1
|
Gianni GM, Likerman J, Navarrete CR, Gianni CR, Zlotnik S. Ghost-arc geochemical anomaly at a spreading ridge caused by supersized flat subduction. Nat Commun 2023; 14:2083. [PMID: 37045842 PMCID: PMC10097660 DOI: 10.1038/s41467-023-37799-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 03/27/2023] [Indexed: 04/14/2023] Open
Abstract
The Southern Atlantic-Southwest Indian ridges (SASWIR) host mid-ocean ridge basalts with a residual subduction-related geochemical fingerprint (i.e., a ghost-arc signature) of unclear origin. Here, we show through an analysis of plate kinematic reconstructions and seismic tomography models that the SASWIR subduction-modified mantle source formed in the Jurassic close to the Georgia Islands slab (GI) and remained near-stationary in the mantle reference frame. In this analysis, the GI lies far inboard the Jurassic Patagonian-Antarctic Peninsula active margin. This was formerly attributed to a large-scale flat subduction event in the Late Triassic-Early Jurassic. We propose that during this flat slab stage, the subduction-modified mantle areas beneath the Mesozoic active margin and surrounding sutures zones may have been bulldozed inland by >2280 km. After the demise of the flat slab, this mantle anomaly remained near-stationary and was sampled by the Karoo mantle plume 183 Million years (Myr) ago and again since 55 Myr ago by the SASWIR. We refer to this process as asthenospheric anomaly telescoping. This study provides a hitherto unrecognized geodynamic effect of flat subduction, the viability of which we support through numerical modeling.
Collapse
Affiliation(s)
- Guido M Gianni
- Instituto Geofísico Sismológico Ing. Fernando Volponi (IGSV), Universidad Nacional de San Juan, San Juan, Argentina
- National Scientific and Technical Research Council (CONICET), Capital Federal, Argentina
| | - Jeremías Likerman
- National Scientific and Technical Research Council (CONICET), Capital Federal, Argentina
- Instituto de Estudios Andinos Don Pablo Groeber, Universidad de Buenos Aires, Capital Federal, Argentina
| | - César R Navarrete
- National Scientific and Technical Research Council (CONICET), Capital Federal, Argentina
- Laboratorio Patagónico de Petro-Tectónica, Universidad Nacional de la Patagonia "San Juan Bosco", Comodoro Rivadavia, Chubut, Argentina
| | - Conrado R Gianni
- Instituto Geofísico Sismológico Ing. Fernando Volponi (IGSV), Universidad Nacional de San Juan, San Juan, Argentina
| | - Sergio Zlotnik
- Laboratori de Cálcul Numéric, Escola Técnica Superior d'Enginyers de Camins, Canals i Ports, Universitat Politécnica de Catalunya, Barcelona, Spain.
- Centre Internacional de Métodes Numérics a l'Enginyeria (CIMNE), Barcelona, Spain.
| |
Collapse
|
2
|
Liu CZ, Dick HJ, Mitchell RN, Wei W, Zhang ZY, Hofmann AW, Yang JF, Li Y. Archean cratonic mantle recycled at a mid-ocean ridge. SCIENCE ADVANCES 2022; 8:eabn6749. [PMID: 35648865 PMCID: PMC9159695 DOI: 10.1126/sciadv.abn6749] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 04/15/2022] [Indexed: 05/26/2023]
Abstract
Basalts and mantle peridotites of mid-ocean ridges are thought to sample Earth's upper mantle. Osmium isotopes of abyssal peridotites uniquely preserve melt extraction events throughout Earth history, but existing records only indicate ages up to ~2 billion years (Ga) ago. Thus, the memory of the suspected large volumes of mantle lithosphere that existed in Archean time (>2.5 Ga) has apparently been lost somehow. We report abyssal peridotites with melt-depletion ages up to 2.8 Ga, documented by extremely unradiogenic 187Os/188Os ratios (to as low as 0.1095) and refractory major elements that compositionally resemble the deep keels of Archean cratons. These oceanic rocks were thus derived from the once-extensive Archean continental keels that have been dislodged and recycled back into the mantle, the feasibility of which we confirm with numerical modeling. This unexpected connection between young oceanic and ancient continental lithosphere indicates an underappreciated degree of compositional recycling over time.
Collapse
Affiliation(s)
- Chuan-Zhou Liu
- State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
- Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061, China
- CAS Center for Excellence in Deep Earth Sciences, Guangzhou 510640, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Henry J.B. Dick
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Ross N. Mitchell
- State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
| | - Wu Wei
- State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhen-Yu Zhang
- State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | | | - Jian-Feng Yang
- State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
| | - Yang Li
- State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
| |
Collapse
|
3
|
Petrogenesis of Lava from Christmas Island, Northeast Indian Ocean: Implications for the Nature of Recycled Components in Non-Plume Intraplate Settings. GEOSCIENCES 2022. [DOI: 10.3390/geosciences12030118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Lava samples from the Christmas Island Seamount Province (CHRISP) record an extreme range in enriched mantle (EM) type Sr-Nd-Pb-Hf isotope signatures. Here we report osmium isotope data obtained on four samples from the youngest, Pliocene petit-spot phase (Upper Volcanic Series, UVS; ~4.4 Ma), and four samples from the earlier, Eocene (Lower Volcanic Series, LVS; ~40 Ma) shield building phase of Christmas Island. Osmium concentrations are low (5–82 ppt) with initial Os isotopic values (187Os/188Osi) ranging from (0.1230–0.1679). Along with additional new geochemical data (major and trace elements, Sr-Nd-Pb isotopes, olivine δ18O values), we demonstrate the following: (1) The UVS is consistent with melting of shallow Indian mid-ocean ridge basalt (MORB) mantle enriched with both lower continental crust (LCC) and subcontinental lithospheric mantle (SCLM) components; and (2) The LVS is consistent with recycling of SCLM components related to Gondwana break-up. The SCLM component has FOZO or HIMU like characteristics. One of the LVS samples has less radiogenic Os (γOs –3.4) and provides evidence for the presence of ancient SCLM in the source. The geochemistry of the Christmas Island lava series supports the idea that continental breakup causes shallow recycling of lithospheric and lower crustal components into the ambient MORB mantle.
Collapse
|
4
|
High 3He/ 4He in central Panama reveals a distal connection to the Galápagos plume. Proc Natl Acad Sci U S A 2021; 118:2110997118. [PMID: 34799449 PMCID: PMC8617460 DOI: 10.1073/pnas.2110997118] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/15/2021] [Indexed: 11/18/2022] Open
Abstract
We report the discovery of anomalously high 3He/4He in “cold” geothermal fluids of central Panama, far from any active volcanoes. Combined with independent constraints from lava geochemistry, mantle source geochemical anomalies in Central America require a Galápagos plume contribution that is not derived from hotspot track recycling. Instead, these signals likely originate from large-scale transport of Galápagos plume material at sublithospheric depths. Mantle flow modeling and geophysical observations further indicate these geochemical anomalies could result from a Galápagos plume-influenced asthenospheric “mantle wind” that is actively “blowing” through a slab window beneath central Panama. The lateral transport of plume material represents a potentially widespread yet underappreciated mechanism that scatters enriched geochemical signatures in mantle domains far from plumes. It is well established that mantle plumes are the main conduits for upwelling geochemically enriched material from Earth's deep interior. The fashion and extent to which lateral flow processes at shallow depths may disperse enriched mantle material far (>1,000 km) from vertical plume conduits, however, remain poorly constrained. Here, we report He and C isotope data from 65 hydrothermal fluids from the southern Central America Margin (CAM) which reveal strikingly high 3He/4He (up to 8.9RA) in low-temperature (≤50 °C) geothermal springs of central Panama that are not associated with active volcanism. Following radiogenic correction, these data imply a mantle source 3He/4He >10.3RA (and potentially up to 26RA, similar to Galápagos hotspot lavas) markedly greater than the upper mantle range (8 ± 1RA). Lava geochemistry (Pb isotopes, Nb/U, and Ce/Pb) and geophysical constraints show that high 3He/4He values in central Panama are likely derived from the infiltration of a Galápagos plume–like mantle through a slab window that opened ∼8 Mya. Two potential transport mechanisms can explain the connection between the Galápagos plume and the slab window: 1) sublithospheric transport of Galápagos plume material channeled by lithosphere thinning along the Panama Fracture Zone or 2) active upwelling of Galápagos plume material blown by a “mantle wind” toward the CAM. We present a model of global mantle flow that supports the second mechanism, whereby most of the eastward transport of Galápagos plume material occurs in the shallow asthenosphere. These findings underscore the potential for lateral mantle flow to transport mantle geochemical heterogeneities thousands of kilometers away from plume conduits.
Collapse
|
5
|
Richter M, Nebel O, Maas R, Mather B, Nebel-Jacobsen Y, Capitanio FA, Dick HJB, Cawood PA. An Early Cretaceous subduction-modified mantle underneath the ultraslow spreading Gakkel Ridge, Arctic Ocean. SCIENCE ADVANCES 2020; 6:6/44/eabb4340. [PMID: 33127673 PMCID: PMC7608816 DOI: 10.1126/sciadv.abb4340] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 09/14/2020] [Indexed: 06/11/2023]
Abstract
Earth's upper mantle, as sampled by mid-ocean ridge basalts (MORBs) at oceanic spreading centers, has developed chemical and isotopic heterogeneity over billions of years through focused melt extraction and re-enrichment by recycled crustal components. Chemical and isotopic heterogeneity of MORB is dwarfed by the large compositional spectrum of lavas at convergent margins, identifying subduction zones as the major site for crustal recycling into and modification of the mantle. The fate of subduction-modified mantle and if this heterogeneity transmits into MORB chemistry remains elusive. Here, we investigate the origin of upper mantle chemical heterogeneity underneath the Western Gakkel Ridge region in the Arctic Ocean through MORB geochemistry and tectonic plate reconstruction. We find that seafloor lavas from the Western Gakkel Ridge region mirror geochemical signatures of an Early Cretaceous, paleo-subduction zone, and conclude that the upper mantle can preserve a long-lived, stationary geochemical memory of past geodynamic processes.
Collapse
Affiliation(s)
- Marianne Richter
- Isotopia Laboratory, School of Earth, Atmosphere and Environment, Monash University, Clayton, Victoria 3800, Australia.
- School of Earth, Atmosphere and Environment, Monash University, Clayton, Victoria 3800, Australia
| | - Oliver Nebel
- Isotopia Laboratory, School of Earth, Atmosphere and Environment, Monash University, Clayton, Victoria 3800, Australia
- School of Earth, Atmosphere and Environment, Monash University, Clayton, Victoria 3800, Australia
| | - Roland Maas
- School of Earth Sciences, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Ben Mather
- School of Geosciences, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Yona Nebel-Jacobsen
- Isotopia Laboratory, School of Earth, Atmosphere and Environment, Monash University, Clayton, Victoria 3800, Australia
- School of Earth, Atmosphere and Environment, Monash University, Clayton, Victoria 3800, Australia
| | - Fabio A Capitanio
- School of Earth, Atmosphere and Environment, Monash University, Clayton, Victoria 3800, Australia
| | - Henry J B Dick
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543-1539, USA
| | - Peter A Cawood
- Isotopia Laboratory, School of Earth, Atmosphere and Environment, Monash University, Clayton, Victoria 3800, Australia
- School of Earth, Atmosphere and Environment, Monash University, Clayton, Victoria 3800, Australia
| |
Collapse
|
6
|
Nielsen SG, Horner TJ, Pryer HV, Blusztajn J, Shu Y, Kurz MD, Le Roux V. Barium isotope evidence for pervasive sediment recycling in the upper mantle. SCIENCE ADVANCES 2018; 4:eaas8675. [PMID: 30009259 PMCID: PMC6040842 DOI: 10.1126/sciadv.aas8675] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 05/31/2018] [Indexed: 06/08/2023]
Abstract
The upper mantle, as sampled by mid-ocean ridge basalts (MORBs), exhibits significant chemical variability unrelated to mechanisms of melt extraction at ridges. We show that barium isotope variations in global MORBs vary systematically with radiogenic isotopes and trace element ratios, which reflects mixing between depleted and enriched MORB melts. In addition, modern sediments and enriched MORBs share similar Ba isotope signatures. Using modeling, we show that addition of ~0.1% by weight of sediment components into the depleted mantle in subduction zones must impart a sedimentary Ba signature to the overlying mantle and induce low-degree melting that produces the enriched MORB reservoir. Subsequently, these enriched domains convect toward mid-ocean ridges and produce radiogenic isotope variation typical of enriched MORBs. This mechanism can explain the chemical and isotopic features of enriched MORBs and provide strong evidence for pervasive sediment recycling in the upper mantle.
Collapse
Affiliation(s)
- Sune G. Nielsen
- NIRVANA (Non-traditional Isotope Research for Advanced Novel Applications) Laboratories, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Tristan J. Horner
- NIRVANA (Non-traditional Isotope Research for Advanced Novel Applications) Laboratories, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Helena V. Pryer
- NIRVANA (Non-traditional Isotope Research for Advanced Novel Applications) Laboratories, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Jerzy Blusztajn
- NIRVANA (Non-traditional Isotope Research for Advanced Novel Applications) Laboratories, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Yunchao Shu
- NIRVANA (Non-traditional Isotope Research for Advanced Novel Applications) Laboratories, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Mark D. Kurz
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Véronique Le Roux
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| |
Collapse
|
7
|
Barry TL, Davies JH, Wolstencroft M, Millar IL, Zhao Z, Jian P, Safonova I, Price M. Whole-mantle convection with tectonic plates preserves long-term global patterns of upper mantle geochemistry. Sci Rep 2017; 7:1870. [PMID: 28500352 PMCID: PMC5431867 DOI: 10.1038/s41598-017-01816-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 04/04/2017] [Indexed: 11/29/2022] Open
Abstract
The evolution of the planetary interior during plate tectonics is controlled by slow convection within the mantle. Global-scale geochemical differences across the upper mantle are known, but how they are preserved during convection has not been adequately explained. We demonstrate that the geographic patterns of chemical variations around the Earth’s mantle endure as a direct result of whole-mantle convection within largely isolated cells defined by subducting plates. New 3D spherical numerical models embedded with the latest geological paleo-tectonic reconstructions and ground-truthed with new Hf-Nd isotope data, suggest that uppermost mantle at one location (e.g. under Indian Ocean) circulates down to the core-mantle boundary (CMB), but returns within ≥100 Myrs via large-scale convection to its approximate starting location. Modelled tracers pool at the CMB but do not disperse ubiquitously around it. Similarly, mantle beneath the Pacific does not spread to surrounding regions of the planet. The models fit global patterns of isotope data and may explain features such as the DUPAL anomaly and long-standing differences between Indian and Pacific Ocean crust. Indeed, the geochemical data suggests this mode of convection could have influenced the evolution of mantle composition since 550 Ma and potentially since the onset of plate tectonics.
Collapse
Affiliation(s)
- T L Barry
- Department of Geology, University of Leicester, Leicester, LE1 7RH, UK.
| | - J H Davies
- School of Earth and Ocean Sciences, Cardiff University, Cardiff, CF10 3AT, Wales, UK
| | - M Wolstencroft
- JBA Risk Management, Broughton Hall, Skipton, North Yorkshire, BD23 3AE, UK
| | - I L Millar
- NERC Isotope Geosciences Laboratory, British Geological Survey, Keyworth, Nottingham, NG12 5GG, UK
| | - Z Zhao
- School of Earth Science and Resources, China University of Geosciences, Beijing, 100083, China
| | - P Jian
- Beijing SHRIMP Centre, Institute of Geology, Chinese Academy of Geological Sciences, Beijing, 100037, China
| | - I Safonova
- Sobolev Institute of Geology and Mineralogy SB RAS, Novosibirsk, 630090, Russia.,Novosibirsk State University, Novosibirsk, 630090, Russia
| | - M Price
- School of Earth and Ocean Sciences, Cardiff University, Cardiff, CF10 3AT, Wales, UK
| |
Collapse
|
8
|
Nielsen SG, Marschall HR. Geochemical evidence for mélange melting in global arcs. SCIENCE ADVANCES 2017; 3:e1602402. [PMID: 28435882 PMCID: PMC5384804 DOI: 10.1126/sciadv.1602402] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 02/16/2017] [Indexed: 06/07/2023]
Abstract
In subduction zones, sediments and hydrothermally altered oceanic crust, which together form part of the subducting slab, contribute to the chemical composition of lavas erupted at the surface to form volcanic arcs. Transport of this material from the slab to the overlying mantle wedge is thought to involve discreet melts and fluids that are released from various portions of the slab. We use a meta-analysis of geochemical data from eight globally representative arcs to show that melts and fluids from individual slab components cannot be responsible for the formation of arc lavas. Instead, the data are compatible with models that first invoke physical mixing of slab components and the mantle wedge, widely referred to as high-pressure mélange, before arc magmas are generated.
Collapse
Affiliation(s)
- Sune G. Nielsen
- NIRVANA Laboratories, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Horst R. Marschall
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- Institut für Geowissenschaften, Goethe Universität Frankfurt, Altenhöferalle 1, 60438 Frankfurt am Main, Germany
| |
Collapse
|
9
|
Golowin R, Portnyagin M, Hoernle K, Hauff F, Gurenko A, Garbe-Schönberg D, Werner R, Turner S. Boninite-like intraplate magmas from Manihiki Plateau require ultra-depleted and enriched source components. Nat Commun 2017; 8:14322. [PMID: 28181497 PMCID: PMC5309764 DOI: 10.1038/ncomms14322] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 12/16/2016] [Indexed: 11/23/2022] Open
Abstract
The Ontong Java and Manihiki oceanic plateaus are believed to have formed through high-degree melting of a mantle plume head. Boninite-like, low-Ti basement rocks at Manihiki, however, imply a more complex magma genesis compared with Ontong Java basement lavas that can be generated by ∼30% melting of a primitive mantle source. Here we show that the trace element and isotope compositions of low-Ti Manihiki rocks can best be explained by re-melting of an ultra-depleted source (possibly a common mantle component in the Ontong Java and Manihiki plume sources) re-enriched by ≤1% of an ocean-island-basalt-like melt component. Unlike boninites formed via hydrous flux melting of refractory mantle at subduction zones, these boninite-like intraplate rocks formed through adiabatic decompression melting of refractory plume material that has been metasomatized by ocean-island-basalt-like melts. Our results suggest that caution is required before assuming all Archaean boninites were formed in association with subduction processes. Large igneous provinces may form very quickly, but compositions often differ. Here, the authors find that boninite-like rocks at Manihiki are a result of re-melting of an ultra-depleted source therefore putting into question that all boninitic rocks on Earth must be related to subduction processes.
Collapse
Affiliation(s)
- Roman Golowin
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstrasse 1-3, 24148 Kiel, Germany
| | - Maxim Portnyagin
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstrasse 1-3, 24148 Kiel, Germany.,V.I.Vernadsky Institute of Geochemistry and Analytical Chemistry, Kosigin street 19, Moscow 119991, Russia
| | - Kaj Hoernle
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstrasse 1-3, 24148 Kiel, Germany.,Christian-Albrechts-University of Kiel, Ludewig-Meyn-Strasse 10, 24118 Kiel, Germany
| | - Folkmar Hauff
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstrasse 1-3, 24148 Kiel, Germany
| | - Andrey Gurenko
- Centre de Recherches Pétrographiques et Géochimiques, UMR 7358, Université de Lorraine, 54501 Vandoeuvre-lès-Nancy, France
| | | | - Reinhard Werner
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstrasse 1-3, 24148 Kiel, Germany
| | - Simon Turner
- Department of Earth and Planetary Sciences, Macquarie University, New South Wales 2109, Australia
| |
Collapse
|
10
|
Subduction of the oceanic Hikurangi Plateau and its impact on the Kermadec arc. Nat Commun 2014; 5:4923. [PMID: 25230110 DOI: 10.1038/ncomms5923] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 08/06/2014] [Indexed: 11/09/2022] Open
Abstract
Large igneous province subduction is a rare process on Earth. A modern example is the subduction of the oceanic Hikurangi Plateau beneath the southern Kermadec arc, offshore New Zealand. This segment of the arc has the largest total lava volume erupted and the highest volcano density of the entire Kermadec arc. Here we show that Kermadec arc lavas south of ~32°S have elevated Pb and Sr and low Nd isotope ratios, which argues, together with increasing seafloor depth, forearc retreat and crustal thinning, for initial Hikurangi Plateau-Kermadec arc collision ~250 km north of its present position. The combined data set indicates that a much larger portion of the Hikurangi Plateau (the missing Ontong Java Nui piece) than previously believed has already been subducted. Oblique plate convergence caused southward migration of the thickened and buoyant oceanic plateau crust, creating a buoyant 'Hikurangi' mélange beneath the Moho that interacts with ascending arc melts.
Collapse
|
11
|
Mougel B, Agranier A, Hemond C, Gente P. A highly unradiogenic lead isotopic signature revealed by volcanic rocks from the East Pacific Rise. Nat Commun 2014; 5:4474. [PMID: 25027032 DOI: 10.1038/ncomms5474] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 06/20/2014] [Indexed: 11/09/2022] Open
Abstract
Radiogenic isotopes in oceanic basalts provide a window into the different geochemical components defining the composition of Earth's mantle. Here we report the discovery of a novel geochemical signature in volcanic glasses sampled at a sub-kilometre scale along the East Pacific Rise between 15°37'N and 15°47'N. The most striking aspect of this signature is its unradiogenic lead ((206)Pb/(204)Pb=17.49, (207)Pb/(204)Pb=15.46 and (208)Pb/(204)Pb=36.83). In conjunction with enriched Sr, Nd and Hf signatures, Pb isotopes depict mixing lines that trend away from any known mantle end-members. We suggest that this unradiogenic lead component sampled by magmatic melts corresponds to a novel upper mantle reservoir that should be considered in the Pb isotope budget of the bulk silicate Earth. Major, trace element and isotope compositions are suggestive of an ancient and lower continental origin for this unradiogenic lead component, possibly sulphide-bearing pyroxenites that were preserved even after prolonged stirring within the ambient upper mantle.
Collapse
Affiliation(s)
- Berengere Mougel
- Laboratoire Domaines Océaniques, UMR6538, IUEM, 29280 Plouzané, France
| | - Arnaud Agranier
- Laboratoire Domaines Océaniques, UMR6538, IUEM, 29280 Plouzané, France
| | - Christophe Hemond
- Laboratoire Domaines Océaniques, UMR6538, IUEM, 29280 Plouzané, France
| | - Pascal Gente
- Laboratoire Domaines Océaniques, UMR6538, IUEM, 29280 Plouzané, France
| |
Collapse
|
12
|
Timm C, Bassett D, Graham IJ, Leybourne MI, de Ronde CEJ, Woodhead J, Layton-Matthews D, Watts AB. Louisville seamount subduction and its implication on mantle flow beneath the central Tonga–Kermadec arc. Nat Commun 2013; 4:1720. [DOI: 10.1038/ncomms2702] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2012] [Accepted: 03/05/2013] [Indexed: 11/09/2022] Open
|
13
|
Warren JM, Shimizu N, Sakaguchi C, Dick HJB, Nakamura E. An assessment of upper mantle heterogeneity based on abyssal peridotite isotopic compositions. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008jb006186] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
14
|
How supercontinents and superoceans affect seafloor roughness. Nature 2008; 456:938-41. [DOI: 10.1038/nature07573] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Accepted: 10/17/2008] [Indexed: 11/08/2022]
|