Advances on Stratigraphy and Paleontology of the Muhi Quarry from the Mid-Cretaceous (Albian-Cenomanian) of Hidalgo, Central Mexico

Resumen

The Muhi quarry of
Zimapán Hidalgo, Central México, is one of the most important
Cretaceous fish localities of the country because of the great
diversity of fishes, and the significance of their record in
America. Here we present some advances of the stratigraphy,
including a litostratigraphic description, a generalized report of
the marine fauna recovered, and the depositional environment of the
outcrop. The sequence consists of a light gray mudstone/biomicrite,
with chert forming nodules and/or thin layers, and additional marls
are intercalated; the strata are assigned to La Negra Facies of the
Mid-Cretaceous (Albian-Cenomanian) El Doctor Formation from
northeastern Querétaro, south-central and northwestern Hidalgo (this
report). The lithology and fossils are indicative of open sea shelf
to deep shelf margin Standard Facies Zones, comparable to the
Standard Microfacies Types SMF 2 (microbioclastic limestone) and SMF
3 (pelagic mudstone).