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Corradino M, Balazs A, Faccenna C, Pepe F. Arc and forearc rifting in the Tyrrhenian subduction system. Sci Rep 2022; 12:4728. [PMID: 35304876 PMCID: PMC8933539 DOI: 10.1038/s41598-022-08562-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 03/04/2022] [Indexed: 11/18/2022] Open
Abstract
The evolution of forearc and backarc domains is usually treated separately, as they are separated by a volcanic arc. We analyse their spatial and temporal relationships in the Tyrrhenian subduction system, using seismic profiles and numerical modelling. A volcanic arc, which included the Marsili volcano, was involved in arc-rifting during the Pliocene. This process led to the formation of an oceanic backarc basin (~ 1.8 Ma) to the west of the Marsili volcano. The eastern region corresponded to the forearc domain, floored by serpentinised mantle. Here, a new volcanic arc formed at ~ 1 Ma, marking the onset of the forearc-rifting. This work highlights that fluids and melts induce weakening of the volcanic arc region and drive the arc-rifting that led to the backarc basin formation. Later, the slab rollback causes the trench-ward migration of volcanism that led to the forearc- rifting under the control of fluids released from the downgoing plate.
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Affiliation(s)
- M Corradino
- Department of Earth and Marine Sciences, University of Palermo, Via Archirafi, 22, 90123, Palermo, Italy
| | - A Balazs
- Department of Earth Sciences, ETH Zürich, Zürich, Switzerland
| | - C Faccenna
- GFZ German Research Centre for Geosciences, Potsdam, Germany.,Department of Sciences, Università Roma TRE, Rome, Italy
| | - F Pepe
- Department of Earth and Marine Sciences, University of Palermo, Via Archirafi, 22, 90123, Palermo, Italy.
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Back-Arc Spreading Centers and Superfast Subduction: The Case of the Northern Lau Basin (SW Pacific Ocean). GEOSCIENCES 2022. [DOI: 10.3390/geosciences12020050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The Lau Basin is a back-arc region formed by the subduction of the Pacific plate below the Australian plate. We studied the regional morphology of the back-arc spreading centers of the Northern Lau basin, and we compared it to their relative spreading rates. We obtained a value of 60.2 mm/year along the Northwest Lau Spreading Centers based on magnetic data, improving on the spreading rate literature data. Furthermore, we carried out numerical models including visco-plastic rheologies and prescribed surface velocities, in an upper plate-fixed reference frame. Although our thermal model points to a high temperature only near the Tonga trench, the model of the second invariant of the strain rate shows active deformation in the mantle from the Tonga trench to ~800 km along the overriding plate. This explains the anomalous magmatic production along all the volcanic centers in the Northern Lau Back-Arc Basin.
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Volcanism in slab tear faults is larger than in island-arcs and back-arcs. Nat Commun 2017; 8:1451. [PMID: 29129913 PMCID: PMC5682279 DOI: 10.1038/s41467-017-01626-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 10/04/2017] [Indexed: 11/25/2022] Open
Abstract
Subduction-transform edge propagators are lithospheric tears bounding slabs and back-arc basins. The volcanism at these edges is enigmatic because it is lacking comprehensive geological and geophysical data. Here we present bathymetric, potential-field data, and direct observations of the seafloor on the 90 km long Palinuro volcanic chain overlapping the E-W striking tear of the roll-backing Ionian slab in Southern Tyrrhenian Sea. The volcanic chain includes arc-type central volcanoes and fissural, spreading-type centers emplaced along second-order shears. The volume of the volcanic chain is larger than that of the neighbor island-arc edifices and back-arc spreading center. Such large volume of magma is associated to an upwelling of the isotherms due to mantle melts upraising from the rear of the slab along the tear fault. The subduction-transform edge volcanism focuses localized spreading processes and its magnitude is underestimated. This volcanism characterizes the subduction settings associated to volcanic arcs and back-arc spreading centers. The volcanism of subduction settings concentrates in island-arcs and back-arc basins. Here, the authors show that the lithospheric tear faults bounding roll-backing slabs may focus huge volcanism with a volume of the erupted products exceeding that of the island-arcs edifices and back-arcs spreading centres.
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Seismic evidence of effects of water on melt transport in the Lau back-arc mantle. Nature 2015; 518:395-8. [PMID: 25642964 DOI: 10.1038/nature14113] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Accepted: 11/20/2014] [Indexed: 11/08/2022]
Abstract
Processes of melt generation and transport beneath back-arc spreading centres are controlled by two endmember mechanisms: decompression melting similar to that at mid-ocean ridges and flux melting resembling that beneath arcs. The Lau Basin, with an abundance of spreading ridges at different distances from the subduction zone, provides an opportunity to distinguish the effects of these two different melting processes on magma production and crust formation. Here we present constraints on the three-dimensional distribution of partial melt inferred from seismic velocities obtained from Rayleigh wave tomography using land and ocean-bottom seismographs. Low seismic velocities beneath the Central Lau Spreading Centre and the northern Eastern Lau Spreading Centre extend deeper and westwards into the back-arc, suggesting that these spreading centres are fed by melting along upwelling zones from the west, and helping to explain geochemical differences with the Valu Fa Ridge to the south, which has no distinct deep low-seismic-velocity anomalies. A region of low S-wave velocity, interpreted as resulting from high melt content, is imaged in the mantle wedge beneath the Central Lau Spreading Centre and the northeastern Lau Basin, even where no active spreading centre currently exists. This low-seismic-velocity anomaly becomes weaker with distance southward along the Eastern Lau Spreading Centre and the Valu Fa Ridge, in contrast to the inferred increase in magmatic productivity. We propose that the anomaly variations result from changes in the efficiency of melt extraction, with the decrease in melt to the south correlating with increased fractional melting and higher water content in the magma. Water released from the slab may greatly reduce the melt viscosity or increase grain size, or both, thereby facilitating melt transport.
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Spatially resolved sampling reveals dynamic microbial communities in rising hydrothermal plumes across a back-arc basin. ISME JOURNAL 2014; 9:1434-45. [PMID: 25489728 DOI: 10.1038/ismej.2014.228] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Revised: 10/21/2014] [Accepted: 10/28/2014] [Indexed: 11/09/2022]
Abstract
Within hydrothermal plumes, chemosynthetic processes and microbe-mineral interactions drive primary productivity in deep-ocean food webs and may influence transport of elements such as iron. However, the source of microorganisms in plumes and the factors governing how these communities assemble are poorly understood, in part due to lack of data from early stages of plume formation. In this study, we examined microbial community composition of rising hydrothermal plumes from five vent fields along the Eastern Lau Spreading Center. Seafloor and plume microbial communities were significantly dissimilar and shared few phylotypes. Plume communities were highly similar to each other with significant differences in community membership only between Kilo Moana and Mariner, two vents that are separated by extremes in depth, latitude and geochemistry. Systematic sampling of waters surrounding the vents revealed that species richness and phylogenetic diversity was typically highest near the vent orifice, implying mixing of microbial communities from the surrounding habitats. Above-plume background communities were primarily dominated by SAR11, SAR324 and MG-I Archaea, while SUP05, Sulfurovum, Sulfurimonas, SAR324 and Alteromonas were abundant in plume and near-bottom background communities. These results show that the ubiquitous water-column microorganisms populate plume communities, and that the composition of background seawater exerts primary influence on plume community composition, with secondary influence from geochemical and/or physical properties of vents. Many of these pervasive deep-ocean organisms are capable of lithotrophy, suggesting that they are poised to use inorganic electron donors encountered in hydrothermal plumes.
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Beinart RA, Sanders JG, Faure B, Sylva SP, Lee RW, Becker EL, Gartman A, Luther GW, Seewald JS, Fisher CR, Girguis PR. Evidence for the role of endosymbionts in regional-scale habitat partitioning by hydrothermal vent symbioses. Proc Natl Acad Sci U S A 2012; 109:E3241-50. [PMID: 23091033 PMCID: PMC3511114 DOI: 10.1073/pnas.1202690109] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Deep-sea hydrothermal vents are populated by dense communities of animals that form symbiotic associations with chemolithoautotrophic bacteria. To date, our understanding of which factors govern the distribution of host/symbiont associations (or holobionts) in nature is limited, although host physiology often is invoked. In general, the role that symbionts play in habitat utilization by vent holobionts has not been thoroughly addressed. Here we present evidence for symbiont-influenced, regional-scale niche partitioning among symbiotic gastropods (genus Alviniconcha) in the Lau Basin. We extensively surveyed Alviniconcha holobionts from four vent fields using quantitative molecular approaches, coupled to characterization of high-temperature and diffuse vent-fluid composition using gastight samplers and in situ electrochemical analyses, respectively. Phylogenetic analyses exposed cryptic host and symbiont diversity, revealing three distinct host types and three different symbiont phylotypes (one ε-proteobacteria and two γ-proteobacteria) that formed specific associations with one another. Strikingly, we observed that holobionts with ε-proteobacterial symbionts were dominant at the northern fields, whereas holobionts with γ-proteobacterial symbionts were dominant in the southern fields. This pattern of distribution corresponds to differences in the vent geochemistry that result from deep subsurface geological and geothermal processes. We posit that the symbionts, likely through differences in chemolithoautotrophic metabolism, influence niche utilization among these holobionts. The data presented here represent evidence linking symbiont type to habitat partitioning among the chemosynthetic symbioses at hydrothermal vents and illustrate the coupling between subsurface geothermal processes and niche availability.
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Affiliation(s)
- Roxanne A. Beinart
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138
| | - Jon G. Sanders
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138
| | - Baptiste Faure
- Biology Department, Pennsylvania State University, University Park, PA 16802
- Institut de Recherche pour le Développement, Laboratoire d'Ecologie Marine, Université de la Réunion, 97715 Saint Denis de La Réunion, France
| | - Sean P. Sylva
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543
| | - Raymond W. Lee
- School of Biological Sciences, Washington State University, Pullman, WA 99164; and
| | - Erin L. Becker
- Biology Department, Pennsylvania State University, University Park, PA 16802
| | - Amy Gartman
- School of Marine Science and Policy, University of Delaware, Lewes, DE 19958
| | - George W. Luther
- School of Marine Science and Policy, University of Delaware, Lewes, DE 19958
| | - Jeffrey S. Seewald
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543
| | - Charles R. Fisher
- Biology Department, Pennsylvania State University, University Park, PA 16802
| | - Peter R. Girguis
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138
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Contrasting crustal production and rapid mantle transitions beneath back-arc ridges. Nature 2011; 469:198-202. [PMID: 21228874 DOI: 10.1038/nature09690] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Accepted: 11/18/2010] [Indexed: 11/09/2022]
Abstract
The opening of back-arc basins behind subduction zones progresses from initial rifting near the volcanic arc to seafloor spreading. During this process, the spreading ridge and the volcanic arc separate and lavas erupted at the ridge are predicted to evolve away from being heavily subduction influenced (with high volatile contents derived from the subducting plate). Current models predict gradational, rather than abrupt, changes in the crust formed along the ridge as the inferred broad melting region beneath it migrates away from heavily subduction-influenced mantle. In contrast, here we show that across-strike and along-strike changes in crustal properties at the Eastern Lau spreading centre are large and abrupt, implying correspondingly large discontinuities in the nature of the mantle supplying melt to the ridge axes. With incremental separation of the ridge axis from the volcanic front of as little as 5 km, seafloor morphology changes from shallower complex volcanic landforms to deeper flat sea floor dominated by linear abyssal hills, upper crustal seismic velocities abruptly increase by over 20%, and gravity anomalies and isostasy indicate crustal thinning of more than 1.9 km. We infer that the abrupt changes in crustal properties reflect rapid evolution of the mantle entrained by the ridge, such that stable, broad triangular upwelling regions, as inferred for mid-ocean ridges, cannot form near the mantle wedge corner. Instead, the observations imply a dynamic process in which the ridge upwelling zone preferentially captures water-rich low-viscosity mantle when it is near the arc. As the ridge moves away from the arc, a tipping point is reached at which that material is rapidly released from the upwelling zone, resulting in rapid changes in the character of the crust formed at the ridge.
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Lin SC, Kuo BY, Chung SL. Thermomechanical models for the dynamics and melting processes in the Mariana subduction system. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2010jb007658] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Bézos A, Escrig S, Langmuir CH, Michael PJ, Asimow PD. Origins of chemical diversity of back-arc basin basalts: A segment-scale study of the Eastern Lau Spreading Center. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008jb005924] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Keller NS, Arculus RJ, Hermann J, Richards S. Submarine back-arc lava with arc signature: Fonualei Spreading Center, northeast Lau Basin, Tonga. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jb005451] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Nicole S. Keller
- Research School of Earth Sciences; Australian National University; Canberra, ACT Australia
| | - Richard J. Arculus
- Research School of Earth Sciences; Australian National University; Canberra, ACT Australia
| | - Jörg Hermann
- Research School of Earth Sciences; Australian National University; Canberra, ACT Australia
| | - Simon Richards
- Research School of Earth Sciences; Australian National University; Canberra, ACT Australia
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Pearce JA, Stern RJ. Origin of back-arc basin magmas: Trace element and isotope perspectives. BACK-ARC SPREADING SYSTEMS: GEOLOGICAL, BIOLOGICAL, CHEMICAL, AND PHYSICAL INTERACTIONS 2006. [DOI: 10.1029/166gm06] [Citation(s) in RCA: 155] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
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Tamura Y. Some geochemical constraints on hot fingers in the mantle wedge: evidence from NE Japan. ACTA ACUST UNITED AC 2003. [DOI: 10.1144/gsl.sp.2003.219.01.11] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractMantle melting and the production of magmas along the NE Japan arc may be controlled by hot regions in the mantle wedge (hot fingers) that move toward the volcanic front along upward-sloping trajectories. At depths equivalent to 1–2 GPa, where magmas are expected to segregate from mantle diapirs, the hot-finger structures result in a decreasing thermal gradient away from volcanic front. Low-alkali tholeiite is therefore formed by the greater degree of diapiric melting near the volcanic front; high-alumina basalt and alkali olivine basalt are produced by lesser degrees of diapiric melting to the west. The grouping of volcanoes at the volcanic front is interpreted as being controlled by thermal structure in the mantle wedge, and groups are concentrated above the tips of the hot fingers. Map-view variations of minimum 87Sr/86Sr of NE Japan volcanoes are interpreted as resulting from transport of fertile and high-87Sr/86Sr mantle material into the magma source region in the hot fingers. Given that mantle diapirs are formed in the lower part of the mantle wedge, a greater proportion of fertile material will be contained in the diapirs at the tips of the hot fingers, resulting in higher 87Sr/86Sr magmas along the volcanic front. Conveyor-like return flow carries the sheet-like remnants of the fingers to depth along the top of the subducting slab.
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Affiliation(s)
- Y. Tamura
- Institute for Frontier Research on Earth Evolution (IFREE), Japan Marine Science and Technology Centre (JAMSTEC)
Yokosuka 237-0061, Japan
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Abstract
AbstractThe East Scotia Ridge exhibits systematic variations in axial morphology and basalt geochemistry. Central segments have morphology typical of intermediate-rate spreading centres and erupt mainly normal mid-ocean ridge basalt (N-MORB). Segments near the ridge ends exhibit anomalous, inflated, axial morphology and erupt more evolved basalts, influenced by the Bouvet plume in the north. As the end segments lie closer to the volcanic arc, these variations could be caused by coupled flow within the mantle wedge, as inferred from similar studies in the Lau Basin. Three of the four zones of crustal accretion defined from the Lau Basin may be identified in the East Scotia Sea, although there is no counterpart to a zone of diminished magma supply observed at the East Lau Spreading Centre. Superimposed on the pattern of plate-driven flow is a ridge-parallel flow related to inflow of Atlantic mantle into the East Scotia Sea back-arc region at both ends of the South Sandwich slab. The inflow causes enhanced magmatism and propagation of the end segments towards the middle of the back-arc region, and may be related to trench-parallel flow beneath the rapidly retreating slab. Alternatively, it may be driven by buoyancy flux from Atlantic hot spots. There is no evidence that retreat was ever driven by escape flow of Pacific mantle.
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Affiliation(s)
- Roy Livermore
- British Antarctic Survey
High Cross, Madingley Road, Cambridge CB3 0ET, UK
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Larter RD, Vanneste LE, Morris P, Smythe DK. Structure and tectonic evolution of the South Sandwich arc. ACTA ACUST UNITED AC 2003. [DOI: 10.1144/gsl.sp.2003.219.01.13] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractDetailed analysis of marine magnetic profiles from the western part of the East Scotia Sea confirms continuous, organized back-arc spreading since at least 15 Ma ago. In the eastern part of the East Scotia Sea, the South Sandwich arc lies on crust that formed at the back-arc spreading centre since 10 Ma ago, so older back-arc crust forms the basement of the present inner forearc. Interpretations of two multichannel seismic reflection profiles reveal the main structural components of the arc at shallow depth, including evidence of trench-normal extension in the mid-forearc, and other features consistent with ongoing subduction erosion. The seismic profile interpretations have been used to constrain simple two-dimensional gravity models. The models were designed to provide constraints on the maximum possible thickness of the arc crust, and it is concluded that this is 20 and 19.2 km on the northern and southern lines, respectively. On the northern line the models indicate that the forearc crust cannot be much thicker than normal oceanic crust. Even with such thin crust, however, the magmatic growth rate implied by the cross-section of the arc crust is within the range recently estimated for two other arcs that have been built over a much longer interval.
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Affiliation(s)
- Robert D. Larter
- British Antarctic Survey
High Cross, Madingley Road, Cambridge CB3 0ET, UK
| | - Lieve E. Vanneste
- British Antarctic Survey
High Cross, Madingley Road, Cambridge CB3 0ET, UK
| | - Peter Morris
- British Antarctic Survey
High Cross, Madingley Road, Cambridge CB3 0ET, UK
| | - David K. Smythe
- Department of Geology and Applied Geology, University of Glasgow
UK
- GeoLogica Ltd
191 Wilton Street, Glasgow G20 6DF, UK
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