DOCSLIB.ORG

IFM-GEOMAR Report No. 50

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
IFM-GEOMAR Report No. 50 RV SONNE Fahrtbericht / Cruise Report SO233 WALVIS II 14.05-21.06.2014 Cape Town, South Africa - Walvis Bay, Namibia WAL 233 VIS O I S Walvis I Bay W 4 1 ge a l 0 id v 2 Cape i . R s 5 Town s B 0 i . a v 4 l y 1 a 2 1 n W . w 0 o 6 T . 2 e 0 p 1 a 4 C GEOMAR GEOMAR REPORT Berichte aus dem GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel Nr. 22 (N. Ser.) November 2014 RV SONNE Fahrtbericht / Cruise Report SO233 WALVIS II 14.05-21.06.2014 Cape Town, South Africa - Walvis Bay, Namibia Berichte aus dem GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel Nr. 22 (N. Ser.) November 2014 ISSN Nr.: 2193-8113 Das GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel The GEOMAR Helmholtz Centre for Ocean Research Kiel ist Mitglied der Helmholtz-Gemeinschaft is a member of the Helmholtz Association of Deutscher Forschungszentren e.V. German Research Centres Herausgeber / Editor: Kaj Hoernle, Reinhard Werner, and Carsten Lüter GEOMAR Report ISSN N..r 2193-8113, DOI 10.3289/GEOMAR_REP_NS_22_2014 Helmholtz-Zentrum für Ozeanforschung Kiel / Helmholtz Centre for Ocean Research Kiel GEOMAR Dienstgebäude Westufer / West Shore Building Düsternbrooker Weg 20 D-24105 Kiel Germany Helmholtz-Zentrum für Ozeanforschung Kiel / Helmholtz Centre for Ocean Research Kiel GEOMAR Dienstgebäude Ostufer / East Shore Building Wischhofstr. 1-3 D-24148 Kiel Germany Tel.: +49 431 600-0 Fax: +49 431 600-2805 www.geomar.de 1 CONTENT Summary ................................................................................................................................................. 2 Zusammenfassung.................................................................................................................................. 3 1. Acknowledgements ............................................................................................................................. 4 2. Participants.......................................................................................................................................... 5 2.1. Ship´s Crew............................................................................................................................ 5 2.2. Principal Investigators for WALVIS II ..................................................................................... 5 2.3. Shipboard Scientific Party ...................................................................................................... 5 2.4. Institutions .............................................................................................................................. 6 3. Major Objectives and Background of SO-233 WALVIS II ................................................................... 7 3.1. The Hotspot Hypothesis......................................................................................................... 8 3.2. Walvis Ridge in Context of the Tristan-Gough Hotspot System............................................. 8 3.3. Biological Investigations....................................................................................................... 10 4. Cruise Narrative ................................................................................................................................ 12 5. Bathymetry and Rock Sampling ........................................................................................................ 20 5.1. Methods ............................................................................................................................... 20 5.1.1. Bathymetry (Simrad Kongsberg EM120) ................................................................ 20 Data Acquisition...................................................................................................... 20 Data Processing ..................................................................................................... 21 5.1.2. Sediment Echo-Sounding (Atlas PARASOUND) .................................................... 21 5.1.3. Dredging, Site Selection, and Laboratory Work...................................................... 22 Shipboard Procedure.............................................................................................. 22 Shore Based Analyses ........................................................................................... 23 5.2. Rock Sampling Report and Preliminary Results of Bathymetric Mapping ........................... 23 5.3.1. The Bifurcated Southwestern Part of Walvis Ridge (DR3 - 13) .............................. 23 5.3.2. The Narrow Central Part of Walvis Ridge (DR15 - 35) ........................................... 27 5.3.3. The Broad Central Part of Walvis Ridge (DR37 - 64) ............................................. 32 Major Morphological Features ................................................................................ 32 Rock Sampling........................................................................................................ 34 5.3.4. The Northern Part of Walvis Ridge (DR66 - 90) ..................................................... 40 6. Biology............................................................................................................................................... 49 6.1. Methods ............................................................................................................................... 49 6.1.1. Shipboard Collecting Procedures ........................................................................... 49 6.1.2. Meiofauna ............................................................................................................... 49 6.1.3. Macrofauna ............................................................................................................. 49 6.2. Preliminary Results and Discussion ............................................................................................... 50 6.2.1. General Observations and Collecting Report ......................................................... 50 6.2.2. Meiofauna ............................................................................................................... 50 6.2.3. Macrofauna ............................................................................................................. 51 6.2.4. TV-Observation of the Sea Floor ............................................................................ 51 7. References ........................................................................................................................................ 52 Appendices: I. Sampling Summary/Station List II. Rock Description III. Biological Sampling 2 SUMMARY R/V SONNE cruise SO-233 WALVIS II conducted geological, morphological, and biological studies in the area of the aseismic Walvis Ridge and the adjacent ocean floor (South Atlantic). The Walvis Ridge is a textbook example of a hotspot track connected to a continental flood basalt province and represents the Atlantic “type locality” for the enriched mantle one (EM-I) geochemical endmember in intraplate volcanic rocks. Despite its importance in the global hotspot reference frame, endmember geochemical composition, and uncertainties in its formation and evolution, basement sampling of the Walvis Ridge remained poor to date, in particular along its easternmost 1500 km. The geological studies carried out during SO-233 therefore aimed for extensive multi-beam mapping using a SIMRAD EM 120 echo-sounding system, sediment echo-sounding using a ATLAS PARASOUND sub-bottom profiling system, and hard rock sampling by dredging and TV-grab of the Walvis Ridge and associated features. The major targets of the WALVIS II project are (1) to test for age progressive volcanism along the ridge, (2) to differentiate between classical hotspot and plate fracturing models for its formation, and (3) to constrain the origin, temporal and spatial evolution of melting conditions and source compositions (in particular regarding the EM-I endmember and proposed zonation models of mantle plumes). The biology program conducted on SO-233 comprised sampling of benthic organisms and meiofauna using a TV-multi-corer, a TV-grab, sediment traps installed in the geological dredges, and by collecting marine invertebrates from the hard rocks yielded by dredging. The biological investigations of the WALVIS II project intend to describe the benthic diversity of deep-sea invertebrates of the Walvis Ridge and will help to identify proxies of species connectivity and dispersal between the Walvis Ridge and neighboring ridge like structures (e.g. Agulhas Ridge). Another objective is to test whether connectivity of benthic communities in the Angola and Cape Basins is interrupted by the Walvis Ridge. SO-233 multi-beam mapping revealed that the southern bifurcated section of the Walvis Ridge appears to have formed through the coalescence of former volcanic islands. The new bathymetric data also yielded several evidence for large-scale extensional tectonic movements which are most likely related to the separation of the Walvis Ridge and Rio Grande Rise that were rifted apart by the mid Atlantic Ridge. Seventy-one dredge hauls have been conducted during SO-233. Of these, 28 delivered massive lavas, 24 volcaniclastic rocks including breccias containing lava fragments, 22 sedimentary rocks, and 11 Mn-Fe-oxide crusts and nodules. The volcanic rocks comprise a broad variety of lavas as well as epiclastic, hydroclastic, and pyroclastic rocks. Carbonates dominate among the non-volcanic rocks, many of them represent relicts of fossil coral reefs. Despite technical
Load more

Recommended publications
  • The Mineral Industry of Namibia in 1999
    THE MINERAL INDUSTRY OF NAMIBIA By George J. Coakley Namibia is located on the southwestern coast of Africa many years, De Beers Consolidated Mines Ltd. had held an between South Africa and Angola. The 825,418-square- exclusive right to exploit the diamond-bearing Orange River kilometer country had an estimated population of 1.77 million alluvial and marine beach sand deposits within the Sperrgebiet. in 1999 and a gross domestic product (GDP) per capita of about Namdeb Diamond Corp. (Pty.) Ltd. increased diamond $4,3001 based on purchasing power parity. In 1999, the mineral production to nearly 1.3 million carats, or about comparable industry of Namibia provided about 43% of exports and 20% of with that of 1998. Namdeb began phasing out production at its the country’s GDP (U.S. Central Intelligence Agency, Auchas Mine and planned to open the new Daberas Mine at the Namibia—Economy—World factbook, accessed December 5, end of 2000; the new mine will have an expected mine life of 10 2000, at URL http://www.odci.gov/cia/publications/Factbook/ years. During its first full year of operation, De Beers’ geos/wa.html#Econ). Diamond remained the most important NamGem Diamond Manufacturing Co. diamond cutting and sector of the mining industry followed by uranium, for which polishing plant near Okahandja produced 100 finished stones Namibia ranked as the world’s fourth largest producer. per day at an average size of 14 points based on 100 points to a Namibia was also the largest producer of salt in Africa. carat. According to the Chamber of Mines of Namibia (2000, p.
    [Show full text]
  • Large Igneous Provinces: a Driver of Global Environmental and Biotic Changes, Geophysical Monograph 255, First Edition
    2 Radiometric Constraints on the Timing, Tempo, and Effects of Large Igneous Province Emplacement Jennifer Kasbohm1, Blair Schoene1, and Seth Burgess2 ABSTRACT There is an apparent temporal correlation between large igneous province (LIP) emplacement and global envi- ronmental crises, including mass extinctions. Advances in the precision and accuracy of geochronology in the past decade have significantly improved estimates of the timing and duration of LIP emplacement, mass extinc- tion events, and global climate perturbations, and in general have supported a temporal link between them. In this chapter, we review available geochronology of LIPs and of global extinction or climate events. We begin with an overview of the methodological advances permitting improved precision and accuracy in LIP geochro- nology. We then review the characteristics and geochronology of 12 LIP/event couplets from the past 700 Ma of Earth history, comparing the relative timing of magmatism and global change, and assessing the chronologic support for LIPs playing a causal role in Earth’s climatic and biotic crises. We find that (1) improved geochronol- ogy in the last decade has shown that nearly all well-dated LIPs erupted in < 1 Ma, irrespective of tectonic set- ting; (2) for well-dated LIPs with correspondingly well-dated mass extinctions, the LIPs began several hundred ka prior to a relatively short duration extinction event; and (3) for LIPs with a convincing temporal connection to mass extinctions, there seems to be no single characteristic that makes a LIP deadly. Despite much progress, higher precision geochronology of both eruptive and intrusive LIP events and better chronologies from extinc- tion and climate proxy records will be required to further understand how these catastrophic volcanic events have changed the course of our planet’s surface evolution.
    [Show full text]
  • South Africa and Namibia, 20 July - 12 August 2017
    South Africa and Namibia, 20 July - 12 August 2017. VLADIMIR DINETS This trip was an introduction to Africa for my wife and daughter; the latter was two and a half years old at the time and enjoyed it a lot. We had three weeks to kill while a container with our stuff was traveling from New Jersey to our new home in Okinawa. We started from Cape Town, drove east to Hermanus and then north to Oranjemund, flew to Windhoek, briefly explored a few locations up to Etosha, returned to Windhoek and spent one day and two nights in Johannesburg. In 2017, Cape Town area, Namaqualand and Namibia were experiencing a major drought. Full moon was on August 7; that made finding small mammals difficult during the Namibian part of the trip. I had six Sherman traps and caught only twelve rodents of two species (two pygmy mice in the far south and Namaqua rock rats almost everywhere else). Bats seemed absent with few exceptions. I saw almost a hundred species, all but four of which I had seen before (see my 2008 trip report), and removed a few species from my “better view much desired” list. South Africa Simon’s Town is a convenient base for exploring the area; M4 south from it is a good place to look for chacma baboons, while humpback whales are often feeding offshore (we saw one, and heard a few while scuba diving). Watch for South African fur seals, too. Four-striped grass mice (locally called “field mice”) were abundant in wooded parts of penguin colonies.
    [Show full text]
  • 1 Scoping Report for the Heritage Assessment Related to the Proposed Eskom Kudu-Oranjemund Project in the Northern Cape Province
    Archaetnos Culture & Cultural Resource Consultants BK 98 09854/23 SCOPING REPORT FOR THE HERITAGE ASSESSMENT RELATED TO THE PROPOSED ESKOM KUDU-ORANJEMUND PROJECT IN THE NORTHERN CAPE PROVINCE For: LANDSCAPE DYNAMICS PO Box 947 Groenkloof 0027 REPORT: AE01639V By: Prof. A.C. van Vollenhoven (L. Akad. S.A.) BA, BA (Hons), DTO, NDM, MA (UP), MA (US), DPhil (UP), Man Dip (TUT), DPhil (History) Accredited member of ASAPA Accredited member of SASCH July 2016 Archaetnos P.0.Box 55 GROENKLOOF 0027 Tel: 083 291 6104 Fax: 086 520 4173 Email: [email protected] Members: AC van Vollenhoven BA, BA (Hons), DTO, NDM, MA (Archaeology) [UP], MA (Culture History) [US], DPhil (Archaeology) [UP], Man Dip [TUT], DPhil (History) [US] 1 1. Introduction This report deals with the results of a scoping baseline (desktop) study relating to the Heritage Assessment for the proposed ESKOM Kudu-Oranjemund Project. The project entails the following: Establishment of the existing 400kV AT Oranjemund including – . 400kV yard and equipment including busbar; . Installing a 1 x 315MVA 400/220kV transformer; . Create at least 4 x 400kV line bays to allow for potential development; Construction of 2 x 400kV lines from the Orange River to Oranjemund Substation – approximately 5 km of which a 3 km wide corridor should be investigated and authorized. 2. Methodology Terms of reference . Identify as much as possible objects, sites, occurrences and structures of an archaeological or historical nature (cultural heritage sites) located on the property. Assess the significance of the cultural resources in terms of their archaeological, historical, scientific, social, religious, aesthetic and tourism value.
    [Show full text]
  • High Seas Deep-Sea Fishing Grounds in the South East Atlantic Ocean 51
    50 Worldwide review of bottom fisheries in the high seas MAP 1 High seas deep-sea fishing grounds in the South East Atlantic Ocean 51 South East Atlantic Ocean FAO Statistical Area 47 (and a portion of 34) GEOGRAPHIC DESCRIPTION OF THE REGION Angola, Namibia and South Africa are the three countries bordering the South East Atlantic Region (FAO Statistical Area 47) along the African coast. This region extends from the Central Atlantic in the north at 6°S to the Southern Ocean in the south at 50°S. The western limit of the South East Atlantic is the 20°W meridian, which means that the southern Mid-Atlantic Ridge is within the region, at around 15°W, and extends over the entire region from north to south. Other important bottom topographic features in this region are the Walvis Ridge and the Valdivia Bank, joining the exclusive economic zone (EEZ) of Tristan da Cunha on the northern part of the Namibian continental shelf at around 18°S, and in the southern part, the Meteor Rise and the Agulhas Ridge. These are the areas largely targeted in the deep-sea bottom fisheries in the region, together with associated or isolated seamounts areas such as Ewing and Molloy Seamounts, Vema Seamount and those in SEAFO Subdivision A1 (SEAFO, 2007a). It is important to note that in the South East Atlantic, the continental shelf along the coasts does not extend beyond the EEZs of the coastal states. MANAGEMENT REGIME APPLICABLE TO DEEP-SEA BOTTOM FISHERIES IN THE HIGH SEAS Regional Fisheries Management Organization/Arrangement The South East Atlantic Fisheries Organisation (SEAFO) was established in 2003 with the entry into force of the Convention on the conservation and management of fisheries resources in the South East Atlantic Ocean.
    [Show full text]
  • KELP BLUE NAMIBIA (Pty) Ltd
    KELP BLUE NAMIBIA (Pty) Ltd EIA SCOPING & IMPACT ASSESSMENT REPORT AND ENVIRONMENTAL MANAGEMENT PLAN FOR THE PROPOSED KELP CULTIVATION PILOT PROJECT NEAR LÜDERITZ, KARAS REGION Prepared for: Kelp Blue Namibia (Pty) Ltd August 2020 1 DOCUMENT CONTROL Report Title EIA SCOPING & IMPACT ASSESSMENT REPORT FOR THE PROPOSED KELP CULTIVATION PILOT PROJECT NEAR LÜDERITZ, KARAS REGION Report Author Werner Petrick Client Kelp Blue Namibia (Pty) Ltd Project Number NSP2020KB01 Report Number 1 Status Final to MEFT and MFMR Issue Date August 2020 DISCLAIMER The views expressed in the document are the objective, independent views of the author with input from various Environmental and Social Experts (i.e. Specialists). Neither Werner Petrick nor Namisun Environmental Projects and Development (Namisun) have any business, personal, financial, or other interest in the proposed Project apart from fair remuneration for the work performed. The content of this report is based on the author’s best scientific and professional knowledge, input from the Environmental Specialists, as well as available information. Project information contained herein is based on the interpretation of data collected and data provided by the client, accepted in good faith as being accurate and valid. Namisun reserves the right to modify the report in any way deemed necessary should new, relevant, or previously unavailable or undisclosed information become available that could alter the assessment findings. This report must not be altered or added to without the prior written consent of the author. Project Nr: NSP2020KB01 EIA SCOPING & IMPACT ASSESSMENT REPORT AND EMP FOR August 2020 Report number: 1 THE PROPOSED KELP CULTIVATION PILOT PROJECT 2 Table of Contents 1 INTRODUCTION ..................................................................................................................................
    [Show full text]
  • The Mineral Industry of Namibia in 2016
    2016 Minerals Yearbook NAMIBIA [ADVANCE RELEASE] U.S. Department of the Interior February 2020 U.S. Geological Survey The Mineral Industry of Namibia By James J. Barry In 2016, the diamond sector continued to be a significant 16%, for Swakop Uranium; about 10%, for Rössing Uranium contributor to Namibia’s economy. In terms of the average Ltd.; and 9% each, for B2Gold Namibia (Pty) Ltd., De Beers value of diamond production in dollars per carat ($533), the Marine Namibia (Pty) Ltd. (Debmarine), and Skorpion Zinc and country ranked second in the world after Lesotho. In terms of Namzinc (Pty) Ltd. (Chamber of Mines of Namibia, 2017, p. 19, the total value of its rough diamond production ($915 million), 90–91). the country ranked fifth after South Africa. Namibia was ranked ninth in the world in terms of rough diamond production by Production weight (carats). Namibia’s total diamond exports were valued at In 2016, copper electrowon production increased by 54% about $1.1 billion (about 1.9 million carats of diamond) in 2016. to 16,391 metric tons (t) from 10,659 t in 2015, which was According to the World Nuclear Association, Namibia’s Rössing attributed to the Tschudi Mine reaching nameplate capacity Mine and Langer Heinrich Mine were capable of providing 10% of 17,000 metric tons per year (t/yr). Uranium production of the world’s uranium output; the Langer Heinrich Mine was increased by 22% to 3,654 t (uranium content) in 2016 from one of the leading producing uranium mines in the world. The 2,993 t in 2015.
    [Show full text]
  • Geophysical Study of the Easternmost Walvis Ridge, South Atlantic:Deep
    More free publications from Archimer Art. No 305 Contribution COB No254 Geophysical study of the easternmost Walvis Ridge, South Atlantic: Deep structure J. GOSLIN Institut de Physique du Globe de Paris, Laboratoire de Géophysique Marine, 4 Avenue de Neptune, 941 00, St. Maur-des-Fossés, France J. C. SIBUET Centre Océanologique de Bretagne, B.P. 337, 29273, Brest, France ABSTRACT proposed that the landward termination of ously been described (for example, Houtz the Walvis Ridge consists of two basaltic and others, 1968). The seismic source A seismic-refraction study of the basement ridges enclosiner a 2-km-thick aboard RiV Jean Charcot was the Flexotir sedimentary structure of the South West sedimentary basin and probYably continuing (Grau, 1969). All profiles were shot with a African continental shelf was carried out eastward beneath the sedimentam cover of shooting interval of 30 sec (that is, about between lat 17"s and 24"s using expendable the continental shelf. We suggésted that every 100 m). None of the profiles was re- sonobuoys. Striking differences exist both sediment coming from the south had par- versed. The analog signal from the in the topography and sedimentary struc- tially filled the central basin and that the sonobuoys was recorded on a variable-area ture between the shelf north and south of ridge had acted as a dam to any further film recorder and on magnetic tape, which the Walvis Ridge. South of the ridge, as far northward transport of sediment, thus ex- allowed replays of tape through appro- as lat 23"S, the shelf consists of a prograded plaining the contrast in sediment cover be- priate filters when necessary (Figs.
    [Show full text]
  • The Environmental Management Plan for Establishing Agricultural Projects Within the Oranjemund Constituency Report No: 201219A 20 December 2019
    The Environmental Management Plan for establishing Agricultural Projects within the Oranjemund Constituency Report No: 201219A 20 December 2019 Prepared for: Prepared by: Oranjemund Constituency Office KPM Environmental Consulting P.O. Box 705 P.O. Box 26328 Oranjemund Windhoek Namibia Namibia Office: +264 63 233 367 Office: +264 81 147 3344 E-mail: [email protected] E-mail: [email protected] Document Status Proponent Oranjemund Constituency Office Title of the The Environmental Management Plan for establishing proposed Activity Agricultural Projects within the Oranjemund Constituency Activity Type Establishment of Agricultural Projects Location of the The Agricultural Project will be located along the Orange River Activity and between Oranjemund and Rosh Pinah at four different areas: • Farm 212 Hohenfels GPS Coordinates: 16.81000000 and 29.20750000 • Lucerne A and Lucerne B GPS Coordinates: 16.72416667 and 28.46027778 • Upper portion closer to Plot B of Debaras 2 GPS Coordinates: 17.32388889 and 29.20750000 • Rosh Pinah GPS Coordinates: 17.01055556 and 28.54805556 Competent Environmental Commission (Ministry of Environment and Authority Tourism) EIA Consultant KPM Environmental Consulting Contact person: Mr. Festus Kapembe Tel. +264 81 147 3344 E-mail: [email protected] Proponent Mr. Lazarus Nangolo Constituency Councillor Oranjemund Constituency //Kharas Region Council P.O. Box 705 Oranjemund Tel. +264 63 233 367 EIA for establishing Agricultural Projects within the Oranjemund Constituency Page 1 PURPOSE OF THIS DOCUMENT This document, Environmental Impact Assessment (EIA) Report and Environmental Management Plan (EMP) for the establishment of an Agricultural Project for Oranjemund Constituency Office presents the findings of the impact assessment with respect to issues and concerns raised during the scoping phase of the EIA.
    [Show full text]
  • Rio Grande Rise Hot Spot System' Implicationsfor African and South American Plate Motions Over Plumes
    JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 95, NO. BI1, PAGES 17,475-17,502,OCTOBER 10, 1990 Evolution of the Walvis Ridge-Rio Grande Rise Hot Spot System' Implicationsfor African and South American Plate Motions Over Plumes JOHN M. O'CONNOR AND ROBERT A. DUNCAN College of Oceanography,Oregon State University,Corvallis Crystallizationages of volcanicrocks, dredged or drilled from the Walvis Ridge (ten sites)and the Rio GrandeRise (one site), have been determined by the 40Ar/39Ar incremental heating technique. The fundamentallyage-progressive distribution of thesebasement ages suggests a commonhot spot sourcefor volcanismon the island of Tristan da Cunha, along the Walvis Ridge and Rio Grande Rise, and for the formation of the continental flood basalts located in Namibia (Africa) and Brazil (South America). The WalvisRidge-Rio Grande Rise volcanic system evolved along a sectionof the SouthAtlantic spreading-axis, as the African and South American plates migratedapart, astride,or in closeproximity to, an upwelling plume. Reconstructionsof the spatialrelationship between the spreading-axis,the Tristan hot spot, and the evolvingWalvis Ridge-Rio Grande Rise volcanic feature show that, at about70 Ma, thespreading-axis began to migratewestward, away from the hot spot. The resultingtransition to intraplatehot spotvolcanism along the Walvis Ridge (and associatedtermination of Rio GrandeRise formation)also involveda northward migrationof previouslyformed African seafloor over the hot spot. Rotationparameters for Africanmotion overfixed hot spots(i.e., absolutemotion) have been recalculated such that the predictedtrail of the Tristan hotspot agrees with the distribution of radiometricand fossil basement ages along the Walvis Ridge. African absolutemotion has been extended to the Southand North American plates, by the additionof relativemotion reconstructionpoles.
    [Show full text]
  • Country Profile – Namibia
    Country profile – Namibia Version 2005 Recommended citation: FAO. 2005. AQUASTAT Country Profile – Namibia. Food and Agriculture Organization of the United Nations (FAO). Rome, Italy The designations employed and the presentation of material in this information product do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations (FAO) concerning the legal or development status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. The mention of specific companies or products of manufacturers, whether or not these have been patented, does not imply that these have been endorsed or recommended by FAO in preference to others of a similar nature that are not mentioned. The views expressed in this information product are those of the author(s) and do not necessarily reflect the views or policies of FAO. FAO encourages the use, reproduction and dissemination of material in this information product. Except where otherwise indicated, material may be copied, downloaded and printed for private study, research and teaching purposes, or for use in non-commercial products or services, provided that appropriate acknowledgement of FAO as the source and copyright holder is given and that FAO’s endorsement of users’ views, products or services is not implied in any way. All requests for translation and adaptation rights, and for resale and other commercial use rights should be made via www.fao.org/contact-us/licencerequest or addressed to [email protected]. FAO information products are available on the FAO website (www.fao.org/ publications) and can be purchased through [email protected].
    [Show full text]
  • Walvis Ridge Namibia 2020
    Walvis Ridge Namibia Proposed EBSA Description General Information Summary The Walvis Ridge Namibia EBSA lies contiguous to the Walvis Ridge EBSA in the high seas. Together, these two EBSAs span the full extent of the significant hotspot track (seamount chain formed by submarine volcanism) that comprises the aseismic Walvis Ridge and the Guyot Province. This unique feature forms a submarine ridge running north-east to south-west from the Namibian continental margin to Tristan da Cunha and Gough islands at the southern Mid-Atlantic Ridge. The Walvis Ridge Namibia EBSA encompasses the globally rare connection of a hotspot track to continental flood basalt in the Namibian EEZ. Given the high habitat heterogeneity associated with the complex benthic topography, it is likely that the area supports a relatively higher biological diversity, and is likely to be of special importance to vulnerable sessile macrofauna and demersal fish associated with seamounts. Productivity in the Namibian portion of Walvis Ridge is also particularly high because of upwelling resulting from the interaction between the geomorphology of the feature and the nutrient-rich, north- flowing Benguela Current. Although there are fisheries operating over Walvis Ridge in northern Namibia, the EBSA focus area is currently in good condition. Introduction of the area The aseismic Walvis Ridge is a seamount chain formed by hotspot submarine volcanism, some of which are guyots, that is connected to a continental flood basalt province in northern Namibia. The ridge presents a barrier between North Atlantic Deep Water to the north and Antarctic Bottom Water to the south. The surface oceanographic regime is the South Atlantic Subtropical Gyre bounded by the productive waters of the Benguela Current System and the Subtropical Convergence Zone.
    [Show full text]