Stratigraphic evidence for the Ross orogeny in the Ellsworth Mountains, West Antarctica: implication for the evolution of the paleo-Pacific margin of Gondwana

Early Paleozoic crustal deformation has been recognized along the paleo-Pacific margin of Gondwana, including southern Africa and the Transantarctic Mountains of East Antarctica. Previously, no stratigraphic evidence for the Ross orogeny had been recognized within the Ellsworth Mountains of West Antarctica, believed to have been contiguous with the Transantarctic Mountains prior to the Mesozoic breakup of Gondwana. A disconformity between Middle to Upper Cambrian Heritage Group and Upper Cambrian to Devonian Crashsite Group strata indicates that the Ross orogeny did affect the Ellsworth Mountains, providing additional evidence that these rocks were once part of East Antarctica. Elsewhere in the Ellsworth Mountains, the disconformity is expressed by an abrupt change from shallow carbonate-platform deposits to siliciclastic shelf deposits. -from Authors