Expedition 352 summary

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doi: 10.14379/iodp.proc.352.101.2015
Author(s): Pearce, Julian A.; Reagan, Mark K.; Petronotis, Katerina; Morgan, Sally; Almeev, Renat; Avery, Aaron J.; Carvallo, Claire; Chapman, Timothy; Christeson, Gail L.; Ferré, Eric C.; Godard, Marguerite; Heaton, Daniel E.; Kirchenbaur, Maria; Kurz, Walter; Kutterolf, Steffen; Li Hongyan; Li Yibing; Michibayashi, Katsuyoshi; Nelson, Wendy R.; Prytulak, Julie; Python, Marie; Robertson, Alastair H. F.; Ryan, Jeffrey G.; Sager, William W.; Sakuyama, Tetsuya; Shervais, John W.; Shimizu, Kenji; Whattam, Scott A.
International Ocean Discovery Program, Expedition 352 Scientists, College Station, TX
Author Affiliation(s): Primary:
Cardiff University, School of Earth and Ocean Sciences, Cardiff, United Kingdom
Other:
University of Iowa, United States
Texas A&M University, United States
University of Leicester, United Kingdom
Leibniz University of Hanover, Germany
Florida State University, United States
Université Pierre et Marie Curie, France
University of Sydney, Australia
University of Texas, Austin, United States
Southern Illinois University, United States
Université Montpellier II, France
Oregon State University, United States
Universität Köln, Germany
Universityy of Graz, Austria
Hemholtz Center for Ocean Research Kiel, Germany
Chinese Academy of Sciences, Guangzhou Institute of Geochemistry, China
Chinese Academy of Geological Sciences, China
Shizuoka University, Japan
University of Houston, United States
Imperial College London, United Kingdom
Hokkaido University, Japan
University of Edinburgh, United Kingdom
University of South Florida, United States
Japan Agency for Marine-Earth Science and Technology, Japan
Utah State University, United States
Korea University, South Korea
Volume Title: Proceedings of the International Ocean Discovery Program; Izu-Bonin-Mariana fore arc; Expedition 352 of the riserless drilling platform, Yokohama, Japan to Keelung, Taiwan; Sites U1439-U1442, 30 July-29 September 2014
Volume Author(s): Pearce, Julian A.; Reagan, Mark K.; Petronotis, Katerina; Morgan, Sally; Almeev, Renat; Avery, Aaron J.; Carvallo, Claire; Chapman, Timothy; Christeson, Gail L.; Ferré, Eric C.; Godard, Marguerite; Heaton, Daniel E.; Kirchenbaur, Maria; Kurz, Walter; Kutterolf, Steffen; Li Hongyan; Li Yibing; Michibayashi, Katsuyoshi; Nelson, Wendy R.; Prytulak, Julie; Python, Marie; Robertson, Alastair H. F.; Rayan, Jeffrey G.; Sager, William W.; Sakuyama, Tetsuya; Shervais, John W.; Shimizu, Kenji; Whattam, Scott A.
Source: Proceedings of the International Ocean Discovery Program; Izu-Bonin-Mariana fore arc; Expedition 352 of the riserless drilling platform, Yokohama, Japan to Keelung, Taiwan; Sites U1439-U1442, 30 July-29 September 2014, Julian A. Pearce, Mark K. Reagan, Katerina Petronotis, Sally Morgan, Renat Almeev, Aaron J. Avery, Claire Carvallo, Timothy Chapman, Gail L. Christeson, Eric C. Ferré, Marguerite Godard, Daniel E. Heaton, Maria Kirchenbaur, Walter Kurz, Steffen Kutterolf, Li Hongyan, Li Yibing, Katsuyoshi Michibayashi, Wendy R. Nelson, Julie Prytulak, Marie Python, Alastair H. F. Robertson, Jeffrey G. Rayan, William W. Sager, Tetsuya Sakuyama, John W. Shervais, Kenji Shimizu and Scott A. Whattam; International Ocean Discovery Program, Expedition 352 Scientists, College Station, TX. Proceedings of the International Ocean Discovery Program, Vol.352, 32p. Publisher: International Ocean Discovery Program, Washington, DC, United States. ISSN: 2377-3189 CODEN: IDSDA6
Note: In English. 46 refs.; illus., incl. 2 tables, geol. sketch map
Summary: The objectives for International Ocean Discovery Program Expedition 352 were to drill through the entire volcanic sequence of the Bonin fore arc to 1. Obtain a high-fidelity record of magmatic evolution during subduction initiation and early arc development, 2. Test the hypothesis that fore-arc basalt lies beneath boninite and understand chemical gradients within these units and across the transition, 3. Use drilling results to understand how mantle melting processes evolve during and after subduction initiation, and 4. Test the hypothesis that the fore-arc lithosphere created during subduction initiation is the birthplace of suprasubduction zone ophiolites. Expedition 352 successfully cored 1.22 km of igneous basement and 0.46 km of overlying sediment , providing diverse, stratigraphically controlled suites of fore-arc basalt (FAB) and boninites related to seafloor spreading and earliest arc development. FAB and related rocks were recovered at the two deeper water sites (U1440 and U1441) and boninites and related rocks were recovered at the two sites (U1439 and U1442) drilled upslope to the west. FAB lavas and dikes are depleted in high-field strength trace elements such as Ti and Zr relative to mid-ocean-ridge basalt but have relatively diverse concentrations of trace elements because of variation in degrees of melting, and potentially, the amount of subducted fluids involved in their genesis. FAB are relatively differentiated, and average degree of differentiation increases wit h depth, which is consistent with crystal fractionation in a persistent magma chamber system beneath a spreading center. Holes U1439C and U1442A yielded entirely boninite differentiation series lavas that generally become more primitive and have lower TiO2 concentrations upward. The presence of dikes at the base of the sections at Sites U1439 and U1440 provides evidence that boninitic and FAB lavas are both underlain by their own conduit systems and, therefore, that FAB and boninite group lavas are likely offset more horizontally than vertically. We thus propose that seafloor spreading related to subduction initiation migrated from east to west after subduction initiation and during early arc development. Initial spreading was likely rapid, and an axial magma chamber was present. Melting was largely decompressional during this period, but subducted fluids affected some melting. As subduction continued and spreading migrated to the west, the embryonic mantle wedge became more depleted and the influence of subducted constituents dramatically in creased, causing the oceanic crust to be boninitic rather than tholeiitic. The general decrease in fractionation upward in the boninite holes reflects the eventual disappearance of persistent magma chambers, either because spreading rate was decreasing with distance from the trench or because spreading was succeeded by off-axis magmatism trench-ward of the ridge. The extreme depletion of the sources for all boninitic lavas was likely related to the incorporation of mantle residues from FAB generation. This mantle depletion continued during generation of lower silica boninitic magmas, exhausting clinopyroxene from the mantle such that the capping high-silica, low-titanium boninites were generated from harzburgite. Additional results of the cruise include recovery of Eocene to recent deep-sea sediment that records variation in sedimentation rates with time resulting from variations in climate, the position of the carbonate compensation depth, and local structural control. Three phases of highly explosive volcanism (latest Pliocene to Pleistocene, late Miocene to earliest Pliocene, and Oligocene) were identified, represented by 132 graded air fall tephra layers.
Year of Publication: 2015
Research Program: DSDP Deep Sea Drilling Project
IODP Integrated Ocean Drilling Program
IPOD International Phase of Ocean Drilling
Key Words: 13 Areal Geology, General; Algae; Alkaline earth metals; Andesites; Areal geology; Basalts; Basement; Basins; Biostratigraphy; Boninite; Boreholes; Cenozoic; Cores; Crust; DSDP Site 458; DSDP Site 459; Deep Sea Drilling Project; Dikes; Expedition 352; Fore-arc basins; Geochemistry; IODP Site U1439; IODP Site U1440; IODP Site U1441; IODP Site U1442; IPOD; Igneous rocks; International Ocean Discovery Program; Intrusions; Isotope ratios; Isotopes; Izu-Bonin Arc; Lava; Lead; Leg 60; Lithostratigraphy; Magmatism; Mariana Islands; Marine sediments; Metals; Microfossils; Micronesia; Nannofossils; Nd-144/Nd-143; Neodymium; North Pacific; Northwest Pacific; Oceania; Oceanic crust; Pacific Ocean; Paleomagnetism; Pb-206/Pb-204; Pb-207/Pb-204; Pb-208/Pb-204; Petrology; Physical properties; Plantae; Plate tectonics; Radioactive isotopes; Rare earths; Sediments; Sr-87/Sr-86; Stable isotopes; Strontium; Subduction zones; Volcanic rocks; Volcanism; West Pacific
Coordinates: N282400 N282700 E1424600 E1423600
Record ID: 2015104832
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute.
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