Linking arc initiation to silicic melt evolution in an oceanic arc setting using detrital zircons

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doi: 10.1130/abs/2017CD-29233
Author(s): Barth, Andrew P.; Tani, Kenichiro; Meffre, Sebastein; Wooden, J. L.; Coble, Matthew A.
Author Affiliation(s): Primary:
Indiana University-Purdue University, Department of Earth Sciences, Indianapolis, IN, United States
Other:
Natural History Museum, Japan
University of Tasmania, Australia
U. S. Geological Survey, United States
Stanford University, United States
Volume Title: Geological Society of America, Cordilleran Section, 113th annual meeting
Source: Abstracts with Programs - Geological Society of America, 49(4); Geological Society of America, Cordilleran Section, 113th annual meeting, Honolulu, HI, May 23-25, 2017. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0016-7592 CODEN: GAAPBC
Note: In English
Summary: Understanding the petrologic evolution of oceanic arc magmas through time is important because these arcs reveal the processes of formation and the early evolution of juvenile continental crust. We examined Pb/U and trace element compositions in zircons recovered at IODP Site 351-U1438 located in the proximal back-arc of the northern Kyushu-Palau Ridge at 27.3 °N. A 1.2 km thick section of Paleogene volcaniclastic rocks, increasingly lithified and hydrothermally altered with depth, constitutes a proximal rear arc sedimentary record of arc initiation and early evolution of the Izu-Bonin arc. The ages and compositions of U1438 zircons are compatible with provenance in one or more growing submarine edifices of this arc and capture a record of juvenile silicic arc melt evolution. Detrital zircon Pb/U maximum depositional ages range from 28 to 37 Ma, are consistent with depositional age models based on combined magnetostratigraphic and biostratigraphic constraints, and indicate zircon-bearing melts were generated <10 Ma after arc initiation. The abundances of selected trace elements with high native concentrations in zircon provide insight into the petrogenesis of host melts, and indicate short-term variations in melt compositions. The U1438 zircons span the compositional range between zircons from mid-ocean ridge gabbros and zircons from relatively enriched continental arcs, as predicted for melts in a primitive oceanic arc setting derived from a highly depleted mantle source. Melt zircon saturation temperatures and Ti-in-zircon thermometry suggest a provenance in relatively cool and silicic melts that evolved toward more Th and U-rich compositions with time. Age similarities and geochemical affinity of some detrital zircons to igneous zircons in Eocene leucotonalite and granodiorite from a partially exhumed intrusive suite at Komahashi-Daini Seamount in the northern Kyushu-Palau Ridge suggests that these zircons also can yield insight into the link between silicic volcanism and mid-crustal intrusion in the Paleogene Izu-Bonin arc.
Year of Publication: 2017
Research Program: IODP Integrated Ocean Drilling Program
IODP2 International Ocean Discovery Program
Key Words: 07 Marine Geology and Oceanography; Expedition 351; IODP Site U1438; International Ocean Discovery Program; Izu-Bonin Arc; Melts; North Pacific; Northwest Pacific; Pacific Ocean; West Pacific
Coordinates: N272300 N272301 E1341907 E1341905
Record ID: 2017076397
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States