High-precision U-Pb zircon geochronology of the Late Triassic Chinle Formation, Petrified Forest National Park (Arizona, USA): Temporal constraints on the early evolution of dinosaurs

Ramezani, Jahandar; Hoke, G. D.; Fastovsky, David E.; Bowring, Samuel A.; Therrien, François; Dworkin, Steven I.; Atchley, Stacy C.; Nordt, Lee C.

doi:10.1130/b30433.1

Cited by 171 publications

(210 citation statements)

References 56 publications

Supporting

Mentioning

195

Contrasting

Order By: Relevance

“…Zircon grains were isolated from bulk rock by standard crushing, pulverizing, magnetic, and high-density liquid separation techniques. All U-Pb analyses were made on carefully selected, single zircon crystals that were pretreated by a chemical-abrasion technique modified after Mattinson (2005) and analyzed following the procedures described in Ramezani et al (2011). Chemical abrasion involved leaching in 29 M HF at 210 °C for 11.5 to 12 h. This intensive leach schedule often caused extensive disintegration (or near-complete dissolution) of zircons, but it was deemed necessary in order to fully mitigate the effects of Pb loss due to accumulated radiation damage in ca.…”

Section: Geochronology Methodsmentioning

confidence: 99%

The end of Midcontinent Rift magmatism and the paleogeography of Laurentia

et al. 2017

View full text Add to dashboard Cite

Paleomagnetism of the North American Midcontinent Rift provides a robust paleogeographic record of Laurentia (cratonic North America) from ca. 1110 to 1070 Ma, revealing rapid equatorward motion of the continent throughout rift magmatism. Existing age and paleomagnetic constraints on the youngest rift volcanic and sedimentary rocks have been interpreted to record a slowdown of this motion as rifting waned. We present new paleomagnetic and geochronologic data from the ca. 1090-1083 Ma "late-stage" rift volcanic rocks exposed as the Lake Shore Traps (Michigan), the Schroeder-Lutsen basalts (Minnesota), and the Michipicoten Island

show abstract

Section: Geochronology Methodsmentioning

confidence: 99%

The end of Midcontinent Rift magmatism and the paleogeography of Laurentia

et al. 2017

View full text Add to dashboard Cite

show abstract

“…The quarry is situated at the top of the Painted Desert Sandstone #4 (Parker and Martz, 2011),~30 m below the Black Forest Bed of the Petrified Forest Member. The Black Forest Bed is a sandstone unit dominated by reworked tuffaceous material (Ash, 1992) and has provided a U/Pb date (sample BFB) of 209.926 ± 0.072 Ma from detrital zircons (Ramezani et al, 2011). This provides a minimum age for the quarry.…”

Section: Introductionmentioning

confidence: 99%

A juvenile Koskinonodon perfectus (Temnospondyli, Metoposauridae) from the Upper Triassic of Arizona and its implications for the taxonomy of North American metoposaurids

Gee

Parker²

2017

J. Paleontol.

View full text Add to dashboard Cite

Abstract.-Metoposaurids are temnospondyl amphibians that are well known from Upper Triassic deposits in North America, Europe, India, and Africa. Two species of metoposaurids, Koskinonodon perfectus and Apachesaurus gregorii, are among the most common fossils found in the Petrified Forest National Park (PEFO) of the southwestern United States. The two are distinguished on the basis of several cranial traits and the morphology of their intercentra, and are more informally distinguished by their overall size and biostratigraphic range. While material of adult metoposaurids is extremely common in Upper Triassic deposits, described material of juveniles is very rare, which limits the study of ontogenetic trajectories that would assist in assessing whether diagnostic traits of the smaller A. gregorii are also ontogenetically influenced traits in juveniles of K. perfectus. Here we report on material from a juvenile specimen of K. perfectus from the Petrified Forest Member (Norian) of the Chinle Formation in the PEFO. This specimen is significant because it represents the highest known occurrence of the species within the PEFO, documents a rare occurrence of a juvenile specimen of a North American metoposaurid, and records a rare North American metoposaurid specimen that includes associated cranial and postcranial material. Additionally, the combination of cranial features diagnostic of K. perfectus and intercentra of proportions intermediate between K. perfectus and A. gregorii in this specimen raises questions about the utility of several characters for species discrimination in North American metoposaurids.

show abstract

“…Six single zircons were selected based on grain morphology using a binocular microscope and analysed by the U -Pb isotope dilution thermal-ionization mass spectrometry (ID-TIMS) technique following the detailed procedures described in Ramezani et al [29] and used in Rubidge et al [27]. All zircons were pre-treated by a chemical abrasion (CA-TIMS) method modified after Mattinson [30] to mitigate the effects of radiation-induced Pb loss, and spiked with the EARTHTIME ET535 mixed 205 Pb -233 U-235 U tracer prior to dissolution and analysis.…”

Section: (C) U-pb Geochronologymentioning

confidence: 99%

When and how did the terrestrial mid-Permian mass extinction occur? Evidence from the tetrapod record of the Karoo Basin, South Africa

et al. 2015

View full text Add to dashboard Cite

A mid-Permian (Guadalupian epoch) extinction event at approximately 260 Ma has been mooted for two decades. This is based primarily on invertebrate biostratigraphy of Guadalupian -Lopingian marine carbonate platforms in southern China, which are temporally constrained by correlation to the associated Emeishan Large Igneous Province (LIP). Despite attempts to identify a similar biodiversity crisis in the terrestrial realm, the low resolution of mid-Permian tetrapod biostratigraphy and a lack of robust geochronological constraints have until now hampered both the correlation and quantification of terrestrial extinctions. Here we present an extensive compilation of tetrapod-stratigraphic data analysed by the constrained optimization (CONOP) algorithm that reveals a significant extinction event among tetrapods within the lower Beaufort Group of the Karoo Basin, South Africa, in the latest Capitanian. Our fossil dataset reveals a 74 -80% loss of generic richness between the upper Tapinocephalus Assemblage Zone (AZ) and the mid-Pristerognathus AZ that is temporally constrained by a U-Pb zircon date (CA-TIMS method) of 260.259 + 0.081 Ma from a tuff near the top of the Tapinocephalus AZ. This strengthens the biochronology of the Permian Beaufort Group and supports the existence of a mid-Permian mass extinction event on land near the end of the Guadalupian. Our results permit a temporal association between the extinction of dinocephalian therapsids and the LIP volcanism at Emeishan, as well as the marine end-Guadalupian extinctions.

show abstract

High-precision U-Pb zircon geochronology of the Late Triassic Chinle Formation, Petrified Forest National Park (Arizona, USA): Temporal constraints on the early evolution of dinosaurs

Cited by 171 publications

References 56 publications

The end of Midcontinent Rift magmatism and the paleogeography of Laurentia

The end of Midcontinent Rift magmatism and the paleogeography of Laurentia

A juvenile Koskinonodon perfectus (Temnospondyli, Metoposauridae) from the Upper Triassic of Arizona and its implications for the taxonomy of North American metoposaurids

When and how did the terrestrial mid-Permian mass extinction occur? Evidence from the tetrapod record of the Karoo Basin, South Africa

Contact Info

Product

Resources

About