Paleozoiczno-mezozoiczny dryft Australii
Abstract
PALEMESOZOIC DRIFT OF AUSTRALIA
Summary
The problem of drift of Australia is discussed on the basis at recent papers. Up to the present it was assumed that Gondwana protocontinent existed already in the Late Precambrian or early Paleozoic times. However, there is growing evidence which speaks against that hypothesis. Taking into account paleomagnetic data and results of analyses of Cambrian trilobite faunas (P. A. Jell, 1974) it may be assumed that the continents of the southern hemisphaere were no united into a single block in these times. According to paleomagnetic data for the Cambrian position of South America (M. K. Creer, 1965) does not correspond to that of Australia (E. Irwing, 1964). Cambrian fauna of South America belonged to different faunal province than that of Australia (J. W. Cowie, 1971) and mixing of these faunas, which should have taken place if there was a connection between these continents, is not found. Paleomagnetic reconstructions (E. Irwing, 1964; M. K. Creer, 1965; M. W. Mc Elhinny, B. J. J. Embleton, 1974, P. A. Jell) as well as some paleobiogeographic (J. W. Cowie, 1971) and paleoclimatic (W. Volkheimer, 1967) data make it possible to assume that continents of the southern hemisphaere were grouped in two continental blocks at the beginning of the Paleozeic Era: one, eastern Gondwana block comprising Australia and Antarctica and another, western Gondwana block comprising Africa and South America (Fig. 1). This is the starting point for further analysis of the drift of Australia.
Summary
The problem of drift of Australia is discussed on the basis at recent papers. Up to the present it was assumed that Gondwana protocontinent existed already in the Late Precambrian or early Paleozoic times. However, there is growing evidence which speaks against that hypothesis. Taking into account paleomagnetic data and results of analyses of Cambrian trilobite faunas (P. A. Jell, 1974) it may be assumed that the continents of the southern hemisphaere were no united into a single block in these times. According to paleomagnetic data for the Cambrian position of South America (M. K. Creer, 1965) does not correspond to that of Australia (E. Irwing, 1964). Cambrian fauna of South America belonged to different faunal province than that of Australia (J. W. Cowie, 1971) and mixing of these faunas, which should have taken place if there was a connection between these continents, is not found. Paleomagnetic reconstructions (E. Irwing, 1964; M. K. Creer, 1965; M. W. Mc Elhinny, B. J. J. Embleton, 1974, P. A. Jell) as well as some paleobiogeographic (J. W. Cowie, 1971) and paleoclimatic (W. Volkheimer, 1967) data make it possible to assume that continents of the southern hemisphaere were grouped in two continental blocks at the beginning of the Paleozeic Era: one, eastern Gondwana block comprising Australia and Antarctica and another, western Gondwana block comprising Africa and South America (Fig. 1). This is the starting point for further analysis of the drift of Australia.