Multi-isotope tracing of the 1.3–0.9 Ga evolution of Fennoscandia; crustal growth during the Sveconorwegian orogeny

Magmatism between 1.3 and 0.9 Ga at the southwestern margin of Fennoscandia, comprising mainly granitic batholiths subordinate bimodal volcanic rocks, provides a nearly continuous magmatic record Fennoscandian tectonic evolution. Here, we present new published zircon Hf, K-feldspar Pb whole-rock Sr isotopic data from rocks. The ?Hf evolution since 1300 Ma starts out as relatively juvenile, with flat superchondritic trend 1300–1130 followed by steeper towards lower, but still values 1070–1010 Ma. During 1000–920 period, flattens near-chondritic values. variations steep trends correspond to previously documented extensional compressional periods, respectively. Although change ca. 1100 may indicate emergence reservoir (i.e. colliding continent), there is no corresponding in or composition. We argue that are better explained varying proportions isotopically evolved crust juvenile mantle magma source regions, similar Nd Hf pull-downs pull-ups observed many accretionary orogenic systems. therefore conclude processes without involvement exotic sources best explanation for before during Sveconorwegian orogeny, orogeny involved generation significant volumes SW Fennoscandia.