Brachiopod biogeography of the Asia-Australia hemisphere during Pragian (Early Devonian) times

WA Museum Records and Supplements | Updated 1 decade ago

Abstract - Pragian (Early Devonian) brachiopod data from the Asia-Australia hemisphere have been analysed numerically in an attempt to decipher biogeographic relationships which may have implications with respect to the dynamics of crustal blocks in the hemisphere. Results of numerical analysis accord with earlier qualitative analysis (Talent et al. 1987): that there was a high level of brachiopod provincialism during mid-Palaeozoic times. Quantitative analysis moreover revealed new aspects of interrelationships between brachiopod associations from block to block. Three provinces are indicated around the margins of the Siberian continent in much the same way as provinces are arrayed around the margins of the main continental blocks of the present day, the positions of the latter-and presumably of those arranged around the Siberian continent during Pragian times-being determined by latitude and the circulation pattern of colder and warmer waters. The two provincially discrete entities (West Ural and Polar Ural faunas, 1 and 2) on the margin of the Russian Platform are likewise explicable in terms of palaeolatitude and palaeoceanic circulation. The four regions of the Southern Hemisphere--Melbourne, Tabberabbera-Molong, West Tasman and Takaka (New Zealand)-are represented by Pragian brachiopod associations indicative of a discrete province, though the Takaka (New Zealand) faunas are rather more endemic than the others.