The Granulatisporites confluens Oppel-zone and early permian marine faunas from the grant formation on the Barbwire Terrace, Canning Basin, Western Australia

Abstract

A taxonomically diverse plant microfossil assemblage recovered from a fully cored, marine, glacigene sequence of the Grant Formation, Canning Basin, Western Australia, contains 68 palynomorph species derived mostly from ferns, lycopods, gymnosperms and algae. The assemblage has been assigned to the newly defined Granulatisporites confluens Oppel-zone. G. confluens was first described from Late Palaeozoic sequences of the Chaco-Parana Basin, Argentina, and together with other key species indicates close correlation with assemblages from South America, India, Africa and, to a lesser extent, Antarctica. The associated marine fauna is diverse and includes foraminiferids, crinoids, bryozoans, molluscs and brachiopods. Twenty species of Mollusca and Brachiopoda have been identified, including the new species Terrakea capillata Waterhouse. The presence of Strophalosia cf. subcircularis Clarke indicates strong links with younger Asselian faunas of eastern and southern Australia (lower Wasp Head, lower Tiverton and Glencoe Formations) and with faunas of the Bap Formation, India. Correlation with Faunizones 1-2 of Tasmania and the Allandale (s.l.) faunas of New South Wales, and the distribution of Eurydesma playfordi and closely allied species, negate previous claims that the Allandale fauna is of late Tastubian (Sakmarian) age. Within Australia, palynological assemblages of the G. confluens Oppel-zone are also known from the offshore Bonaparte Basin (Western Australia, Northern Territory), Collie Basin (Western Australia) and the Troubridge Basin (South Australia) and. with further study, should be identified in eastern Australia. Faunal, palynological and lithological evidence indicates that sporadic, Gondwana-wide marine transgressions took place during the earliest Permian and that these events are widely recorded in periglacial sediments. Show more