DOCSLIB.ORG

Deep Sea Drilling Project Initial Reports Volume 26

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Deep Sea Drilling Project Initial Reports Volume 26 INDEX Africa Antarctica, separation, 918 Bottom water, 937 Agulhas Plateau, 949 Boundaries, criteria used to locate, 678 Albian foraminifera assemblages, 750 Boundary, biostratigraphic, 677 Albian-Cenomanian foraminifera, 747 foraminifera, Amphipyndax enesseffi Zone, 774 Miocene/Pliocene, 678 Amsterdam-St. Paul volcanic complex, 924 Oligocene/Miocene, 678 Angiosperms, 816 Pleistocene/Holocene, 680 Angular unconformity, 283, 288 Pliocene/Miocene, 687 Antarctic Bottom Water, 918 Pliocene/Quaternary, 679 Antarctica, separation of Africa, 918 Quaternary/Pliocene, 677, 687 Argon, nonradiogenic, 514 Brachiopod, 167 Argon analyses, 513 Broken Ridge, 8, 9, 233, 243, 281, 288, 359, 370, 418, Artostrobiom urna Zone, 772, 774, 775 925, 950 Aseismic ridges, 571, 910 Broken Ridge-Naturaliste Plateau, 7 Australian continental margin, 419 Bryozoans, 166, 167 Australian plate, 233 Calcareous nannoplankton, Site 251, 84 Authigenic garnet, 80, 85, 593, 594, 915 Calcispheres, 335, 747 Basalt, 80, 161, 162, 238, 301, 329, 331, 336, 466 Campanian-lower Eocene unconformity, 619 classification of tholeiites, 480 Carbon emmission spectrography, 541 criteria for recognizing altered, 472 Carbon-carbonate analysis, 16 crystallization differentiation, 481 Carbonate compensation depth, 140, 306, 336, 419, 950 electrical resistivity of, 505 Carlsberg Ridge, Central Indian Ridge, spreading on, grain-size range, 533 913 hematite in, 533 Celadonite,471 normative compositions, 477 Cenozoic species, nannoplankton, 619 ocean ridge, 484 Central Indian Basin, 418 olivine, 28, 235, 299, 329, 478 Ceratolithus tricorniculatus Zone, 623 petrography of, 466 Chemical analysis, authigenic, garnet, 594 phase chemistry, 484 Chemical analysis of pyroclastics, 560 plagioclase feldspars in, 485 Chemistry of basalts, 472 porphyritic, 471 Chert, 745 pyroxenes in, 484 Circumpolar current, 7, 9, 135, 140, 359, 929 rare-earth elements in, 569 Classification of pyroclastics, 553 sill, 466 tholeiites, 480 Site 250, 487, 914 Climatic shifts, 613 Site 251, 489, 915 Conglomerates, 237 Site 253, 489 Coniacian/Santonian foraminifera, 750 Site 254, 489 Coniacian/Santonian boundary, 750 Site 256, 489 Contamination, foraminifera, 677 Site 257, 466, 489 Corals, 167 thermal conductivity, 454 Cretaceous, nannoplankton, 669 thermally unstable state of, 529 Paleogene, nannoplankton, 669, 670 trace elements in, 483 sedimentation, 938 xenoliths, 470 systematics, foraminifera, 751 Basalt flows, graded, 470 Cretaceous magnetic lineations, 951 Basalt-sediment contact, 467 Cretaceous zonation, Radiolaria, 773 Basaltic flows, 418 Cretaceous/Tertiary boundary, 32 Basaltic terrain, 244 Crinoids, 166, 167, 745 Basis for age determination, Crozet Basin, 135, 140, 418, 913, 915 foraminifera, 13 Crustal ages, 9, 34 nannoplankton, 13 Wharton Basin sites, 930 Beach gravels, 929 Crystallization differentiation, basalt, 481 Bengal Fan, 919 Crystallization fractionation, 489 Biogenic ooze, 235 Current, Bottom, 23, 34, 140, 914 Bottom current, 23, 140, 914 Darling Fault Zone, 947 Bottom current circulation, 34, 918 Datum levels, 677 1123 Davie Ridge, 949 Site 255, 287, 690 Deccan traps, 949 Site 256, 304, 695 Detrital clay, 299, 329 Site 257, 335, 695 Detrital sediments, 914 Site 258, 368, 695 Deuteric oxidation, 533 Turonian, 750 Diamantina Fracture Zone, 359, 925 upper Pliocene, 679 Diamictites, 237, 244, 553 Zone N21, 84, 687 Diatoms, 671 Zone N20, 84 Dictyomitra veneta Zone, 772, 773, 774, 775 Zone N19, 84 Differentiation of magma, 489 Zone N16-N18, 681 Direct-reading spectrography, 541 Zone N4-N8, 33, 681 Discoaster asymmetricus Zone, 623 Zone P21, 166 barbadiensis Zone, 670 Zone P18, 166 druggi Zone, 623 Framboidal pyrite, 603, 604 exilis Zone, 623, 625 Garnet, authigenic, 80, 85, 593, 594 quinqueramus Zone, 623 Gartnerago obliquus Zone, 626, 635, 672 saipanemsis Subzone, 167, 670 Gastropods, 241 tani nodifer, 167 Geochemical measurements, Disconformities, 34, 914 Site 250, 29 Dissolution effects, 85 Site 251, 81 Dissolution facies, 7, 9, 930, 932, 934 Site 252, 138 Dissolved organic carbon, 615 Site 253, 163 Distribution of sediments, Indian Ocean, 7 Site 254, 239 Dolomite, 28 Site 255, 285 Drag folding, 922 Site 256, 303 Drake passage, 950 Site 257, 332 Drilling mud usage, 573 Site 258, 365 Ebridians, 671 Geochemistry, 542 Echinoids, 167 Geochemistry, rare-earth element concentrations in Eiffelithus turriseiffeli Zone, 306, 625, 633 pyroclastics, 563 Electrical resistivity of basalt, 505 Geochemistry of pyroclastics, 560 Endiopsode field, 484 Geochemistry of basalt, 567, 569 Environment of deposition, 617 Geochemistry of sediments, 542, 547 Fauna, shallow-water, 168 Geophysical measurements, 417 Fish debris, stratigraphic results, 910 Geothermal measurements, 451 system of descriptors, 827 sediment temperatures, 456 Fission track method, 515 Site 251, 456 Foraminifera, Site 253, 456 Albian-Cenomanian, 747, 750 Site 254, 458 basis for age determination, 13 Site 256, 460 Coniacian-Santonian, 750 Site 257, 461 contamination, 677 Gephyrocapsa oceanica Zone, 623 Cretaceous, systematics, 751 Gingin chalk, 626, 633, 636, 751 early Miocene, 678 Glass, fresh, 470 Globigerinatheka semiinvoluta Zone, 167 Globigerinatheka semiinvoluta Zone, 167 larger, 167 Gondwanaland, 7, 9, 281, 295, 327, 359, 910, 918, 929, lower Pliocene, 678 945 method of preparation, 675 Graded basalt flows, 470 middle Miocene, 678 Grain-size analyses, 15 middle Miocene/upper Miocene Boundary, 678 Grain-size range, basalt, 533 middle Pliocene, 679 Gypsum, 605 Miocene/Pliocene boundary, 241, 678 Harmonic mean thermal conductivity, 454 Oligocene marker species, 678 Hematite in basalt, 533 Pleistocene/Holocene, boundary, 687 as an alteration product of basalt, 507 Pliocene/Quaternary, boundary, 679 Hiatus, Quaternary, 680 Late Cretaceous, 932 Quaternary/Pliocene boundary, 241, 687 Oligocene, 935 Site 250, 32, 680 formation in the deep sea, model for, 937 Site 251, 83, 681 in the Eastern Indian Ocean, 933 Site 252, 687 High-temperature oxidation, 529 Site 253, 166, 687 Holocene/Pleistocene boundary, 695 Site 254, 241, 690 Hydrogarnets, 597 1124 Indian Ocean, 910 Microscopic pyrite, 603 distribution of sediments, 7 Micula staurophora Zone, 626, 635 formation of, 910 Mid-latitudinal Neogene sequence, 83 oldest sediment, 7 Mid-Ocean Ridge, 7 sediment thickness distribution, 910 Middle Eocene sedimentation, 939 southwestern, 911 Middle Miocene foraminifera, 678 Indian Ocean Ridge, southeast branch, 417 Middle Miocene/upper Miocene boundary, fora- Indian plate, 233 minifera, 678 Indonesia, 947 Middle Pliocene, foraminifera, 679 Indus Cone, 950 Miocene, subdivision of the, 678 Inoceramus, 287, 745, 750, 751 Miocene/Oligocene boundary, 690 Intrabasalt hiatus, 930 Miocene/Pliocene boundary, foraminifera, 241, 678 Invertebrate fossils, 167 Molluscs, 166, 242 Investigator Fracture Zone, 932 Mozambique Basin, 21, 33, 466, 913, 914, 918 Iron postdepositional migration of, 563 Mozambique Plateau, 417 Iron-rich tholeiitic basalt, 570 Mudstone, 235 Isotope fractionation, 615 Nannoplankton, Kamptnerius magnificus Zone, 626, 635 basis for age determination, 13 Kerguelen Plateau, 281, 925, 950 Cenozoic species, 619 Lanthanium and samarium enrichment factors, 549 Cretaceous, 669 Lapilli, 161, 553 Mesozoic species, 620 Larger foraminifera, 167 Paleoenvironment, 670 Late Cretaceous hiatus, 932, 933 Paleogene, 669 Late Pliocene and Quaternary, paleoclimate, 743 preservation of, 622 Limestone, 745 Site 250, 33, 626, 669 Lithiophorite, 299 Site 251, 628, 669 Lithologic nomenclature, 14 Site 252, 628, 670 Lithology, 26, 78, 137 Site 253, 167, 628, 670 Lithology, site 253, 157 Site 254, 242, 632, 671 Site 254, 235 Site 255, 288, 632 Site 255, 283 Site 256, 306, 633, 671 Site 256, 299 Site 257, 634, 671 Site 257, 329 Site 258, 369, 635, 672 Site 258, 363 solution of, 670 Lithraphidites alatus Zone, 625, 635 taxonomy, 636 Lower Miocene/middle Miocene boundary, Nannoplankton zonation, foraminifera, 678 Ceratolithus tricorniculatus Zone, 623 Lower Pliocene foraminifera, 678 Discoaster asymmetricus Zone, 623 Lysocline, 34, 85, 305, 306 Discoaster barbadiensis Zone, 670 M sequence of magnetic anomalies, 932 Discoaster druggi Zone, 623 Macrofossil debris, 237 Discoaster exilis Zone, 623, 625 Macrofossils, 244 Discoaster quinqueramus Zone, 623 Madagascar Basin, 417 Discoaster saipanensis Subzone, 167, 670 Maghemite, 533 Discoaster tani nodifer Zone, 167 Magma, differentiation of, 489 Eiffellithus turriseiffeli Zone, 306, 625, 633 Magnetic anomalies, 520, 919 Gartnerago obliquum Zone, 626, 635, 672 Magnetic lineations, 945 Gephyrocapsa oceanica Zone, 623 Magnetic measurements, correlation of resistivity with Kamptnerius magnificus Zone, 626, 635 petrology, 507 Lithraphidites alatus Zone, 625, 635 Magnetic susceptibility, 517 Marthasterites furcatus Zone, 626, 635, 672 Major elements, 542 Mesozoic, 625 Manganese, postdepositional migration of, 563 Micula staurophora Zone, 335, 626, 635 Mantle plume, 549, 571 Prediscosphaera cretacea Zone, 625, 634, 672 Marker species foraminifera, Oligocene, 678 Reticulofenestra hillae Subzone, 670 Marthasterites furcatus Zone, 626, 635, 672 Reticulofenestra pseudoumbilica Zone, 623 Median destructive field, 519 Rhabdosphaera inflata Subzone, 671 Mesozoic species, nannoplankton, 620, 625 Sphenolithus heteromorphus Zone, 623 Method of preparation, foraminifera, 675 Triquetrorhabdulus carinatus Zone, 623 Methods, X-ray mineralogy, 573 Natal Basin, 417 Methods of resistivity measurements in basalt, 505 Natural remanent magnetization, 519 Methods
Load more

Recommended publications
  • Connecting the Deep Earth and the Atmosphere
    In Mantle Convection and Surface Expression (Cottaar, S. et al., eds.) AGU Monograph 2020 (in press) Connecting the Deep Earth and the Atmosphere Trond H. Torsvik1,2, Henrik H. Svensen1, Bernhard Steinberger3,1, Dana L. Royer4, Dougal A. Jerram1,5,6, Morgan T. Jones1 & Mathew Domeier1 1Centre for Earth Evolution and Dynamics (CEED), University of Oslo, 0315 Oslo, Norway; 2School of Geosciences, University of Witwatersrand, Johannesburg 2050, South Africa; 3Helmholtz Centre Potsdam, GFZ, Telegrafenberg, 14473 Potsdam, Germany; 4Department of Earth and Environmental Sciences, Wesleyan University, Middletown, Connecticut 06459, USA; 5DougalEARTH Ltd.1, Solihull, UK; 6Visiting Fellow, Earth, Environmental and Biological Sciences, Queensland University of Technology, Brisbane, Queensland, Australia. Abstract Most hotspots, kimberlites, and large igneous provinces (LIPs) are sourced by plumes that rise from the margins of two large low shear-wave velocity provinces in the lowermost mantle. These thermochemical provinces have likely been quasi-stable for hundreds of millions, perhaps billions of years, and plume heads rise through the mantle in about 30 Myr or less. LIPs provide a direct link between the deep Earth and the atmosphere but environmental consequences depend on both their volumes and the composition of the crustal rocks they are emplaced through. LIP activity can alter the plate tectonic setting by creating and modifying plate boundaries and hence changing the paleogeography and its long-term forcing on climate. Extensive blankets of LIP-lava on the Earth’s surface can also enhance silicate weathering and potentially lead to CO2 drawdown (cooling), but we find no clear relationship between LIPs and post-emplacement variation in atmospheric CO2 proxies on very long (>10 Myrs) time- scales.
    [Show full text]
  • Gondwana Breakup Via Double-Saloon-Door Rifting and Seafloor Spreading in a Backarc Basin During Subduction Rollback
    Available online at www.sciencedirect.com Tectonophysics 445 (2007) 245–272 www.elsevier.com/locate/tecto Gondwana breakup via double-saloon-door rifting and seafloor spreading in a backarc basin during subduction rollback A.K. Martin Repsol YPF Exploración, Al Fattan Plaza, PO Box 35700, Dubai, United Arab Emirates Received 2 February 2007; received in revised form 4 July 2007; accepted 21 August 2007 Available online 28 August 2007 Abstract A model has been developed where two arc-parallel rifts propagate in opposite directions from an initial central location during backarc seafloor spreading and subduction rollback. The resultant geometry causes pairs of terranes to simultaneously rotate clockwise and counterclockwise like the motion of double-saloon-doors about their hinges. As movement proceeds and the two terranes rotate, a gap begins to extend between them, where a third rift initiates and propagates in the opposite direction to subduction rollback. Observations from the Oligocene to Recent Western Mediterranean, the Miocene to Recent Carpathians, the Miocene to Recent Aegean and the Oligocene to Recent Caribbean point to a two-stage process. Initially, pairs of terranes comprising a pre-existing retro-arc fold thrust belt and magmatic arc rotate about poles and accrete to adjacent continents. Terrane docking reduces the width of the subduction zone, leading to a second phase during which subduction to strike-slip transitions initiate. The clockwise rotated terrane is caught up in a dextral strike-slip zone, whereas the counterclockwise rotated terrane is entrained in a sinistral strike-slip fault system. The likely driving force is a pair of rotational torques caused by slab sinking and rollback of a curved subduction hingeline.
    [Show full text]
  • JOIDES Resolution Expedition 361 (Southern African Climates) Site
    IODP Expedition 361: Southern African Climates Site U1475 Summary Background and Objectives Site U1475 is located on the southwestern flank of Agulhas Plateau (41°25.61′S, 25°15.64′E), ~450 nmi south of Port Elizabeth, South Africa, in a water depth of 2669 mbsl. The Agulhas Plateau, which was formed during the early stages of the opening of the South Atlantic about 90 Ma (Parsiegla et al., 2008), is a major bathymetric high that is variably coated with sediments (Uenzelmann Neben, 2001). The 230,000 km2 plateau, which ascends up to ~2500 m above the adjacent seafloor, is bounded on the north by the 4700 m deep Agulhas Passage and is flanked by the Agulhas Basin in the west and the Transkei Basin in the northeast. The northern part of the plateau is characterized by rugged topography, while the central and southern part of the plateau exhibits a relatively smooth topography (Allen and Tucholke, 1981) and has greater sediment thickness (Uenzelmann Neben, 2001). A strong water mass transport flows across the Agulhas Plateau region (Macdonald, 1993), which involves the water column from the surface down to Upper Circumpolar Deep Water. The hydrography of the upper ocean is dominated by the Agulhas Return Current, which comprises the component of the Agulhas Current that is not leaked to the South Atlantic Ocean but rather flows eastwards from the retroflection (Lutjeharms and Ansorge, 2001). Antarctic Intermediate Water, below the Agulhas Return Current, also follows the same flow path near South Africa as the Agulhas Current showing a similar retroflection (Lutjeharms, 1996).
    [Show full text]
  • The Shatsky Rise Oceanic Plateau Structure from Two-Dimensional Multichannel Seismic Refl Ection Profi Les and Implications for Oceanic Plateau Formation
    Downloaded from specialpapers.gsapubs.org on June 2, 2015 The Geological Society of America Special Paper 511 2015 The Shatsky Rise oceanic plateau structure from two-dimensional multichannel seismic refl ection profi les and implications for oceanic plateau formation Jinchang Zhang* William W. Sager† Department of Oceanography, Texas A&M University, College Station, Texas 77843, USA Jun Korenaga Department of Geology and Geophysics, Yale University, New Haven, Connecticut 06520, USA ABSTRACT The Shatsky Rise is one of the largest oceanic plateaus, a class of volcanic fea- tures whose formation is poorly understood. It is also a plateau that was formed near spreading ridges, but the connection between the two features is unclear. The geologic structure of the Shatsky Rise can help us understand its formation. Deeply penetrating two-dimensional (2-D) multichannel seismic (MCS) refl ection profi les were acquired over the southern half of the Shatsky Rise, and these data allow us to image its upper crustal structure with unprecedented detail. Synthetic seismo- grams constructed from core and log data from scientifi c drilling sites crossed by the MCS lines establish the seismic response to the geology. High-amplitude basement refl ections result from the transition between sediment and underlying igneous rock. Intrabasement refl ections are caused by alternations of lava fl ow packages with dif- fering properties and by thick interfl ow sediment layers. MCS profi les show that two of the volcanic massifs within the Shatsky Rise are immense central volcanoes. The Tamu Massif, the largest (~450 km × 650 km) and oldest (ca. 145 Ma) volcano, is a single central volcano with a rounded shape and shallow fl ank slopes (<0.5°–1.5°), characterized by lava fl ows emanating from the volcano center and extending hun- dreds of kilometers down smooth, shallow fl anks to the surrounding seafl oor.
    [Show full text]
  • This Article Appeared in a Journal Published by Elsevier. the Attached
    This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier’s archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright Author's personal copy Marine Geology 266 (2009) 65–79 Contents lists available at ScienceDirect Marine Geology journal homepage: www.elsevier.com/locate/margeo Sedimentary deposits on the southern South African continental margin: Slumping versus non-deposition or erosion by oceanic currents? Gabriele Uenzelmann-Neben a,⁎, Katrin Huhn b a Alfred-Wegener-Institut für Polar- und Meeresforschung, Am Alten Hafen 26, 27572 Bremerhaven, Germany b MARUM, Center for Marine Environmental Sciences, University of Bremen, Leobener Str., 28359 Bremen, Germany article info abstract Article history: Seismic profiles extending from the southern South African shelf into the deep sea reveal a strong erosional Received 5 January 2009 activity, which affects large parts of the continental margin. Quaternary to Oligocene units and, in places, the Received in revised form 15 July 2009 complete sedimentary column appear to have been removed. Mass movements were previously considered Accepted 17 July 2009 as the origin of this erosion. However, structures indicating slumping can be identified in only a few places.
    [Show full text]
  • Geochemistry, Geophysics, Geosystems
    Geochemistry, Geophysics, Geosystems RESEARCH ARTICLE The Strike-Slip West Wishbone Ridge and the Eastern Margin of 10.1002/2017GC007372 the Hikurangi Plateau Key Points: R. S. Barrett1,2 , B. Davy3 , T. Stern1 , and K. Gohl4 The West Wishbone Ridge is recognized as having been a dextral 1Victoria University of Wellington, Institute of Geophysics, Wellington, New Zealand, 2Now at Christian-Albrechts- strike-slip fault during the Cretaceous University of Kiel, Institute of Geophysics, Kiel, Germany, 3GNS Science, Avalon, Lower Hutt, New Zealand, 4Department of The present-day eastern margin of the Hikurangi Plateau between Geosciences, Alfred Wegener Institute Helmholtz-Center for Polar and Marine Research, Bremerhaven, Germany 42-438S is located using seismic reflection data and gravity modeling We identify over-thickened oceanic Abstract The West Wishbone Ridge (WWR), east of New Zealand, has previously been interpreted as a crust north of, and proximal to the Cretaceous plate boundary, although both the nature and timing of motion along this feature have been Hikurangi Plateau disputed. Here, using recently acquired seismic reflection data from the region of the intersection of the WWR with the Chatham Rise, we show that the WWR was primarily a dextral strike-slip fault during the Late Correspondence to: R. Barrett, Cretaceous. The WWR first propagated along the eastern margin of the Hikurangi Plateau after the collision [email protected] of the Hikurangi Plateau with the Chatham Rise, in response to the slowing of spreading at the Osbourn Trough while spreading continued unabated east of the East Wishbone Ridge, from ca. 105 Ma. Reorienta- Citation: tion of spreading at the Osbourn Trough at this time resulted in short-lived, oblique subduction beneath Barrett, R.
    [Show full text]
  • Washington, DC 20546
    46 Final. Report IMPROVING THE GEOLGICAL 1"'ERPRE"IATION OF IGGNETIC AND GRAVITY SATELTiITE ANOI'IALIES (4/1/85 - 11/31/86) Grant No. NAW-736 (Basic) submitted to Eational Aeronautics & Space Administration Code EE1 NASA Headquarters .Washington, DC 20546 January, 1987 (NASA-CR- 180 149) IMPEDVING ?kE GEOLOGICAL Nd7- 154 18 .Ih!IEEEBE'IATION OF EAGbETIC ABC GhAVXTY SAZELLIIE ANGEALIES Final 3e~crt,1 Apr. 1585 - 31 Nov, 19k6 (Furdue Uriv-) 124 p Unclds CSCL 086 G3/46 437b3 William J. Hinze and Lawrence W. Braile Ralph R.B. von Frese Department of Earth & De*. of Geology & Atmospheric Sciences Mine ralogy Purdue University Ohio State University West Lafayette, IN 47907 Columbus, OH 43210 IFIPIMVIIG THE GEOLGICAL INTERPRFTATION OF MIy;NETIC AND GRAVITY SATELLITE A"&IES Abstract Quantitative analysis of the geologic component of observed satellite magnetic and gravity fields requires accurate isolation of the geologic component of the observations, theoretically sound and viable inversion techniques, and integration of collateral, constraining geologic and geophysical data. A number of significant contributions have been made in this study which make quantitative analysis more accurate. These include procedures for 1) screening and processing orbital data for lithospheric signals based on signal repeatability and wavelength analysis; 2) producing accurate gridded anormly values at constant elevations from the orbital data by three-dimensional least squares collocation; 3) increasing the stability of equivalent point source inversion and criteria for the selection of the optimum wing parameter; 4) enhancing inversion techniques through an iterative procedure based on the superposition theorem of potential fields; and 5) modeling efficiently regional-scale lithospheric sources of satellite magnetic anomalies.
    [Show full text]
  • Aalenian, 661, 687 Abu Swayel, 208 Abyssal Fan, 562 Acoustic
    INDEX Aalenian, 661, 687 Algal-Oolitic limestones, 171 Abu Swayel, 208 Alkali basalt, 71, 77, 79, 220, 229, 605 Abyssal fan, 562 Alkali-Olivine basalt, 79, 232, 241, 613, Acoustic basement, 73, 75, 81, 406, 408 623, 625 Acritarchs, 159 Alkaline trachyte, 209 Adamellites, 590 Alpine diastrophism, 241-242, 244-245 Adelaide Geosyncline, 547-548 Alula-Fartak Trench, 87 Adelaidean Belt, 742 Aluvial fans, 154 Aden, 271, 358 Amarante Passage, 26 Aden Volcanic Series, 220, 267, 271, 278 Amba Aradam Formation, 218 Adigrat Sandstone, 273-274 Ambokahave Shales, 677 Aeclian deposits, 161 America-Antarctica Ridge, 97 Aeolan sand, 548 Amery Ice Shelf, 702, 705-707, 730 Aeromagnetic surveys, 554, 726 Amiran Flysch, 326 Afanasy Nikitin Seamount, 77 Amirante Island, 591 Afar Depression, 88 Amirante Ridge, 591 Afar Rift Zone, 87 Amirante Trench, 117 Afar Series, 279 Amirantes, 129 Afar Triangle, 288 Ammonia beccarrii. 382 Africa, 31 Ammonites, 166, 169, 188, 519, 659-660, African-Antarctic Basin, 54, 77, 86, 136 676,692 Agulhas Bank, 73 Ammonoids, 517-518 Agulhas Basin, 54, 74 Ampandrandava Group, 652 Agulhas Current, 6, 28 Ampasimena Series, 661 Agulhas Fracture Zone, 74, 164 Amphibians, 160,659 Agulhas Plateau, 6, 15, 52, 73-74 Amphibolites, 208, 333, 455, 653, 709, 721, Albany-Fraser Mobile Zone, 527 723-729, 735-736 Albany-Fraser Province, 740, 742 Amphistegina. 606 Albian, 82, 127-128, 165, 189,406,664, Amsterdam Fracture Zone, 631 677, 679, 690 Amsterdam Island, 631-632 Alcock Seamount, 422, 424, 427 Anahita Fracture Zone, 91 Algae, 606 Andaman Island,
    [Show full text]
  • Gondwana Breakup: Messages from the North Natal Valley M
    Gondwana breakup: messages from the North Natal Valley M. Moulin, D. Aslanian, M. Evain, A. Leprêtre, P. Schnürle, F. Verrier, J. Thompson, P. de Clarens, Sylvie Leroy, N. Dias, et al. To cite this version: M. Moulin, D. Aslanian, M. Evain, A. Leprêtre, P. Schnürle, et al.. Gondwana breakup: messages from the North Natal Valley. Terra Nova, Wiley-Blackwell, 2020, 32 (3), pp.205-214. 10.1111/TER.12448. hal-02429986 HAL Id: hal-02429986 https://hal.archives-ouvertes.fr/hal-02429986 Submitted on 20 Nov 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. DR MARYLINE MOULIN (Orcid ID : 0000-0002-5685-2451) Article type : Paper Title of manuscript: Gondwana breakup: messages from the North Natal Valley M. Moulin1*, D. Aslanian1, M. Evain1, A. Leprêtre1,2, P. Schnurle1, F. Verrier1, J. Thompson1, P. De Clarens3, S. Leroy4, N. Dias5,6 and the PAMELA-MOZ35 Team1,2,3,4,5,6,7,8,9,10,11,12,13 1 Ifremer, REM/GM/LGS, Centre de Brest, 29280 Plouzané, France, [email protected] 2 LGO, Laboratoire Geosciences Ocean, IUEM, CNRS, 29280 Plouzané, France 3 Total, R&D, avenue Larribau, 64000 Pau, France 4 UPMC, Univ Paris 6, CNRS UMR 7193, ISTEP, 4 place Jussieu, 75005 Paris, France 5 ISEL - Instituto Superior de Engenharia de Lisboa, Lisboa, Portugal 6 IDL – Instituto Dom Luis, Lisboa, Faculdade das Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal 7 AWI, Am Alten Hafen 26, D-27568 Bremerhaven, Germany 8 BGR, Geozentrum Hannover, Stilleweg 2, 30655 Hannover, Germany 9 INAMI, Praça 25 de Junho, n°380, P.O.
    [Show full text]
  • Large Igneous Provinces and Silicic Large Igneous Provinces
    Large igneous provinces and silicic large 1888 2013 igneous provinces: Progress in our understanding CELEBRATING ADVANCES IN GEOSCIENCE over the last 25 years Invited Review Scott E. Bryan1,† and Luca Ferrari2,3,† 1School of Earth, Environmental and Biological Sciences, Queensland University of Technology, GPO Box 2434, Brisbane, 4001, Australia 2Centro de Geociencias, Universidad Nacional Autonoma de Mexico, Boulevard Juriquilla 3001, Querétaro, 76230, Mexico 3Instituto de Geología, Universidad Nacional Autonoma de Mexico, Circuito Investigacion Cientifi ca, Ciudad Universitaria, Mexico City, 04510, Mexico ABSTRACT margins, where, in the latter setting, large ig- ities, and are characterized by igneous pulse(s) neous province magmatism can be dominated of short duration (1–5 m.y.), during which a Large igneous provinces are exceptional by silicic products. (3) Mineral and energy re- large proportion (>75%) of the total igneous intraplate igneous events throughout Earth’s sources, with major platinum group elements volume was emplaced (Bryan and Ernst, 2008). history. Their signifi cance and potential (PGEs) and precious metal resources, are Continental fl ood basalt provinces, such as the global impact are related to the total volume hosted in these provinces, as well as magma- Deccan Traps, Siberian Traps, and Columbia of magma intruded and released during these tism impacting on the hydro carbon potential River fl ood basalt province, are some of the best geologically brief events (peak eruptions are of volcanic basins and rifted margins through recognized examples of continental large igne- often within 1–5 m.y. in duration) where mil- enhancing source-rock maturation, providing ous provinces (Fig. 1). While continental fl ood lions to tens of millions of cubic kilometers fl uid migration pathways, and initiating trap basalt provinces had been widely recognized of magma are produced.
    [Show full text]
  • Crustal Structure of the Southern Margin of the African Plate: Results
    Originally published as: Stankiewicz, J., Parsiegla, N., Ryberg, T., Gohl, K, Weckmann, U., Trumbull, R., Weber, M. (2008): Crustal Structure of the Southern Margin of the African Continent: Results from Geophysical Experiments. - Journal of Geophysical Research, 113, B10313 DOI: 10.1029/2008JB005612. 1 Crustal Structure of the Southern Margin of the African 2 Continent: Results from Geophysical Experiments. 3 4 J. Stankiewicz, N. Parsiegla, T. Ryberg, K. Gohl, U. Weckmann, R. Trumbull & M. Weber. 5 6 Abstract 7 A number of geophysical onshore and offshore experiments were carried out along a profile across the 8 southern margin of the African Plate in the framework of the Inkaba yeAfrica project. Refraction 9 seismic experiments show that Moho depth decreases rapidly from over 40 km inland to around 30 km 10 at the present coast, before gently thinning out towards the Agulhas-Falkland Fracture Zone, which 11 marks the transition zone between continental and oceanic crust. In the region of the abruptly 12 decreasing Moho depth, in the vicinity of the boundary between the Namaqua-Natal Mobile Belt and 13 the Cape Fold Belt, lower crustal P-wave velocities up to 7.4 km/s are observed. This is interpreted as 14 metabasic lithologies of Precambrian age in the Namaqua-Natal Mobile Belt, or mafic intrusions added 15 to the base of the crust by younger magmatism. The velocity model for the upper crust has excellent 16 resolution, and is consistent with the known geological record. A joint interpretation of the velocity 17 model with an electrical conductivity model, obtained from magnetotelluric studies, makes it possible 18 to correlate a high velocity anomaly north of the centre of the Beattie Magnetic Anomaly with a highly 19 resistive body.
    [Show full text]
  • The Agulhas Plateau: Structure and Evolution of a Large Igneous Province
    Geophys. J. Int. (2008) 174, 336–350 doi: 10.1111/j.1365-246X.2008.03808.x The Agulhas Plateau: structure and evolution of a Large Igneous Province N. Parsiegla, K. Gohl and G. Uenzelmann-Neben Alfred Wegener Institute for Polar and Marine Research, PO Box 12161, 27515 Bremerhaven, Germany. E-mail: [email protected] Accepted 2008 March 28. Received 2008 March 13; in original form 2008 January 5 SUMMARY Large Igneous Provinces (LIP) are of great interest due to their role in crustal generation, magmatic processes and environmental impact. The Agulhas Plateau in the southwest Indian Ocean off South Africa has played a controversial role in this discussion due to unclear evidence for its continental or oceanic crustal affinity. With new geophysical data from seismic refraction and reflection profiling, we are able to present improved evidence for its crustal structure and composition. The velocity–depth model reveals a mean crustal thickness of 20 km with a maximum of 24 km, where three major units can be identified in the crust. In our seismic reflection records, evidence for volcanic flows on the Agulhas Plateau can be observed. The middle crust is thickened by magmatic intrusions. The up to 10 km thick lower crustal body is characterized by high seismic velocities of 7.0–7.6 km s−1. The velocity–depth distribution suggests that the plateau consists of overthickened oceanic crust similar to other oceanic LIPs such as the Ontong-Java Plateau or the northern Kerguelen Plateau. The total volume of the Agulhas Plateau was estimated to be 4 × 106 km3 of which about 10 per cent consists of extruded igneous material.
    [Show full text]