Collision‐Driven Slab Breakoff Magmatism in Northwestern Anatolia, Turkey

Abstract

Abstract Postcollisional Eocene magmatism in northwestern Anatolia produced two E‐W‐trending linear belts of plutons along and north of the Izmir‐Ankara‐Erzincan suture zone (IAESZ), whose geochemical features and age relations support a slab breakoff model for their petrogenetic oinevolution. The suture zone granitoids (SZGs) in the southern belt have ages around 54–48 Ma, are intrusive into blueschist rocks of the IAESZ, and are composed of diorite, quartz diorite, granodiorite, and syenite. The Marmara granitoids (MGs) in the northern belt are slightly younger (48–35 Ma), intrusive into the Paleozoic‐Mesozoic crystalline basement rocks of the Sakarya continent, and composed of monzogranite, granite, and granodiorite. Both SZGs and MGs have moderately to highly evolved medium‐ to high‐K calc‐alkaline compositions and are predominantly metaluminous I‐type granitoids. Nd‐Sr isotope systematics ( \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepacka...