Ojo Alamo Formation
Encyclopedia
The Ojo Alamo Formation is a geologic formation spanning the Mesozoic
/Cenozoic
boundary. Dinosaur
remains are among the fossils that have been recovered from the formation, though all dinosaur remains come from the lowest part of the formation, the Naashoibito member (sometimes considered part of the Kirtland Formation
, which dates to the late Maastrichtian
stage of the Cretaceous period. Some researchers have claimed to find isolated non-avian dinosaur remains in younger parts of the formation dated to the Danian
stage of the Paleogene
period. If this is the case, it would represent the only known instance of a non-avian dinosaur population persisting after the K-Pg extinction event. However, most scientists consider these to have been stratigraphically misinterpreted or reworked from the Naashoibito member.
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
/Cenozoic
Cenozoic
The Cenozoic era is the current and most recent of the three Phanerozoic geological eras and covers the period from 65.5 mya to the present. The era began in the wake of the Cretaceous–Tertiary extinction event at the end of the Cretaceous that saw the demise of the last non-avian dinosaurs and...
boundary. Dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
remains are among the fossils that have been recovered from the formation, though all dinosaur remains come from the lowest part of the formation, the Naashoibito member (sometimes considered part of the Kirtland Formation
Kirtland Formation
The Kirtland Formation is a sedimentary geological formation. It is the product of alluvial muds and overbank sand deposits from the many channels draining the coastal plain that existed on the inland seashore of North America, in the late Cretaceous period. It overlies the Fruitland Formation...
, which dates to the late Maastrichtian
Maastrichtian
The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...
stage of the Cretaceous period. Some researchers have claimed to find isolated non-avian dinosaur remains in younger parts of the formation dated to the Danian
Danian
The Danian is the oldest age or lowermost stage of the Paleocene epoch or series, the Paleogene period or system and the Cenozoic era or erathem. The beginning of the Danian age is at the Cretaceous-Tertiary extinction event...
stage of the Paleogene
Paleogene
The Paleogene is a geologic period and system that began 65.5 ± 0.3 and ended 23.03 ± 0.05 million years ago and comprises the first part of the Cenozoic Era...
period. If this is the case, it would represent the only known instance of a non-avian dinosaur population persisting after the K-Pg extinction event. However, most scientists consider these to have been stratigraphically misinterpreted or reworked from the Naashoibito member.