T259 Evolution of Terrestrial Ecosystems: Community Assembly through Time (Posters)

Wednesday, 7 November 2018
9:00 AM - 6:30 PM
Halls J-K

UPDATES TO THE TAPHONOMY OF THE AARON SCOTT QUARRY (LATE JURASSIC, MORRISON FORMATION, UTAH)

Paper number: T259-14
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Abstract

The Aaron Scott Quarry (Brushy Basin Member, Morrison Formation, Jurassic) was the site of a lake margin with a delta forming along the eastern edge. A large, sustained lake such as this one is unknown from the Morrison Formation, which was deposited when the climate was fairly arid. Aquatic fauna such as crocodiles and turtles are abundant. The quarry consists of four bone layers within a calcite cemented unit approximately one foot thick, which overlies an olive gray shale. Three of the bone layers are rip-up clast conglomerates with disarticulated and broken bones that were deposited by fluvial transport onto a delta. Above the second rip up clast layer, an associated skeleton of a Barosaurus is preserved. The layers dip approximately 8 degrees to the southwest, greater than the regional dip of 5 degrees. The rip of clast layers indicate lowering of the lake level and fluvial transport. The sauropods died near the lake and were not transported, leaving the associated skeletons. The rip up clast layers show incision into the underlying layers. The deposition of these units represents a delta on a lake margin with fluctuating lake levels.

Geological Society of America Abstracts with Programs. Vol. 50, No. 6

doi: 10.1130/abs/2018AM-323785

© Copyright 2018 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.