PERMIAN PALYNOSTRATIGRAPHY OF THE COLLIE BASIN, WESTERN-AUSTRALIA

The Collie Coal Measures and the underlying glacigene Stockton Formation are Permian lithologic units in the small, intracratonic Collie Basin situated near the western margin of the Yilgarn Craton in Western Australia. Palynological data were obtained from a number of cored boreholes and opencut mines. Eighty four miospore species and twenty two acritarch species are recognized and thirteen new combinations are made. A system of mainly informal zones is used to subdivide the Permian sequence, based partly on the previously published stage nomenclature established in eastern Australia. The lowest unit, Stage 2, is entirely included in the Stockton Formation and the Pseudoreticulatispora (Granulatisporites) confluens Zone of Foster and Waterhouse occupies the interval transitional to the Collie Coal Measures. Within the Collie Coal Measures are eight zones based on the successive first appearances of Pseudoreticulatispora pseudoreticulata, Striatopodocarpites fusus, Microbaculispora trisina, Praecolpatites sinuosus, Microbaculispora villosa, Dulhuntyispora granulata, Didecitriletes ericianus and Protohaploxypinus rugatus. The youngest sediments of the Collie Coal Measures pre-date the appearance of Dulhuntyispora parvithola and are therefore older than upper Stage 5. These zones are used to correlate the Permian sequences in the three sub-basins of the Collie Basin. A detailed comparison is made with the well documented Permian palynostratigraphy of the northern Karoo Basin of South Africa up to the first appearance of D. ericianus. The palynostratigraphy of the Collie and Karoo Basins is shown to be similar below the P. sinuosus zone. By comparing the palynological results with previously published palynological studies on Western Australian strata with marine faunas, an age range of uppermost Carboniferous/Asselian to early Late Permian is suggested for the Permian of the Collie Basin.