Sediment provenance and tectonic evolution of the Eastern Mentelle Basin: insights into the early rifting history of East Gondwana

Palaeogeographic and tectonic reconstructions of the early rifting (Late Jurassic to Early Cretaceous) of East Gondwana often overlook East Antarctica due to the lack of geological data both onshore and offshore. Nevertheless, Antarctica was likely a significant contributor of clastic material that formed the syn-rift successions of sedimentary basins along the west Australian margin (i.e. Perth, Mentelle basins). Furthermore, the Knox Rift, located onshore Antarctica, may represent a continuation of early rifting in the Mentelle and Perth basins, later abandoned as rifting progressed.

International Ocean Discovery Program (IODP) Expedition 369 recovered for the first time sandstones from the syn-rift sequences of the eastern Mentelle Basin. Located in proximity of the relict triple junction of the Antarctic, Indian and Australian plates, these sandstones present a unique opportunity to provide new insight on the palaeogeographic and tectonic evolution of the Antarctic and Australian plates during the early rifting stages of East Gondwana.

We present initial results from the post-expedition analytical work on the syn-rift sandstones of the eastern Mentelle Basin that aims to improve our understanding of the depositional and tectonic history of the Mentelle Basin in the broader East Gondwana framework. Using our new data and recent isotopic data from previously unaccessed outcrops in East Antarctica, we seek to test the hypothesis of an East Antarctic provenance of sediments in the Mentelle Basin and investigate tectonic links of the Mentelle Basin with the inferred conjugate Knox Rift in East Antarctica.