Rapakivi granites and associating magmatism during the Aptian development stage of the Siberian craton active continental margin (northeast Asia)

We present new data on the U–Th–Pb geochronology, mineralogy, geochemistry, and Sm-Nd and Rb-Sr isotopes for granitoids and associating subalkaline rocks of the Tarbagannakh pluton of the Allakh-Yun tectonic zone in the Verkhoyan fold-thrust belt. These rocks, including trachyandesibasalt dikes, combined into the Uemlyakh complex, were formed ca. 120 Ma from a continental crust source probably with input from and enriched mantle component. Rapakivi granites are reported for the first time in these intrusions – their origin is an important reference for understanding the geodynamic formation setting for this complex. We propose a tectonic model for the formation of these rocks due to slab break-off during the development of the active continental margin in the Aptian age. We discuss that this magmatism was conducive for the widespread development of metasomatic processes until the end of the Aptian age and was at the same time a source of gold mineralization of the overlapping Okhotsk-Koryak metallogenic belt.