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Age Progressive Volcanism in the New England Seamounts and the Opening of the Central Atlantic Ocean
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 89, NO. B12, PAGES 9980-9990, NOVEMBER 10, 1984 AGEPROGRESSIVE VOLCANISM IN THENEW ENGLAND SEAMOUNTS AND THE OPENING OF THE CENTRAL ATLANTIC OCEAN R. A. Duncan College of Oceanography, Oregon State University, Corvallis Abstract. Radiometric ages (K-Ar and •øAr- transient featur e•s that allow calculations of 39Ar methods) have been determined on dredged relative motions only. volcanic rocks from seven of the New England The possibility that plate motions may be Seamounts, a prominent northwest-southeast trend- recorded by lines of islands and seamounts in the ing volcanic lineament in the northwestern ocean basins is attractive in this regard. If, Atlantic Ocean. The •øAr-39Ar total fusion and as the Carey-Wilson-Morgan model [Carey, 1958; incren•ental heating ages show an increase in Wilson, 1963; Morgan, 19•1] proposes, sublitho- seamount construction age from southeast to spheric, thermal anomalies called hot spots are northwest that is consistent with northwestward active and fixed with respect to one another in motion of the North American plate over a New the earth's upper mantle, they would then consti- England hot spot between 103 and 82 Ma. A linear tute a reference frame for directly and precisely volcano migration rate of 4.7 cm/yr fits the measuring plate motions. Ancient longitudes as seamount age distribution. These ages fall well as latitudes would be determined from vol- Within a longer age progression from the Corner cano construction ages along the tracks left by Seamounts (70 to 75 Ma), at the eastern end of hot spots and, providing relative plate motions the New England Seamounts, to the youngest phase are also known, quantitative estimates of conver- of volcanism in the White Mountain Igneous gent plate motions can be calculated [Engebretson Province, New England (100 to 124 Ma). -
Cenozoic Changes in Pacific Absolute Plate Motion A
CENOZOIC CHANGES IN PACIFIC ABSOLUTE PLATE MOTION A THESIS SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAI`I IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN GEOLOGY AND GEOPHYSICS DECEMBER 2003 By Nile Akel Kevis Sterling Thesis Committee: Paul Wessel, Chairperson Loren Kroenke Fred Duennebier We certify that we have read this thesis and that, in our opinion, it is satisfactory in scope and quality as a thesis for the degree of Master of Science in Geology and Geophysics. THESIS COMMITTEE Chairperson ii Abstract Using the polygonal finite rotation method (PFRM) in conjunction with the hotspot- ting technique, a model of Pacific absolute plate motion (APM) from 65 Ma to the present has been created. This model is based primarily on the Hawaiian-Emperor and Louisville hotspot trails but also incorporates the Cobb, Bowie, Kodiak, Foundation, Caroline, Mar- quesas and Pitcairn hotspot trails. Using this model, distinct changes in Pacific APM have been identified at 48, 27, 23, 18, 12 and 6 Ma. These changes are reflected as kinks in the linear trends of Pacific hotspot trails. The sense of motion and timing of a number of circum-Pacific tectonic events appear to be correlated with these changes in Pacific APM. With the model and discussion presented here it is suggested that Pacific hotpots are fixed with respect to one another and with respect to the mantle. If they are moving as some paleomagnetic results suggest, they must be moving coherently in response to large-scale mantle flow. iii List of Tables 4.1 Initial hotspot locations . -
Integrated 2D Geophysical Modeling Over the Juan De Fuca Plate Asif
Integrated 2D geophysical modeling over the Juan de Fuca plate Asif Ashraf*, Irina Filina University of Nebraska-Lincoln Out of three oceanic plates subducting beneath North America along the Cascadia Subduction Zone, the Juan de Fuca (JdF) plate is the most intriguing one as it has an unusual seismicity pattern. The two other plates – the Explorer to the north and the Gorda to the south – are associated with a large number of earthquakes along the subduction zone. In contrast, JdF is seismically quiescent, so the inevitable and potentially devastating megathrust earthquake is expected in that region. To understand the tectonic complexity of the JdF subduction, it is important to understand the overall crustal architecture of the margin as well as to know physical properties (densities and magnetic susceptibilities) of the rocks of both oceanic and continental domains. Hence, we performed 2D integrated geophysical modeling along a published seismic reflection profile spanning from the Juan de Fuca spreading ridge to the High Cascades onshore. In our analysis, we have integrated multiple geophysical data from public sources, namely gravity and magnetic fields with seismic reflections and refractions. Our constructed 2D geophysical model starts from the Axial segment of the JdF spreading ridge. On the western side of the profile, gravity model requires lower densities of the mantle rocks associated with the Cobb hotspot. There are also two bathymetric seamounts near the oceanic ridge that have both gravity and magnetic signatures. Our profile crosses the pseudofault zones that require lower crustal densities with respect to adjacent oceanic crusts. We interpret this as evidence of extensive faulting in that region making the pseudofaults zones of weakness within the JdF plate. -
Mantle Dynamics and Characteristics of the Azores Plateau
Earth and Planetary Science Letters 362 (2013) 258–271 Contents lists available at SciVerse ScienceDirect Earth and Planetary Science Letters journal homepage: www.elsevier.com/locate/epsl Mantle dynamics and characteristics of the Azores plateau C. Adam a,n, P. Madureira a,b, J.M. Miranda c, N. Lourenc-o c,d, M. Yoshida e, D. Fitzenz a,1 a Centro de Geofı´sica de E´vora/Univ. E´vora, 7002-554 E´vora, Portugal b Estrutura de Missao~ para a Extensao~ da Plataforma Continental (EMEPC), 2770-047, Pac-o d’ Arcos, Portugal c Instituto Portugues do Mar e da Atmosfera, Lisboa, Portugal d University of Algarve, IDL, Campus de Gambelas, 8000 Faro, Portugal e Institute for Research on Earth Evolution (IFREE), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Kanagawa 237-0061, Japan article info abstract Article history: Situated in the middle of the Atlantic Ocean, the Azores plateau is a region of elevated topography Received 25 July 2012 encompassing the triple junction between the Eurasian, Nubian and North American plates. The plateau is Received in revised form crossed by the Mid-Atlantic Ridge, and the Terceira Rift is generally thought of as its northern boundary. 2 November 2012 The origin of the plateau and of the Terceira Rift is still under debate. This region is associated with active Accepted 5 November 2012 volcanism. Geophysical data describe complex tectonic and seismic patterns. The mantle under this region Editor: T. Spohn Available online 18 January 2013 is characterized by anomalously slow seismic velocities. However, this mantle structure has not yet been used to quantitatively assess the influence of the mantle dynamics on the surface tectonics. -
A Joint Local and Teleseismic Tomography Study Of
PUBLICATIONS Journal of Geophysical Research: Solid Earth RESEARCH ARTICLE A joint local and teleseismic tomography study 10.1002/2015JB012761 of the Mississippi Embayment and New Madrid Key Points: Seismic Zone • We present detailed 3-D images of Vp 1 1 1 and Vs for the upper mantle below the Cecilia A. Nyamwandha , Christine A. Powell , and Charles A. Langston ME and NMSZ • A prominent low-velocity anomaly 1Center for Earthquake Research and Information, University of Memphis, Memphis, Tennessee, USA with similar Vp and Vs anomalies is imaged in the upper mantle • Regions of similar high Vp and Vs anomalies present above and to the Abstract Detailed, upper mantle P and S wave velocity (Vp and Vs) models are developed for the northern sides of the low-velocity anomaly Mississippi Embayment (ME), a major physiographic feature in the Central United States (U.S.) and the location of the active New Madrid Seismic Zone (NMSZ). This study incorporates local earthquake and teleseismic data from the New Madrid Seismic Network, the Earthscope Transportable Array, and the Correspondence to: FlexArray Northern Embayment Lithospheric Experiment stations. The Vp and Vs solutions contain anomalies C. A. Nyamwandha, with similar magnitudes and spatial distributions. High velocities are present in the lower crust beneath the [email protected] NMSZ. A pronounced low-velocity anomaly of ~ À3%–À5% is imaged at depths of 100–250 km. High-velocity anomalies of ~ +3%–+4% are observed at depths of 80–160 km and are located along the sides and top Citation: of the low-velocity anomaly. The low-velocity anomaly is attributed to the presence of hot fluids upwelling Nyamwandha, C. -
S41598-020-76691-1 1 Vol.:(0123456789)
www.nature.com/scientificreports OPEN Rifting of the oceanic Azores Plateau with episodic volcanic activity B. Storch1*, K. M. Haase1, R. H. W. Romer1, C. Beier1,2 & A. A. P. Koppers3 Extension of the Azores Plateau along the Terceira Rift exposes a lava sequence on the steep northern fank of the Hirondelle Basin. Unlike typical tholeiitic basalts of oceanic plateaus, the 1.2 km vertical submarine stratigraphic profle reveals two successive compositionally distinct basanitic to alkali basaltic eruptive units. The lower unit is volumetrically more extensive with ~ 1060 m of the crustal profle forming between ~ 2.02 and ~ 1.66 Ma, followed by a second unit erupting the uppermost ~ 30 m of lavas in ~ 100 kyrs. The age of ~ 1.56 Ma of the youngest in-situ sample at the top of the profle implies that the 35 km-wide Hirondelle Basin opened after this time along normal faults. This rifting phase was followed by alkaline volcanism at D. João de Castro seamount in the basin center indicating episodic volcanic activity along the Terceira Rift. The mantle source compositions of the two lava units change towards less radiogenic Nd, Hf, and Pb isotope ratios. A change to less SiO2-undersaturated magmas may indicate increasing degrees of partial melting beneath D. João de Castro seamount, possibly caused by lithospheric thinning within the past 1.5 million years. Our results suggest that rifting of oceanic lithosphere alternates between magmatically and tectonically dominated phases. Oceanic plateaus with a crustal thickness to 30 km cover large areas in the oceans and these bathymetric swells afect oceanic currents and marine life 1,2. -
High-Resolution Surveys Along the Hot Spot–Affected Galapagos Spreading Center: 1
University of South Carolina Scholar Commons Faculty Publications Earth, Ocean and Environment, School of the 9-27-2008 High-Resolution Surveys Along the Hot Spot–Affected Galapagos Spreading Center: 1. Distribution of Hydrothermal Activity Edward T. Baker Rachel M. Haymon University of California - Santa Barbara Joseph A. Resing Scott M. White University of South Carolina - Columbia, [email protected] Sharon L. Walker See next page for additional authors Follow this and additional works at: https://scholarcommons.sc.edu/geol_facpub Part of the Earth Sciences Commons Publication Info Published in Geochemistry, Geophysics, Geosystems, Volume 9, Issue 9, 2008, pages 1-16. Baker, E. T., Haymon, R. M., Resing, J. A., White, S. M., Walker, S. L., Macdonald, K. C., Nakamura, K. (2008). High-resolution surveys along the hot spot–affected Galapagos Spreading Center: 1. Distribution of hydrothermal activity. Geochemistry, Geophysics, Geosystems, 9 (9), 1-16. © Geochemistry, Geophysics, Geosystems 2008, American Geophysical Union This Article is brought to you by the Earth, Ocean and Environment, School of the at Scholar Commons. It has been accepted for inclusion in Faculty Publications by an authorized administrator of Scholar Commons. For more information, please contact [email protected]. Author(s) Edward T. Baker, Rachel M. Haymon, Joseph A. Resing, Scott M. White, Sharon L. Walker, Ken C. Macdonald, and Ko-ichi Nakamura This article is available at Scholar Commons: https://scholarcommons.sc.edu/geol_facpub/67 Article Geochemistry 3 Volume 9, Number 9 Geophysics 27 September 2008 Q09003, doi:10.1029/2008GC002028 GeosystemsG G ISSN: 1525-2027 AN ELECTRONIC JOURNAL OF THE EARTH SCIENCES Published by AGU and the Geochemical Society High-resolution surveys along the hot spot–affected Gala´pagos Spreading Center: 1. -
Tectonic-Sedimentary System of the Atlantis‒Meteor Seamounts (North
ISSN 0024-4902, Lithology and Mineral Resources, 2019, Vol. 54, No. 5, pp. 374–389. © Pleiades Publishing, Inc., 2019. Russian Text © The Author(s), 2019, published in Litologiya i Poleznye Iskopaemye, 2019, No. 5. Tectonic-Sedimentary System of the Atlantis‒Meteor Seamounts (North Atlantic): Volcanism and Sedimentation in the Late Miocene‒Pliocene and Position in the Atlantic‒Arctic Rift System N. P. Chamova, *, I. E. Stukalovaa, S. Yu. Sokolova, A. A. Peivea, N. V. Gor’kovaa, A. A. Razumovskiia, M. E. Bylinskayaa, and L. A. Golovinaa aGeological Institute, Russian Academy of Sciences, Pyzhevskii per., 7, Moscow, 119017 Russia *e-mail: [email protected] Received February 19, 2019; revised February 19, 2019; accepted March 13, 2019 Abstract—The paper analyzes original data obtained on the Atlantis‒Meteor seamount system during Cruise 33 of the R/V Akademik Nikolai Strakhov in the eastern North Atlantic. This system is a volcanic rise formed on the Canary abyssal plate and represents one of the key objects for understanding the geological history of opening of the central segment of the Atlantic Ocean. Basalts, tephrites, and organogenic terrigenous lagoonal marine sediments dredged from the Atlantis, Plato, and Cruiser seamounts are considered. Petrog- raphy and compositions of the Atlantis and Cruiser basalts reflect significant differences in settings of their eruptions. Well-crystallized vesicle-free olivine basalts from the Atlantis Seamount were ejected under deep- water conditions. Glassy vesicular basalts of the Cruiser Seamount are typical of shallow subaerial eruptions. Evidence for the accumulation of tuff breccias and tuff gravelstones of the Plato Seamount in subaerial set- tings are obtained. -
Anatomy of an Active Submarine Volcano
Downloaded from geology.gsapubs.org on July 28, 2014 Anatomy of an active submarine volcano A.F. Arnulf1, A.J. Harding1, G.M. Kent2, S.M. Carbotte3, J.P. Canales4, and M.R. Nedimović3,5 1Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California–San Diego, La Jolla, California 92093, USA 2Nevada Seismological Laboratory, 0174, University of Nevada–Reno, Reno, Nevada 89557, USA 3Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA 4Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02540, USA 5Department of Earth Sciences, Dalhousie University, Halifax, Nova Scotia B3H4J1, Canada ABSTRACT To date, seismic experiments have been one Most of the magma erupted at mid-ocean ridges is stored in a mid-crustal melt lens that lies of the keys in our understanding of the inter- at the boundary between sheeted dikes and gabbros. Nevertheless, images of the magma path- nal structure of volcanic systems (Okubo et al., ways linking this melt lens to the overlying eruption site have remained elusive. Here, we have 1997; Kent et al., 2000; Zandomeneghi et al., used seismic methods to image the thickest magma reservoir observed beneath any spreading 2009; Paulatto et al., 2012). However, most ex- center to date, which is principally attributed to the juxtaposition of the Juan de Fuca Ridge periments, especially subaerial-based ones, are with the Cobb hotspot (northwestern USA). Our results reveal a complex melt body, which restricted to refraction geometries with limited is ~14 km long, 3 km wide, and up to 1 km thick, beneath the summit caldera. -
Aula 4 – Tipos Crustais Tipos Crustais Continentais E Oceânicos
14/09/2020 Aula 4 – Tipos Crustais Introdução Crosta e Litosfera, Astenosfera Crosta Oceânica e Tipos crustais oceânicos Crosta Continental e Tipos crustais continentais Tipos crustais Continentais e Oceânicos A interação divergente é o berço fundamental da litosfera oceânica: não forma cadeias de montanhas, mas forma a cadeia desenhada pela crista meso- oceânica por mais de 60.000km lineares do interior dos oceanos. A interação convergente leva inicialmente à formação dos arcos vulcânicos e magmáticos (que é praticamente o berço da litosfera continental) e posteriormente à colisão (que é praticamente o fechamento do Ciclo de Wilson, o desparecimento da litosfera oceânica). 1 14/09/2020 Curva hipsométrica da terra A área de superfície total da terra (A) é de 510 × 106 km2. Mostra a elevação em função da área cumulativa: 29% da superfície terrestre encontra-se acima do nível do mar; os mais profundos oceanos e montanhas mais altas uma pequena fração da A. A > parte das regiões de plataforma continental coincide com margens passivas, constituídas por crosta continental estirada. Brito Neves, 1995. Tipos crustais circunstâncias geométrico-estruturais da face da Terra (continentais ou oceânicos); Característica: transitoriedade passar do Tempo Geológico e como forma de dissipar o calor do interior da Terra. Todo tipo crustal adveio de um outro ou de dois outros, e será transformado em outro ou outros com o tempo, toda esta dança expressando a perda de calor do interior para o exterior da Terra. Nenhum tipo crustal é eterno; mais "duráveis" (e.g. velhos Crátons de de "ultra-longa duração"); tipos de curta duração, muitas modificações e rápida evolução potencial (como as bacias de antearco). -
Effect of Subduction Zones on the Structure of the Small-Scale Currents at Core-Mantle Boundary
Effect of Subduction Zones on the Structure of the Small-Scale Currents at Core-Mantle Boundary. Sergey Ivanov1, Irina Demina1, Sergey Merkuryev1,2 1St-Petersburg Filial of Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio wave Propagation (SPbF IZMIRAN) 2Saint Petersburg State University, Institute of Earth Sciences Universitetskaya nab., 7-9, St. Petersburg, 199034, Russia [email protected] Abstract. The purpose of this work is to compare kinematics of small-scale current vortices located near the core-mantle boundary with high-speed anomalies of seismic wave velocity in the lowest mantle asso- ciated with the subduction zones. The small-scale vortex paths were early obtained by the authors in the frame of the macro model of the main geomagnetic field sources. Two sources were chosen whose kine- matics are characterized by the complete absence of the western drift and whose paths have a very com- plex shape. Both sources are located in the vicinity of the subduction zones characterized by the extensive coherent regions with increased speed of seismic waves in the lowest mantle. One of them is geograph- ically located near the western coast of Canada and the second one is located in the vicinity of Sumatra. For this study we used the global models of the heterogeneities of seismic wave velocity. It was obtained that the complex trajectories of the vortices is fully consistent with the high-speed anomalies of seismic wave velocity in the lowest mantle. It can be assumed that mixing up with the matter of the lowest man- tle, the substance of the liquid core rises along the lowest mantle channel and promotes its further in- crease. -
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Index [Italic page numbers indicate major references] Abaco Knoll, 359 116, 304, 310, 323 Bahama Platform, 11, 329, 331, 332, Abathomphalus mayaroensis, 101 Aquia Formation, 97, 98, 124 341, 358, 360 Abbott pluton, 220 aquifers, 463, 464, 466, 468, 471, Bahama volcanic crust, 356 Abenaki Formation, 72, 74, 257, 476, 584 Bahamas basin, 3, 5, 35, 37, 39, 40, 259, 261, 369, 372, 458 Aquitaine, France, 213, 374 50 ablation, 149 Arcadia Formation, 505 Bahamas Fracture Zone, 24, 39, 40, Abyssal Plain, 445 Archaean age, 57 50, 110, 202, 349, 358, 368 Adirondack Mountains, 568 Arctic-North Atlantic rift system, 49, Bahamas Slope, 12 Afar region, Djibouti, 220, 357 50 Bahamas-Cuban Fault system, 50 Africa, 146, 229, 269, 295, 299 Ardsley, New York, 568, 577 Baja California, Mexico, 146 African continental crust, 45, 331, Argana basin, Morocco, 206 Bajocian assemblages, 20, 32 347 Argo Fan, Scotian margin, 279 Balair fault zone, 560 African Craton, 368 Argo Salt Formation, 72, 197, 200, Baltimore Canyon trough, 3, 37, 38, African margin, 45, 374 278, 366, 369, 373 40, 50, 67, 72 , 81, 101, 102, African plate, 19, 39, 44, 49 arkoses, 3 138, 139, 222, 254, 269, 360, Afro-European plate, 197 artesian aquifers, 463 366, 369, 396, 419,437 Agamenticus pluton, 220 Ashley Formation, 126 basement rocks, 74 age, 19, 208, 223 Astrerosoma, 96 carbonate deposits, 79 Agulhas Bank, 146 Atkinson Formation, 116, 117 crustal structure, 4, 5, 46 Aiken Formation, 125 Atlantic basin, 6, 9, 264 faults in, 32 Aikin, South Carolina, 515 marine physiography, 9 geologic