 A carbonate platform developed along the palaeo-Pacific margin of Gondwana during the Cambrian, depositing the Shackleton Limestone on top of the Late Proterzoic argillaceous turbidite Goldie Formation.The Ross orogeny, during the early Paleozoic (Cambro-Ordovician), folded the Transantarctic Mountains along the margin of Gondwana, with associated metamorphism, and granitic batholith intrusions.Noted Cambrian-Ordovician outcrops include the Urfjell Group, Blaiklock Glacier Group, Heritage Group in the Ellsworth Mountains, Byrd Group, and the Skelton and Koettlitz groups.