1.7" Petrified Fern (Osmundacaulis) Trunk Slice - Tasmania

This unique specimen was part of the was part of the Ross Jones collection. He authored the stunning book "Lune River Fossil Fern Trunks of Tasmania"

This is a beautiful, thin slice of a fossil fern trunk of the species Osmundacaulis griggsii. It was collected from the Lune River in Tasmania and has been sliced thin and encapsulated in a polished clear epoxy. This presentation of the fossil allows for visualization of the fascinating internal cell structures of the fern's trunk, which can be viewed in more detail under magnification.

The age of these fern fossils were studied and debated for over four decades. Based on the basaltic volcanic deposits that surrounded the volcanic sandstone deposits from which these fossils were found, it was believed that these Lune River flora thrived through the early Cenozoic Era (65 to 1.8 million years ago) and could be dated no older than that. Around the 1980's, the interest of these fern fossils grew following donations of the material for further study.

Lack of information regarding the stratigraphy of the land resulted in studies of the ferns shifting to morphology comparison of fern fossils from other continents. These studies brought rise to the possibility that the fern fossils could have actually been much older and likely existed around the middle of the Mesozoic Era (roughly 145 million years ago). With this and a combination of isotopic measurements of zircons in the volcanic sandstone deposits that host the Lune River flora, it was concluded that the ferns/flora existed about 182 million years ago (early Jurassic in age).

Studies of very similar, Jurassic aged igneous rocks found in South Africa and Antarctica further confirmed the age of these fern fossils. During the time of these igneous rock formations, the super-continent Gondwana was beginning to separate. Australia, South Africa and Antarctica were all in the same general area, explaining why these similar igneous rocks were found on completely different portions of the earth.

Osmundacaulis griggsii
Lune River, Tasmania
1.7 x .85"
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