Detrital U–Pb and Lu–Hf zircon signatures from the Shackleton Range, East Antarctica: Implications for supercontinent assembly in Nuna, Rodinia, and Gondwana

The Shackleton Range in East Antarctica preserves a unique sedimentary record dating back to the early Mesoproterozoic. Located at a tectonically critical junction where cratonic blocks with African, Australian, Indian, and Laurentian affinities converge, it is a key site for reconstructing East Antarctica’s geodynamic evolution and its role in the supercontinent cycles of Nuna, Rodinia, and Gondwana. This study presents the first comprehensive U–Pb zircon and Lu–Hf isotopic provenance analysis from the region, offering new insights into crustal interactions and tectonic history across the Proterozoic and early Paleozoic. Detrital zircon data from supracrustal rocks of the southern Read Basement show a broad provenance peak between ca. 1800–1400 Ma, dominated by juvenile Hf signatures. These reflect the two-stage assembly of Nuna and magmatism linked to the Laurentian Granite-Rhyolite Province, suggesting a more extensive Laurentia–Antarctica connection than previously recognized. The Wyeth Heights Formation includes Neoarchean zircons and an oldest Eoarchean grain (3703 ± 5 Ma), possibly sourced from the Mawson Continent or other cryptic Archean provinces beneath the East Antarctic Ice Sheet. Late Mesoproterozoic metasediments of the Pioneers Group exhibit a subdued Stenian signal, implying Australo-Antarctica remained tectonically distant from Laurentia until ca. 900 Ma. Cambrian–Ordovician units, including the Mt. Wegener Formation and Blaiklock Glacier Group, show provenance from the East African–Antarctic Orogen (EAAO, 640–500 Ma). These include Mesoproterozoic zircons from the Maud Belt and younger populations linked to the Tonian Oceanic Arc Super Terrane (1000–900 Ma), Mozambique Ocean back-arc magmatism (ca. 650 Ma), EAAO collision-related magmatism (ca. 570 Ma), and post-orogenic magmatism (ca. 520 Ma). The Mt. Wegener basin likely formed as a spatially restricted strike-slip basin during lateral extrusion along the southern EAAO, following Gondwana assembly and subduction initiation along the Paleopacific margin. The Shackleton Range does not appear to be a major Mozambique Ocean suture. Its preservation of eclogite facies rocks, thin-skinned tectonics, and extensive low-grade sedimentary sequences suggests modern analogues in Ligurian-style basins of the Mediterranean, distinguishing it from the majority of other “Pan-African” mobile belts.