LATE ORDOVICIAN EARLY SILURIAN AGE FOR THE MALLOWA SALT OF THE CARRIBUDDY GROUP, CANNING BASIN, WESTERN-AUSTRALIA, BASED ON OCCURRENCES OF TETRAHEDRALETES-MEDINENSIS STROTHER AND TRAVERSE

Fourteen obligate tetrahedral tetrads, assigned to Tetrahedraletes medinensis Strother & Traverse 1979, have been identified in a palynological assemblage derived from a core of the Mallowa Salt, the principal rock salt formation of the Carribuddy Group, Canning Basin, Western Australia. This is the first record of the genus and species in Australia, and is the earliest known occurrence of land plant spores in Australia. The species is a typical element of Gray's (1985) Microfossil Assemblage Zone 1 of mid-Ordovician (Caradocian) to mid-late Early Silurian (Llandovery) age, and is known currently from North America, Europe, Africa and South America. The mean dimensions of the specimens from the Mallowa Salt are within the range of specimens from assemblages of Late Ordovician to earliest Silurian age. These findings provide the firmest age yet determined for the Mallowa Salt of the Carribuddy Group.