DOCSLIB.ORG

The Size of Plume Heterogeneities Constrained by Marquesas Isotopic Stripes Catherine Chauvel, René C

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Size of Plume Heterogeneities Constrained by Marquesas Isotopic Stripes Catherine Chauvel, René C The size of plume heterogeneities constrained by Marquesas isotopic stripes Catherine Chauvel, René C. Maury, Sylvain Blais, Eric Lewin, Hervé Guillou, Gérard Guille, Philippe Rossi, Marc-André Gutscher To cite this version: Catherine Chauvel, René C. Maury, Sylvain Blais, Eric Lewin, Hervé Guillou, et al.. The size of plume heterogeneities constrained by Marquesas isotopic stripes. Geochemistry, Geophysics, Geosys- tems, AGU and the Geochemical Society, 2012, 13 (1), pp.Q07005. 10.1029/2012GC004123. insu- 00720199 HAL Id: insu-00720199 https://hal-insu.archives-ouvertes.fr/insu-00720199 Submitted on 24 Jan 2013 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. Article Volume 13, Number 1 12 July 2012 Q07005, doi:10.1029/2012GC004123 ISSN: 1525-2027 The size of plume heterogeneities constrained by Marquesas isotopic stripes Catherine Chauvel ISTerre, UMR 5275, CNRS, Université Grenoble 1, BP 53, FR-38041 Grenoble CEDEX 09, France ([email protected]) René C. Maury Domaines Océaniques, UMR 6538, Université de Brest, Université Européenne de Bretagne, CNRS, Institut Universitaire Européen de la Mer, Place N. Copernic, FR-29280 Plouzané, France Sylvain Blais Géosciences Rennes, UMR 6518, Université de Rennes 1, Université Européenne de Bretagne, CNRS, Campus de Beaulieu, Avenue du Général Leclerc, FR-35042 Rennes CEDEX, France Eric Lewin ISTerre, UMR 5275, CNRS, Université Grenoble 1, BP 53, FR-38041 Grenoble CEDEX 09, France Hervé Guillou UMR 8212, LSCE-IPSL/CEA-CNRS-UVSQ, Domaine du CNRS, 12 avenue de la Terrasse, FR-91198 Gif-sur-Yvette, France Gérard Guille Laboratoire de Géophysique, CEA-DASE, FR-91680 Bruyères-le-Chatel, France Philippe Rossi BRGM, SGN-CGF, 3 avenue Claude-Guillemin, BP 36009, FR-45060 Orléans CEDEX 2, France Marc-André Gutscher Domaines Océaniques, UMR 6538, Université de Brest, Université Européenne de Bretagne, CNRS, Institut Universitaire Européen de la Mer, Place N. Copernic, FR-29280 Plouzané, France [1] The scale and geometry of chemical and isotopic heterogeneities in the source of plumes have important scientific implications on the nature, composition and origin of plumes and on the dynamics of mantle mixing over time. Here, we address these issues through the study of Marquesas Islands, one of the Archipela- goes in Polynesia. We present new Sr, Nd, Pb, Hf isotopes as well as trace element data on lavas from several Marquesas Islands and demonstrate that this archipelago consists of two adjacent and distinct rows of islands with significantly different isotopic compositions. For the entire 5.5 Ma construction period, the northern islands, hereafter called the Ua Huka group, has had systematically higher 87Sr/86Sr and lower 206Pb/204Pb ratios than the southern Fatu Hiva group at any given 143Nd/144Nd value. The shape and curvature of mixing arrays preclude the ambient depleted MORB mantle as one of the mixing end-members. We believe therefore that the entire isotopic heterogeneity originates in the plume itself. We suggest that the two Marquesas isotopic stripes originate from partial melting of two adjacent fila- ments contained in small plumes or “plumelets” that came from a large dome structure located deep in ©2012. American Geophysical Union. All Rights Reserved. 1 of 23 Geochemistry Geophysics 3 CHAUVEL ET AL.: MARQUESAS ISOTOPIC STRIPES 10.1029/2012GC004123 Geosystems G the mantle under Polynesia. Low-degree partial melting under Marquesas and other “weak” Polynesian hot spot chains (Pitcairn-Gambier, Austral-Cook, Society) sample small areas of the dome and preserve source heterogeneities. In contrast, more productive hot spots build up large islands such as Big Island in Hawaii or Réunion Island, and the higher degrees of melting blur the isotopic variability of the plume source. Components: 14,000 words, 12 figures, 3 tables. Keywords: Marquesas; isotopes; ocean island; plume structure. Index Terms: 1025 Geochemistry: Composition of the mantle; 1030 Geochemistry: Geochemical cycles (0330); 1040 Geochemistry: Radiogenic isotope geochemistry. Received 23 February 2012; Revised 24 May 2012; Accepted 7 June 2012; Published 12 July 2012. Chauvel, C., R. C. Maury, S. Blais, E. Lewin, H. Guillou, G. Guille, P. Rossi, and M.-A. Gutscher (2012), The size of plume heterogeneities constrained by Marquesas isotopic stripes, Geochem. Geophys. Geosyst., 13, Q07005, doi:10.1029/ 2012GC004123. 1. Introduction limited set of samples collected during reconnais- sance sampling in the early 1970s by R.A. Duncan, R. Brousse, H. Craig and H.G. Barsczus, and during a [2] The considerable isotopic heterogeneity in plume-related basalts is attributed to processes such single dredging cruise on Marquesas seamounts as (i) chemical heterogeneity of mantle plumes at [Desonie et al., 1993]. All these studies focused on depth [Kerr et al., 1995], (ii) entrainment of sur- the origin of the isotopic diversity and they did not rounding asthenospheric mantle materials [Hart use recently developed high-precision isotopic anal- et al., 1992] or (iii) plume-lithosphere interac- yses to investigate potential relationships with a tions [Saunders et al., 1992]. There is ongoing plume track or changes in source compositions as a debate about the relative importance of the three function of time or distance to the presumed location processes in the genesis of basaltic magmas from of the active plume. Iceland [Chauvel and Hémond, 2000; Fitton et al., [4] The Marquesas archipelago has also been the 2003; Thirlwall et al., 2004; Kokfelt et al., 2006], object of great interest for geophysical studies, the Galapagos [White et al., 1993; Hoernle et al., 2000; particularly since McNutt and coworkers [McNutt, Blichert-Toft and White, 2001; Saal et al., 2007], 1998; McNutt and Bonneville, 2000] discovered Afar [Furman et al., 2006; Beccaluva et al., 2009; that French Polynesia was built on top of a large Daoud et al., 2010] and Hawaii [Yang et al., 2003; topographic height attributed to the so-called Frey et al., 2005; Fekiacova et al., 2007]. In par- Polynesian Superswell. Its existence is usually ticular, differences in lead isotopes between the Kea thought to be linked to the presence of a large and Loa trends in Hawaii have been attributed to a region of hot material rising from deep in the bilateral asymmetry of the plume [Abouchami et al., mantle [Davaille, 1999; Romanowicz and Gung, 2005; Farnetani and Hofmann, 2009, 2010]. 2002; Courtillot et al., 2003; Montelli et al., 2006] but the way these observations relate to [3] Large isotopic variations in Marquesas basalts have been known for decades [Vidal et al., 1984; geochemical constraints remains unsolved. Duncan et al., 1986; Dupuy et al., 1987; Vidal et al., [5] Here we reexamine the scale of isotopic varia- 1987; Woodhead, 1992; Desonie et al., 1993; Caroff tions using high-precision Sr, Nd, Hf and Pb iso- et al., 1995; Le Dez et al., 1996; Castillo et al., topic measurements obtained on a large set of new 2007] and have been attributed to (i) a concentri- samples that were collected and dated during the cally zoned structure of the Marquesas plume first detailed geological mapping of Marquesas [Duncan et al., 1986], (ii) small-scale hetero- Islands. We demonstrate the existence of isotopic geneities within the plume [Dupuy et al., 1987; stripes different from those suggested recently by Vidal et al., 1987; Le Dez et al., 1996] or (iii) plume- Huang et al. [2011] and we propose that they lithosphere interactions [Duncan et al., 1986; originate from small-scale heterogeneities located Woodhead, 1992; Desonie et al., 1993; Caroff et al., within elongated filaments in rising plumelets 1995]. These models were primarily based on a 2of23 Geochemistry Geophysics 3 CHAUVEL ET AL.: MARQUESAS ISOTOPIC STRIPES 10.1029/2012GC004123 Geosystems G Figure 1. Location map of Marquesas Islands. The bathymetry comes from the global altimetry data set of Smith and Sandwell [1997]. Shades of purple denote depths of 5,000 to 4,000 m; shades of blue, depths of 4,000 to 2,000 m and shades of orange, depths less than 2,000 m. The main trend of the Marquesas chain is N40W. Current Pacific plate motion is 10.5 cm/yr at N65W, corresponding to the line shown in white and labeled plate movement. This line is also the line separating the two groups of islands as shown in Figures 4 and 5. In Hiva Oa, the line is located on the south- western side of the island in the Taaoa Bay (see Figure S1 for more details). MFZ: Marquesas Fracture Zone. coming from a large dome structure. Further com- anomalously shallow given its age [Crough and parison with other ocean islands suggests that weak Jarrard, 1981] and the so-called “Marquesas plume-derived islands such as Polynesia are ideal swell” has been interpreted as resulting from uplift sites to determine the scale of plume hetero- due to a rising mantle plume [Crough and Jarrard, geneities while strong plume-derived islands such 1981]. However, the crustal thickness reaches 15– as Hawaii are the best choices to establish the 20 km below the central part of the Archipelago average composition of plumes. [Filmer et al., 1993; Caress et al., 1995], and the swell could also result from the buoyancy of such a thick basaltic crust [McNutt and Bonneville, 2000]. 2. Geological Setting of the Marquesas The origin of the crustal thickening was attributed Archipelago either to (i) Plio-Quaternary underplating of plume magmas just below the Moho [Caress et al., 1995; [6] The ca.
Load more

Recommended publications
  • Societies Compendium a Compilation of Guidebook References and Cruising Reports
    The Societies Compendium A Compilation of Guidebook References and Cruising Reports Rev 2021.4 – 29 August 2021 Please send us updates to this guide! Keep the Societies Compendium alive by being a contributor. We are especially looking for information on places where we have no cruiser information, or new information on existing content. It’s easy to participate and will help many other cruisers for years to come. Email Soggy Paws at sherry –at- svsoggypaws –dot- com. You can also contact us on Sailmail at WDI5677 The current home (and the most up to date) version of this document is http://svsoggypaws.com/files/#frpoly If you found this Compendium posted elsewhere, it might not be the most current version. Please check the above site for the most up to date copy, and remember…it will always be free! Page 1 Revision Log Many thanks to all who have contributed over the years!! Rev Date Notes Info on anchoring cautions and restrictions in Raiatea from 2021.4 29 August 2021 Jaraman. A few updates on Moorea from Sugar Shack and Major Tom. 2021.3 23 July 2021 “Seniors” discount on Air Tahiti Updates on Raiatea from Trance. Updates from Ari B, and Grace of 2021.2 15 April 2021 Longstone 2021.1 04 January 2020 Updates from Chugach on Mopelia 2020.4 16 December 2020 Updates from Sugar Shack on Mo’orea 2020.3 08 November 2020 Updates from Uproar on Mopelia 2020.2 07 November 2020 Updates from Sugar Shack, Maple, and Baloo 2020.1 22 February 2020 Reorganization of compendium and updates from Sugar Shack 2019.3 28-July 2019 Updates from Sugar Shack and Cool Change Many updates from Moon Rebel, Bora Bora mooring update from 2019.2 06 June 2019 Nehenehe and Nor’Easter.
    [Show full text]
  • Marquesas Islands)
    Motu Iti (Marquesas Islands) The uninhabited island located 42 kilometers northwest of Nuku Hiva, the largest island in the Marquesas. In fact, there Motu Iti of several tiny islets, all rise from the same basaltic base. In the east, the 0.2 -acre main island still a 300 x 80 m measuring, upstream 76 m from the sea projecting rock humps and two smallest rocky reefs. The main island is 670 m long, 565 m wide and reaches a height of 220 meters, it is a geologically very young volcanic island, which consists mainly of basalt rocks. Because of the low geological age Motu Iti is not surrounded by a sea on the outstanding coral Motu Iti (sometimes also called Hatu Iti) is one of the northern Marquesas Islands in French Polynesia. Located west-northwest from Nuku Hiva, Motu Iti is the site of extensive seabird rookeries. Motu Iti is administratively part of the commune (municipality) of Nuku-Hiva, itself in the administrative subdivision of the Marquesas Islands. Marquesas Islands of French Polynesia. Northern Marquesas: Eiao ⢠Hatutu ⢠Motu Iti ⢠Motu One ⢠Nuku Hiva ⢠Ua Huka ⢠Ua Pu. Southern Marquesas: Fatu Hiva ⢠Fatu Huku ⢠Hiva Oa ⢠Moho Tani ⢠Motu Nao ⢠Tahuata ⢠Terihi. Archipelagos of French Polynesia: Aust Motu Iti (Marquesas Islands). From Wikipedia, the free encyclopedia. This article is about the island in French Polonesia. For the islet off of Easter Island, see Motu Iti (Rapa Nui). Motu Iti. Motu Iti (sometimes also called Hatu Iti) is one of the northern Marquesas Islands in French Polynesia.
    [Show full text]
  • Law of Thesea
    Division for Ocean Affairs and the Law of the Sea Office of Legal Affairs Law of the Sea Bulletin No. 82 asdf United Nations New York, 2014 NOTE The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. Furthermore, publication in the Bulletin of information concerning developments relating to the law of the sea emanating from actions and decisions taken by States does not imply recognition by the United Nations of the validity of the actions and decisions in question. IF ANY MATERIAL CONTAINED IN THE BULLETIN IS REPRODUCED IN PART OR IN WHOLE, DUE ACKNOWLEDGEMENT SHOULD BE GIVEN. Copyright © United Nations, 2013 Page I. UNITED NATIONS CONVENTION ON THE LAW OF THE SEA ......................................................... 1 Status of the United Nations Convention on the Law of the Sea, of the Agreement relating to the Implementation of Part XI of the Convention and of the Agreement for the Implementation of the Provisions of the Convention relating to the Conservation and Management of Straddling Fish Stocks and Highly Migratory Fish Stocks ................................................................................................................ 1 1. Table recapitulating the status of the Convention and of the related Agreements, as at 31 July 2013 ........................................................................................................................... 1 2. Chronological lists of ratifications of, accessions and successions to the Convention and the related Agreements, as at 31 July 2013 .......................................................................................... 9 a. The Convention ....................................................................................................................... 9 b.
    [Show full text]
  • Cruising Guide Leeward Islands in French Polynesia
    Cruising Guide Leeward islands in French Polynesia Maeva ! Welcome aboard The Moorings Tahiti (+689) 66 35 93 www.moorings.fr Useful information 4 The Moorings itineraries 14 Summary Baggages......................................................................4 Moorings Itinerary 7 days ............................................15 Banks ..........................................................................4 Moorings Itinerary 10 days ..........................................15 Churches ......................................................................4 Moorings Itinerary 14 days ..........................................15 Communications ..........................................................4 Local Currency ..............................................................4 Emergency phone numbers....................................4 Arrival in Raiatea ..........................................................5 Fishing gear..................................................................5 Raiatea 16 Post Office ..................................................................5 Medical ........................................................................5 (R1) Marina Apooiti - Base Moorings ..........................16 Provisioning..................................................................5 (R20) Marina d’Uturoa ................................................16 Maeva Kayaks..........................................................................5 Uturoa........................................................................17
    [Show full text]
  • Web Supplement to “Ages of Seamounts, Islands and Plateaus on the Pacific Plate”, by Valérie Clouard & Alain Bonneville
    Web Supplement to “Ages of seamounts, islands and plateaus on the Pacific Plate”, by Valérie Clouard & Alain Bonneville Table 1 : Compilation of radiometric datings of seamounts and islands on the Pacific plate from 1645 samples. Data are sorted by chain, and further by island or seamount from south to north as this represents the general trend of Pacific plate motion since 120 Ma. Final sorting is according to the method used and the author. An average age, calculated by weighting each age by the inverse of its variance, is given when several ages have been determined for the same volcanic stage, by the same author, with the same method. In 2 this case the geographical coordinates are given only once for the line. The error associated with a mean age is calculated as 1/S(1/si ). TF denotes total fusion, IH step-heating or incremental heating, S age spectrum, I isochron, w whole rock, s single mineral. Long. E Latitude Age Error Average Average Name (island, seamount, Island or seamount Method Reference (degrees) (degrees) (Ma) (Ma) age (Ma) error plateau or sample) chain (Ma) 219.80 -29.00 0.00 0.00 Macdonald Austral observation (Johnson and Malahoff, 1971) 0.14 0.04 0.21 0.03 Macdonald Austral K/Ar (Diraison, 1991) 0.17 0.05 Macdonald Austral K/Ar (Diraison, 1991) 0.24 0.07 Macdonald Austral K/Ar (Diraison, 1991) 0.33 0.10 Macdonald Austral K/Ar (Diraison, 1991) 0.97 0.29 Macdonald Austral K/Ar (Diraison, 1991) 0.85 0.25 Macdonald Austral K/Ar (Diraison, 1991) 1.64 0.25 Macdonald Austral K/Ar (Diraison, 1991) 218.88 -28.76 29.21 0.61
    [Show full text]
  • Temporal and Geochemical Variability of Volcanic Products of The
    JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 98, NO. BI0, PAGES 17,649-17,665, OCTOBER 10, 1993 Temporaland GeochemicalVariability of VolcanicProducts of the MarquesasHotspot D. L. DESONIE1 AND R. A. DUNCAN Collegeof Oceanicand AtmosphericSciences, Oregon State University, Corvallis J. H. NATLAND 2 ScrippsInstitution of Oceanography,University of California,La Jolla The Marquesasarchipelago is a short,NW-SE trendingcluster of islandsand seamounts that formedas a result of volcanicactivity over a weak hotspot. This volcanicchain lies at the northernmargin of a broad regionof warm and compositionallydiverse mantle that meltsto build severalother subparallel volcanic lineaments.Basalts dredged from submergedportions of volcanoesalong the Marquesaslineament decrease in age from northwestto southeast.The new sampleage distributionyields a volcanicmigration rate significantlyslower than that expectedfor Pacificplate motion over a stationaryMarquesas hotspot. This and the aberrantorientation of the chain indicate deflectionof the plume by westwardupper mantle flow. The interactionof this weak plumewith uppermantle flow accountsfor the temporaland spatialpatterns in Marquesanvolcanism. The compositionsof subaerialand submarine basalts reflect the mixingof at least two mantle sources,distinguished by Sr, Nd, and Pb isotopeand trace elementcompositions. There is a consistentevolutionary pattern at each volcano,from early tholeiitic to later alkalic basalt eruptions. Tholeiitic and transitionallava compositionscan be derivedby variabledegrees of partial
    [Show full text]
  • Cruising Guide Leeward Islands French Polynesia
    Cruising guide Leeward Islands French Polynesia Maeva ! Welcome onboard 1 Useful informations 4 Itineraries 14 Contents Luggage ......................................................................4 One week………………… ………..................................15 Banks…. .....................................................................4 10 days…………………..…….........................................15 Religion.......................................................................4 2 weeks……………………………...................................15 Communication...........................................................4 Money.. .......................................................................4 Emergency………......................................................4 Arrival …………... .....................................................5 Fishing gear………......................................................5 Raiatea 16 Post office ...................................................................5 (R1)Apooiti Marina - Raiatea base.. ..............................16 Health...........................................................................5 (R20) Uturoa Marina.. .....................................................16 Provisioning…………….............................................5 Uturoa...............................................................................17 Kayaks..........................................................................5 Uturoa south east…. ........................................................17 Snorkeling…………………........................................5
    [Show full text]
  • Young Tracks of Hotspots and Current Plate Velocities
    Geophys. J. Int. (2002) 150, 321–361 Young tracks of hotspots and current plate velocities Alice E. Gripp1,∗ and Richard G. Gordon2 1Department of Geological Sciences, University of Oregon, Eugene, OR 97401, USA 2Department of Earth Science MS-126, Rice University, Houston, TX 77005, USA. E-mail: [email protected] Accepted 2001 October 5. Received 2001 October 5; in original form 2000 December 20 SUMMARY Plate motions relative to the hotspots over the past 4 to 7 Myr are investigated with a goal of determining the shortest time interval over which reliable volcanic propagation rates and segment trends can be estimated. The rate and trend uncertainties are objectively determined from the dispersion of volcano age and of volcano location and are used to test the mutual consistency of the trends and rates. Ten hotspot data sets are constructed from overlapping time intervals with various durations and starting times. Our preferred hotspot data set, HS3, consists of two volcanic propagation rates and eleven segment trends from four plates. It averages plate motion over the past ≈5.8 Myr, which is almost twice the length of time (3.2 Myr) over which the NUVEL-1A global set of relative plate angular velocities is estimated. HS3-NUVEL1A, our preferred set of angular velocities of 15 plates relative to the hotspots, was constructed from the HS3 data set while constraining the relative plate angular velocities to consistency with NUVEL-1A. No hotspots are in significant relative motion, but the 95 per cent confidence limit on motion is typically ±20 to ±40 km Myr−1 and ranges up to ±145 km Myr−1.
    [Show full text]
  • Volcanic Successions in Marquesas Eruptive Centers: a Departure from the Hawaiian Model Hervé Guillou, René C
    Volcanic successions in Marquesas eruptive centers: A departure from the Hawaiian model Hervé Guillou, René C. Maury, Gérard Guille, Catherine Chauvel, Philippe Rossi, Carlos Pallares, Christelle Legendre, Sylvain Blais, Céline Liorzou, Sébastien Deroussi To cite this version: Hervé Guillou, René C. Maury, Gérard Guille, Catherine Chauvel, Philippe Rossi, et al.. Volcanic suc- cessions in Marquesas eruptive centers: A departure from the Hawaiian model. Journal of Volcanology and Geothermal Research, Elsevier, 2014, 276, pp.173-188. 10.1016/j.jvolgeores.2013.12.003. insu- 00933782 HAL Id: insu-00933782 https://hal-insu.archives-ouvertes.fr/insu-00933782 Submitted on 25 Feb 2014 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. *Manuscript Click here to view linked References 1 Volcanic successions in Marquesas eruptive centers: A departure 2 from the Hawaiian model 3 Hervé Guillou a*, René C. Maury b, Gérard Guille c, Catherine Chauvel d,e, Philippe Rossi f, Carlos 4 Pallares b,g, Christelle Legendre b, Sylvain Blais h, Céline Liorzou b, Sébastien Deroussi i 5 6 aUMR 8212 LSCE-IPSL/CEA-CNRS-UVSQ, Domaine du CNRS, 12 avenue de la Terrasse, 91198 Gif- 7 sur-Yvette, France 8 bUniversité de Brest; Université Européenne de Bretagne, CNRS; UMR 6538 Domaines Océaniques; 9 Institut Universitaire Européen de la Mer, Place N.
    [Show full text]
  • Marquises, Hiva Oa, Tahuata Et Fatuiva
    Origine du guide Ce petit guide floristique porte sur les trois îles habitées du groupe Sud de l’archipel des Marquises, Hiva Oa, Tahuata et Fatuiva. Les informations présentées proviennent à la fois de l’analyse de la bibliographie botanique existante mais également de prospections de terrain initiées par la Direction de l’Environnement (DIREN) et l’Institut de Recherche pour le Développement (IRD). Ce guide est téléchargeable gratuitement au format pdf sur le site internet de la DIREN : www.environnement.pf Présentation des fiches Ce guide présente 248 espèces végétales se dévelop- pant sur les îles de Hiva Oa, Tahuata et Fatuiva. Il s’agit de la quasi-totalité des plantes reconnues et nommées par les habitants de ces trois îles. Parmi ces 248 espèces, 101 sont des plantes indigènes, 65 sont des introductions polynésiennes et 82 sont des introductions modernes. Les espèces, ou plutôt taxons, sont présentées par ordre alphabétique de leurs noms scientifiques au sein de cinq groupes constitués par les types biolo- giques : arbres, arbustes et arbrisseaux, fougères, herbacées, lianes. Pour chaque taxon, outre son nom scientifique accepté, est indiquée sa famille botanique d’appar tenance. Le statut biogéographique est également précisé : espèces indigènes non introduites par l’homme, introductions polynésiennes implantées lors des Marquises Sud - Guide floristique 1 Hatutaa Motu One Eiao Hatu Iti Nuku Hiva Ua Huka Ua Pou Fatu Uku Hiva Oa Tahuata Mohotani Motu Nao Fatuiva migrations polynésiennes près d’un millier d’années auparavant et introductions modernes importées depuis la redécouverte euro- péenne, essentiellement depuis la fin du xviiie siècle. Parmi les espèces indigènes, le niveau d’endémisme est, le cas échéant, indi- qué : espèces endémiques d’une île, d’un archipel, de Polynésie française ou de Polynésie orientale.
    [Show full text]
  • Law of the Sea
    Bulletin No. 101 Law of the Sea Division for Ocean Affairs and the Law of the Sea Office of Legal Affairs United Nations Division for Ocean Affairs and the Law of the Sea Office of Legal Affairs Law of the Sea Bulletin No. 101 United Nations New York, 2020 NOTE The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or bound- aries. The texts of treaties and national legislation contained in theBulletin are reproduced as submitted to the Secretariat, without formal editing. Furthermore, publication in the Bulletin of information concerning developments relating to the law of the sea emanating from actions and decisions taken by States does not imply recognition by the United Nations of the validity of the actions and decisions in question. United Nations publication ISBN 978-92-1-130387-2 eISBN 978-92-1-004316-8 ISSN 1015-1885 eISSN 2218-6018 Copyright © United Nations, 2020 All rights reserved Printed at the United Nations, New York CONTENTS I. UNITED NATIONS CONVENTION ON THE LAW OF THE SEA Status of the United Nations Convention on the Law of the Sea, of the Agreement relating tothe Implementation of Part XI of the Convention and of the Agreement for the Implementation of the Provisions of the Convention relating to the Conservation and Management of Straddling Fish Stocks and Highly Migratory Fish Stocks, as at 30 November 2019 1.
    [Show full text]
  • Le Patrimoine Naturel
    4 LE PATRIMOINE NATUREL Chapitre rédigé en collaboration avec Frédéric Jacq et Thibault Ramage 89 4 LE PATRIMOINE NATUREL Dans la majorité des groupes, les affinités du mondial (Hawaii arrivant en première place avec 89 %) peuplement s’établissent avec la région orientale et dépasse celui des îles Galapagos et des Fidji (Océan indo- malaise. En raison de son éloignement à l’est Pacifique), ou des Mascareignes (Océan Indien). du Pacifique, qui limite la dispersion des espèces par les courants marins, aériens, ou par les animaux, la L’avifaune a des caractères originaux et une grande Polynésie est, dans tous les groupes, moins riche en richesse en formes endémiques (86 % pour l’avifaune espèces que les zones situées plus à l’ouest, dont elles terrestre) et en espèces d’oiseaux de mer. La Polynésie, sont issues. sur ce plan, constitue l’une des régions insulaires les plus intéressantes. Parmi les autres groupes, les Mais l’isolement géographique des îles, situées à mollusques terrestres et les arthropodes représentés près de 6 000 km des masses continentales les plus par des genres endémiques, sont également très proches, leur regroupement en archipels inégalement intéressants sur le plan biogéographique. éloignés, éclatés sur plus de 5 millions de km² d’océan, sur 21° de longitude et 20° de latitude, ainsi que la Pour ce qui concerne les espèces marines, la richesse diversité des biotopes font de la Polynésie un territoire et l’endémisme sont faibles : la Polynésie française fait d’intérêt majeur sur le plan biogéographique et sur le partie de la province biogéographique Indo-Pacifique, plan de l’évolution.
    [Show full text]