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Wang B, Tian W, Fu B, Fang JQ. Channelized CO2-Rich Fluid Activity along a Subduction Interface in the Paleoproterozoic Wutai Complex, North China Craton. MINERALS 2021; 11:748. [DOI: 10.3390/min11070748] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Greenschist facies metabasite (chlorite schist) and metasediments (banded iron formation (BIF)) in the Wutai Complex, North China Craton recorded extensive fluid activities during subduction-related metamorphism. The pervasive dolomitization in the chlorite schist and significant dolomite enrichment at the BIF–chlorite schist interface support the existence of highly channelized updip transportation of CO2-rich hydrothermal fluids. Xenotime from the chlorite schist has U concentrations of 39–254 ppm and Th concentrations of 121–2367 ppm, with U/Th ratios of 0.11–0.62, which is typical of xenotime precipitated from circulating hydrothermal fluids. SHRIMP U–Th–Pb dating of xenotime determines a fluid activity age of 1.85 ± 0.07 Ga. The metasomatic dolomite has δ13CV-PDB from −4.17‰ to −3.10‰, which is significantly lower than that of carbonates from greenschists, but similar to the fluid originated from Rayleigh fractionating decarbonation at amphibolite facies metamorphism along the regional geotherm (~15 °C/km) of the Wutai Complex. The δ18OV-SMOW values of the dolomite (12.08–13.85‰) can also correspond to this process, considering the contribution of dehydration. Based on phase equilibrium modelling, we ascertained that the hydrothermal fluid was rich in CO2, alkalis, and silica, with X(CO2) in the range of 0.24–0.28. All of these constraints suggest a channelized CO2-rich fluid activity along the sediment–basite interface in a warm Paleoproterozoic subduction zone, which allowed extensive migration and sequestration of volatiles (especially carbon species) beneath the forearc.
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Kemp AIS. Early earth geodynamics: cross examining the geological testimony. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2018; 376:rsta.2018.0169. [PMID: 30275167 PMCID: PMC6189561 DOI: 10.1098/rsta.2018.0169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/15/2018] [Indexed: 05/23/2023]
Abstract
Many studies link the presence of continents on Earth to the operation of plate tectonics. Radiogenic isotope data have, however, long consigned the bulk of crust generation and preservation to the murky realm of the Precambrian Earth, where the prevailing geodynamic systems are highly uncertain due to the sparse and complex nature of the geological record of these early eons. The purpose of this paper is to examine the nature of this geological record, considering the biases and artefacts that may undermine its fidelity, and to assess what are the most robust lines of evidence from which meaningful geodynamic inferences can be drawn. This is pursued with reference to Hadean detrital zircons, Archean gneiss complexes and Archean granite-greenstone terranes, and by considering isotopic proxies of crust-mantle interaction. The evidence reinforces long held views that the formation of some of the oldest continental nuclei involved a distinctive mode of planetary geodynamics that rests uneasily within definitions of modern style plate tectonics. A detailed interrogation of the oldest rocks, integrating multi-scale information from the best preserved whole-rock and mineral archives, and emphasizing careful selection at the sampling and analytical stages, will lead to the most robust input data for petrological and thermodynamic models of early Earth processes.This article is part of a discussion meeting issue 'Earth dynamics and the development of plate tectonics'.
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Affiliation(s)
- Anthony I S Kemp
- School of Earth Sciences, University of Western Australia, Perth 6009, Australia
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Farris DW, Cardona A, Montes C, Foster D, Jaramillo C. Magmatic evolution of Panama Canal volcanic rocks: A record of arc processes and tectonic change. PLoS One 2017; 12:e0176010. [PMID: 28489866 PMCID: PMC5425183 DOI: 10.1371/journal.pone.0176010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 03/31/2017] [Indexed: 11/18/2022] Open
Abstract
Volcanic rocks along the Panama Canal present a world-class opportunity to examine the relationship between arc magmatism, tectonic forcing, wet and dry magmas, and volcanic structures. Major and trace element geochemistry of Canal volcanic rocks indicate a significant petrologic transition at 21–25 Ma. Oligocene Bas Obispo Fm. rocks have large negative Nb-Ta anomalies, low HREE, fluid mobile element enrichments, a THI of 0.88, and a H2Ocalc of >3 wt. %. In contrast, the Miocene Pedro Miguel and Late Basalt Fm. exhibit reduced Nb-Ta anomalies, flattened REE curves, depleted fluid mobile elements, a THI of 1.45, a H2Ocalc of <1 wt. %, and plot in mid-ocean ridge/back-arc basin fields. Geochemical modeling of Miocene rocks indicates 0.5–0.1 kbar crystallization depths of hot (1100–1190°C) magmas in which most compositional diversity can be explained by fractional crystallization (F = 0.5). However, the most silicic lavas (Las Cascadas Fm.) require an additional mechanism, and assimilation-fractional-crystallization can reproduce observed compositions at reasonable melt fractions. The Canal volcanic rocks, therefore, change from hydrous basaltic pyroclastic deposits typical of mantle-wedge-derived magmas, to hot, dry bi-modal magmatism at the Oligocene-Miocene boundary. We suggest the primary reason for the change is onset of arc perpendicular extension localized to central Panama. High-resolution mapping along the Panama Canal has revealed a sequence of inward dipping maar-diatreme pyroclastic pipes, large basaltic sills, and bedded silicic ignimbrites and tuff deposits. These volcanic bodies intrude into the sedimentary Canal Basin and are cut by normal and subsequently strike-slip faults. Such pyroclastic pipes and basaltic sills are most common in extensional arc and large igneous province environments. Overall, the change in volcanic edifice form and geochemistry are related to onset of arc perpendicular extension, and are consistent with the idea that Panama arc crust fractured during collision with South America forming the observed Canal extensional zone.
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Affiliation(s)
- David W. Farris
- Florida State University, Department of Earth, Ocean, and Atmospheric Sciences, Tallahassee, Florida, United States of America
- * E-mail:
| | | | - Camilo Montes
- Yachay Tech University, Department of Geological Sciences, San José de Urcuquí, Ecuador
| | - David Foster
- University of Florida, Department of Geological Sciences, Gainesville, Florida, United States of America
| | - Carlos Jaramillo
- Smithsonian Tropical Research Institute, Unit 0948, APO AA, United States of America
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A 'hidden' 18O-enriched reservoir in the sub-arc mantle. Sci Rep 2014; 4:4232. [PMID: 24577190 PMCID: PMC3937801 DOI: 10.1038/srep04232] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 02/13/2014] [Indexed: 11/09/2022] Open
Abstract
Plate subduction continuously transports crustal materials with high-δ(18)O values down to the mantle wedge, where mantle peridotites are expected to achieve the high-δ(18)O features. Elevated δ(18)O values relative to the upper mantle value have been reported for magmas from some subduction zones. However, peridotites with δ(18)O values significantly higher than the well-defined upper mantle values have never been observed from modern subduction zones. Here we present in-situ oxygen isotope data of olivine crystals in Sailipu mantle xenoliths from South Tibet, which have been subjected to a long history of Tethyan subduction before the India-Asia collision. Our data identify for the first time a metasomatized mantle that, interpreted as the sub-arc lithospheric mantle, shows anomalously enriched oxygen isotopes (δ(18)O = +8.03 ± 0.28 ‰). Such a high-δ(18)O mantle commonly does not contribute significantly to typical island arc basalts. However, partial melting or contamination of such a high-δ(18)O mantle is feasible to account for the high-δ(18)O signatures in arc basalts.
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Abd El-Rahman Y, Helmy HM, Shibata T, Yoshikawa M, Arai S, Tamura A. Mineral chemistry of the Neoproterozoic Alaskan-type Akarem Intrusion with special emphasis on amphibole: Implications for the pluton origin and evolution of subduction-related magma. LITHOS 2012; 155:410-425. [DOI: 10.1016/j.lithos.2012.09.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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England PC, Katz RF. Global systematics of arc volcano position. Nature 2010; 468:E6-7; discussion E7-8. [PMID: 21150944 DOI: 10.1038/nature09154] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Accepted: 04/12/2010] [Indexed: 11/09/2022]
Abstract
Global systematics in the location of volcanic arcs above subduction zones are widely considered to be a clue to the melting processes that occur at depth, and the locations of the arcs have often been explained in terms of the release of hydrous fluids near the top of the subducting slab (see, for example, refs 3-6). Grove et al. conclude that arc volcano location is controlled by melting in the mantle at temperatures above the water-saturated upper-mantle solidus and below the upper limit of stability of the mineral chlorite and in particular, that the arc fronts lie directly above the shallowest point of such melt regions in the mantle. Here we show that this conclusion is incorrect because the calculated arc locations of Grove et al. are in error owing to the inadequate spatial resolution of their numerical models, and because the agreement that they find between predicted and observed systematics arises from a spurious correlation between calculated arc location and slab dip. A more informative conclusion to draw from their experiments is that the limits of chlorite stability (figure 1b of ref. 7) cannot explain the global systematics in the depth to the slab beneath the sharply localized arc fronts.
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Melting above the anhydrous solidus controls the location of volcanic arcs. Nature 2010; 467:700-3. [DOI: 10.1038/nature09417] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Accepted: 07/23/2010] [Indexed: 11/08/2022]
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Niu Y. Some basic concepts and problems on the petrogenesis of intra-plate ocean island basalts. ACTA ACUST UNITED AC 2009. [DOI: 10.1007/s11434-009-0668-3] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Cawood PA, Kröner A, Collins WJ, Kusky TM, Mooney WD, Windley BF. Accretionary orogens through Earth history. ACTA ACUST UNITED AC 2009. [DOI: 10.1144/sp318.1] [Citation(s) in RCA: 570] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractAccretionary orogens form at intraoceanic and continental margin convergent plate boundaries. They include the supra-subduction zone forearc, magmatic arc and back-arc components. Accretionary orogens can be grouped into retreating and advancing types, based on their kinematic framework and resulting geological character. Retreating orogens (e.g. modern western Pacific) are undergoing long-term extension in response to the site of subduction of the lower plate retreating with respect to the overriding plate and are characterized by back-arc basins. Advancing orogens (e.g. Andes) develop in an environment in which the overriding plate is advancing towards the downgoing plate, resulting in the development of foreland fold and thrust belts and crustal thickening. Cratonization of accretionary orogens occurs during continuing plate convergence and requires transient coupling across the plate boundary with strain concentrated in zones of mechanical and thermal weakening such as the magmatic arc and back-arc region. Potential driving mechanisms for coupling include accretion of buoyant lithosphere (terrane accretion), flat-slab subduction, and rapid absolute upper plate motion overriding the downgoing plate. Accretionary orogens have been active throughout Earth history, extending back until at least 3.2 Ga, and potentially earlier, and provide an important constraint on the initiation of horizontal motion of lithospheric plates on Earth. They have been responsible for major growth of the continental lithosphere through the addition of juvenile magmatic products but are also major sites of consumption and reworking of continental crust through time, through sediment subduction and subduction erosion. It is probable that the rates of crustal growth and destruction are roughly equal, implying that net growth since the Archaean is effectively zero.
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Affiliation(s)
- Peter A. Cawood
- School of Earth and Environment, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Alfred Kröner
- Institut für Geowissenschaften, Universität Mainz, 55099 Mainz, Germany
| | - William J. Collins
- School of Earth Sciences, James Cook University, Townsville, Qld 4811, Australia
| | - Timothy M. Kusky
- Department of Earth and Atmospheric Sciences, St. Louis University, St. Louis, MO 63103, USA
| | - Walter D. Mooney
- US Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, USA
| | - Brian F. Windley
- Department of Geology, University of Leicester, Leicester LE1 7RH, UK
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Grove TL, Till CB, Lev E, Chatterjee N, Médard E. Kinematic variables and water transport control the formation and location of arc volcanoes. Nature 2009; 459:694-7. [PMID: 19494913 DOI: 10.1038/nature08044] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Accepted: 04/06/2009] [Indexed: 11/09/2022]
Abstract
The processes that give rise to arc magmas at convergent plate margins have long been a subject of scientific research and debate. A consensus has developed that the mantle wedge overlying the subducting slab and fluids and/or melts from the subducting slab itself are involved in the melting process. However, the role of kinematic variables such as slab dip and convergence rate in the formation of arc magmas is still unclear. The depth to the top of the subducting slab beneath volcanic arcs, usually approximately 110 +/- 20 km, was previously thought to be constant among arcs. Recent studies revealed that the depth of intermediate-depth earthquakes underneath volcanic arcs, presumably marking the slab-wedge interface, varies systematically between approximately 60 and 173 km and correlates with slab dip and convergence rate. Water-rich magmas (over 4-6 wt% H(2)O) are found in subduction zones with very different subduction parameters, including those with a shallow-dipping slab (north Japan), or steeply dipping slab (Marianas). Here we propose a simple model to address how kinematic parameters of plate subduction relate to the location of mantle melting at subduction zones. We demonstrate that the location of arc volcanoes is controlled by a combination of conditions: melting in the wedge is induced at the overlap of regions in the wedge that are hotter than the melting curve (solidus) of vapour-saturated peridotite and regions where hydrous minerals both in the wedge and in the subducting slab break down. These two limits for melt generation, when combined with the kinematic parameters of slab dip and convergence rate, provide independent constraints on the thermal structure of the wedge and accurately predict the location of mantle wedge melting and the position of arc volcanoes.
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Affiliation(s)
- T L Grove
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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Tatsumi Y, Shukuno H, Tani K, Takahashi N, Kodaira S, Kogiso T. Structure and growth of the Izu-Bonin-Mariana arc crust: 2. Role of crust-mantle transformation and the transparent Moho in arc crust evolution. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jb005121] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Kodaira S, Sato T, Takahashi N, Ito A, Tamura Y, Tatsumi Y, Kaneda Y. Seismological evidence for variable growth of crust along the Izu intraoceanic arc. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jb004593] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Stern RJ. When and how did plate tectonics begin? Theoretical and empirical considerations. ACTA ACUST UNITED AC 2007. [DOI: 10.1007/s11434-007-0073-8] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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