Deep beneath the opal fields of Lightning Ridge lies a treasure trove of prehistoric wonders: opalized fossils. These 100-million-year-old relics from the Early Cretaceous period offer a unique window into Australia's ancient past. It is here that the remains of dinosaurs and other prehistoric creatures have been preserved in stunning opal.
How do opalized fossils form?
Opalized fossils form when silica-rich solutions fill cavities left by decomposed organic matter.
This fossil opalization process can occur in two ways:
The silica solution fills an empty cavity, creating a mold of a fossil that preserves external features but lacks internal details.
Silica seeps into organic material before decomposition, replacing organic molecules and preserving fine internal structures.
Dinosaur fossils in opal
Lightning Ridge is the only significant dinosaur site in New South Wales, Australia. Fossils of sauropods, theropods, ornithopods, ornithomimosaurids and ankylosaurs have been found here as have gigantic marine and freshwater Plesiosaurs and rare pterosaur fossils. Dinosaur fossil bones include dinosaur teeth, limb bones, back bones, toe bones, claws and fragments of rib, pelvis and shoulders. Some opal mines in the area contain dinosaur footprints preserved in the roof.
Check out the Australian Museum website to see 3D models of opalized Pliosaur limb bones and vertebrae from Lightning Ridge.
The rare and unique fossils of Lightning Ridge
Some of Australia’s very few Mesozoic mammals which lived in the time of the dinosaurs have been found at Lightning Ridge. One of the most significant discoveries was the jaw of a platypus-like monotreme mammal named Steropodon.
The world's oldest horned turtle and the upper jaw of the oldest known frog fossil in Australia have been found in Lightning Ridge.
Other animals preserved in opal include three species of crocodiles and lungfish, freshwater bony fish, mollusks and crayfish and early bird fossils.
There is a diverse array of fossilized fauna from the area including pine cones, seeds, and stems from conifers, ferns and other plants.
The scientific value of opalized fossils
The opalized fossils of Lightning Ridge reveal a rich and diverse ecosystem that existed 100-million-years ago. At that time, Australia was closer to the South Pole and was undergoing a global greenhouse period. The fossils from Lightning Ridge provide crucial information about Australia's prehistoric flora and fauna, as well as insights into climate change and geological processes.
At the heart of this discovery is the Australian Opal Centre, home to the world's most diverse and scientifically significant collection of opalized fossils. This institution plays a crucial role in preserving and studying these unique specimens.
You can add to our scientific knowledge about Lightning Ridge’s opalized fossils by joining a fossil dig hosted by the Australian Opal Centre!
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