Search the Community

After learning about Weewarrasaurus, I thought it'd be nice to report the 'lesser-known' recent bit of research about the opalised fossil site Lightning Ridge (New South Wales, Australia) It's basically the most up-to-date paper dealing with the geology - including age, stratigraphy and lithology - and vertebrate paleontology. The paper provides many new details about the Griman Creek Formation (GCF), a Cenomanian (mid-Cretaceous) formation which crops out in the area around Lightning Ridge. The GCF is a formation especially known for its diverse vertebrate paleo-ecosystem; of which many species are represented by quite a few opalised fossils The paper is also rather neat as it contains a nice overview of all the vertebrate groups represented at the GCF - an overview complete with a comprehensive (and up-to-date) list of vertebrate taxa, and several nice pictures of opalised vertebrate fossils Finally, the paper also indicates that a new ornithopod genus (Fostoria) from the GCF is soon going to be published Bell, P. R., Fanti, F., Hart, L. J., Milan, L. A., Craven, S. J., Brougham, T., & Smith, E. (2018). Revised geology, age, and vertebrate diversity of the dinosaur-bearing Griman Creek Formation (Cenomanian), Lightning Ridge, New South Wales, Australia. Palaeogeography, Palaeoclimatology, Palaeoecology. Abstract: The mid-Cretaceous Griman Creek Formation (GCF), which crops out near the town of Lightning Ridge in the Surat Basin of north-central New South Wales, Australia, is noteworthy for its opalised vertebrate fauna. The fossil assemblage comprises remains of aspidorhynchid teleosts, lamniform chondrichthyans, dipnoans, chelid and possible meiolaniform turtles, leptocleidid-like and possible elasmosaurid plesiosaurians, anhanguerian pterosaurs, titanosauriform sauropods, megaraptoran theropods, ankylosaurians, several forms of non-iguano- dontian and iguanodontian ornithopods, crocodylomorphs, enantiornithine birds, and stem and true mono- tremes, making it one of the most diverse mid-Cretaceous terrestrial vertebrate faunas in Australia. A detailed stratigraphic survey of twenty subterranean opal mines provides new information on the geology, age and pa- laeoenvironment of the main fossil-bearing beds. Vertebrate remains derive from the ‘Finch Clay facies’, lat- erally-extensive but discontinuous lenses of claystone that likely accumulated relatively rapidly in near-coastal but freshwater embayments (i.e. lagoonal conditions), and probably represent a single, roughly con- temporaneous fauna. U-Pb age dating of detrital zircons extracted from a distinct layer of volcanogenic claystone immediately overlying one of the opalised fossil-bearing layers yields a maximum depositional age of 100.2–96.6 Ma. These new dates confirm an early to mid-Cenomanian age for the fauna, rather than Albian, as has been reported previously. The GCF at Lightning Ridge is therefore equivalent to the middle part of the Winton Formation (Queensland) and several million years older than the sauropod-dominated fauna at Winton. For those who want the paper, PM me your email address and I'll send it to you -Christian