Dinosaurs, the age of the Fruitland and Kirtland Formations, and the Cretaceous-Tertiary boundary in the San Juan Basin, New Mexico

Lucas, Spencer G.; Mateer, Niall J.; Hunt, Adrian P.; O’Neill, F. Michael

doi:10.1130/spe209-p35

Cited by 31 publications

(23 citation statements)

References 11 publications

(31 reference statements)

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“…Upper Triassic strata of the Dockum Basin are exposed along the eastern escarpment of the Southern High Plains in the Texas Panhandle, and continue along the western escarpment and the Pecos River Valley in eastern New Mexico. Researchers from New Mexico (e.g., Lucas & Hunt 1989; Lucas et al 1994, 2001) and Texas (Lehman 1994a, b; Lehman & Chatterjee 2005; Martz 2008) advocate two competing stratigraphic schemes. We note that this debate is largely about priority and nomenclature, and both stratigraphic schemes agree that the units relevant here, the upper portion of the Cooper Canyon Formation in Texas and the Bull Canyon Formation in New Mexico, are equivalents in time.…”

Section: Geological Setting Of the Patricia Site (Locality Number Ttumentioning

confidence: 99%

Cranial anatomy of the Late Triassic phytosaurMachaeroprosopus, with the description of a new species from West Texas

Hungerbühler¹,

Mueller

Chatterjee

et al. 2012

Earth and Environmental Science Transactions of the Royal Socie

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The skull anatomy of a new species of the phytosaur Machaeroprosopus is described for the first time on the basis of two specimens from the Upper Triassic Cooper Canyon Formation of Texas. Additional information is provided by a third specimen referred to Machaeroprosopus sp. A paranasal bone, an additional paired element of the narial region, is identified. Important new data are presented for the braincase, including the morphology of the epipterygoid and presphenoid, an anterior process of the prootic, an anteroventral process of the laterosphenoid, and a parasphenoid process. Machaeroprosopus lottorum n. sp. is characterised by four apomorphies: a supratemporal fenestra closed on the skull roof with bevelled anterior rim, a comparatively short squamosal, a flat and rugose narial rim, and medially extended palatines that come close to form an ossified secondary palate. With respect to the supratemporal fenestra, the supraoccipital–parietal complex and several features of the squamosal, Machaeroprosopus lottorum n. sp. bridges the morphological gap between species previously referred to the genera Pseudopalatus and Redondasaurus. A parsimony analysis of known species of Machaeroprosopus supports the hypothesis that the development of the rostral crest in Machaeroprosopus is a sexually dimorphic feature, and questions the validity of the genus Redondasaurus. Consequently, Redondasaurus is here considered a junior synonym of Machaeroprosopus.

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Section: Geological Setting Of the Patricia Site (Locality Number Ttumentioning

confidence: 99%

Cranial anatomy of the Late Triassic phytosaurMachaeroprosopus, with the description of a new species from West Texas

Hungerbühler¹,

Mueller

Chatterjee

et al. 2012

Earth and Environmental Science Transactions of the Royal Socie

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“…7 and 13). Photographs of other Ojo Alamo specimens are in Lucas et al (1987), as follows: Albertosaurus and Tyranosaurus (Fig. 3), Alamosaurus sanjuanensis (Fig.…”

Section: Barrel Spring Sitementioning

confidence: 99%

Dinosaurs that did not die: Evidence for Paleocene dinosaurs in the Ojo Alamo Sandstone, San Juan Basin, New Mexico

Fassett¹,

Zielinski²,

Budahn³

2002

Catastrophic Events and Mass Extinctions: Impacts and Beyond

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Palynologic and paleomagnetic data confirm a Paleocene age for the Ojo Alamo Sandstone (and its contained dinosaurs) throughout the San Juan Basin of New Mexico. The recently reported discovery of 34 skeletal elements from a single hadrosaur in the Ojo Alamo provides unequivocal evidence that these bones were not reworked from underlying Cretaceous strata. Geochemical studies of samples from several single-dinosaur-bone specimens from the Paleocene Ojo Alamo Sandstone and the underlying Late Cretaceous (Campanian) Kirtland Formation show that mineralized bones from these two rock units contain distinctly different abundances of uranium and rare-earth elements and demonstrate that Cretaceous and Paleocene bones were mineralized at different times when mineralizing fluids had distinctly different chemical compositions. These findings indicate that the dinosaur bone from the Paleocene Ojo Alamo is indigenous and not reworked.These data show that a relatively diverse assemblage of dinosaurs survived the end-Cretaceous asteroid-impact extinction event of 65.5 Ma. The San Juan Basin's Paleocene dinosaur fauna is herein named the Alamoan fauna. Magnetic-polarity chronology shows that these survivors lived for about one million years into the Paleocene and then became extinct around 64.5 Ma. We suggest that a plausible survival mechanism for this Lazarus fauna may have been the large numbers of buried dinosaur eggs, laid just before the asteroid impact occurred. These buried eggs would have provided a safe haven for developing dinosaur embryos for the first one to two years after the impact, thereby making it possible for them to survive the worst of the impact's early devastation.

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“…1987; Bajpai and Prasad 2000), and the Nanxiong basin in China (Sloan 1987;Rigby et al 1993;Buck et al 1994;Stets et al 1996). Later, workers in Montana, New Mexico, Bolivia, and India refuted the notion of Paleocene dinosaurs by documenting evidence of reworking of Cretaceous fossils during the Paleocene (Retallack et al 1986;Lucas et al 1987;Eaton et al 1989;Cappetta 1990;Lofgren et al 1990;Courtillot et al 2000). However, to date, no one has presented evidence refuting the presence of Tertiary dinosaurs in the Nanxiong basin.…”

Section: Introductionmentioning

confidence: 99%

“Tertiary Dinosaurs” in the Nanxiong Basin, Southern China, Are Reworked from the Cretaceous

Buck¹,

Hanson²,

Hengst³

et al. 2004

The Journal of Geology

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The Nanxiong and Shanghu Formations of southeastern China span the KT boundary interval and preserve an important paleontological record. A 1285-m section across the KT boundary was measured, and lithological units were documented and sampled. Strata were deposited in alluvial fan/playa mudflat environments in a highly seasonal, semiarid climate. Previous workers placed the KT boundary at the Nanxiong/Shanghu formational contact. The uppermost Nanxiong and lowermost Shanghu Formations contain an assemblage of dinosaur egg fragments and Tertiary fossils, which led to the notion that dinosaurs survived into the Paleocene. On the basis of our results, we argue that the mixed KT assemblage is a result of debris flows reworking Cretaceous fossils. Depositional environments and paleoclimate did not change significantly across the KT boundary.

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Dinosaurs, the age of the Fruitland and Kirtland Formations, and the Cretaceous-Tertiary boundary in the San Juan Basin, New Mexico

Abstract: Dinosaurs from the Upper Cretaceous Fruitland Formation and Kirtland Shale in the San Juan Basin, NewMexico, pertain to the following taxa: Ornithomimidae, cf.

Cited by 31 publications

References 11 publications

Cranial anatomy of the Late Triassic phytosaurMachaeroprosopus, with the description of a new species from West Texas

Cranial anatomy of the Late Triassic phytosaurMachaeroprosopus, with the description of a new species from West Texas

Dinosaurs that did not die: Evidence for Paleocene dinosaurs in the Ojo Alamo Sandstone, San Juan Basin, New Mexico

“Tertiary Dinosaurs” in the Nanxiong Basin, Southern China, Are Reworked from the Cretaceous

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