Magmatic Processes At Sn Ae Fell Volcano, Iceland, Constrained By Zircon Ages, Isotopes, And Trace Elements

We present the first zircon-based U-Pb geochronology, trace element concentrations, and O and Hf isotope compositions for Sn AE fell, an off-rift volcano in eastern Iceland. These data provide constraints on the longevity and petrogenetic conditions of the Sn AE fell magmatic system. U-Pb zircon ages range from 545 +/- 59 to 266 +/- 16 ka (2SE), but differences between grain core and mantle ages within each sample reveal zircon residence times of 100-200 kyr-far longer than observed at other Neovolcanic systems in Iceland. Zircon delta O-18 is restricted to similar to 3.5-4 parts per thousand, and zircon epsilon(Hf) ranges similar to+13 to similar to+17, which is substantially more radiogenic than Sn AE fell basalts. This combined O and Hf isotopic perspective suggests rhyolite petrogenesis at Sn AE fell can be attributed to fractional crystallization of mantle-derived basaltic magmas with limited influence of pre-existing crustal material. Trace element evidence further characterizes the magmatic source material: Sc/Yb 更多