Detrital provenance evidence for Eocene drainage partitioning and rift-flank exhumation along the Transantarctic Mountains

Document Type

Article

Publication Date

11-1-2026

Abstract

Cenozoic models of Antarctic ice sheet evolution emphasize the influence of underlying bedrock topography, yet the timing and magnitude of landscape changes that shaped ice-flow pathways remain poorly constrained. Here we present provenance data from Eocene–Miocene sandstones of the Victoria Land Basin, including new detrital zircon U–Pb ages and zircon Hf isotope compositions from Eocene McMurdo Erratic sandstones, together with detrital apatite fission-track (DAFT) data from both the McMurdo Erratics and the CIROS-1 drill core. Zircon age spectra and Hf values from the Eocene sandstones, together with polymodal DAFT populations spanning Eocene to Miocene strata, indicate sediment derivation from progressive exhumation of polylithic (igneous, metamorphic, and sedimentary) source rocks along the Transantarctic Mountains (TAM) rift flank. Our results are consistent with high sediment flux from rapidly eroding TAM catchments during Eocene–Oligocene deposition in the Victoria Land Basin. Furthermore, our provenance analysis, integrating new and previously published thermochronologic datasets, is not readily reconciled with previously proposed fluvial connections between the Ross Sea and Eocene sandstones along the Amundsen Shelf. Although high sediment flux and mineral fertility biases can attenuate individual detrital signals, the observed downstream patterns are difficult to reconcile with suppression of the dominant zircon and apatite signatures characteristic of TAM source regions under the inferred Paleogene drainage architecture. Instead, the Ross and Amundsen embayments prior to Oligocene glaciation likely hosted distinct, regionally constrained drainage networks. These provenance constraints highlight the need for expanded thermochronologic sampling to refine models of Antarctic Paleogene topography and drainage systems.

Publication Title

Earth and Planetary Science Letters

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