GSM 2017 Nebraska Day 2
Sep 5, 2017Public
Photo: At Ashfall Fossil Beds is this 3D map of Nebraska, which I will use in subsequent albums to show where we are each day. As shown, Ashfall is in the north center part of the state.
Photo: I have zoomed in here to show Niobrara State Park, where some of us camped the previous night, and which is illustrated in the Day 1 album. The red line is the SD-NE border.
Photo: The visitor center features some fossils of the smaller animals found on the site. The Ashfall Fossil Beds are rare fossil site types called lagerstätten that, due to extraordinary local conditions, capture a moment in time ecological "snapshot" in a range of well-preserved fossilized organisms. Ash from a Yellowstone hotspot eruption 10-12 million years ago created these fossilized bone beds.
Photo: The Ashfall Fossil Beds are especially famous for fossils of mammals from the middle Miocene geologic epoch. The Ashfall Fossil Beds are stratigraphically part of the Serravallian-age Ogallala Group. (See next photo to read text.)
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Photo: Plesiosaurus is a genus of extinct, large marine sauropterygian reptile that lived during the early part of the Jurassic Period. It is distinguishable by its small head, long and slender neck, broad turtle-like body, a short tail, and two pairs of large, elongated paddles. (See next photo to read text.)
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Photo: (See next photos for specimens.)
Photo: (Fossil on left; reconstructed model on right.)
Photo: (Fossil on bottom; reconstructed model on top.)
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Photo: Two barrel-bodied rhino bulls battling it out.
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Photo: All fossils have already been removed from this portion of the site.
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Photo: The remains of Teleoceras (extinct hippo-like relatives of rhinos) are so numerous and concentrated that the main section of Ashfall is called the "Rhino Barn". Other fossils at the "Rhino Barn" include the remains of horses and camels. The "barn" was built to protect the fragile fossils from the weather so they could remain in the locations in which they were found.
Photo: This is a cross section of the actual site. (See next photo to read the smaller test.)
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Photo: I asked a student volunteer if speaking to the public left them little time to excavate the fossils. He said their primary job is to explain the site to the public. They only excavate when no one is there to speak to. Excavation is not that urgent because these fossils are well protected and are the same species as ones already excavated. (Excuse the blurry photo.)
Photo: Teleoceras is an extinct genus of grazing rhinoceros. It lived in North America and southwestern France during the Miocene epoch, which ended about 5.3 million years ago, through the early Pliocene epoch. Teleoceras had much shorter legs than modern rhinos, and a barrel chest, making its build more like that of a hippopotamus than a modern rhino. Like the hippo, it was probably also semi-aquatic. Teleoceras had a single small nasal horn. It was a quite heavy animal, reaching 1.81 tons in weight
Photo: A stunning fossil was found in the 2016 season. Ashfall Fossil Beds summer intern Mikayla Struble (Montana State University) was conducting work in the Hubbard Rhino Barn when she uncovered the skull of a three-toed horse skeleton identified as Pseudhipparion gratum.
Photo: “There was a very good chance that this was not a skeleton - just an isolated skull, but the excavation has progressed to where it is apparent that it is a quite complete skeleton” said Rick Otto, Park Superintendent. Not much bigger than a large dog, Pseudhipparion is the smallest of the Ashfall horses. It is also the most abundant with remains of more than 50 individuals, from newborns to old adults, that have been excavated at the site to date.
Photo: Rhino skeleton. The Ashfall deposit preserves the fossilized remains of ancient animals that perished in a dense volcanic ash fall which occurred during the late Miocene, approximately 12 million years ago; the animals had come to a waterhole seeking relief.