2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM

Paper No. 17
Presentation Time: 8:00 AM-6:00 PM

Paleoenvironmental Settings and Characteristics of Early Cretaceous Dinosaur Footprints of San Juan Raya, Southern Mexico

VERDE-RAMÍREZ, Angeles1, SILVA-ROMO, Gilberto2 and MENDOZA-ROSALES, Claudia C.2, (1)Instituto de Geología, UNAM, Avenida Universidad # 3000, Ciudad Universitaria, Mexico City, 04510, Mexico, (2)Facultad de Ingeniería, UNAM, Avenida Universidad # 3000, Ciudad Universitaria, Mexico City, 04510, Mexico, angelesverde@gmail.com

Recently discovered footprints (2006) in Barremian Lower- Aptian strata of San Juan Raya Formation in Puebla State, Southern Mexico provide the evidence of groups of dinosaurs in the area. In this locality, the inhabitants have found only prints; preliminary studies suggest a prevalence of Sauropods and Ornithopods ichnites. The UTM coordinates of the site are 14QPR4625520790. The 54 footprints are preserved in 4 track ways: 1) 27 footprints, rounded and elongated in shape which ranging 34 - 56 cm long and 29 - 58 cm wide; 2) 13 ichnites, less preserved than the others, which ranging 34 - 53 cm long and 43 – 20 cm wide; 3) 9 well preserved footprints that average 40 cm long and 39 cm wide and 4) 3 ichnites which average 40 cm long and 37 cm wide; these two last tracks present the common tridactyl morphology of ornithopod ichnites. The sauropod and ornithopod prints are in different beeding planes. The succession where dinosaur footprints have been found has been interpreted as a peritidal environment. We analyzed a 10 meters thick sequence of interbedded siliciclastic rocks that include paleontological evidence of several species of ostreids and gastropods. These rocks are sandstones and mudstones that present cross bedding, ripples and ophiomorpha ichnofossils in some levels. Mudstone strata are thicker than sandstones and they present biostroms of benthic organisms. This investigation contributes with San Juan Raya people in their eco-tourist project.