Type Geological formation Region North America Underlies Black Peaks Formation | Country United States, Texas Overlies Aguja Formation | |
The Javelina Formation is a geological formation in Texas. Dating has shown that the strata date to the Maastrichtian stage of the Late Cretaceous, approximately 70 to 66.5 million years old. The middle part of the formation has been dated to about 69 million years ago plus or minus 1 Ma and the top situated near the Cretaceous–Paleogene boundary (in the overlying Black Peaks Formation), dated to 66 Ma ago. Dinosaur remains are among the fossils that have been recovered from the formation.
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Age
The exact age range of the Javelina Formation has been difficult to determine. Only one geological site in the Javelina Formation has thus far yielded the correct rock types for radiometric dating. The outcrop, situated in the middle strata of the formation about 90 meters below the K-Pg boundary and within the local range of Alamosaurus fossils and below two sites that have yielded Quetzalcoatlus fossils, was dated to 69.0 plus or minus 0.9 million years old in 2010.
Vertebrate paleofauna
It also contains the rays Rhombodus and Dasyatis.