EARLY CRETACEOUS MACROFLORAS OF WESTERN AUSTRALIA

WA Museum Records and Supplements | Updated 1 decade ago

Abstract - Western Australian, Lower Cretaceous, macrofloras from the Broome Sandstone and Callawa Formation (Canning Basin), Nanutarra Formation and Birdrong Sandstone (Carnarvon Basin), Cronin Sandstone (Officer Basin), and Leederville and Bullsbrook Formations (Perth Basin) incorporate a range of lycophytes, ferns, pteridosperms, bennettitaleans, and conifers, The new monotypic genus Roebuckia is established for spatulate fern fronds (R. spatulata) of possible vittariacean alliance. Other newly established species include Phyllopteroides westralensis, Elatocladus ginginensis, and Carpolithes bullsbrookensis, Although the Western Australian fossil suites reveal some specific differences from other Australian late Mesozoic assemblages, several shared index taxa and the high proportion of bennettitaleans support correlation with the Victorian Neocomian Ptilophyllum-Pachypteris austropapillosa Zone (Zone B). Some Western Australian taxa are shared with Indian assemblages but fewer similarities exist with other Gondwanan Early Cretaceous floras. The representation of several hydrophilous fern, lycophyte, and pteridosperm groups together with growth indices from fossil woods implies a seasonal humid mesothermal climate for the Western Australian eratonic margin during the Neocomian-Barremian. Minor differences between the Western Australian assemblages are attributable to local depositional and preservational factors.