INTEGRATED APPROACH FOR CORRELATION OF UPPER JURASSIC (OXFORDIAN AND KIMMERIDGIAN) STRATA BETWEEN THE U.S. GULF COASTAL PLAIN AND WESTERN EUROPE

Correlation of Upper Jurassic strata from the U.S. Gulf Coastal Plain and Western Europe provides a temporal framework for examining the distribution of carbonate, evaporite, and siliciclastic deposits. Correlation has been achieved through the integration of biostratigraphy, chemostratigraphy, and sequence stratigraphy.

The Upper Jurassic strata of the U.S. Gulf Coastal Plain consist of sandstones of the Norphlet Formation, carbonates of the Smackover Formation and evaporites and siliciclastics of the Haynesville Formation. Smackover carbonates have been dated as Oxfordian based on the ammonite taxa Ochetoceras, Proscaphites, Dichotomosphinctes, Discosphinctes, Orthosphinctes, Idoceras, and Euaspidoceras, and ⁸⁷Sr/⁸⁶Sr values between 0.706934 and 0.707042 (normalized to 0.1194). Haynesville deposits have been dated as Kimmeridgian based on the occurrence of the ammonites, Idoceras cajaense Burchkardt and Idoceras zacatecanum Burckhardt.

The Upper Jurassic (Oxfordian and Kimmeridgian) of the Paris Basin (France) and the Lusitanian and Algarve Basins (Portugal) consist primarily of carbonates and marls. In the Paris Basin, the Oxfordian strata include the Terraine à Chailles, Calcaires à polypiers, and Calcaires de Creüe, and the Kimmeridgian strata include Oolite de Lamothe and Calcaires à astartes. In the Lusitanian Basin, the Oxfordian strata include the Montejunto, Abadia, and Montegordo beds. In the Algarve Basin, the Oxfordian and Kimmeridgian strata include the Peral and Jordana beds. These Western European units have been dated as Oxfordian and Kimmeridgian based on the occurrence of ammonites within the Plicatilis to Planulata zones, the dinoflagellate species G. jurassica, R. aemula, R. cladaphora, C. polonicum and spinose, and ⁸⁷Sr/⁸⁶Sr values between 0.706857 and 0.707233 (normalized to 0.1194).

Correlation of Upper Jurassic units indicates that deposition in Western Europe occurred in both open and restricted marine conditions. In the U.S. Gulf Coast, Late Jurassic deposition was dominated by shallow marine deposition in the Oxfordian, restricted marginal marine sedimentation in the early Kimmeridgian, and marginal marine to non-marine sedimentation in the late Kimmeridgian.