Magmatic and geodynamic evolution of Urumieh-Dokhtar basic volcanism, Central Iran: major, trace element, isotopic, and geochronologic implications

作者：Yeganehfar Hadi; Ghorbani Mohammad Reza^*; Shinjo Ryuichi; Ghaderi Majid

来源：International Geology Review, 2013, 55(6): 767-786.

DOI：10.1080/00206814.2012.752554

• basic volcanic rocks
• Central Iran
• subduction
• asthenosphere and lithosphere
• mantle wedge
• adakite
• Oligocene
• Miocene

Basic volcanic rocks from the West Nain area of the UrumiehDokhtar Magmatic Assemblage demonstrate significant subduction-related geochemical characteristics; these along with the new age data obtained for the volcanic rocks shed new light on the geodynamic evolution of the Iranian segment of AlpineHimalayan orogeny. The late Oligocene (26.5 Ma) high-Nb basic volcanic rocks are likely to represent a transient rather enriched asthenospheric mantle underlying the otherwise dominantly Eoceneearly Oligocene West Nain island arc. Lithospheric mantle geochemical signatures of the low-Zr volcanic rocks (20.6 Ma) and high-Th volcanic rocks (19.7 Ma) imply replacement of the underlying mantle. The substitution of asthenospheric mantle by a lithospheric mantle wedge might have been associated with or perhaps caused by an increase in the subduction rate. Culmination of the West Nain magmatism into slab melting that produced the early Miocene (18.7 Ma) adakitic rocks is compatible with subsequent ascent that triggered slab decompression melting.

• 出版日期2013-4-20