Team members at Everything Dinosaur review the Rebor Saurophaganax maximus “Notorious Big” dinosaur model in the “volcanic cavern” colour scheme. In total, three colour variants of this Late Jurassic apex predator have been introduced by Rebor in 2022, “Badlands” was highlighted in an earlier (March 2022), blog post: Rebor Saurophaganax “Badlands” . This week, we posted up more pictures of the “jungle” colour variant: Rebor Saurophaganax “Jungle” and today, we conclude by focusing on the stunning, crimson “volcanic cavern” Saurophaganax dinosaur model.

Rebor Saurophaganax in the "volcanic cavern" colour scheme.
The crimson coloured Rebor Saurophaganax maximus “Notorious Big” in the “volcanic cavern” colour scheme.

Volcanic Ash and the Brushy Basin Member

The name of this brightly coloured, 1:35 scale dinosaur model has links with volcanism. Naming a Saurophaganax model “volcanic cavern” is highly appropriate and we congratulate Rebor for their choice of moniker. The holotype material collected by J. W. Stovall in 1931 and 1932 comes from a site in Cimarron County, Oklahoma (OMNH Quarry 1). The sediments represent the Brushy Basin Member of the Morrison Formation, one of the youngest geological units associated with the famous, highly fossiliferous Morrison Formation.

The upper portions of the Brushy Basin Member are dominated by layers of weathered volcanic ash. Altered volcanic ash is particularly abundant in the Brushy Basin Member of the upper part of the Morrison Formation. In one 110-metre-thick section in eastern Utah, 35 separate beds of volcanic ash were deposited over a period of 2.2 million years.

Rebor Saurophaganax maximus "volcanic cavern".
Rebor Saurophaganax in the “volcanic cavern” colour scheme shown in anterior view.

A “Popcorn” Texture

A characteristic of the Brushy Basin Member is the amount of bentonite present. This is a form of weathered ash that has become mixed with fine clay. It is extremely absorbent and tends to swell up as it absorbs moisture giving the ground a bubbly appearance resembling popcorn.

During the Late Jurassic, subduction of the North American tectonic plate led to the creation of a line of volcanoes along the western margins of North America. Periodically, these volcanoes would erupt and eject huge volumes of ash into the atmosphere. The ash clouds would drift eastwards and blanket the land further inland. Saurophaganax lived during this time of volcanic activity and these reptiles would have witnessed the volcanism and suffered the consequences as a result of the periodic eruptions that took place far to the west.

Rebor Saurophaganax volcanic cavern colour scheme
The impressive Rebor Saurophaganax maximus dinosaur model in the “volcanic cavern” colour scheme. Fossils of this large theropod have been recovered from the Brushy Basin Member of the Morrison Formation. The upper sections of the Brushy Basin Member contain extensive layers of volcanic ash which once weathered form the clay material bentonite. Naming a model of Saurophaganax after volcanism is highly appropriate.

Dating the Strata from Zircons

These volcanic ash deposits yield, extremely resistant zircon crystals which can be used to precisely date the time of deposition by measuring the radiometric decay of isotopes within the igneous material (usually uranium to lead decay). Radiometric dating permits scientists to make an estimate of the age of the bedding planes and infer the age of the fossils that they contain. The presence of the weathered volcanic ash has assisted palaeontologists in working out the age of Brushy Basin component layers.

Rebor Saurophaganax "volcanic cavern".
Rebor Saurophaganax maximus in the “volcanic cavern” colour scheme shown in right lateral view.

To view the Rebor Saurophaganax maximus in the “volcanic cavern” colour scheme and the rest of the Rebor prehistoric animal figures: Rebor Dinosaur and Prehistoric Animal Models.

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