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THE JURASSIC‐CRETACEOUS BOUNDARY IN THE SUBSURFACE OF EASTERN MEXICO
Author(s) -
Chapa A. Cantú
Publication year - 1982
Publication title -
journal of petroleum geology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.725
H-Index - 42
eISSN - 1747-5457
pISSN - 0141-6421
DOI - 10.1111/j.1747-5457.1982.tb00542.x
Subject(s) - ammonite , geology , cretaceous , paleontology , subdivision , boundary (topology) , geography , archaeology , mathematical analysis , mathematics
The continuous appearance of certain ammonite genera in the cores of some wells were helpful in identifying the Jurassic‐Cretaceous boundary in the subsurface of eastern Mexico. These genera belong to the families Haploceratidae, Berriasellidae, and Protancyloceratinae. The studied wells are located in a large region of the eastern Gulf Coastal Plain of Mexico, the length of which is roughly 1,500 km. Radioactivity well logging made it possible to locate the exact stratigraphic position of the ammonites in the different wells studied. As a result, it was possible to do both local and regional correlations of the upper beds of the Jurassic. As a result of the present study, the biostratigraphic subdivision of the upper Tithonian of Mexico can be given as follows: — a zone of Salinites and Parodontoceras at the top; and — a zone of Suarites at the base.