paleo gallery
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Big Horn Basin RanchDIGSITE. Dinosaur bones were first discovered on the Big Horn Basin ranch when access roads were built through the hills and the lowland fields were plowed for crops. The major dinosaur deposits are in the hilly, “badland” type topography.

This topography, coupled with the steep gullies and rock exposures, allowed us to examine the vertical stratigraphy and begin to unravel the location of the major bone deposits.

Geologist Bob Simon's careful inspection of the dinosaur-bearing layers (Morrison Formation) soon revealed that the area is relatively typical of a Jurassic basinal setting.

My thanks to Bob Simon for the following scientific information on the digsite, the death zones and the digsite geology:

During MorrisonDuring the Morrison. The area of the digsite was a river system with significant river meanders, point bars, over-bank deposits and multiple flooding events. Evidence also suggests that these river systems may have dried up and/or shifted over time during more semi-arid conditions.

This tells us that a sequence of sedimentologic events over time created a very complex stratigraphic pattern in the Morrison-age strata. This had a direct impact on the preservation and placement of the Jurassic dinosaur bones and dinosaur skeletons, and why bones at the ground surface level are few and far between.

Bone bearing layers and death zonesDeath Zones & bone-bearing layers. Within the main quarry there have been at least 5 death zones established. These are distinct, vertical layers that differ in age and within which dinosaur remains are found. Some of the layers contain articulated (in living position), complete dinosaurs, while others contain a wide variety of mixed and jumbled-up bones from many species.

Learn more about the 5 Death Zones and the 15+ Jurassic species found at the digsite.