[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Age of Winton Formation dinosaur fauna in Australia



From: Ben Creisler
bcreisler@gmail.com


A new online paper:

Ryan T. Tucker, Eric M. Roberts, Yi Hub, Anthony I.S. Kemp & Steven W.
Salisbury (21012)
Detrital zircon age constraints for the Winton Formation, Queensland:
Contextualizing Australia's Late Cretaceous dinosaur faunas.
http://dx.doi.org/10.1016/j.gr.2012.12.009
http://www.sciencedirect.com/science/article/pii/S1342937X12004157


The Winton Formation provides an important snapshot of Australia's
late Mesozoic terrestrial biota, boasting a vertebrate fauna that
includes dinosaurs, crocodyliforms, aquatic squamates, turtles,
lungfish and teleost fishes, and a flora that has previously been
considered to include some of the world's earliest known flowering
plants. Despite its significance, poor age control has thus far
prevented precise regional and global correlations, limiting the depth
of palaeobiogeographic assessments. The goal of this study was to use
U-Pb isotope dating of detrital zircons by laser ablation to refine
the depositional age range of selected horizons within the Winton
Formation. We applied this technique, with refined instrumental tuning
protocols, to systematically investigate detrital zircon grain ages
for five samples from different stratigraphic levels and
vertebrate-bearing fossil locations throughout the Winton Formation.
Seven different metrics for interpreting the maximum depositional age
of each of the detrital zircon samples were compared and our results
suggest that sedimentation of the Winton Formation commenced no
earlier than latest Albian (~ 103.0-100.5 Ma) and that deposition of
the upper vertebrate fossil-rich portion of the section began roughly
near or after the Cenomanian-Turonian boundary (93.9 Ma),
demonstrating that the formation and its important flora and fauna
were deposited primarily during the Late Cretaceous. These results
provide a significant advancement in understanding the age of the
Winton Formation's flora and fauna, and will help to contextualize
Australia's Late Cretaceous terrestrial biota within a broader
Gondwanan framework.