Year-end Sale % OFF 
Abstract
Abstract Understanding the origins of the mantle melts that drive voluminous silicic volcanism is challenging because primitive magmas are generally trapped at depth. The central Taupō Volcanic Zone (TVZ; New Zealand) hosts an extraordinarily productive region of rhyolitic caldera volcanism. Accompanying and interspersed with the rhyolitic products, there are traces of basalt to andesite preserved as enclaves or pyroclasts in caldera eruption products and occurring as small monogenetic eruptive centers between calderas. These mafic materials contain MgO-rich olivines (Fo79–86) that host melt inclusions capturing the most primitive basaltic melts fueling the central TVZ. Olivine-hosted melt inclusion compositions associated with the caldera volcanoes (intracaldera samples) contrast with those from the nearby, mafic intercaldera monogenetic centers. Intracaldera melt inclusions from the modern caldera volcanoes of Taupō and Okataina have lower abundances of incompatible elements, reflecting distinct mantle melts. There is a direct link showing that caldera-related silicic volcanism is fueled by basaltic magmas that have resulted from higher degrees of partial melting of a more depleted mantle source, along with distinct subduction signatures. The locations and vigor of Taupō and Okataina are fundamentally related to the degree of melting and flux of basalt from the mantle, and intercaldera mafic eruptive products are thus not representative of the feeder magmas for the caldera volcanoes. Inherited olivines and their melt inclusions provide a unique “window” into the mantle dynamics that drive the active TVZ silicic magmatic systems and may present a useful approach at other volcanoes that show evidence for mafic recharge.
Highlights
The magmatic systems that underpin largescale silicic volcanism encompass large portions of the crust, with partially molten mushy reservoirs that can be thousands of cubic kilometers in volume (Bachmann and Huber, 2016)
Intracaldera olivine-hosted melt inclusions (MIs) associated with silicic eruptions have lower high field strength element (HFSE) concentrations, which reflect fundamental differences in the mantle melting regimes beneath versus between the caldera volcanoes in the central Taupō Volcanic Zone (TVZ)
Compositions from the intracaldera MIs can be modeled by ∼10%–30% melting of a depleted mid-oceanridge mantle (DMM) source across a range of different pressures and mineralogies (Figs. 3C and 3D; Table DR4)
Summary
The magmatic systems that underpin largescale silicic volcanism encompass large portions of the crust, with partially molten mushy reservoirs that can be thousands of cubic kilometers in volume (Bachmann and Huber, 2016). The central Taupō Volcanic Zone (TVZ; Fig. 1), New Zealand, is a frequently active and exceptionally productive region of Quaternary silicic volcanism, fueled by a basalt flux from the mantle that is unusually high for its continental arc setting (Wilson et al, 2009). Over the past ∼60 k.y., a volume of >780 km magma (>99% silicic) has erupted from the central TVZ, almost entirely from two caldera volcanoes: Okataina and Taupō (Fig. 1; Wilson et al, 2009). We investigated the compositions of primitive melts feeding young volcanism in the central TVZ to see if there were any differences between the caldera centers and the less active areas in between. Reconstructing the primitive magmas fueling voluminous silicic volcanism using olivine-hosted melt inclusions: Geology, v.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
