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Detrital-zircon age spectra have been determined for sedimentary rocks from the Delamerian orogen, southern Australia. In Neoproterozoic sedimentary rocks, patterns progressively change from Mesoproterozoic- to Neoproterozoic-dominated detritus and there are few zircons that are close to the depositional age. The base of the Cambrian Kanmantoo Group marks an abrupt change in provenance to detrital patterns dominated by Ross and Delamerian (600–500 Ma) and Grenvillean ages (1200–1000 Ma). These patterns are strikingly similar to those obtained from Lachlan fold belt sedimentary rocks, indicating that the sedimentation recorded in the Kanmantoo Group marks a change from deposition of sediments derived from the Australian cratons to those representative of the early Paleozoic Gondwana mudpile. If sedimentary rocks with zircon-provenance characteristics such as those of the Kanmantoo rocks extend under elements of the Lachlan fold belt, they would provide suitable protoliths for the S-type granites of southeastern Australia.

Permian-Triassic strata from Parapara Peak in the Takaka terrane, western province, New Zealand, are dominated by detrital zircon peaks at ca. 240 Ma comparable to the Torlesse terrane of the eastern province. This contrasts with lower Paleozoic strata (Onekaka schist), which is comparable to other lower Paleozoic terranes (including adjacent Buller terrane) from the Gondwana margin that are characterized by detrital zircon patterns with characteristic peaks at ca. 500‐650 Ma and ca. 1000‐1150 Ma, a less distinct peak around 1400‐1700 Ma, and scattered Archean ages. These data indicate the close proximity of the eastern and western provinces by Permian time and a probable source region of Parapara Peak strata and Torlesse terrane in the New England fold belt of southeast Australia.

Ion-microprobe zircon U/Pb age data are presented for two metasedimentary sequences in Fiordland, New Zealand: one is a correlative of the Lachlan fold belt in southeast Australia and incorporates metamorphosed Ordovician turbidites intruded by 350–370 Ma S-type granites, and the other is equivalent in age to the older Delamerian fold belt and is derived from Cambrian-Ordovician protoliths (Kanmantoo Group) intruded by 480 Ma granitic orthogneiss. The latter was exhumed from lower crustal depths and is considered to be representative of basement not only in New Zealand but also in the formerly contiguous regions of southeast Australia and Antarctica. This basement underwent melting and low-pressure–high-temperature metamorphism at 350–370 Ma and yields detrital zircon with ages identical to those of inherited zircon in the mid-Paleozoic S-type granites.

The Delamerian orogen (southeast Australia) and the Wilson terrane (northern Victoria Land, Antarctica) constitute a formerly continuous lower Paleozoic fold-and-thrust belt developed along the paleo-Pacific margin of eastern Gondwana. Major folds and thrust faults in these regions, rooted in mid-crustal detachment zones, transported Cambrian-Ordovician granites and high-temperature- low-pressure metamorphic rocks divergently toward their respective western craton margins and eastern orogen margins and associated cover sequences. The structural imprints are related to the accretion of lower Paleozoic terranes at the eastern margin of the Delamerian orogen and the Wilson terrane. The continuity of the contemporaneous structure patterns in Australia and Antarctica is evidence for continuous convergent tectonism along the lower Paleozoic-Pacific margin of Gondwana.

The present configuration of Wilson Group, Bowers Supergroup and Robertson Bay Group in northern Victoria Land (Fig. 1) has been attributed to high-angle block-faulting1–3 or more recently4 to major strike-slip faulting along the Lanterman and Leap Year Fault zones. In this latter interpretation4, adjacent units have allochthonous relationships and constitute separate geological terranes. We offer additional support for the concept of allochthonous terranes in northern Victoria Land but suggest here an alternative model to explain terrane juxtapositions. Our model emphasizes the role of thrust tectonics and implies severe structural telescoping of entire terranes with significant loss of intervening crust. We further suggest that this occurred during the Lower Palaeozoic Ross Orogeny in response to the collision of Antarctica with a westwardly directed eastern continental block. This requires that the northern Victoria Land segment of Gondwana was a zone of major plate convergence throughout the Cambrian–early Ordovician period.