alamar and La Boca formations. La Joya Formation, a conglomerate composed mostly of clasts derived from underlying redbeds, unconformably overlies El Alamar Formation in the Huizachal uplift succession and is overlain in turn by thick evaporite and carbonate of the Minas Viejas Formation, which occupies the stratigraphic position of, but is in part younger than, the Louann Salt in the Gulf of Mexico. La Joya Formation overlies La Boca Formation, a thick succession of red fluvial and volcanic strata, at Valle de Huizachal. The pre-evaporite Mesozoic section consists entirely of fluvial deposits composed of upward-fining successions as much as 10 m thick interbedded with thick siltstone intervals deposited in floodplain settings; volcanic rocks are locally interbedded in the lower part of the La Boca Formation at Valle de Huizachal, but volcanic rocks are not part of the stratigraphic section in the Huizachal uplift, although mafic dikes cut the continental strata. Depositional age interpretations derived from detrital zircon young grain ages presented here indicate that the Louann and Campeche salt deposits are correlative with some part of the Cahuasas Formation redbeds.

AAPG Datapages/Search and Discovery Article #90369 © 2020 AAPG Hedberg Conference, Geology and Hydrocarbon Potential of the Circum-Gulf of Mexico Pre-salt Section, Mexico City, Mexico, February 4-6, 2020