Terra Australis Orogen

The Terra Australis Orogen was a vast Neoproterozoic-to-Paleozoic mountain-building belt along Gondwana’s southern margin, shaped by subduction, terrane accretion, and continental collision.

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Subduction: The descent of one tectonic plate beneath another into the mantle. Oceanic plates descended beneath Gondwana, driving magmatism and building the orogenic belt.
Gondwana: A Paleozoic and Mesozoic supercontinent comprising most of the Southern Hemisphere’s present continents. The belt developed along Gondwana’s southern margin.
Gondwana margin: The boundary zone around Gondwana where oceanic and continental tectonic processes interacted. The orogen occupied a long segment of this southern boundary.
Delamerian Orogen: An early Paleozoic mountain belt in southeastern Australia and parts of Antarctica. It represents an early Paleozoic phase along the Terra Australis margin.
Gondwana assembly: The Neoproterozoic and early Paleozoic formation of the supercontinent Gondwana from separate continental blocks. Orogenic activity accompanied and helped record the assembly of Gondwana.
Terrane accretion: The attachment of a distinct fragment of crust to a continent or another tectonic plate. Accreted crustal fragments enlarged Gondwana’s southern margin through time.
Rodinia: A Neoproterozoic supercontinent assembled before the formation of Gondwana. The belt’s earliest development followed the breakup of Rodinia.
Accretionary prism: A wedge of sediment and rock scraped from a subducting plate and piled onto the overriding plate. Prism formation is one way subduction added material to the belt’s margin.
Lachlan Fold Belt: A Paleozoic belt of deformed sedimentary, volcanic, and intrusive rocks in southeastern Australia. Its accreted rocks preserve a major segment of the Australian orogenic system.
Paleo-Pacific Ocean: The ancestral ocean occupying the region of the modern Pacific during much of geological time. Subduction along this ocean’s margins sustained long-lived activity in the belt.