Multiproxy approach reveals evidence of highly variable paleoprecipitation in the Upper Jurassic Morrison Formation (western United States)

2014 ◽  
Vol 126 (7-8) ◽  
pp. 1105-1116 ◽  
Author(s):  
T. S. Myers ◽  
N. J. Tabor ◽  
N. A. Rosenau
Keyword(s):  
United States ◽  
Upper Jurassic ◽  
Western United States ◽  
Morrison Formation ◽  
Multiproxy Approach

scholarly journals The neck of Barosaurus was not only longer but also wider than those of Diplodocus and other diplodocines

2013 ◽  
Author(s):  
Michael P Taylor ◽  
Mathew J Wedel
Keyword(s):  
United States ◽  
Cervical Vertebrae ◽  
Ground Level ◽  
Upper Jurassic ◽  
Western United States ◽  
Morrison Formation ◽  
Feeding Style ◽  
Functional Complex ◽  
Characteristic Features

Barosaurus is a diplodocid sauropod from the Upper Jurassic Morrison Formation of the western United States, and is known for its very long neck. It is related to the sympatric Diplodocus, and often thought of as more or less identical except with a longer neck. The holotype YPM 429 includes three and a half posterior cervical vertebrae, somewhat distorted and damaged, which are nevertheless very distinctive and quite different from those of Diplodocus. The cervicals of the better known and more complete referred Barosaurus specimen AMNH 6341 show the same characteristic features as the holotype, though not to the same extent: transversely broad but anteroposteriorly short zygapophyseal facets; prezygapophyses carried on broad, squared-off rami; zygapophyses shifted forward relative to the centrum; diapophyses, parapophyses and neural spines shifted backwards; and broad diapophyseal “wings”. These features form a single functional complex, enabling great lateral flexibility, but restricting vertical flexibility. This may indicate that Barosaurus used a different feeding style from other sauropods perhaps sweeping out long arcs at ground level. The Morrison Formation contains at least nine diplodocid species in six to eight genera whose relationships are not yet fully understood, but Barosaurus remains distinct from its relatives.

scholarly journals Sedimentology and Stratigraphy of the Morrison Formation in Dinosaur National Monument

1992 ◽  
Vol 16 ◽  
pp. 86-91
Author(s):  
Christine Turner ◽  
Fred Peterson
Keyword(s):  
United States ◽  
Colorado Plateau ◽  
Upper Jurassic ◽  
Western United States ◽  
Morrison Formation ◽  
National Monument ◽  
Dinosaur National Monument

The overall goal of this study is to establish a stratigraphic, sedimentologic, and geochronologic framework for the Upper Jurassic Morrison Formation within Dinosaur National Monument and to tie that framework to the rest of the Colorado Plateau and other important vertebrate fossil-bearing localities in the western United States. The study is also intended to complement ongoing paleontological inventories of the Morrison Formation within Dinosaur National Monument (DNM).

scholarly journals The neck of Barosaurus: longer, wider and weirder than those of Diplodocus and other diplodocines

2016 ◽  
Author(s):  
Michael P Taylor ◽  
Mathew J Wedel
Keyword(s):  
United States ◽  
Cervical Vertebrae ◽  
Ground Level ◽  
Upper Jurassic ◽  
Western United States ◽  
Morrison Formation ◽  
Feeding Style ◽  
Functional Complex ◽  
Characteristic Features

Barosaurus is a diplodocid sauropod from the Upper Jurassic Morrison Formation of the western United States, and is known for its very long neck. It is closely related to the sympatric Diplodocus, and often thought of as more or less identical except with a longer neck. The holotype YPM 429 includes three and a half posterior cervical vertebrae, somewhat distorted and damaged, which are nevertheless very distinctive and quite different from those of Diplodocus. The cervicals of the better known and more complete referred Barosaurus specimen AMNH 6341 show the same characteristic features as the holotype, though not to the same extent: transversely broad but anteroposteriorly short zygapophyseal facets; prezygapophyses carried on broad, squared-off rami; zygapophyses shifted forward relative to the centrum; diapophyses, parapophyses and neural spines shifted backwards; and broad diapophyseal “wings”. These features form a single functional complex, enabling great lateral flexibility, but restricting vertical flexibility. This may indicate that Barosaurus used a different feeding style from other sauropods perhaps sweeping out long arcs at ground level. The Morrison Formation contains at least nine diplodocid species in six to eight genera whose relationships are not yet fully understood, but Barosaurus remains distinct from its relatives.

scholarly journals The neck of Barosaurus: longer, wider and weirder than those of Diplodocus and other diplodocines

2016 ◽  
Author(s):  
Michael P Taylor ◽  
Mathew J Wedel
Keyword(s):  
United States ◽  
Cervical Vertebrae ◽  
Ground Level ◽  
Upper Jurassic ◽  
Western United States ◽  
Morrison Formation ◽  
Feeding Style ◽  
Functional Complex ◽  
Characteristic Features

Barosaurus is a diplodocid sauropod from the Upper Jurassic Morrison Formation of the western United States, and is known for its very long neck. It is closely related to the sympatric Diplodocus, and often thought of as more or less identical except with a longer neck. The holotype YPM 429 includes three and a half posterior cervical vertebrae, somewhat distorted and damaged, which are nevertheless very distinctive and quite different from those of Diplodocus. The cervicals of the better known and more complete referred Barosaurus specimen AMNH 6341 show the same characteristic features as the holotype, though not to the same extent: transversely broad but anteroposteriorly short zygapophyseal facets; prezygapophyses carried on broad, squared-off rami; zygapophyses shifted forward relative to the centrum; diapophyses, parapophyses and neural spines shifted backwards; and broad diapophyseal “wings”. These features form a single functional complex, enabling great lateral flexibility, but restricting vertical flexibility. This may indicate that Barosaurus used a different feeding style from other sauropods perhaps sweeping out long arcs at ground level. The Morrison Formation contains at least nine diplodocid species in six to eight genera whose relationships are not yet fully understood, but Barosaurus remains distinct from its relatives.

The promise of taphonomy as a nomothetic discipline: taphonomic bias in two dinosaur-bearing faunas in North America

2021 ◽  
pp. 1-18
Author(s):  
Connor T. Leach ◽  
Emma Hoffman ◽  
Peter Dodson
Keyword(s):  
Upper Cretaceous ◽  
Upper Jurassic ◽  
Western United States ◽  
Morrison Formation ◽  
Faunal Assemblages ◽  
Hell Creek Formation ◽  
The World ◽  
Fossil Preservation ◽  
Dinosaur Fossil ◽  
Dinosaur Park Formation

The fossil record of dinosaurs is a rich, if biased, one with nearly complete skeletons, partial skeletons, and isolated parts found in diverse, well-studied faunal assemblages around the world. Among the recognized biases are the preferential preservation of large dinosaurs and the systematic underrepresentation of small dinosaurs. Such biases have been quantitatively described in the Upper Cretaceous (Campanian) Dinosaur Park Formation of Alberta, where large, nearly complete dinosaurs were found and described early in collecting history and small, very incomplete dinosaurs were found and described later. This pattern, apparently replicated in the Maastrichtian Hell Creek Formation of Montana, is so striking that it begs the question of whether this is a nomothetic principle for the preservation of dinosaur faunas elsewhere. We tested this hypothesis by analyzing the very well-studied dinosaur fauna of the Upper Jurassic (Kimmeridgian) Morrison Formation of the western United States. The Morrison Formation fails to show any correlation between body size and completeness, order of discovery, or order of description. Both large and small dinosaurs of the Morrison include highly complete as well as highly incomplete taxa, and both large and small dinosaurs were discovered and described early in collecting history as well as more recently. The differences in preservation between the Dinosaur Park Formation and the Morrison Formation are so striking that we posit a Dinosaur Park model of dinosaur fossil preservation and a Morrison model. Future study will show whether either or both represent durable nomothetic models for dinosaur fossil preservation.

scholarly journals The Morrison Formation Extinct Ecosystems Project

1996 ◽  
Vol 20 ◽  
pp. 20-27
Author(s):  
Christine Turner ◽  
Fred Peterson ◽  
D. Chure ◽  
T. Demko ◽  
G. Engelmann
Keyword(s):  
United States ◽  
Late Jurassic ◽  
The United States ◽  
Upper Jurassic ◽  
Morrison Formation

The Morrison Project is a multidisciplinary effort to interpret the ancient ecosystem that was present in the Western Interior of the United States during deposition of the Upper Jurassic Morrison Formation. The project began in June of 1994 and the first two years of research (1994-95, 1995-96) were devoted primarily to identifying problems and gathering information that would form the basis for later interpretations. Efforts during the final year (1996-97) were directed toward resolving remaining problems or conflicting findings and synthesizing the various research endeavors into a reconstruction of the Late Jurassic ecosystem.

Taphonomy and Paleoecology of the Dinosaur Beds of the Jurassic Morrison Formation

Paleobiology ◽  
1980 ◽  
Vol 6 (2) ◽  
pp. 208-232 ◽  
Author(s):  
Peter Dodson ◽  
A. K. Behrensmeyer ◽  
Robert T. Bakker ◽  
John S. McIntosh
Keyword(s):  
Large Scale ◽  
Upper Jurassic ◽  
Depositional Environments ◽  
Western United States ◽  
Morrison Formation ◽  
Complete Spectrum ◽  
Large Herbivores ◽  
Short Supply ◽  
Terrestrial Mammals ◽  
Aquatic Vertebrates

The Upper Jurassic Morrison Formation has yielded one of the richest dinosaur faunas of the world. Morrison sediments are distributed over more than a million square kilometers in the western United States and represent a mosaic of riverine, lacustrine and floodplain environments developed on a vast alluvial plain nourished by debris from the ancestral Rocky Mountains. Plant productivity must have been reasonably high to support abundant large-bodied herbivores, but the absence of coals, scarcity of small aquatic vertebrates, the abundance of oxidized sediments, and presence of calcretes lead us to believe that water was periodically in short supply. A strongly seasonal climate may have necessitated annual large-scale movements of large herbivores, accounting in part for their remarkably broad and uniform geographic distribution. Dinosaur diversity is lower in the Morrison than in the Late Cretaceous, and taphonomic alteration is higher. Massed accumulations of thousands of bones are characteristic of the Morrison. Morrison dinosaurs were not confined to specific depositional environments but were distributed across the complete spectrum of available habitats, from lakes to dry floodplains; this type of distribution is similar to that of large terrestrial mammals such as elephants and rhinos and is different from that of hippos and crocodiles. Common Morrison taxa were Camarasaurus, Apatosaurus, Diplodocus, Allosaurus and Stegosaurus; these genera probably constituted a true dinosaur community. Stegosaurus may have been partially segregated from the other genera, and Camptosaurus more strongly so. Camarasaurus and Diplodocus were gregarious, with juveniles and subadults of the former particularly common; Apatosaurus was less abundant and more solitary in its habits. Juveniles and subadults are known for a number of dinosaurs.

Taphonomy and Paleoecology of the Dinosaur Beds of the Jurassic Morrison Formation

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 208-232 ◽  
Author(s):  
Peter Dodson ◽  
A. K. Behrensmeyer ◽  
Robert T. Bakker ◽  
John S. McIntosh
Keyword(s):  
Large Scale ◽  
Upper Jurassic ◽  
Depositional Environments ◽  
Western United States ◽  
Morrison Formation ◽  
Complete Spectrum ◽  
Large Herbivores ◽  
Short Supply ◽  
Terrestrial Mammals ◽  
Aquatic Vertebrates

The Upper Jurassic Morrison Formation has yielded one of the richest dinosaur faunas of the world. Morrison sediments are distributed over more than a million square kilometers in the western United States and represent a mosaic of riverine, lacustrine and floodplain environments developed on a vast alluvial plain nourished by debris from the ancestral Rocky Mountains. Plant productivity must have been reasonably high to support abundant large-bodied herbivores, but the absence of coals, scarcity of small aquatic vertebrates, the abundance of oxidized sediments, and presence of calcretes lead us to believe that water was periodically in short supply. A strongly seasonal climate may have necessitated annual large-scale movements of large herbivores, accounting in part for their remarkably broad and uniform geographic distribution. Dinosaur diversity is lower in the Morrison than in the Late Cretaceous, and taphonomic alteration is higher. Massed accumulations of thousands of bones are characteristic of the Morrison. Morrison dinosaurs were not confined to specific depositional environments but were distributed across the complete spectrum of available habitats, from lakes to dry floodplains; this type of distribution is similar to that of large terrestrial mammals such as elephants and rhinos and is different from that of hippos and crocodiles. Common Morrison taxa wereCamarasaurus, Apatosaurus, Diplodocus, AllosaurusandStegosaurus;these genera probably constituted a true dinosaur community.Stegosaurusmay have been partially segregated from the other genera, andCamptosaurusmore strongly so.CamarasaurusandDiplodocuswere gregarious, with juveniles and subadults of the former particularly common;Apatosauruswas less abundant and more solitary in its habits. Juveniles and subadults are known for a number of dinosaurs.

Writing Time in Metaphors

2018 ◽  
Author(s):  
Jennifer J. Smith
Keyword(s):  
United States ◽  
The United States ◽  
Western United States ◽  
Entire System ◽  
Language And Culture ◽  
Space Race ◽  
Do So

Coherence of place often exists alongside irregularities in time in cycles, and chapter three turns to cycles linked by temporal markers. Ray Bradbury’s The Martian Chronicles (1950) follows a linear chronology and describes the exploration, conquest, and repopulation of Mars by humans. Conversely, Louise Erdrich’s Love Medicine (1984) jumps back and forth across time to narrate the lives of interconnected families in the western United States. Bradbury’s cycle invokes a confluence of historical forces—time as value-laden, work as a calling, and travel as necessitating standardized time—and contextualizes them in relation to anxieties about the space race. Erdrich’s cycle invokes broader, oppositional conceptions of time—as recursive and arbitrary and as causal and meaningful—to depict time as implicated in an entire system of measurement that made possible the destruction and exploitation of the Chippewa people. Both volumes understand the United States to be preoccupied with imperialist impulses. Even as they critique such projects, they also point to the tenacity with which individuals encounter these systems, and they do so by creating “interstitial temporalities,” which allow them to navigate time at the crossroads of language and culture.

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