| Popis: |
Paleomagnetism of the Upper Devonian reef complexes in the Canning Basin, Western Australia, was reinvestigated with a primary aim of testing its magnetization age. Samples were collected from back reef and reefal limestones, basinal red beds, syndepositional allochthonous blocks, and sediment infillings in syndepositional cracks and voids. A characteristic remanence, similar to that identified in a previous study, was found in six autochthonous sites in outcrop and four diamond drill cores, with a mean direction of declination D = 27.5°, inclination I = −19.9° (half angle of 95% confidence cone α95 = 15.2°). The primary origin of this remanence was demonstrated by both a syndepositional breccia test and an allochthonous block test. The corresponding Late Devonian pole position (62.0°S, 23.2°E with half angle of 95% confidence cone A95 = 14.6°) overlaps with the previously reported paleopole from this reef complex and other Late Devonian paleopoles from Australia. The evidence indicates that the spread of late Middle to Early Carboniferous paleopoles from Australia is caused by a phase of rapid apparent polar wander, rather than the tectonic discordance of southeastern Australia in relation to the craton. |
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