1
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Olive JA, Ekström G, Buck WR, Liu Z, Escartín J, Bickert M. Mid-ocean ridge unfaulting revealed by magmatic intrusions. Nature 2024; 628:782-787. [PMID: 38600388 DOI: 10.1038/s41586-024-07247-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 02/27/2024] [Indexed: 04/12/2024]
Abstract
Mid-ocean ridges (MORs) are quintessential sites of tectonic extension1-4, at which divergence between lithospheric plates shapes abyssal hills that cover about two-thirds of the Earth's surface5,6. Here we show that tectonic extension at the ridge axis can be partially undone by tectonic shortening across the ridge flanks. This process is evidenced by recent sequences of reverse-faulting earthquakes about 15 km off-axis at the Mid-Atlantic Ridge and Carlsberg Ridge. Using mechanical models, we show that shallow compression of the ridge flanks up to the brittle failure point is a natural consequence of lithosphere unbending away from the axial relief. Intrusion of magma-filled fractures, which manifests as migrating swarms of extensional seismicity along the ridge axis, can provide the small increment of compressive stress that triggers reverse-faulting earthquakes. Through bathymetric analyses, we further find that reverse reactivation of MOR normal faults is a widely occurring process that can reduce the amplitude of abyssal hills by as much as 50%, shortly after they form at the ridge axis. This 'unfaulting' mechanism exerts a first-order influence on the fabric of the global ocean floor and provides a physical explanation for reverse-faulting earthquakes in an extensional environment.
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Affiliation(s)
- Jean-Arthur Olive
- Laboratoire de Géologie, CNRS - École Normale Supérieure - PSL University, Paris, France.
| | - Göran Ekström
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA
| | - W Roger Buck
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA
| | - Zhonglan Liu
- College of Earth Sciences, Jilin University, Changchun, China
| | - Javier Escartín
- Laboratoire de Géologie, CNRS - École Normale Supérieure - PSL University, Paris, France
| | - Manon Bickert
- Geo-Ocean, Univ. Brest, CNRS, Ifremer, UMR6538, Plouzané, France
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2
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Tian X, Behn MD, Ito G, Schierjott JC, Kaus BJP, Popov AA. Magmatism controls global oceanic transform fault topography. Nat Commun 2024; 15:1914. [PMID: 38429287 PMCID: PMC10907720 DOI: 10.1038/s41467-024-46197-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 02/16/2024] [Indexed: 03/03/2024] Open
Abstract
Oceanic transform faults play an essential role in plate tectonics. Yet to date, there is no unifying explanation for the global trend in broad-scale transform fault topography, ranging from deep valleys to shallow topographic highs. Using three-dimensional numerical models, we find that spreading-rate dependent magmatism within the transform domain exerts a first-order control on the observed spectrum of transform fault depths. Low-rate magmatism results in deep transform valleys caused by transform-parallel tectonic stretching; intermediate-rate magmatism fully accommodates far-field stretching, but strike-slip motion induces across-transform tension, producing transform strength dependent shallow valleys; high-rate magmatism produces elevated transform zones due to local compression. Our models also address the observation that fracture zones are consistently shallower than their adjacent transform fault zones. These results suggest that plate motion change is not a necessary condition for reproducing oceanic transform topography and that oceanic transform faults are not simple conservative strike-slip plate boundaries.
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Affiliation(s)
- Xiaochuan Tian
- Department of Earth and Environmental Sciences, Boston College, Chestnut Hill, MA, USA.
| | - Mark D Behn
- Department of Earth and Environmental Sciences, Boston College, Chestnut Hill, MA, USA
| | - Garrett Ito
- Department of Earth Sciences, University of Hawaii, Honolulu HI, USA
| | - Jana C Schierjott
- Department of Earth Sciences, University of Hawaii, Honolulu HI, USA
| | - Boris J P Kaus
- Institute of Geosciences, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Anton A Popov
- Institute of Geosciences, Johannes Gutenberg University Mainz, Mainz, Germany
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3
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Simon-Lledó E, Amon DJ, Bribiesca-Contreras G, Cuvelier D, Durden JM, Ramalho SP, Uhlenkott K, Arbizu PM, Benoist N, Copley J, Dahlgren TG, Glover AG, Fleming B, Horton T, Ju SJ, Mejía-Saenz A, McQuaid K, Pape E, Park C, Smith CR, Jones DOB. Carbonate compensation depth drives abyssal biogeography in the northeast Pacific. Nat Ecol Evol 2023; 7:1388-1397. [PMID: 37488225 PMCID: PMC10482686 DOI: 10.1038/s41559-023-02122-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 06/08/2023] [Indexed: 07/26/2023]
Abstract
Abyssal seafloor communities cover more than 60% of Earth's surface. Despite their great size, abyssal plains extend across modest environmental gradients compared to other marine ecosystems. However, little is known about the patterns and processes regulating biodiversity or potentially delimiting biogeographical boundaries at regional scales in the abyss. Improved macroecological understanding of remote abyssal environments is urgent as threats of widespread anthropogenic disturbance grow in the deep ocean. Here, we use a new, basin-scale dataset to show the existence of clear regional zonation in abyssal communities across the 5,000 km span of the Clarion-Clipperton Zone (northeast Pacific), an area targeted for deep-sea mining. We found two pronounced biogeographic provinces, deep and shallow-abyssal, separated by a transition zone between 4,300 and 4,800 m depth. Surprisingly, species richness was maintained across this boundary by phylum-level taxonomic replacements. These regional transitions are probably related to calcium carbonate saturation boundaries as taxa dependent on calcium carbonate structures, such as shelled molluscs, appear restricted to the shallower province. Our results suggest geochemical and climatic forcing on distributions of abyssal populations over large spatial scales and provide a potential paradigm for deep-sea macroecology, opening a new basis for regional-scale biodiversity research and conservation strategies in Earth's largest biome.
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Affiliation(s)
| | - Diva J Amon
- SpeSeas, D'Abadie, Trinidad and Tobago
- Marine Science Institute, University of California, Santa Barbara, CA, USA
| | | | - Daphne Cuvelier
- Institute of Marine Sciences-Okeanos, University of the Azores, Horta, Portugal
| | | | - Sofia P Ramalho
- Centre for Environmental and Marine Studies & Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Katja Uhlenkott
- German Centre for Marine Biodiversity Research, Senckenberg am Meer, Wilhelmshaven, Germany
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University, Oldenburg, Germany
| | - Pedro Martinez Arbizu
- German Centre for Marine Biodiversity Research, Senckenberg am Meer, Wilhelmshaven, Germany
| | | | - Jonathan Copley
- Ocean & Earth Science, University of Southampton, Southampton, UK
| | - Thomas G Dahlgren
- NORCE Climate and Environment, Bergen, Norway
- Department of Marine Sciences, University of Gothenburg, Göteborg, Sweden
| | | | - Bethany Fleming
- National Oceanography Centre, Southampton, UK
- Ocean & Earth Science, University of Southampton, Southampton, UK
| | | | - Se-Jong Ju
- Korea Institute of Ocean Science and Technology, Busan, South Korea
- Ocean Science Major, University of Science and Technology, Daejeon, South Korea
| | | | | | - Ellen Pape
- Marine Biology Research Group, Ghent University, Ghent, Belgium
| | - Chailinn Park
- Korea Institute of Ocean Science and Technology, Busan, South Korea
- Ocean Science Major, University of Science and Technology, Daejeon, South Korea
| | - Craig R Smith
- Department of Oceanography, University of Hawai'i at Manoa, Honolulu, HI, USA
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4
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Honing in on the climate signal in seafloor topography. Proc Natl Acad Sci U S A 2022; 119:e2209199119. [PMID: 35881780 PMCID: PMC9371738 DOI: 10.1073/pnas.2209199119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
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5
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Influence of late Pleistocene sea-level variations on midocean ridge spacing in faulting simulations and a global analysis of bathymetry. Proc Natl Acad Sci U S A 2022; 119:e2204761119. [PMID: 35867751 PMCID: PMC9282452 DOI: 10.1073/pnas.2204761119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We address the hypothesis that changes in Pleistocene sea level have consequences for abyssal-hill bathymetry. A model illustrates how reductions in magma production caused by rising sea level could trigger faults at 100-ky intervals at intermediate spreading-rate ridges (>2.3 cm/y) and at 41-ky intervals at faster spreading-rate ridges (>3.8 cm/y). Analysis of 17 different regional ridge systems gives characteristic length scales that closely align with the predictions from the faulting model. Furthermore, a robust spectral peak is found at the 41-ky obliquity period at fast-spreading ridges. Together, these results constitute strong evidence for a pervasive influence of Pleistocene variations in glaciation and sea level on the pattern of abyssal hills. It is established that changes in sea level influence melt production at midocean ridges, but whether changes in melt production influence the pattern of bathymetry flanking midocean ridges has been debated on both theoretical and empirical grounds. To explore the dynamics that may give rise to a sea-level influence on bathymetry, we simulate abyssal hills using a faulting model with periodic variations in melt supply. For 100-ky melt-supply cycles, model results show that faults initiate during periods of amagmatic spreading at half-rates >2.3 cm/y and for 41-ky melt-supply cycles at half-rates >3.8 cm/y. Analysis of bathymetry across 17 midocean ridge regions shows characteristic wavelengths that closely align with the predictions from the faulting model. At intermediate-spreading ridges (half-rates >2.3 cm/y and ≤3.8 cm/y) abyssal hill spacing increases with spreading rate at 0.99 km/(cm/y) or 99 ky (n= 12; 95% CI, 87 to 110 ky), and at fast-spreading ridges (half-rates >3.8 cm/y) spacing increases at 38 ky (n= 5; 95% CI, 29 to 47 ky). Including previously published analyses of abyssal-hill spacing gives a more precise alignment with the primary periods of Pleistocene sea-level variability. Furthermore, analysis of bathymetry from fast-spreading ridges shows a highly statistically significant spectral peak (P < 0.01) at the 1/(41-ky) period of Earth’s variations in axial tilt. Faulting models and observations both support a linkage between glacially induced sea-level change and the fabric of the sea floor over the late Pleistocene.
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6
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Spatial and Temporal Variations in Crustal Structure in the Eurasian Basin. JOURNAL OF MARINE SCIENCE AND ENGINEERING 2022. [DOI: 10.3390/jmse10020157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
To understand the tectonic–magmatic history, crustal structure and crustal accretion mode of the Eurasian Basin in the Arctic, we calculated the crustal thickness, residual bathymetry (RB) and non-isostatic topography of the Eurasian Basin by using the latest bathymetry, free-air gravity anomaly, crustal age and sediment thickness data. The tectonic–magmatic process of the Eurasian Basin can be divided into two stages. During magnetic isochrons 24-13 (C24-C13), the crustal structure of the basin was characterized by regional variations, while the crustal structure of the basin was characterized by local variations during magnetic isochrons 13-0 (C13-0). On the whole, the western part of the basin had a thicker crustal thickness and higher RB than the eastern part of the basin during C24-C13, which should result from the northward movement of Greenland. During magnetic isochrons 24-20 (C24-C20), the crustal structure of the eastern part of the basin had abnormally strong asymmetry. We speculate that there may be mantle upwelling beneath the Kara Sea Shelf in the south of the Eastern Eurasian Basin, which provides a large amount of melt for the crustal accretion of the southern part of the Eastern Eurasian Basin. The melt focusing supply could generate abnormally thick crust (>7 km) during magma enhancement period. The Western Eurasian Basin had stronger spatial variability and more frequency asymmetric polarity reversal than the Eastern Eurasian Basin during magnetic isochrons 6-0 (C6-0). We attribute this to the inflow of the North Atlantic mantle.
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7
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Simon-Lledó E, Bett BJ, Huvenne VA, Schoening T, Benoist NM, Jeffreys RM, Durden JM, Jones DO. Megafaunal variation in the abyssal landscape of the Clarion Clipperton Zone. PROGRESS IN OCEANOGRAPHY 2019; 170:119-133. [PMID: 30662100 PMCID: PMC6325340 DOI: 10.1016/j.pocean.2018.11.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 10/24/2018] [Accepted: 11/15/2018] [Indexed: 05/14/2023]
Abstract
The potential for imminent polymetallic nodule mining in the Clarion Clipperton Fracture Zone (CCZ) has attracted considerable scientific and public attention. This concern stems from both the extremely large seafloor areas that may be impacted by mining, and the very limited knowledge of the fauna and ecology of this region. The environmental factors regulating seafloor ecology are still very poorly understood. In this study, we focus on megafaunal ecology in the proposed conservation zone 'Area of Particular Environmental Interest 6' (study area centred 17°16'N, 122°55'W). We employ bathymetric data to objectively define three landscape types in the area (a level bottom Flat, an elevated Ridge, a depressed Trough; water depth 3950-4250 m) that are characteristic of the wider CCZ. We use direct seabed sampling to characterise the sedimentary environment in each landscape, detecting no statistically significant differences in particle size distributions or organic matter content. Additional seafloor characteristics and data on both the metazoan and xenophyophore components of the megafauna were derived by extensive photographic survey from an autonomous underwater vehicle. Image data revealed that there were statistically significant differences in seafloor cover by nodules and in the occurrence of other hard substrata habitat between landscapes. Statistically significant differences in megafauna standing stock, functional structuring, diversity, and faunal composition were detected between landscapes. The Flat and Ridge areas exhibited a significantly higher standing stock and a distinct assemblage composition compared to the Trough. Geomorphological variations, presumably regulating local bottom water flows and the occurrence of nodule and xenophyophore test substrata, between study areas may be the mechanism driving these assemblage differences. We also used these data to assess the influence of sampling unit size on the estimation of ecological parameters. We discuss these results in the contexts of regional benthic ecology and the appropriate management of potential mining activities in the CCZ and elsewhere in the deep ocean.
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Affiliation(s)
- Erik Simon-Lledó
- National Oceanography Centre, University of Southampton, Waterfront Campus, European Way, SO14 3ZH Southampton, UK
- Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, UK
| | - Brian J. Bett
- National Oceanography Centre, University of Southampton, Waterfront Campus, European Way, SO14 3ZH Southampton, UK
| | - Veerle A.I. Huvenne
- National Oceanography Centre, University of Southampton, Waterfront Campus, European Way, SO14 3ZH Southampton, UK
| | - Timm Schoening
- GEOMAR Helmholtz Centre for Ocean Research, D-24148 Kiel, Germany
| | - Noelie M.A. Benoist
- National Oceanography Centre, University of Southampton, Waterfront Campus, European Way, SO14 3ZH Southampton, UK
- Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, UK
| | - Rachel M. Jeffreys
- School of Environmental Science, University of Liverpool, L69 3GP Liverpool, UK
| | - Jennifer M. Durden
- National Oceanography Centre, University of Southampton, Waterfront Campus, European Way, SO14 3ZH Southampton, UK
| | - Daniel O.B. Jones
- National Oceanography Centre, University of Southampton, Waterfront Campus, European Way, SO14 3ZH Southampton, UK
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8
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Jiang Y, Chen J, Sun Y, Li Q, Cai Z, Li J, Guo Y, Hu W, Liu Y. Fast Deposition of Aligning Edge-On Polymers for High-Mobility Ambipolar Transistors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1805761. [PMID: 30417512 DOI: 10.1002/adma.201805761] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/14/2018] [Indexed: 06/09/2023]
Abstract
Fast deposition of aligning ambipolar polymers for high-performance organic field-effect transistors (OFETs) and inverter circuits are highly desired for both scientific studies and industry applications. Here, large-area and ordered polymer films are prepared by a bar-coating method at a rate of 120 mm s-1 in air. Atomic force microscopy and grazing-incidence wide-angle X-ray scattering analysis indicate uniform edge-on poly(fluoroisoindigo-difluorobithiophene-fluoroisoindigo-bithiophene) (PFIBI-BT) in 11.7 ± 1 nm film (≈5 layers). The elongated, uniformly oriented grains can reduce the adverse effects of the grain boundaries and facilitate charge transport in polymers. Furthermore, OFETs based on parallel film show high hole/electron mobilities up to 5.5/4.5 cm2 V-1 s-1 , which are approximately nine times of the devices prepared by spin-coating. The gain of the inverter is as high as 174, which is one of the highest values in polymer inventers currently. These results demonstrate that the excellent bipolar performance of few-layer PFIBI-BT can be ensured while achieving the compatibility of the experimental process with industrial preparation.
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Affiliation(s)
- Yingying Jiang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry Chinese Academy of Sciences, Beijing, 100190, P. R. China
- School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Jinyang Chen
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry Chinese Academy of Sciences, Beijing, 100190, P. R. China
- School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Yunlong Sun
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry Chinese Academy of Sciences, Beijing, 100190, P. R. China
- School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Qingyuan Li
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry Chinese Academy of Sciences, Beijing, 100190, P. R. China
- School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Zhengxu Cai
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Material Science & Engineering, Beijing Institute of Technology, Beijing, 100081, P. R. China
| | - Junyu Li
- DSM DMSC R&D Solutions, P.O. Box 18, 6160, MD Geleen, The Netherlands
| | - Yunlong Guo
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Wenping Hu
- Tianjin Key Laboratory of Molecular Optoelectronic Science, Department of Chemistry, School of Science, Tianjin University, Tianjin, 300072, P. R. China
| | - Yunqi Liu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry Chinese Academy of Sciences, Beijing, 100190, P. R. China
- School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
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9
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Byrnes JS, Karlstrom L. Anomalous K-Pg-aged seafloor attributed to impact-induced mid-ocean ridge magmatism. SCIENCE ADVANCES 2018; 4:eaao2994. [PMID: 29441360 PMCID: PMC5810608 DOI: 10.1126/sciadv.aao2994] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 01/09/2018] [Indexed: 05/22/2023]
Abstract
Eruptive phenomena at all scales, from hydrothermal geysers to flood basalts, can potentially be initiated or modulated by external mechanical perturbations. We present evidence for the triggering of magmatism on a global scale by the Chicxulub meteorite impact at the Cretaceous-Paleogene (K-Pg) boundary, recorded by transiently increased crustal production at mid-ocean ridges. Concentrated positive free-air gravity and coincident seafloor topographic anomalies, associated with seafloor created at fast-spreading rates, suggest volumes of excess magmatism in the range of ~105 to 106 km3. Widespread mobilization of existing mantle melt by post-impact seismic radiation can explain the volume and distribution of the anomalous crust. This massive but short-lived pulse of marine magmatism should be considered alongside the Chicxulub impact and Deccan Traps as a contributor to geochemical anomalies and environmental changes at K-Pg time.
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Affiliation(s)
- Joseph S. Byrnes
- Department of Earth Sciences, University of Minnesota, 116 Church Street Southeast, Minneapolis, MN 55455, USA
- Department of Earth Sciences, University of Oregon, 1272 University of Oregon, Eugene, OR 97403, USA
- Corresponding author.
| | - Leif Karlstrom
- Department of Earth Sciences, University of Oregon, 1272 University of Oregon, Eugene, OR 97403, USA
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10
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Sternai P, Caricchi L, Garcia-Castellanos D, Jolivet L, Sheldrake TE, Castelltort S. Magmatic pulse driven by sea-level changes associated with the Messinian salinity crisis. NATURE GEOSCIENCE 2017; 10:783-787. [PMID: 29081834 PMCID: PMC5654511 DOI: 10.1038/ngeo3032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 08/23/2017] [Indexed: 06/07/2023]
Abstract
Between 5 and 6 million years ago, during the so-called Messinian salinity crisis, the Mediterranean basin became a giant salt repository. The possibility of abrupt and kilometre-scale sea-level changes during this extreme event is debated. Messinian evaporites could signify either deep- or shallow-marine deposits, and ubiquitous erosional surfaces could indicate either subaerial or submarine features. Significant and fast reductions in sea level unload the lithosphere, which can increase the production and eruption of magma. Here we calculate variations in surface load associated with the Messinian salinity crisis and compile the available time constraints for pan-Mediterranean magmatism. We show that scenarios involving a kilometre-scale drawdown of sea level imply a phase of net overall lithospheric unloading at a time that appears synchronous with a magmatic pulse from the pan-Mediterranean igneous provinces. We verify the viability of a mechanistic link between unloading and magmatism using numerical modelling of decompression partial mantle melting and dike formation in response to surface load variations. We conclude that the Mediterranean magmatic record provides an independent validation of the controversial kilometre-scale evaporative drawdown and sheds new light on the sensitivity of magmatic systems to the surface forcing.
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Affiliation(s)
- Pietro Sternai
- Department of Earth Sciences, University of Geneva, Geneva, Switzerland
| | - Luca Caricchi
- Department of Earth Sciences, University of Geneva, Geneva, Switzerland
| | | | - Laurent Jolivet
- Intitut des Sciences de la Terre d’Orléans, University
of Orléans, Orléans, France
| | - Tom E. Sheldrake
- Department of Earth Sciences, University of Geneva, Geneva, Switzerland
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11
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Sea level fall during glaciation stabilized atmospheric CO 2 by enhanced volcanic degassing. Nat Commun 2017; 8:15867. [PMID: 28681844 PMCID: PMC5504290 DOI: 10.1038/ncomms15867] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 05/09/2017] [Indexed: 11/08/2022] Open
Abstract
Paleo-climate records and geodynamic modelling indicate the existence of complex interactions between glacial sea level changes, volcanic degassing and atmospheric CO2, which may have modulated the climate system's descent into the last ice age. Between ∼85 and 70 kyr ago, during an interval of decreasing axial tilt, the orbital component in global temperature records gradually declined, while atmospheric CO2, instead of continuing its long-term correlation with Antarctic temperature, remained relatively stable. Here, based on novel global geodynamic models and the joint interpretation of paleo-proxy data as well as biogeochemical simulations, we show that a sea level fall in this interval caused enhanced pressure-release melting in the uppermost mantle, which may have induced a surge in magma and CO2 fluxes from mid-ocean ridges and oceanic hotspot volcanoes. Our results reveal a hitherto unrecognized negative feedback between glaciation and atmospheric CO2 predominantly controlled by marine volcanism on multi-millennial timescales of ∼5,000-15,000 years.
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12
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Olive JA, Behn MD, Ito G, Buck WR, Escartín J, Howell S. Response to Comment on "Sensitivity of seafloor bathymetry to climate-driven fluctuations in mid-ocean ridge magma supply". Science 2016; 353:229. [PMID: 27418498 DOI: 10.1126/science.aaf2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 06/08/2016] [Indexed: 11/02/2022]
Abstract
Tolstoy reports the existence of a characteristic 100 thousand year (ky) period in the bathymetry of fast-spreading seafloor but does not argue that sea level change is a first-order control on seafloor morphology worldwide. Upon evaluating the overlap between tectonic and Milankovitch periodicities across spreading rates, we reemphasize that fast-spreading ridges are the best potential recorders of a sea level signature in seafloor bathymetry.
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Affiliation(s)
- J-A Olive
- Lamont-Doherty Earth Observatory, Columbia University, Palisades NY, USA.
| | - M D Behn
- Woods Hole Oceanographic Institution, Woods Hole MA, USA
| | - G Ito
- University of Hawaii, Honolulu HI, USA
| | - W R Buck
- Lamont-Doherty Earth Observatory, Columbia University, Palisades NY, USA
| | - J Escartín
- CNRS, Institut de Physique du Globe de Paris, Paris, France
| | - S Howell
- University of Hawaii, Honolulu HI, USA
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13
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Tolstoy M. Comment on "Sensitivity of seafloor bathymetry to climate-driven fluctuations in mid-ocean ridge magma supply". Science 2016; 353:229. [PMID: 27418497 DOI: 10.1126/science.aaf0625] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 06/08/2016] [Indexed: 11/02/2022]
Abstract
Olive et al (Reports, 16 October 2015, p. 310) and Goff (Technical Comment, 4 September 2015, p. 1065) raise important concerns with respect to recent findings of Milankovitch cycles in seafloor bathymetry. However, their results inherently support that the Southern East Pacific Rise is the optimum place to look for such signals and, in fact, models match those observations quite closely.
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Affiliation(s)
- Maya Tolstoy
- Department of Earth and Environmental Sciences, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY, USA
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14
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Huybers P, Langmuir C, Katz RF, Ferguson D, Proistosescu C, Carbotte S. Comment on “Sensitivity of seafloor bathymetry to climate-driven fluctuations in mid-ocean ridge magma supply”. Science 2016; 352:1405. [DOI: 10.1126/science.aae0451] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 05/17/2016] [Indexed: 11/03/2022]
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15
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Olive JA, Behn MD, Ito G, Buck WR, Escartín J, Howell S. Response to Comment on "Sensitivity of seafloor bathymetry to climate-driven fluctuations in mid-ocean ridge magma supply". Science 2016; 352:1405. [PMID: 27313035 DOI: 10.1126/science.aaf2021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 05/17/2016] [Indexed: 11/02/2022]
Abstract
Huybers et al present new bathymetric spectra from an intermediate-spreading ridge as evidence for a primary contribution of sea level cycles to the morphology of the seafloor. Although we acknowledge the possibility that sea level-modulated magmatic constructions may be superimposed on a first-order tectonic fabric, we emphasize the difficulty of deciphering these different contributions in the frequency domain alone.
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Affiliation(s)
- J-A Olive
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA.
| | - M D Behn
- Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - G Ito
- University of Hawaii, Honolulu, HI, USA
| | - W R Buck
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA
| | - J Escartín
- CNRS, Institut de Physique du Globe de Paris, Paris, France
| | - S Howell
- University of Hawaii, Honolulu, HI, USA
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16
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Lund DC, Asimow PD, Farley KA, Rooney TO, Seeley E, Jackson EW, Durham ZM. Enhanced East Pacific Rise hydrothermal activity during the last two glacial terminations. Science 2016; 351:478-82. [DOI: 10.1126/science.aad4296] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- D. C. Lund
- Deptartment of Marine Sciences, University of Connecticut, Groton, CT 06340, USA
| | - P. D. Asimow
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - K. A. Farley
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - T. O. Rooney
- Department of Geological Sciences, Michigan State University, East Lansing, MI 48824, USA
| | - E. Seeley
- Deptartment of Marine Sciences, University of Connecticut, Groton, CT 06340, USA
| | - E. W. Jackson
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, USA
| | - Z. M. Durham
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, USA
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