The potential petrogenetic link between a crystal-poor rhyolite (the Rhyolite Canyon Tuff) and its associated subvolcanic intrusion and crystal-rich post-caldera lavas from Turkey Creek, Arizona (USA), is examined using zircon chemical abrasion{\textendash}thermal ionization mass spectrometry U-Pb geochronology and inductively coupled plasma mass spectrometry trace element analyses. U-Pb ages indicate that zircon growth within the rhyolite and the dacite-monzonite porphyry magmas was coeval over \~{}300 k.y. prior to the large eruptive event. Trends in zircon trace elements (Hf, Y/Dy, Sm/Yb, Eu/Eu*) through time in the dacitic-monzonitic units and rhyolite reflect melt evolution dominated by crystal fractionation. Importantly, the Y/Dy ratio in zircons in both units remains mostly similar for the first \~{}150 k.y. of the system{\textquoteright}s evolution, but the dominant population in the rhyolitic unit diverges from that of the dacite-monzonite porphyry \~{}150 k.y. before eruption. We interpret this divergence in trace element composition to record the assembly time of the melt-rich cap within its intermediate mush zone in the upper crustal reservoir. These results are consistent with (1) a connection between plutonic and volcanic realms in the upper crust, (2) a protracted time scale for constructing an intermediate mush large enough to hold 500 km3 of rhyolite, and (3) the prolonged extraction of that melt prior to eruption.
}, year = {2016}, journal = {Geology}, volume = {44}, pages = {267 - 270}, month = {04/2016}, isbn = {0091-7613}, url = {https://doi.org/10.1130/G37539.1}, doi = {10.1130/G37539.1}, language = {eng}, }