Zircon age peaks: Production or preservation of continental crust?

摘要: Zircon age peaks are commonly interpreted either as crustal production or selective preservation of subduction-produced crust selectively preserved during continent-continent collision. We contribute to this ongoing debate, using the Nd isotopic compositions felsic igneous rocks and their distribution accretionary collisional phases orogens. The proportion juvenile input into continental is estimated with a mixing model arc-like mantle reworked end members. Orogen length duration proxies for volume show that amount produced at zircon phase orogens ≥3 times fact most both does not require craton collisions its preservation, thus favoring interpretation peaks. Most older than 600 Ma before final supercontinent assembly preservation. Episodic destabilization compositionally heterogeneous layer base may produce plume events leading enhanced subduction production. Our isotope cumulative growth based on past 2.5 b.y. suggests step-like curve rapid in