We present new zircon U-Pb isotopic data for volcanic rocks from deformed metavolcanic-sedimentary successions of the widespread Ross Supergroup in the Queen Maud Mountains, Antarctica. Zircon U-Pb analyses of Liv Group volcanic rocks thought to be Neoproterozoic in age instead have early Paleozoic ages. Zircon U-Pb analyses of five samples assigned to the Fairweather Formation have yielded $524\pm 9$ to $514\pm 9$ Ma (2σ) crystallization ages, whereas six samples assigned to the Taylor Formation have yielded $510\pm 12$ to $490\pm 6$ Ma (2σ) crystallization ages. Although these ages imply that the Fairweather Formation is generally older than the Taylor Formation, the age uncertainties show a 17-My overlap that is consistent with previous suggestions for temporal correlation of these formations. On a regional scale, Liv Group volcanism overlapped with the emplacement of ∼535–490 Ma plutonic rocks associated with the early Paleozoic Queen Maud batholith as well as igneous rocks found elsewhere along the early Paleozoic Pacific-Gondwana margin. Collectively, these igneous rocks provide plausible zircon sources for similar age detrital zircon populations found in outboard siliciclastic rocks belonging to the Leverett, Taylor, Fairweather, Greenlee, and Starshot Formations of the Queen Maud Mountains. The youngest crystallization age yielded by the deformed Taylor Formation (∼490 Ma) assumes regional significance because it represents the youngest volcanic rock yet identified within the Ross orogen in Antarctica and provides important new evidence for latest Cambrian or younger deformation, possibly associated with orogenic collapse during slab rollback at the terminal stages of the Ross orogeny.

Some of the most important Cenozoic sedimentary rocks in Antarctica are glacial erratics of fossiliferous Palaeogene to Neogene siliclastic rocks known as the McMurdo Erratics. Detrital zircon U–Pb isotopic data reported herein provide new information on the provenance of these siliciclastic rocks. The U–Pb age data from a sandstone glacial erratic that is likely of Eocene age show a dominant age cluster that ranges from 488 to 635 Ma, accompanied by subsidiary Neoproterozoic–Archaean peaks. The dominant Neoproterozoic–Ordovician age cluster, in conjunction with the arkosic lithologies of some erratics and the local presence of granitic and metasedimentary clasts, indicates that the Neoproterozoic–Ordovician basement complex of the Transantarctic Mountains likely served as a major source for the Eocene siliciclastic sediments. This is consistent with derivation of the McMurdo Erratics from locations proximal to the Transantarctic Mountains such as the Discovery Deep and/or major mountain outlet glacier areas.

The Ross orogenic belt in Antarctica is one of several Neoproterozoic-early Palaeozoic orogens that crisscrossed Gondwana and are associated with Gondwana’s assembly. We present new age data from the Queen Maud Mountains, Ross orogen, from areas that hitherto have lacked precise ages from the local plutonic rocks. The zircon U-Pb igneous crystallization ages (n = 7) and a hornblende ⁴⁰Ar/³⁹Ar cooling age (n = 1) constrain plutonism to primarily lie within the Cambrian to Ordovician. Cumulative zircon U-Pb crystallization age data yield polymodal age distributions (516 Ma, 506–502 Ma, and 488 Ma age peaks) that are similar to other areas of the Queen Maud-Horlick Mountains, consistent with regional magmatic flare-ups along the Pacific-Gondwana margin during these times. The ages of deformed plutons constrain deformation to the Cambrian (Series 2) to Ordovician (Lower), with some regions indicating a transition to post-tectonic magmatism and cooling at ~509-470 Ma. Collectively, the data indicate that the Queen Maud-Horlick Mountains share a similar petrotectonic history with other regions of the Pacific-Gondwana margin, providing new evidence that this tectonostratigraphic province is part of and not exotic to the larger igneous-sedimentary successions developed in the peri-Gondwana realm under a broadly convergent margin setting.