How do accretionary orogens build new continental crust?

Accretionary orogens contribute to the growth of continental crust through processes like volcanism and structural deformation at convergent plate margins. Rising magma creates new crust by transporting less dense material upward while leaving denser components behind. Major geological formations like the Central Asian Orogenic Belt demonstrate how subduction and accretion accumulate arc magmatic rocks and tectonic fragments over time.

What we know

• Orogeny involves both structural deformation of existing continental crust and the creation of new continental crust through volcanism at convergent plate margins. [2]
• Magma rising in an orogen carries less dense material upwards while leaving more dense material behind, causing compositional differentiation of the lithosphere. [2]
• The Central Asian Orogenic Belt serves as a primary laboratory for studying geologically recent crustal growth via accretionary orogenic processes. [5]
• Accretionary orogenic belts consist of a large volume of magmatic arcs, arc-related basins, accretionary complexes, seamounts, continental fragments, and ophiolites. [5]

Still open

• The exact formation history of the Central Asian Orogenic Belt is highly disputed, with scientists debating whether it formed through the accretion of multiple oceanic arcs and continental crusts or via accumulating subduction-accretion complexes on a magmatic arc.

Where to go next

• what caused itWhat causes mountain building at convergent plate margins?
• how it workedHow does magma differentiation shape Earth's lithosphere?
• a case in pointWhat is the Central Asian Orogenic Belt?
• the bigger pictureHow are geological continents defined on tectonic plates?
• whenWhen did the ancient supercontinent Columbia assemble?
• an unexpected connectionWhy are ancient orogenic belts rich in oil and gas?Accretionary orogens that build continental crust also form massive metallogenic domains containing valuable mineral ores, oil, and gas.

Sources

• [1]orogeny (Wikidata Q184554) · CC0 1.0
• [2]Orogeny · CC BY-SA 4.0
• [3]Continent · CC BY-SA 4.0
• [4]Columbia (supercontinent) · CC BY-SA 4.0
• [5]Central Asian Orogenic Belt · CC BY-SA 4.0