Article Search
Volume 27.1
January–April 2024
Full table of contents
ISSN: 1094-8074, web version;
1935-3952, print version
Recent Research Articles
See all articles in 27.1 January-April 2024
See all articles in 26.3 September-December 2023
See all articles in 26.2 May-August 2023
See all articles in 26.1 January-April 2023
Janet Bertog
Department of Physics and Geology
Northern Kentucky University
Highland Heights, Kentucky 41099
USA
bertogj@nku.edu
Janet Bertog began working at the South Dakota School of Mines Museum of Geology in Rapid City, South Dakota in 1990. She graduated with a bachelor of science in geology in 1995 and her master of science in paleontology in 1997 at the South Dakota School of Mines. She completed her PhD in geology at the University of Cincinnati in 2002. She has worked at Northern Kentucky University since 2003, where she has been working on the paleontology and taphonomy of the Aaron Scott Quarry.
David L. Jeffery
Department of Petroleum Engineering and Geology
Marietta College
Marietta, Ohio 45750
USA
jefferyd@marietta.edu
Dave Jeffery is currently an Associate Professor of Geology in the department of Petroleum Engineering and Geology at Marietta College in southeastern Ohio where he has been for the last ten years. His current interests include the stratigraphic and paleoecological aspects of Jurassic dinosaur deposits in Utah and Permian tetrapod trackways in Ohio. Before coming to Marietta, Dave worked for seven years as a petroleum geologist for ARCO/Vastar and then BP in Houston. He worked in both exploration and development, primarily in basins throught the US western states from North Dakota and down to west Texas. Dave earned his PhD from Texas A&M University working on paleoecological trends in Mississippian carbonate ramp and mudmound reef strata in the Sacramento Mountains of New Mexico. Prior to that, he completed his MS at Bowling Green State University working on taxonomy of Mississippian gastropods. During his graduate studies he worked summer jobs for national parks including Badlands in South Dakota and the Guadalupe mountains in West Texas.
Katherine Coode
Department of Physics and Geology
Northern Kentucky University
Highland Heights, Kentucky 41099
USA
katherin_coode@usgs.gov
Katherine Coode was an undergraduate student at Northern Kentucky University, graduating in 2010 with a double major in geology and geography and minors in physics and honors. She is currently working on her master of science degree in geospatial technology and groundwater hydrology at Bowling Green State University in Ohio.
William B. Hester
Department of Physics and Geology
Northern Kentucky University
Highland Heights, Kentucky 41099
USA
archromeo@yahoo.com
William Hester was an undergraduate student at Northern Kentucky University, graduating in 2009 with a major in anthropology. He is currently working on his Master of Arts in history.
Rath R. Robinson
Department of Physics and Geology
Northern Kentucky University
Highland Heights, Kentucky 41099
USA
RathR@aol.com
Rath Robinson was an undergraduate student at Northern Kentucky University, graduating in 2009. He completed a double major in geology and anthropology.
John Bishop
Department of Petroleum Engineering and Geology
Marietta College
Marietta, Ohio 45750
USA
jbishop187@aol.com
John Bishop has worked in the late Jurassic for the past 28 years mostly in the San Raphael swell in southern Utah. His specialty is in the taphonomy and taxonomy of the Morrison Formation.
FIGURE 1. General location of the Aaron Scott Site in Emery County, Utah (modified from the US Census Bureau, 2000)
FIGURE 2. General stratigraphy of the Morrison Formation in the vicinity of the Aaron Scott Site.
FIGURE 3. Sequence stratigraphy of the Aaron Scott Site, showing the position of the dinosaur bones and overlying Unio clams. Beds coarsen upward and measured sections tend to coarsen upward and westward as well. Erosional truncational surfaces are bold correlation lines while truncated and onlapping bedding are finer correlation lines.
FIGURE 4. Reconstruction of a circum-lacustrine environment combined from Alberdi et al. (2001) and Mancuso and Marsicano (2008) showing the position of the six taphofacies: A) swampy environment with periodic fluvial influence; B) swampy/lacustrine environment; C) delta plain; D) delta front; E) prodelta; and F) offshore lacustrine. The Aaron Scott Quarry is at position D. (Adapted from Mancuso and Marsicano, 2008).
FIGURE 5. Stratigraphic view of the Aaron Scott Site showing the vertical distribution of the bones in the quarry. The diplodocid bones tend to be slightly higher stratigraphically than other bones in the quarry.
FIGURE 6. Quarry map of the Barosaurus associated skeleton of the Aaron Scott Site showing distribution of the bones collected 2005-2012 in map view.
FIGURE 7. A distribution of the bones of the diplodocid based on FTI groups (Frison and Todd, 1986).
FIGURE 8. Rose diagram showing the orientation of the sauropod bones. A poor bimodal distribution is indicated, with one set of bones oriented to the west and a second set oriented northwest-southeast.
FIGURE 9. Ternary diagram showing the expected bones of a complete sauropod skeleton and the path of enrichment that bones would take if they were transported from their source compared to if they were enriched at the source. Bones of the sauropod indicate an enrichment in group 1 bones, suggesting a terminal transport deposition of the bones.
FIGURE 10. A distribution of the non-sauropod bones on Voorhie’s groups. The bones were plotted with and without the Allosaurus teeth because the abundance of Allosaurus teeth suggest that the Allosaurus was feeding on the sauropod and that the teeth were not transported into the area. Excluding the Allosaurus teeth, the bones show an enrichment of group 1 bones, suggesting a terminal transport deposition of these bones.
FIGURE 11. Rose diagram showing the orientation of the non-sauropod bones. The distribution of these bones shows very weak orientation, but does indicate a bimodal distribution with one set oriented to the west and a second set oriented northwest-southeast.
FIGURE 12. Histogram of bone weathering and abrasion for non-sauropod bones (sauropod bones had weathering of zero and are not included on this diagram). Weathering rank of 2 indicates flaking and cracking of the outer layer of the bone and is the most common in non-fragmented bones. Fragmented bones are ranked as a 5, indicating that the bones have broken apart and may have been rounded
FIGURE 13. Examples of weathering stages of bones at the Aaron Scott Quarry. 13.1) Dryosaurus vertebra (VP 8612) with weathering stage 2. Note that the neural arch was broken prior to burial. Scale bar equals 5 cm.
FIGURE 14. Fragments of bones (VP 8958) with weathering stage 5. Scale bar equals 5 cm.
FIGURE 15. Allosaurus metatarsal (VP 8628) with weathering stage 0. Scale bar equals 5cm.
FIGURE 16. Barosaurus caudal vertebra (A. S. S. 772) with weathering stage 0. Scale bar equals 5 cm.
TABLE 1. Comparison of taphofacies recognized in the Morrison Formation, including A) a site example, lithology, paleontology, weathering of the bones (where available), transportability of the bones (where available), and B) the fauna represented (available in PDF only).
TABLE 2.Summary of taphofacies recognized in circum-lacustrine environments including 1) swampy environments with episodic fluvial influence, 2) fluvial environments which were periodically covered by lacustrine deposits (fluvio-deltaic), and 3) a swampy/lacustrine environment.
TABLE 3. Voorhie’s groups for non-sauropod bones based on data from coyote skeletons (Voorhies, 1969) and Fluvial Transport Index Groups for sauropod bones based on elephant bones (Frison and Todd, 1986).
TABLE 4. Weathering and abrasion scale of bones.
TABLE 5. Faunal list of organisms at the Aaron Scott Quarry.
Bivalvia Linnaeus, 1758 | |||||||||
Unionoida Rafinesque, 1820 | |||||||||
Unionidae Rafinesque, 1820 | |||||||||
Reptilia Laurenti, 1768 | |||||||||
Testudines Batsch, 1788 | |||||||||
Cryptodira Cope, 1868 | |||||||||
Glyptopsidae Marsh, 1890 | |||||||||
Glyptops Marsh, 1890 | |||||||||
Glyptops cf. plicatulus | |||||||||
Sphenodontia Williston, 1925 | |||||||||
Sphenodontidae Cope, 1869 | |||||||||
Opisthias Marsh, 1890 | |||||||||
Opisthias rarus Gilmore, 1905 | |||||||||
Archosauria Cope, 1869 | |||||||||
Crocodyliformes Benton and Clark, 1988 | |||||||||
Goniopholididae Cope, 1875 | |||||||||
Indet. cf. Eutretauranosuchus sp. Mook, 1967 | |||||||||
Dinosauria Owen, 1842 | |||||||||
Saurischia Seeley, 1888 | |||||||||
Theropoda Marsh 1881 | |||||||||
Carnosauria Heune, 1920 | |||||||||
Allosauridae Marsh, 1879 | |||||||||
Allosaurus Marsh, 1877 | |||||||||
Allosaurus cf. fragilis Marsh, 1877 | |||||||||
Coelurusauria Huene, 1914 | |||||||||
Coeluridae Marsh, 1881 | |||||||||
Coelurus sp. Marsh, 1879 | |||||||||
Sauropoda Marsh, 1878 | |||||||||
Diplodocidae Marsh, 1884 | |||||||||
Barosaurus Marsh, 1890 | |||||||||
Apatosaurus March, 1877 | |||||||||
Camarasauridae Cope, 1877 | |||||||||
Camarosaurus Cope, 1877 | |||||||||
Ornithischia Seeley, 1888 | |||||||||
Ornithopoda Marsh, 1881 | |||||||||
Dryosauridae Milner & Norman, 1985 | |||||||||
Dryosaurus sp. Marsh, 1894 | |||||||||
Stegosauria Marsh, 1877 | |||||||||
Stegosauridae Marsh, 1880 | |||||||||
Stegosaurus sp. Marsh, 1877 | |||||||||
Mammalia Linnaeus, 1758 | |||||||||
Triconodonta Osborn, 1888 | |||||||||
TABLE 6. Comparison of the Aaron Scott Quarry to the Huescar-1 locality, interpreted to be a fluvio-deltaic depositional setting. Red text indicates areas where the different examples match.
Taphonomic patterns of a dinosaur accumulation in a lacustrine delta system in the Jurassic Morrison Formation, San Rafael Swell, Utah, USA
Plain Language Abstract
The Aaron Scott Quarry was deposited along the margin of a large lake. Remains of several dinosaurs and other animals accumulated on this delta over a period of time as a result of a prolonged drought. Animals congregated near the lake as other watering holes dried up.
Resumen en Español
text
Traducción: Enrique Peñalver
Résumé en Français
Motifs taphonomiques d'une accumulation de dinosaure dans un système de delta lacustre dans la Formation de Morrison du jurassique, San Rafael Swell, Utah, États-Unis
Le membre du bassin de Brushy de la Formation de Morrison du Jurassique supérieur est largement reconnue comme ayant accumulé dans un écosystème semi-aride de fleuves sinueux/ plaines inondables. Toutefois, dans le centre de l'Utah, la partie inférieure du membre du bassin de Brushy est interprété comme un lac d'eau douce, intérieur et fermé avec un delta formant sa marge est. La faune de la Carrière de Aaron Scott comprend de nombreux dinosaures ainsi que des taxons semi-aquatiques typiques comme des tortues et des crocodiles et offre une occasion unique d'étudier la taphonomie d'un cadre lacustre fluvio-deltaïque au Jurassique. Nous interprétons que pendant une période de sécheresse, de nombreux animaux se sont rassemblés sur le delta, pendant que d'autres points d'eau locaux se sont taris. Au fil du temps, leurs carcasses se sont accumulées, ont été brisées, abrasées et retravaillés par une variété d'agents biologiques et physiques avant le recouvrement final. L'alignement préférentiel des os fossiles suggère deux sens d'écoulement: le canal distributeur coule au large du delta et un courant induit par les vagues à 90 degrés du canal. Les os sont répartis en une couche d'environ 1 m d'épaisseur. Les os à la base sont très fragmentés et abrasés tandis que ceux plus élevés dans le lit appartiennent à un seul individu d'un sauropode diplodocidé. De nombreuses dents d'Allosaurus sont associées aux os du diplodocidé et peuvent avoir été perdu au cours de charognage répété par plusieurs Allosaurus.
Mots-clés: delta; lac; sauropode; dinosaure; taphonomie
Translator: Kenny J. Travouillon
Deutsche Zusammenfassung
Taphonomische Muster einer Dinosaurieransammlung im lakustrinen Deltasystem der jurassischen Morrison Formation, San Rafael Swell, Utah, USA
Es ist weithin anerkannt, dass das oberjurassische Brushy Basin Member der Morrison Formation in einem semi-ariden mäandrierenden Fluss/Flussauenökosystem entstand. Jedoch geht in Zentral-Utah die Interpretation dahin, dass das untere Brushy Basin Member ein umschlossener Frischwassersee im Inland mit einem Flussdelta an seinem östlichen Rand war. Die Aaron Scott Quarry Fauna beinhaltet viele Dinosaurier aber auch typische semi-aquatische Taxa wie Schildkröten und Krokodile und stellt eine einzigartige Gelegenheit dar, die Taphonomie eines fluvio-deltaischen Milieus im Jura zu untersuchen. Wir interpretieren, dass sich während einer Dürreperiode zahlreiche Tiere im Delta versammelten, während andere lokale Wasserlöcher austrockneten. Mit der Zeit sammelten sich die Körper an, zerbrachen, wurden erodiert und durch verschiedene Arten von biologischen und physikalischen Mitteln aufgearbeitet bevor sie endgültig begraben wurden. Die bevorzugte Ausrichtung der Knochen weist auf zwei Fließrichtungen hin: der Hauptarm der vom Delta abfließt und die welleninduzierte Strömung mit 90 Grad zum Kanal. Die Knochen sind in einer 1 Meter mächtigen Schicht verteilt. Die Knochen an der Basis sind in hohem Maße fragmentiert und erodiert, während die weiter oben liegenden zu einem Einzelindividuum eines diplodociden Sauropoden gehören. Mit den diplodociden Knochen sind zahlreiche Allosaurus-Zähne assoziiert, die durch wiederholtes Aasfressen mehrerer Allosaurus verloren wurden.
Schlüsselwörter: Delta; See; Sauropode; Dinosaurier; Taphonomie
Translator: Eva Gebauer
Arabic
Translator: Ashraf M.T. Elewa
-
-
-
Review: The Princeton Field Guide to Mesozoic Sea Reptiles
The Princeton Field Guide to Mesozoic Sea Reptiles
Article number: 26.1.1R
April 2023